In this work, terephthalic acid degradation was studied with two strains that were isolated and identified as closely related to Comamonas (99%) and Rhodococcus (99%) genus. A characterization of both strains was carried out during batch experiments performed at two oxygen transfer capacities (0.094 ± 0.011 and 0.538 ± 0.042 g O₂/L/h) and five concentrations of terephthalic acid (2.5 to 15.0 g/L). Maximum degradation rates of 0.073 ± 0.004 and 0.062 ± 0.003 g TOC/L/h, were observed, for Comamonas sp. and Rhodococcus sp., respectively. However, a degradation rate of 0.159 ± 0.011 g TOC/L/h was reached with a mixed culture. Haldane, Aiba, Edwards and Andrews models were used to fit terephthalic acid degradation kinetics, being Haldane the model that best fitted the results. Several parameters were determined including, maximum growth rate, growth yield, substrate affinity and inhibition constant.

Prioritization of watersheds has gained more importance in natural resources management, particularly in the context of watershed management. Flooding potential is one of the main indices used to prioritize watersheds. The objective of this study is to investigate the Pol-Doab Shazand Watershed flooding conditions as a result of land use change and prioritization of its subwatersheds using rainfall – runoff data. For this purpose, after computation of design flow with different return periods, factor analysis technique was applied to determine the best flow with proper return period towards evaluation and prioritization of subwatersheds. The results showed that the design flow with 25-year return period (Q25) is suitable. The results indicate that subwatershed 22 is the highest priority because of large changes in peak flow, and subwatershed 2 given the lowest priority since changes in peak flow is the lowest.

Sachet water is growing in importance as a source of drinking water for many people in Nigeria. In recent years, doubts over the quality of sachet water have grown. Commentators often cite poor distribution and storage practice for contamination of sachets. However, the integrity of the production process has been shown to be a weakness but has not received attention from the regulator or producers because of a lack of proper regulation of the industry. This study implemented the hazards analysis and critical control points (HACCP) framework in eight sachet water factories in Ibadan, Nigeria. The objective was to test HACCP's viability as a proactive management tool for improving sachet water quality. The findings show that HACCP can be adopted within the sachet water industry. However, the implementation of HACCP requires both technical and behavioural changes within the production process.

The challenge of stricter wastewater standards is resulting in configuration changes to wastewater treatment. As facilities upgrade, the type of sludge produced is changing, with growing quantities of secondary and chemical sludge at the expense of primary sludge. It is already understood that secondary sludge is harder to treat than its primary equivalent; therefore, increasing the quantity of this type of sludge will have detrimental impacts downstream. As legislation tightens further, extended aeration times may be required during processing to remove more nutrients. Work has shown that extended aeration further exacerbates the treatability of secondary sludge. This paper explains how tightening wastewater legislation fundamentally alters the nature of the sludge produced, and how these alterations impact further processing, especially with respect to sludge production and type; sludge energy content; performance of anaerobic digestion and dewatering, and potential for thermal energy recovery.

Water supply is a core service on which civilised society depends. It involves considerable energy consumption, CO₂ emissions and costs. As such, scientific efforts in the water industry in recent years have focused on improving the sustainability of water supply. This paper examines the potential for energy recovery in the water industry which may be exploited through the use of mini or micro-hydropower installations. A case study of water infrastructure in Ireland is included in the analysis to highlight the potential of this concept in practice. The results of this investigation show that in certain circumstances significant energy, environmental and economic savings are available with modest investment.

Environmental flows are waters released from storages to improve degraded ecosystems. Subsequent monitoring is then used to determine incremental benefits. These flows in the Hawkesbury Nepean and the Durance are very low compared with those advocated for other systems. In the former, water is used in Sydney and Wollongong, while the Durance water is diverted to supply 16 hydropower stations. In this system, reserved flows have been set at 2.5% of mean discharge, while in the Australian river, environmental flows have varied, but are usually 3.6% or less in the current regime. Additionally, increasing the transparencies of barrages and weirs will enhance the effectiveness of current environmental flows. Implementation of such flows imposes many problems because of structural difficulties for releasing water and compromising regulatory infrastructures. Additionally, with the onset of global warming, both systems will suffer significant water losses.

This article details how a council service established an integrated management system (IMS) within a wider corporate framework. In this context, an IMS was used as a tool to improve (i) Performance, (ii) Quality, (iii) Environment, and (iv) Health and Safety Management. A key factor was that the IMS had to be appropriate for accreditation and integratible with an emerging corporate management framework. In this case study, the authors provided a literature review before considering the issues facing the management team in implementing the IMS. Next, the discussion reflected on how the IMS has delivered improvements before concluding with recommendations on how to implement an IMS within similar services. These points of learning may be relevant beyond local government. This article therefore provides a summary of action research and the steps taken to deliver an IMS within a broader context.

A batch test approach was used to assess the in situ attenuation by natural reservoir systems of selected disinfection by-products (DBPs). The aim was to determine which natural attenuation processes (volatilisation, photolysis and biodegradation) dominated for selected trihalomethanes (THMs) and N-nitrosodimethylamine (NDMA), common DBPs present in reclaimed water which could be used to potentially augment drinking water supplies. Attenuation rates for THMs were found to be all very similar, with half-lives ranging from 1.5–1.6 days for open batch tests. The dominant attenuation mechanisms for THMs were volatilisation with hydrolysis and biodegradation of potentially minor importance. NDMA had a half-life of 3.5–4.3 days for vials exposed to light. The most important attenuation mechanism for NDMA was photolysis with volatilisation and biodegradation of minor importance. The results indicate that the selected DBPs could be effectively attenuated by a natural reservoir system such as a surface water reservoir.

This paper puts forward the importance of decision support systems (DSS) for the planning and management of water resources. A case study of the Pinhão river basin, in Portugal, is presented. Given the importance of vineyards in the Douro region, it is important to determine if water availability will be enough to meet present and future water demands. In order to answer this question, DSS tools were used to assess different scenarios. The MIKE BASIN software was used in the hydrographical basin of Pinhão river, assisted by a geographic information system, GIS, which allowed the modelling of the basin, both temporally and spatially, facilitating the visualisation and interpretation of results. According to the attained results, it was verified that, at present, the hydrographical basin meets the considered water needs. The DSS proved to be an important tool to assist the decision-making process in the studied river basin.

Turkey's wetlands that represent a very diverse set of ecosystems are subject to considerable risks of biodiversity loss arising from the changes in their hydrology. Maintaining the full spectrum of naturally occurring flows in many rivers is almost impossible in Turkey's economically competing watersheds. Environmental flow assessments may still represent a compromise between water resources development and river ecology maintenance. In the presented study, changes in the water regimes observed in the period 1960–2000 are investigated together with concurrent ecological conditions for over 35 wetlands belonging to different ecological regions. The results, which are presented with indicator-based risk figures to potentially correlate biodiversity loss to decreases in environmental flows in course of time, broadly indicate that substantial risks are estimated in Turkey in terms of environmental flows for wetland systems. Few exceptions appear in the north-east in accordance with the recent climate change predictions indicating precipitation increase trends in the region.

Drawing from the lessons learnt from the Fukushima nuclear disaster in Japan, the assessment of subsurface environmental hazard around nuclear power plants has emerged as a critical task. Consequently, aiming to better understand the possible environmental impact of radiation leaks into the groundwater, a prescreening programme was initiated in 2011 by the Taiwanese government. As part of this programme, this study conducted various borehole prospecting techniques to identify in situ hydrogeological characteristics at Chin-Shan Nuclear Power Plant. Borehole electrical log, sonic log and temperature/conductivity log were conducted to explain the regional lithologic conditions and permeability of the formation. In conjunction with this, the interwell tracer and pumping test was carried out to simultaneously determine the hydraulic parameters. In our opinion, the implementation of such in situ end-to-end investigations is essential in interpreting in situ fluid and solute transport dynamics prior to programming any numerical scheme for early warning, vulnerability assessment and regular monitoring of a nuclear power plant site.

Fractured-rock aquifers are inherently difficult for determining flow dynamics because of variability in fracture orientation and extension. A confined, fractured-rock aquifer in a semi-arid mountainous area of the Rio Grande Rift Zone was analysed for its response to recharge events that produced a pressure pulse within its potentiometric surface. The pulse was evaluated at the well scale and subaquifer level to evaluate flowpaths, travel times and dispersion and compare the bulk-scale aquifer response to possible velocities from slug test hydraulic conductivity measurements. Travel time and dispersion from the pulse proved comparable to probable travel times based on hydraulic conductivity measurements. Evaluation of the pressure pulse and the hydraulic conductivity measurements allowed for a holistic interpretation of the fractured-rock aquifer through analysis of two distinct data sets that provided corroborative evidence of flow dynamics and fracture connectivity. This holistic approach reduced uncertainty regarding the individual hydraulic conductivity values.

High-pollutant concentrations have led to the breakout of planktonic bloom and the breakdown of the ecosystem in many lakes in China and other countries. The removal of the organic and inorganic pollutants from industrial, agricultural and domestic wastewater and the restoration of the aquatic ecosystem of the polluted water bodies are persistent issues. Constructed wetlands are often used, and most depend on emerged plants. In this study, Daphnia magna, a type of zooplankton, and five species of submerged plants were used to remove nitrogen and phosphorus from reclaimed domestic wastewater in four scenery lakes of a garden in Peking, China. Water quality was assessed by the local environmental inspection station as the government inspection and a commercial company as the third party inspection, and the gathered data proved that ecological restoration was successful in this study.

Numerical odour standards are often used in conjunction with dispersion modelling to assess the acceptability of the odour environment around wastewater treatment works (WWTWs). However, the odour standards applied are based on very limited research, and there is very little information available regarding how well these standards work in practice. This paper describes the results of a study examining the relationship between odour modelling results and reported complaints around 15 WWTWs in the United Kingdom. Predicted odour concentrations around each of the works were calculated using industry standard odour emission rates. Records of reported odour complaints were obtained from the relevant local authority environmental health department. The study found that odour modelling results did not correlate well with the location of the reported complaints and that in most cases, odour modelling underestimated the area from which complaints would be received.

This research explores the external effects of erosion as a criterion based on the perceptions of residents of populated areas within a watershed. We applied a multiple correspondence analysis to survey responses in order to reveal the attitudes of residents towards erosion in the study area. This analysis is combined with an analysis of the adjusted residuals, with the goal of identifying the most important erosion externalities that characterize part of south-eastern Spain. Our results demonstrated that the survey approach, combined with the statistical analysis, is capable of revealing differences among communities within a watershed in the perceived externalities of erosion. We identified the following key variables: municipality, conservation status of access routes, conservation status of sewer systems, conservation status of landscape, nature outings per year and agriculture abandonment.

Batch tests were carried out with sawdust obtained from oak (Quercus robur), maple (Acer platanoides), pine (Pinus sylvestris), beech (Fagus sylvatica) and wood chips from oak and pine. Leaching of organic compounds expressed as dissolved organic carbon (DOC) in mg/kg of dry mass took place during the first 24 h. The following additional variables were analysed: pH, conductivity, colour, phenols, tannins and lignin, and biochemical oxygen demand (BOD₇). When leachates obtained with oak wood chips and pine wood chips were compared, no significant difference was observed. However, in batch tests with sawdust, DOC released by oak (90 000 mg/kg) was significantly higher (P = 0.0001) than DOC released by pine (30 000 mg/kg). The results suggest that particle size is not the only variable affecting the leaching of organic compounds from wood. Regarding BOD, colour [platinum-cobalt (Pt-Co)], phenols, tannins and lignin, the leaching patterns differed among species, and oak was the species with the highest released values.

The effects of five natural products on the growth of three harmful algae species including Chattonella marina Hara et Chihara, Alexandrium tamarense Balech and Karenia mikimotoi (Miyake & Kominami ex Oda) G. Hansen & Ø. Moestrup were observed. Four products including ε-polylysine, betaine, stachydrine and berberine exhibited selectively inhibitory effects against the three algae. However, the other product chitosan had no obvious inhibition against the above algae. Berberine and ε-polylysine exhibited relatively higher inhibitory capability against C. marina, and betaine had the highest inhibitory effect against A. tamarense. While only berberine could effectively inhibit the growth of K. mikimotoi with LC_{50, 120} at 3.1 mg/L. The fast inhibitory effect against K. mikimotoi and environmental safety of berberine suggested that it might be a potential algaecide against K. mikimotoi.

Soil salinity level in shelterbelts under different emitter distance and different planting years was compared using 3 years of monitoring data from a typical oasis located in an extremely arid area in northwest China. The variation trend of salinity level during the whole growing season and in nonirrigation season was analysed. The results indicate that: (1) under narrow emitter distance (1.5 m), the soil layer with the highest salinity level was located deepest (50–85 cm). Under wide emitter distance (3 m), the soil layer with the highest salinity level was located shallower (45–80 cm); (2) drip irrigation effectively decreased the soil salinity level. With the increased in irrigating years, the salt-leaching effect was better. Most of the soil salts were brought downward to the soil layer below 30 cm, 50 cm and 70 cm, respectively, in shelterbelts that have been irrigating for 1 year, 2 years and 3 years; (3) soil salinity level presented an increasing trend during the growing season. The largest change of soil salinity level fore-and-aft the irrigation was found in 20-cm depth, followed by the 40-cm depth and then the 60-cm depth; (4) in nonirrigation season, salt was accumulating at the surface in shelterbelts. Among all the shelterbelts with different forest age, the salinity level on the surface was the highest in the 2-year-old shelterbelt.

The spatial discretization scale determines the degree to which the spatial heterogeneity of the surface condition and the stream network can be represented. Discretization scale can have a significant impact on watershed model results, with respect to both hydrology and water quality. The impact of critical source area (CSA) on simulated water yield for each cell can be assessed for streamflow and run-off using the Annualized Agricultural Non-Point Source (AnnAGNPS) model. The total number of cells simulated for the six watersheds ranged from 8 to 352 for various CSA combinations. Increasing the number of subwatersheds increased water and sediment yield in many watersheds. Increasing the number of cells influences the depiction of land use and soil type accordingly and therefore influences run-off. The applied CSAs were also compared with topographic parameters such as average cell slope, average channel slope and length to width ratio of each watershed.

After the initial impoundment of the Three Gorges Reservoir (TGR), most of its tributaries have been influenced because of the backwater and the input of nutrients. The spatiotemporal variability in euphotic depth and its major influencing factors were investigated in the Xiaojiang River Basin of the TGR to reveal this change. Analyses were based on the photosynthetically active radiation (PAR) and water quality indices in five sampling sites of the Xiaojiang River from May 2007 to April 2009. Results showed only slight spatial variation in the average euphotic depth while significant temporal variation was taken place. Moreover, correlation analysis indicated that the diffuse attenuation coefficients for PAR (K_d(PAR)) was significantly correlated to the total suspended solids (TSS) (R² = 0.6794), but not to chlorophyll-a (Chl-a) (R² = 0.045). The unique hydrological conditions of the TGR might be the determinants of the spatiotemporal variability.

New environmental policies establish the need to maintain the ecological integrity of freshwater ecosystems. The hydrologic regime is a key element in determining river processes and therefore the definition of environmental flow regimes (EFR) is essential to achieve this goal. The EFR can be broadly defined as the water required to sustain freshwater and estuarine ecosystems, and the human livelihood that depend on these ecosystems. Nevertheless, the role of the EFR and the methods to calculate them has not been clearly stated in many countries. This paper sets out a procedure to calculate EFRs, which includes not only a minimum flow, but also a temporal variability of this flow. The procedure integrates the results of hydrologic and habitat simulation methods in a temporal scale that takes into consideration the natural hydrologic seasonality while providing a certain level of flexibility to regulate water resources still meeting the requirements of the Spanish Water Planning legislation. The results highlighted the advantages of using different methodological approaches to calculate EFRs. Therefore, this study concludes the validity of a relatively simple hydrologic method for defining minimum environmental flows at a period of maximum hydrologic stress, but also the need to consider different approaches to take into account as many ecosystem elements as possible.

Years of research have called for more science to be integrated into water management decisions and for a shift from supply-side to demand-side management; yet, there remains a strong emphasis on supply-side approaches and in many areas limited attention to hydrological data. A survey and interviews with decision-makers in western North Carolina reveal that there is only low-level concern about water quantity, and this drives a continued emphasis on supply-side management and no perceived need for hydrological data. The historical realities of low demand and abundant water have generated a perception of ‘water supply’ as disconnected from physical, hydrological systems and allowed for ad hoc decision-making processes to prevail. The lack of well-established processes may, ironically, provide significant opportunities for employing collaboration among researchers and decision-makers to develop policies and processes that integrate data into making water management decisions and thus prompt increased attention to water demand.

Hailuogou (HLG) River and Huangbengliu (HBL) Gulley are typical alpine glacial and nonglacial rivers in Mount Gongga China, respectively. To differentiate distinct hydrologic regimes of the two rivers, δ¹⁸O and δ²H were measured on 196 water samples collected almost monthly from May 2008 to December 2009. The results indicate that: (i) the measured isotopic data show that stream water is overall isotopically more enriched in ²H and ¹⁸O than ice-snow meltwater but more depleted than precipitation and ground water; (ii) these data also suggest that stream flow is generally more dominated by ice-snow meltwater in HLG River than in HBL Gulley; (iii) δ²H/δ¹⁸O relationship suggests that isotopic composition of precipitation is well preserved in stream flow, and evaporation is only minor in both HBL Gulley and HLG River; (iv) this study highlights that ice-snow meltwater is a substantially important water source in alpine regions on south-eastern edge of Tibetan Plateau.

Despite the pressing environmental, economic and social issues surrounding water abstraction, scientific methods for managing its ecological impacts remain in their infancy. In this paper, we demonstrate statistically significant relationships between in-stream ecological condition using macroinvertebrates and the hydrological effect of groundwater abstraction on surface water flows in streams originating from Permo-Triassic sandstone aquifers in the English midlands. Ecological condition was most strongly correlated to the effect of abstraction on medium-low flows (Q₇₅) compared with effects at other flows, water quality, habitat or seasonal effects. Ecological impacts occurred when the effect of abstraction on Q₇₅ flows exceeded 60%. The same relationships were shown among individual macroinvertebrate taxa, validating the biological responses. The hydroecological model has provided a scientific basis for making local decisions on investigation sites and has helped to focus resources to areas at risk of not meeting Good Ecological Status under the Water Framework Directive because of abstraction.

This paper presents the performance of two full-scale up-flow anaerobic sludge blanket–activated sludge process (UASB-ASP)-based sewage treatment plants (STPs) (surface and diffused aeration-based activated sludge processes as post-treatment units). Performance of this combination is compared with UASB–polishing ponds and UASB–ozonation-based STPs. Post-treatment units removed 89 and 92% of anionic surfactants (AS) by surface and diffused aeration, respectively. Finally, 0.61 and 0.23 mg/L of AS were discharged from post-treatment steps after overall reduction of 90–92%. Final concentrations from UASB-ASP-based STPs were low compared with UASB–polishing ponds (3.60–4.91 mg/L) and UASB–ozonation (1.52 and 0.53 mg/L). Overall, UASB-ASP-based STPs were working efficiently for the removal of organics in terms of chemical oxygen demand (COD) (84%) and biochemical oxygen demand (BOD) (93%), but they need further modifications for the removal of AS up to the level of risk quotient [risk quotient (RQ)] ≤ 1 for no risk to aquatic environment.

Inorganic nitrogen (IN) release kinetics and exchangeable inorganic nitrogen (EIN) of the sediments from shallow lakes in the middle and lower reaches of the Yangtze River region were investigated. The results showed that the EIN contents of the studied sediments ranged from 131 to 274 mg/kg. With the increase of the total nitrogen (TN) contents, their EIN also significantly increased. Their ratios of EIN to TN ranged from 5 to 17%, and with the increase of their TN contents, their ratios decreased. The relative contribution of NH₄⁺-N and NO₃^-N to EIN ranged from 83 and 11% to 89 and 17%, respectively. The curves of the NO₃^-N release kinetics of the studied sediments were not completely consistent with those of IN and NH₄⁺-N. The amounts of the IN released from sediments not only relate to their EIN contents, but also to other N fractions.

The water body is just like a quasi-static fluid after the impoundment of the Three Gorges Reservoir in China to 175 m water level in late 2010. In this paper, fluid dynamic model and numerical method were presented to analyse its dynamic characteristic. Then, based on an oil spill model coupled with the hydrodynamic model, the oil fractions evolvement with time as well as the recovery process with emergency actions under oil spills were numerically simulated and illustrated in the Three Gorges Reservoir. Emergency actions were accordingly analysed based on the simulated pollution area and density, by which a decay parameter was additionally brought into the simulation to understand the recovery of polluted area. The simulated results could be an aid for better emergency response strategy in case of oil spill accidents in the Three Gorges Reservoir in China.

Rapid urbanization and industrialization, uncontrolled population growth, indiscriminate waste discharge and poor infrastructure are problems that African cities are facing. This paper describes an exemplary case study from Jimma, south-west Ethiopia. A cross-sectional study was conducted along the Awetu-Kito drainage system in Jimma town to assess the level of pollution from urban dwellers and related activities. The study indicates that the Environmental Protection Agency (EPA) norms for biochemical oxygen demand (BOD), dissolved oxygen (DO) and orthophosphates are not met downstream of the major industrial and institutional activities. Small-scale industries, Jimma University and residential areas contributed 50, 15 and 23% pollution load on the river, respectively. It can be concluded that the pollution effect in Jimma town is mainly as a result of the growing (uncontrolled) industrial activities and not to discharge of household wastewater. Given the same trends of urbanization and population growth, similar development (socio-economic) indicators and similar climatic conditions, the key findings for Jimma are transferable to other mid-sized African cities.

The Cullera Estany is a coastal lagoon located in a highly intensified agriculture and tourist area in Valencia. This coastal lagoon has connections with the sea that produce marine intrusion and generate a freshwater interface. Four sampling campaigns were carried out during 2010 in order to analyse the phytoplankton composition and its relation to nutrient content through a Redundancy Analysis. Temperature, dissolved oxygen, nitrite and salinity are the main factors controlling the dynamics of phytoplankton community. During July and October, there is water column stratification; meanwhile in March, there is a well-mixed water column. In addition, in May and July campaigns, hypoxia/anoxia conditions are detected at the bottom. The most abundant phytoplankton groups are Diatoms and Cryptophyceae. Diatoms and Cyanophyceae respond positively to temperature while Cryptophyceae, Prasinophyceae and Dinophyceae respond to high salinity and dissolved oxygen values. Furthermore, picoplankton is correlated inversely with nutrient concentrations.

This study used spatial interpolation methods and a geographic information system that examines spatial and temporal variations in areas with drainage problems. Monthly groundwater depths were measured from 2005 to 2009, and the lowest depths were used to create groundwater maps for each year using five different interpolation. Cross-validation using root mean squared error (RMSE) and the correlation coefficient (r) as indices were used to compare the accuracy of each method. A comparison of interpolated and observed values indicated radial basis function (RBF) to be the optimal method for interpolating lowest groundwater depth in 2005, whereas simple kriging (SK) was found to be the optimal method for 2006, 2007, 2008 and 2009. With the exception of 2007, from 2005 to 2009, approximately 8% of the study area was determined to have a groundwater depth ranging from 0 to 1 m. Between 2005 and 2009, the percentage of the area found to have drainage problems that negatively affected plant growth varied from 60.83% to 86.53%.

The Qiantang River, located in Zhejiang Province, China, is a major water supplier to a highly populated region for multiple uses. With economic development, the received pollutants exceeded its assimilative capacity, leading to algal blooms or fish kills. This study was an up-to-date evaluation of the assimilative capacity of the Qiantang River, investigating the influence of stream flow. A confidence of 75 and 90% of instream flows were selected as the design flows, while the traditional one-dimensional point discharge model and QUAL2K model were used to analyse biochemical oxygen demand (BOD) assimilative capacity. The results showed that the assimilative capacity of 75% confidence instream flow was larger than that of 90% confidence. The assimilative capacity based on QUAL2K model considered almost all rates of BOD gain and loss, which were larger than that of one-dimensional point discharge model. The total amount of BOD discharged into Qiantang River was 17 1283 t·a⁻¹ in 2004. Under 75 and 90% confidence river flow conditions, the calculated total BOD reduction percentage of the whole river was 38.2 and 55.9%, respectively. Furthermore, the results were used as criteria for developing a BOD total maximum daily load (TMDL) in order to achieve the sustainable use of water resources derived from Qiantang River watershed.

This study estimates income and price elasticities of demand for improved drinking water quality in Peshawar, Pakistan. The estimates indicate that improved water can be described as a necessity but normal and an ordinary and price elastic service. Confidence intervals show however that the classification as a necessity is statistically significant. Income elasticities of willingness to pay for drinking water are estimated. The study finds that income and willingness to pay vary directly and significantly. The elasticity estimates, in general, are greater than zero, but less than unity. The study concludes that improvements in drinking water are more beneficial to low-income groups than for high-income groups.

To clarify the effect of peat and groundwater quality parameters on groundwater arsenic (As) contamination, As concentrations and the source of nitrogen (N) in groundwater and peat, and oxidation-reduction potential (ORP) and ammonium-N concentration of groundwater were compared between As-contaminated and uncontaminated areas in Bangladesh. Groundwater in the contaminated area had a reducing ORP with a high ammonium-N concentration, whereas groundwater in the uncontaminated area had a non-reducing ORP with a low ammonium-N concentration. Peat was present only in the contaminated area, whose As concentration was very high, indicating the critical role of peat in groundwater As contamination. The source of N in peat and groundwater was identified as chemical N fertilizer. N present in peat and groundwater served as a nutrient, enhancing microbial activity. In the reducing ORP condition, As was thought to be released intensively to groundwater by the mechanism of reductive release.

Scour phenomenon around a series of impermeable, nonsubmerged spur dikes has been investigated with both experimental and numerical methods. The experiments were conducted under different states of flow intensity (U/U_cr). The scour geometry was measured with a high-resolution laser bed-profiler (LBP). For the numerical simulation phase, a three-dimensional computational fluid dynamics (CFD) model, namely SSIIM 2.0, was used to compute the sediment transport around the spur dikes. The numerical model was based on the finite-volume method. Two turbulence models, namely k-ε standard and k-ε with re-normalization group (RNG) extensions, were used to predict turbulence, and the k-ε model with some RNG extensions was selected because of its best agreement with the measurements. Furthermore, a variety of grids and empirical sediment transport equations were used to find the best state for simulation of scour around a series of spur dikes. Finally, a comparison between experimental and numerical results was carried out to verify the CFD model.

Waterbodies receiving effluent from six crude oil flow stations in the Niger Delta area of Nigeria were assessed. A total of six hundred and forty-five observations for 19 parameters were used to assess the quality of these waters using the Canadian water quality index. A high correlation was obtained between copper and ammonia (R = 0.9996, P < 0.01) on one hand, and dissolved oxygen and BOD (R = 0.786, P < 0.01) on the other. Of the six stations, only one can be classified to be in good conditon, two were in fair conditions, two were marginal, while one was of poor quality. The quality of waterbodies assessed depends more on the degree of violation of standards and the number of times standards were violated. Furthermore, the quality of these waterbodies are affected more by the hydroglogy and geology of the Niger Delta than any other factor.

The effect of extracellular polymeric substances (EPSs) on the solubilisation of municipal wastewater sludge by protease-secreting bacteria was investigated. The untreated sludge is an environmental menace, so sludge management techniques are introduced to treat and dispose sludge in a proper way. Sludge pretreatment is needed to increase the solubilisation and the efficiency of treatment methods. The present study deals with sludge solubilisation by bacterial enzymatic pretreatment. The EPS present in the sludge was removed by sodium hydroxide and formaldehyde to enhance solubilisation and increase the bacterial enzymatic activity. After the removal of EPS with different normalities of NaOH, there was about 11–18% sludge solubilisation and about 8–16% sludge reduction during bacterial pretreatment. Bacterial enzymatic pretreated sludge was further treated using aerobic digesters. From the results obtained in aerobic digestion, 0.06 N NaOH was chosen as the optimal concentration to remove EPSs.

A washland can effectively reduce peak flow of a high flow event at a certain location. A number of washlands located in a basin influence each other's hydrological function, and hence, their hydrological role should be evaluated from a river network perspective. Here, we present an approach to determine optimal locations of constructed washlands in a basin, considering their mutual effect. The problem is formulated as a multiobjective problem with maximizing peak flow reduction effect as one objective and minimizing the total volume of washlands, which is associated with cost, as another. By simplifying modelling algorithm for hydrological routing, we show that consideration of all possible cases is feasible for the situation of a typical basin. This approach guarantees global optimum and shows a full spectrum of Pareto front, which will help decision-makers in problems of multiple objective functions. The proposed approach is demonstrated for the Anseong River basin.

This study aimed to assess the quality of road runoff in heavy traffic and residential areas of Hamedan province, in the western region of Iran. To investigate the effects of salt pollution, 14 runoff samples were collected from streets during the winter and spring of 2009. Streets received different amounts of deicing salt depending on the traffic density. Results showed that deicing salt has major affects on sodium (Na⁺), calcium (Ca²⁺), magnesium (Mg²⁺), chloride (Cl⁻), bicarbonate (), sulfate () and phosphate () pollution. This is important because this type of watercourse contamination can lead to serious problems, such as eutrophication. We also found an increase in lead (Pb²⁺) concentration, which was not attributable to the application of deicing agents, but that was due to the combustion of leaded gasoline. Speciation of Ca, Mg, Pb and P chemical species in the samples was calculated using Visual Minteq 2.6 program. The results indicated that Ca and Mg were mainly present as free ions, Pb was mainly present as PbCO₃ (aq), while the dominant P species were and .

The aim of this study is the protection of groundwater resources from nitrate pollution by regulating land use and by establishing guidelines for agricultural activities within specific wellhead protection areas. Wellhead protection zones are specifically designed in four wells in the municipality of Nea Moudania, an area of intensive agricultural activities in northern Greece. Recent water samples from these wells indicate high levels of nitrates concentrations. Wellhead protection areas are delineated through a geographic information systems (GIS) analysis in order to determine the boundaries of protection zones, as well as to identify the land use patterns and the specific crop types around the contaminated wells. Different land use management techniques for groundwater protection zoning are also examined with respect to their implementation cost. The purpose of this analysis is to identify the least expensive management strategy for wellhead protection. The results show that land use changes are always more expensive than implementing agro-environmental measures.

According to the Water Authority of Israel, Israel's water economy is on the brink of a crisis. Demands are increasing, exceeding the capacity of the natural sources, which are being depleted. Water, as a resource in short supply, necessitated administrative actions in order to attain its efficient utilization, in accordance with the goals set by the state. In addition, the issue of water allocation in Israel is strongly connected to internal politics and not necessarily to a clear overall policy. This article presents a simulation model which examined a large number of different scenarios and returns the possible outcomes of water allocations in a routine situation of uncertainty. The findings show that even under ideal conditions, a water shortage in Israel is inevitable and urban consumption will demand the largest allocation of water. As a result, the Israeli rural sector will be required to reorganize the water allocation system and production structure.

Mass exchange between river stream and riverbed is critical towards remediation of contaminated river system. Spatial moment analysis of reactive and radioactive solute in river channel with underlying porous bed is applied to understand the qualitative description of solute plume in riverbed and river stream. Semi-analytical solutions for zeroth-, first- and second-order spatial moment of reactive and radioactive solute are derived in Laplace domain. The spatial moments of concentration are numerically inverted. Parabolic velocity in river channel and exponentially decaying velocity in porous bed are linked using a slip velocity at the interface. The model is verified against the semi-analytical solution for zeroth moment of conservative solute. The model was applied to understand the relative impact of sorption and decay on the transport of solute plume released in a river system. Sorption was assumed to be limited in the riverbed; hence, the zeroth moment of solute in the river stream remains unchanged for different rates of retardation. The model can be applied to verify numerical models or to predict qualitative description of solute concentration and extent of contamination in a river system.

The aim of this work was to evaluate the utility of Azolla filiculoides growing in a hydroponic system for the phytoremediation of continental water polluted with cadmium and copper during 7 days of exposure. Cadmium and copper chloride were added to the medium at concentrations of 0.5–10 mg/L and 0.1–25 mg/L, respectively. Cadmium and copper levels were measured in each plant using flame atomic absorption spectrophotometry. The analytical methodology used to measure cadmium and copper levels was validated with standard reference material (SRM) – 1570 (spinach) National Institute of Standards and Technology. The results indicated that cadmium and copper phytoremediation was statistically significant with a maximum increase in plant tissue of 1623.20 and 6013.1 μg/g, respectively. This photosynthetic efficiency was chronically damaged when Azolla filiculoides were exposed to 10 mg/L of Cd and 25 mg/L of Cu. The Azolla plants were not affected in the other phytoremediation treatments with copper.

This paper presents the findings of a small-scale pilot study that sought to identify and explore attitudes toward water use in the pharmaceutical industry based in the United Kingdom. As a result of a series of in-depth semi-structured interviews, it is established that because water use is viewed as a comparatively inexpensive resource, this undermines investment in water efficient technologies. However, the study also reveals such attitudes to sit alongside largely positive attitudes toward the need for increased water efficiency on a global organisational level. The paper concludes by arguing that greater attention should be accorded to the geographical location in which views toward water use are ascertained. In particular, it is highlighted that the geographical location of individuals, and organisations, can affect views toward water use. These differences are then argued to have the potential to undermine global initiatives on water use because individuals and organisations, in particular locations, may not see water use as an issue worthy of a response.

The impacts of land use/cover changes (LUCC) on a developed basin in Malaysia were evaluated. Three storm events in different intensities and durations were required for KINEROS2 (K2) calibration and LUCC impact analysis. K2 validation was performed using three other rainfall events. Calibration results showed excellent and very good fittings for runoff and sediment simulations based on the aggregated measure. Validation results demonstrated that the K2 is reliable for runoff modelling, while K2 application for sediment simulation was only valid for the period 1984–1997. LUCC impacts analysis revealed that direct runoff and sediment discharge increased with the progress of urban development and unmanaged agricultural activities. These observations were supported by the NDVI, landscape and hydrological trend analyses.

Spatial and temporal distribution characteristics of total nitrogen and ammonium nitrogen in the sediments, pore water and overlying water of Xiangxi Bay in China Three-Gorge Reservoir were investigated. In surveys, the sampling was undertaken from six sites of Xiangxi Bay on three dates: 29 March 2009, 28 March 2010 and 17 August 2010. Mean values of total nitrogen and ammonium nitrogen contents in the sediments and pore water of Xiangxi Bay all increased with time, especially in summer. There were intimate relationships between internal nitrogen loading and water ecosystem. Correlation coefficients R were 0.7408 (between total nitrogen in pore water and total nitrogen in sediments) and 0.7483 (between total nitrogen in sediments and chlorophyll-a in surface water), respectively. Total nitrogen concentration differences between pore water and overlying water were all positive and had good correlation with chlorophyll-a concentration of Xiangxi Bay. The release of nitrogen in sediments had an important impact on phytoplankton growth in Xiangxi Bay.

Aquatic biota in terms of phytoplankton, zooplankton and benthic fauna were qualitatively and quantitatively followed seasonally during 2007 in a North African small reservoir, Aswan Reservoir. Simultaneously, seasonal variations in water quality were investigated in order to determine how far the aquatic biota could be altered by physicochemical and biotic factors. In phytoplankton of the investigated reservoir, 75 species belonging to four systematic groups were recorded, comprising 11 Cyanoprokaryota, 24 Bacillariophyceae, 2 Dinophyceae and 38 Chlorophyceae. Most numerous zooplankton were Rotifera (23 species). Cladocera and Copepoda were less numerous, with only seven and three species, respectively. Early development stages of copepods, nauplii and copepodites were sometimes recorded in considerable numbers. Twenty-two invertebrate species related to five animal groups were exclusively benthic fauna: three Oligochaeta, nine Mollusca, seven larvae of Chironomidae, one Platyhelminthes, one Hirudinea and one Decapoda. Generally, the estimated values of phytoplankton species richness were relatively higher than those of zooplankton or benthic fauna. In particular, phytoplankton was influenced by physicochemical factors – water transparency, salinity and soluble reactive silica contents – as well as biotic factors – zooplankton and benthic fauna. Levels of pH value, Mg⁺², NO₃-N and chlorophyll-a contents appeared to be the most influential parameters dictating the pattern of seasonal periodicity of benthic fauna. Numerically, the phytoplankton was somewhat more abundant in winter and autumn than in spring or summer. The peak of zooplankton population densities was observed in spring season. Benthic fauna tended to be abundant in summer and autumn seasons, showing a reverse seasonal trend from that of zooplankton. Cyanoprokaryota and Bacillariophyceae were the most important groups that determined the seasonal fluctuation pattern of phytoplankton. Rotifera and Copepoda were the most predominant groups influencing the seasonal periodicity of zooplankton. Oligochaeta and Mollusca alternated the dominancy of benthic fauna community in Aswan Reservoir.

Exploratory data analysis such as hierarchical cluster analysis and principal component analysis were applied to water quality dataset of the Kaduna River, obtained during 3 years (2008–2010), monthly monitoring of eight key different sampling sites for 19 parameters to extract correlations and similarities between variables and to classify river sampling sites in groups of similar quality. Hierarchical cluster analysis grouped eight sampling sites into three statistically significant clusters of similar water composition. Six varifactors were obtained after varimax rotation of initial principal components using principal component analysis. These techniques gave an insight into the sources of pollution. Anthropogenic influence (municipal, industrial wastewater and agricultural run-off) was the major source of river water pollution.

The Jordan River Basin is under great hydric stress. Increases in population and agricultural demand are contributing to the closure of the basin. This paper analyses the results of integrated water resources planning model (WEAP) by studying the vulnerability of water resources in the lower Jordan River under a changing climate pattern and growing water demands. Water balance models show that all aquifers supplying the city of Amman will be depleted within the next few decades. Mitigation measures should include the introduction of additional water into the basin through the Red Sea–Dead Sea canal, in addition to demand management measures such as water conservation and increase in irrigation efficiency. The findings of this study would provide a useful guide to the co-riparians for policy formulation, decision making and dispute resolution. Cooperation among the five riparian countries may be improved by building a Geographic Information System (GIS) database that provides access to accurate data for hydrological analysis.

During the last decades, a major factor that analysts and policy makers take into account in the assessment of the environment is climate change. This global physical process is expected to cause problems in natural and human environment. Thus, modelling climate change impacts may lead to prevention policies to minimize the degradation of life quality because of lack of water resources in the future. This study implicates Geographical Information System (GIS) and hydrological modelling tools to various scenarios of climate change such as the increase of temperature the decrease of rainfall, or even both of them, to estimate the potential impact of climate change on surface runoff in a typical catchment in Andros Island, Greece. Primary results indicate a proportional runoff decrease in the next 50 years because of global climate changes.

The frequent outbreaks of water eutrophication in Gehu Lake are regarded as one of the most troublesome environmental issues in Southeast China. Based on the water's potential capacity to accept pollutant loads, a catchment-scale environmental management system was established to ensure inflows of clean water into Taihu Lake. Considering the complexity of the hydrological regimes operating within the river-network plain, the capacities of the water environment for loads of COD and nutrients were estimated using the Water Quality Analysis Simulation Program, Version 7.3 (WASP 7.3) model. The calibration and the verification of this model were based on water quality measurements during the period 2009–2010. The variables of water quality that were examined are COD, NH₄-N, TN and TP. The simulated distributions of the COD, NH₄-N, TN and TP in the water column agree with the observations, but it indicates that more measurements are needed to verify the predictability of the simulations. The simulation results show that the average relative error is small, and the change trend of each indicator is consistent. The results have shown that the WASP model can be used to evaluate the future water quality changes in case that the pollution continues with the same rate. The work presented in this paper is expected to be a theoretical basis in exploring the degradation mechanism for self-purification capacity of water bodies and in designing and constructing of Gehu Lake ecosystem restoration goals.

This paper applies Soft Systems Methodology (SSM) within the context of action research and Integrated Flood Management (IFM). A case study from the Adayar watershed, Chennai, is provided as an example of how SSM can be used to understand complex situations and as a problem-solving strategy for flood management. Flat topography, uncontrolled urban development, population growth, sand bar formation at the river mouth and low tidal action render complexity to flood management in Chennai. For effective flood management, a participatory and integrated approach, which includes stakeholders in the decision-making process and an enabling institutional set-up, is essential. As part of an integrated approach, the relationship between various organizations and the public is identified. SSM is an approach for addressing fuzzy problematic situations involving human activity. In this paper, SSM techniques like ‘Rich Picture Diagrams’ and ‘CATWOE analysis’ and participatory action research tools like ‘pairwise ranking’ and ‘force field analysis’ were investigated. Two workshops were conducted to define and explore the problematic situation, the role of various actors involved in the problem, to develop the conceptual model, to rank decision-making criteria, and to analyse the forces for and against to solve the problem. The flood management approach provided in this paper can be used by government agencies and policy makers to manage floods.

Sites along Sugar Creek and the Apalachee River were monitored to compare the water quality in cattle farming regions with the forested regions of the Oconee watershed. Dissolved oxygen (6.68 mg/L) and turbidity [23.91 nephelometric turbidity units (NTU)] in Sugar Creek and the Apalachee River were similar. Overall, cattle farming sites along Sugar Creek had higher levels of NO₃⁻ and PO₄⁻³ during the summer months. In contrast, the forested sites on the Apalachee River had elevated concentrations of inorganic nutrients only during spring rain events. The concentration of faecal bacteria was greater in the cattle farming areas compared with the level of faecal bacteria in the forested areas, and microbial source tracking with the bovine-associated Bacteroides (BoBac) DNA marker indicated that cattle were the major source of faecal bacteria in Sugar Creek.

Because of the shortage of water source in the extreme arid area, generally, there are several years of no irrigation on mature shelterbelts. In this study, the shelterbelt soil in different texture were compared based on distribution analysis of the soil moisture and salt levels of shelterbelts under large-scale drip irrigation in Kalamiji Oasis in the lower reaches of Tarim River, Northwest China. The following conclusions were drawn. (1) In Kalamiji Oasis, the groundwater level declined at a rate of 0.5 m/a as a result of popularization of drip irrigation technology. (2) There was a larger heterogeneity in distribution for soil moisture in the sandy/loamy shelterbelt than in the clay shelterbelt. (3) Under non-irrigation conditions, sandy/loamy shelterbelt has lower soil moisture and salinity, and clay shelterbelt has higher soil moisture and salinity. (4) The shelterbelt with the shallowest groundwater depth had highest soil moisture level, and the shelterbelt with the deepest groundwater level had the lowest soil moisture content. (5) In sandy and loamy shelterbelts, the shelterbelts with the shallowest groundwater depths had the lower salinity levels and the shelterbelts with the deepest groundwater depths had the highest salinity levels. (6) In clay shelterbelts, the shelterbelts with the shallowest groundwater depths had the highest salinity levels, and the shelterbelts with the deepest groundwater depths had the lowest salinity levels. Additionally, it is essential to implement irrigation at least once a year.

To increase the performance of a primary sedimentation tank (clarifier), it is essential to have a uniform and calm flow field. The use of suitable baffle configurations may help forming favourable flow field and increase the efficiency of the primary sedimentation tank. To find the proper position and height of a baffle in a rectangular primary sedimentation tank, computational investigations are performed. Also, laboratory experiments are conducted to verify the numerical results, and the measured velocity fields that were by acoustic Doppler velocimeter (ADV) are used. The results of computational investigations performed in the present study indicate that the favourable flow field (uniform in the settling zone) would be enhanced for the case that the baffle position and height provide small circulation regions volume, or the recirculation region forms a small portion of the flow field and dissipate the kinetic energy in the tank.

Environmental regulation, increased pressure on water resources and rising cost for wastewater discharges make wastewater treatment for recycling an essential investment for many industries. Ammonia is a major pollutant in many industrial and agricultural wastewaters, and its elimination is essential for wastewater to be reused or meeting local discharge standards. In this study, the removal of ammonia from dilute aqueous solution has been investigated using sweep gas and vacuum membrane distillation (SGMD and VMD). Factors that affect the separation process such as feed and air flow rates, vacuum degree and feed temperature have been investigated. Overall, mass transfer coefficients (K_ov) were calculated, and the results indicated that K_ov for VMD is higher than that for SGMD under similar operation. Overall, ammonia mass transfer coefficient up to 12.06 × 10⁻⁵ and 5.63 × 10⁻⁵m/s can be achieved for VMD and SGMD, respectively. The ammonia removal efficiency was enhanced by increasing sweep gas flow rate or by decreasing downstream pressure.

Constructed wetland sediments are frequently contaminated with nitrogen and phosphorus. There is a risk that accumulated pollutants can either be remobilised or reach the groundwater. Five identical mesocosms, which were filled with subsoil collected from full-scale integrated constructed wetland (the first cell receives the most contaminated influent), were set up to examine nutrient removal within sediment layers. The results indicated that accumulated nutrients leached out into inflow water and that the sediment capacity of nutrient retention decreased as the wetlands aged. Furthermore, the mesocosm planted with Phragmites australis achieved better treatment results compared with the one planted with Agrostis stolonifera. The risk of contamination to groundwater does not exist because none of the treated water reached the bottom outlet during the study period. Both the bentonite (clay) and biogeochemical processes taking place within sediments proved to be efficient in preventing polluted water from infiltrating into lower lying soils.

Data collected from five Wildfowl & Wetlands Trust constructed wetland systems offering a range of styles and inflow water types between 2005 and 2009 were examined and compared to identify long-term trends in nutrient removal. Ammonia-nitrogen concentrations were reduced between 31.9 and 96.8%. In contrast, the concentrations of nitrate-nitrogen and total oxidised nitrogen in the effluent exceeded the influent in many of the systems. Reduction in ortho-phosphate-phosphorus and total phosphorous were between −10.5 and 87.6%, and between 6.9 and 92.5%, respectively. Removal efficiencies of biochemical oxygen demand were between 0.0 and 87.3%, and reductions of total suspended solids ranged from −249.3 to 57.6%. Ammonia-nitrogen reduction was effective during summer. Long-term nitrogen removal has been efficient and consistent. However, phosphorous reduction was only sufficient during the early stages of operation, and generally declined as the wetland aged.

To accomplish this study, the total concentration of suspended particles, PM₁₀ and PM_2.5, was mapped at intercity bus stations in the central square of Hamedan. To measure the particulate matter (PM), portable air sampling systems that collect integrated filter samples were used. The PM concentration was collected at various time intervals and measured gravimetrically. The results were then analysed using the ArcView GIS 3.3 software to map the particulate dispersion patterns. The mean concentrations of the total suspended particles (TSP), PM₁₀ and PM_2.5 were 1220.94 ± 1418.5, 524.7 ± 217.5 and 386 ± 193.6 μg/m³, which were 16, 7.72 and 4.7 times greater than the World Health Organization (WHO) air quality standard, respectively. The PM concentration was not correlated with wind velocity or air temperature, but was correlated with humidity (P = 0.01). Overall, the results of this pilot study indicate that people at bus stations are exposed to respirable particulate matter (RPM) at levels high enough to pose a serious health risk.

This review draws on knowledge for the treatment of heavy-metal leachate in contaminated mine sites. Mine waste rock dumps and tailings generate a continuous stream of metalliferous and saline leachate over the long term. The mining industry has many legacy sites, which have compromised aquatic ecosystems and groundwater because of heavy-metal contamination. Chemical and engineering methods are available and have been extensively utilised. However, these methods require intensive energy and often produce substantial volumes of secondary waste. We therefore argue in favour of phytoremediation as a sustainable remediation strategy leading towards efficient and sustainable metal removal and immobilisation through constructed wetlands.

A method for computing flooded areas in relation to precedent climatic conditions in a plain area is evaluated. The studied area includes the most important production area for cattle breeding in Argentina; therefore, waterlogging periods create significant economic losses. In order to conduct this study, Landsat images that represent different hydrological conditions were used. The method is based on the frequency analysis of rainfall records of the 30, 60 and 120 days prior each image, thus obtaining a seasonally weighted mean frequency. In order to minimize biases of individual images, the images were combined linearly so as to obtain composed images with the desired antecedent precipitation frequency. Then, the flooded areas were associated with the frequency of the antecedent rainfall. Therefore, frequencies equal to or higher than 50% are associated with semi-permanent or permanent lentic waterbodies. Consequently, lower frequencies are associated with waterlogged areas reaching 35% of flooded area for a 20% precipitation frequency.

In many developing countries, the groundwater monitoring network is randomly designed, and consequently needs to be revised and optimised to reduce operation time and cost, remove redundant piezometric data, and strengthen sparseness data zone with supplementary observation well. The geostatistical approach used in this work is based on the universal kriging variance combined with cross-validation test. Hence, a rational interpolation of water table elevations was performed to evaluate the accuracy of data employed in the piezometric head modelling. In this study, the groundwater monitoring network of the Sfax superficial aquifer in the south east of Tunisia was optimised. The elimination of five observation wells induces the invariability in the variance of estimate due to their less contribution in interpretations of the groundwater level behaviour. However, 38 wells were added at areas of high variance of the kriging in order to ameliorate the spatial coverage of the monitoring network.

In this study, the effects of different parameters on flow structure and flow hydraulics for combining sewer junction consisting of manhole and lateral inflow were investigated numerically. For this purpose, the effects of dimension variations, main and lateral pipe slope, angle and the joint position of lateral pipe beside manhole, manhole geometry, and the outflow rate of manhole on flow structure and energy loss coefficients were investigated. Results show that the rate of energy loss decreases by heightening the installation position of lateral pipe beside manhole. In addition, it was shown that the slope variations of main and lateral pipes and outflow rate do not affect the rate of energy loss.

The quantity of precipitation received by the monsoons is enormous. The south-west monsoons, unlike the north-east monsoons, have been studied in great detail. This study deals with rainwater collection during the NE monsoons and involves an examination of the stochastic nature of a turbulent boundary layer and the effect of crosswinds on rain droplet trajectories and thence their collection. It must be borne in mind that whilst mid latitude precipitations typically range from a few millimetres per hour, the north-east monsoon showers experience rainfall rates often 10 times higher than this value and their calculations deserve special attention. Probability distribution functions are calculated to quantify the coordinates of the landing trajectories on rooftop collectors. This investigation was essential to emulate the prevalent conditions of intense driving rain on top of high rises where setting up of a collector will be most suitable to directly harness rainwater in its purest form before contamination.

In this work were determined triclosan and 4n-nonylphenol in water from a reservoir that is used to provide water to a purification plant in an important city in Colombia. The analytical methodology was validated using solid-phase extraction and analysis by gas chromatography-mass spectrometry (GC-MS). The analysis by GC-MS showed good linearity in the range of 0.05–5 μg/L for both compounds. Recoveries from 79 to 109% and standard deviations of 2.5–7.7 for low concentrations and from 3.8 to 9.6 (n = 5) for high concentrations were obtained for both compounds. In Colombia, this is the first time that these compounds have been analysed in water supplying of a drinking water treatment plant. The validated method was applied to the analysis of 27 samples collected in August 2010 in 11 locations from the reservoir and in the influent and effluent of the drinking water treatment plant. In total, seven samples were found to contain triclosan.

This study was aimed at assessing the prevalence of pathogenic Escherichia coli strains, relative to the total count of E. coli, faecal coliforms and other heterotrophic mesophilic aerobic bacteria (HMAB) isolated in groundwater in the equatorial region of Cameroon (Central Africa). Bacteria were isolated using standard methods. Pathogenic E. coli strains were then identified using haemagglutination and antisera tests. The maximum abundance of HMAB, faecal coliforms and E. coli strains were 4.9 × 10⁶, 5.6 × 10³ and 1 × 10³ colony-forming units (CFU)/100 mL, respectively. The count of pathogenic E. coli strains reached 3 CFU/100 mL. The counts of commensal and pathogenic E. coli strains underwent temporal and spatial fluctuations. In 21% of sampling sites, the abundance of faecal coliforms was significantly correlated to that of E. coli (P < 0.05). However, the isolated bacterial count was not significantly correlated to that of the pathogenic E. coli strains (P > 0.05). The bacteria abundance dynamics may be impacted by many interacting factors.

Suitability of the Natural Resources Conservation Service (NRCS) curve number (CN) model of run-off prediction was evaluated on three humid tropical forested catchments in Kimakia, Kenya. The catchments were dominated by Pinus patula (catchment A), Arundinaria alpina (catchment C) and Pennisetum clandestinum (catchment M). The study used discharge and rainfall data collected between 1958 and 1986. Seventy-three (73) isolated storms were graphically separated into baseflow, interflow and surface run-off. Forest cover types significantly improved catchments characteristics that influence baseflow and interflow generation in catchment C but not those that influence surface run-off production. In its original form, the NRCS CN model resulted in direct run-off estimates that deviated from observed ones by between 43.8% and 55.3%. These discrepancies were minimized through modification of the β and CN parameters. CN generated empirically using storm rainfall predicted the direct run-off satisfactorily. Therefore, the modified NRCS CN model adequately estimates direct run-off from humid tropical forested catchments.

The purpose of this study is to provide a better understanding of the impact of agricultural activities on groundwater quality in a semi-arid coastal environment (Korba, Tunisia). Impacts have been assessed through groundwater samples that were analysed for a range of chemical and biological parameters. Results indicate that groundwater overexploitation for irrigation and fertiliser use have affected the quality of the groundwater not only by direct contamination but also seawater intrusion. The implementation of appropriate regulatory and economic instruments to foster sustainable practices in the agricultural sector have been analysed within the framework of the EC (European Community) FP6 (funding program 6) INECO (Institutional and Economic Instruments for Sustainable Water Management in the Mediterranean Region) Project. Through stakeholder involvement processes, the project analysed issues relating to the regulation and control of groundwater abstractions, the promotion of wastewater reuse, efficiency improvements in irrigation water use, as well as instruments to strengthen the socioeconomic and institutional environment towards better managing and conserving available groundwater resources.

Permeable pavement systems (PPS) are frequently associated with high removal efficiencies for water quality parameters. Their effluent can, therefore, be recycled, for example, for sprinkling onto gardens. Nevertheless, some stakeholders fear that potentially pathogenic organisms within the treated run-off could be too high, and therefore they request disinfection before recycling. The aim of this paper is, therefore, to assess the efficiency of a batch flow combined titanium dioxide (TiO₂) and ultraviolet (UV) light photocatalytic reactor in removing water-borne microbial contaminants from the effluent of PPS. Combined TiO₂ and UV photocatalytic reaction times between 80 and 100 min were required for the complete removal of Escherichia coli, total coliforms and faecal Streptococci, which had mean initial counts of 1.5 × 10⁷, 4.4 × 10⁶ and 6.9 × 10⁵ colony-forming units (CFU) per 100 mL, respectively. In comparison, UV disinfection alone resulted in insignificant microbial removal. Suspended TiO₂ powder was more effective than small immobilised TiO₂ crystals.

Developing a robust flood forecasting and warning system (FFWS) is essential in flood-prone areas. Hydrodynamic models, which are a major part of such systems, usually suffer from computational instabilities and long runtime problems, which are particularly important in real-time applications. In this study, two artificial intelligence models, namely artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS), were used for flood routing in an FFWS in Madarsoo river basin, Iran. For this purpose, different rainfall patterns were transformed to run-off hydrographs using the Hydrologic Engineering Center (HEC)-1 hydrological model and routed along the river using HEC river analysis system RAS hydrodynamic model. Then, the simulated hydrographs with different lag times were used as inputs for training of ANN and ANFIS models to simulate flood hydrograph at the basin outlet. Results showed that the simulations obtained from ANN and ANFIS coincided with the results simulated by the HEC-RAS, and application of such models is strongly suggested as a backup tool for flood routing in FFWSs.

Water companies in the United Kingdom have been dealing with seasonal algal blooms for many decades, with escalating costs as bloom occurrences have increased markedly with elevated demand on water supply. Environmentally friendly water treatment solutions, such as ultrasound and barley straw, are defined as those that use less energy and chemicals. Barley straw has been used quite extensively by certain UK water companies, and results are generally positive. Ultrasound has only recently been used as a treatment for algal removal, with limited results from several successful trials finding cyanobacteria to be the most susceptible algal group at field scale, with results also indicating susceptibility in other algal groups; however, energy costs are higher than barley straw. Ultrasound has been extremely successful at removing bacteria in wastewater treatment; therefore, ultrasound should be considered as an in-works solution where its effectiveness would be enhanced while reducing energy requirements.

Groundwater reservoir (GR) of both local precipitation and surplus water transferred from the Han River Basin is an effective method to prevent further lowering of the groundwater table. In this study, when the different volumes of infiltration water from the fuzzy mathematical analysis were input in the simulation, the rate at which the groundwater table rose ranged from 1.47 to 3.45 m/a. The effective storage rate (ESR) values of GR and the local reservoir was calculated, and ranged from 80.50 to 90.95% and from 49.66 to 80.90%, respectively. In GR, the ESR decreased as artificial recharge increased. Comparison of the ESR values between local reservoir and GR showed that if the volume of artificial recharge water available was < 7.86 × 10⁸ m³/a, then GR was a better storage method than the local reservoir. According to our results, this situation would occur 80.30% of the time.

Climate variability induces considerable interannual fluctuations in spring discharge, especially in mountain areas, where groundwater is recharged mainly by rain and snow melt. This study presents the discharge climatological model (DISCLIM), which was developed to test a complexity-reduced approach to perform historical reconstruction in the lack of physical assumptions. The Mount Cervialto aquifer (Southern Italy) is the test site, where a powerful karst spring is monitored since the 1920s and is very sensitive to climatic conditions. DISCLIM incorporates seasonal precipitation and climate indicators only. Despite its simplicity, DISCLIM has been able to well estimate the yearly fluctuations of discharge hydrological, explaining about 90% of the interannual variability at the calibration stage, and more than 80% at validation stage. This means that DISCLIM can be easily used for estimating the discharge in historical times, when no all the hydrological balance data are available for the purpose.

The treatment of agriculturally polluted water to potable standards is costly for water companies. Changes in agricultural practice can reduce these costs while also meeting the objectives of European Union (EU) environmental legislation. In this paper, the uptake of source control interventions (SCIs) by water and sewage companies in England and Wales as a means of controlling agricultural pollution is investigated. Data were gathered using semistructured interviews with water and sewage company representatives. Interview data were processed using thematic and content analysis. Results showed that SCIs are increasingly being adopted in England and Wales. Of the four types of SCI identified, the so-called ‘Liaison’ type dominated. This type of intervention requires intermediary organisations with local expertise in water catchments. Differences in pollution source control between EU countries, and England and Wales are examined. Evidence indicated that ‘Liaison’ SCI s types may be more prevalent in countries where water supplies are privatised.

The temporal concentration variations and spatial distribution of nitrogen compounds (nitrate, nitrite, ammonium) in the natural surface waters of Stara Zagora Region, Bulgaria, over a period of 1 year were assessed in the present study. Nitrate-nitrogen concentrations in all surface water samples, except for the December value – 21.8 mg/L in Zetyovo Reservoir, were within the permissible national quality standards. NO₂ ^–-N could be classified as a priority pollutant of Chirpan and Zetyovo Reservoirs waters. The greatest extent of NH ₄ ⁺-N pollution was registered in Chirpan Reservoir surface waters. The correlation study revealed appreciable mutual relationship only between NH₄ ⁺-N and NO ₂ ^–-N in the surface waters. The hierarchical cluster analysis (HCA) exhibited divergent apportionment of nitrogen compounds in the surface water bodies.

This study compares concentrations of trihalomethanes (THMs) in municipal water for 2001–2007 from the small and large systems in two provinces in Canada (Newfoundland and Quebec) based on source waters, disinfectants, seasons and treatment approaches. Approximately 71 and 94%, respectively, of the municipal systems in Quebec and Newfoundland are small systems (serving fewer than 3000 people). The small systems serve approximately 8.6% (0.57 million) and 44.1% (0.18 million) of the populations in Quebec and Newfoundland, respectively. Concentrations of THMs and its variability are much higher in the small systems (Quebec: 0–941 μg/L; Newfoundland: 0–875 μg/L) than in the systems with populations 10 000 or more (Quebec: 0–364 μg/L; Newfoundland: 2.3–205 μg/L). The study reveals that the differences in THMs between the small and medium/large systems are because of different types of source waters, treatments, disinfection strategies and seasons. The results emphasize that regulatory agencies must focus more on the occurrence of DBPs in small systems and identify strategies to reduce their levels in drinking water.

The objective of this study was to assess water quality in the Lake Oconee watershed and evaluate the best management practices used by cattle farms to reduce water contamination. Inorganic nutrient concentrations, algal abundance and faecal bacteria were highest in the cattle farming areas. The diatom community where cattle had no access was dominated by Achnanthidium minutissimum (Kützing) Czarnecki and Fragilaria crotonensis Kitton, and in sites where cattle were allowed direct access to the lake, Asterionella formosa Hassal, Nitzschia palea (Kützing) Smith and Navicula rostellata Kützing dominated. The latter three taxa are well-known high-nutrient diatoms. High populations of green algae (coccoid Desmidiaceae) were found where cattle had access. Sources of faecal pollution were identified using polymerase chain reaction detection, with Bifidobacterium adolescentis as a marker of human faecal pollution and Bacteroides (BoBac) indicating cattle faecal pollution. Overall, riparian buffers were most effective at reducing pollution from cattle operations.

Experience of retrofitting sustainable drainage systems (SuDS) in the United Kingdom is limited, and there are no well-established procedures for evaluating the feasibility, value or cost-effectiveness of doing this, particularly at the catchment scale. This paper demonstrates a two-phase process for evaluating the potential to retrofit SuDS to address combined sewer discharges in three subcatchments within the Thames Tideway catchment of London. The first phase evaluates what might be achieved with various levels of disconnection (‘global’ disconnection scenarios) using hydraulic models, while the second phase considers how disconnection might practically be achieved. High levels of disconnection are technically possible but practicably difficult. In selected cases, and with aggressive implementation of SuDS, combined sewer overflow CSO discharges could potentially be eliminated or reduced to acceptable levels without the need for any modifications to underground assets. However, retrofit SuDS could not eliminate the requirement for some form of sewer modification in any subcatchments.

A survey was conducted of 400 households in the peri-urban area of Bangkok to investigate typical household water consumption, daily water use activities, public perception towards wastewater reuse and detergent consumption. Four categories of greywater, including cooking, dish washing, bathing and laundry washing wastewater, their properties and potential application for reuse were examined. Average water consumption was estimated to be 208 L/person/day. The wastewater was already reused in 42% of households, and that laundry wastewater was widely used for plant watering and floor washing. More than 80% of households accepted the use of treated greywater, while 50% of households did not accept the use of treated blackwater. Biochemical oxygen demand (BOD), chemical oxygen demand (COD) and suspended solid (SS) were high in cooking, dish washing and laundry, and lower in bathing wastewater, while anionic surfactant were high in laundry and dish washing wastewater. The finding results clearly demonstrate the possibility of greywater reclamation and reuse in the area.

Sonication is a well-known sludge pretreatment technique with the advantages of simple operation and high efficiency. However, it is an energy-intensive process. Hence, it is very important to predetermine its sludge disintegration efficiency at varying pretreatment conditions in order to minimize the ultrasonic energy consumption. In this study, it was found that the ultrasonic sludge disintegration occurred in two stages: rapid and subsequent slow disintegration stages. For this reason, it was aimed to develop a simple and accurate mathematical model to describe the two-stage sludge disintegration as a function of pretreatment conditions. Sludge concentration and ultrasonic density along with sonication period were involved in this model as independent variables. It was determined that the mathematical model can predict accurately the degree of sludge disintegration. Thus, the proposed model was seen to be very useful for evaluating the disintegration efficiency and/or for process design using the operating parameters under different conditions.

This study quantifies the impact of the oxidation ditch horizontal water velocity on the energy consumption of a full-scale wastewater treatment plant (WWTP). A WWTP was modelled by means of the ASM2d platform, showing very good correlation with reference operational data. As to reduce the energy requirements of the plant while guarantying the same nutrient removal performance, two approaches were used. A classical aeration control optimization, yielding a 4% energy reduction, was compared with an increase of the oxidation ditch propelling power. The horizontal water velocity in the oxidation ditches was estimated at only 0.15 m/s. By increasing the horizontal water velocity to 0.3 m/s, an 8% energy reduction could be achieved. Moreover, a synergistic effect for classic control optimization and oxidation ditch water velocity optimization resulted in a 14% energy reduction. Energy spent in propelling power counteracts the aeration energy gain derived by an increase in the oxidation ditch horizontal velocity. An optimum in the water velocity was quantified at 0.3 m/s, comparably with its design value.

Embodied (or embedded) greenhouse gas emissions are commonly overlooked in corporate carbon accounting, although they can represent a large proportion of overall emissions. In this paper, we utilise embodied emission data submitted to Ofwat, the economic regulator of water and sewerage companies in England and Wales, as part of their review of price limits. This is the first time that water and sewerage companies have presented embodied emissions associated with their capital programmes. In total, embodied emissions add an extra 50% on top of companies' operational greenhouse gas emissions. We consider the drivers for embodied emissions and show that capital maintenance programmes are the largest source. We highlight the relationship between capital expenditure and embodied emissions, and discuss why there are significant differences in embodied emission intensities between companies. Many of the differences arise from the way the common methodology for estimating embodied emissions is applied.

Four municipal wastewater treatment plants (WWTPs) in India based on different technologies are compared by conducting Life Cycle Assessment (LCA) using field data. CML 2 baseline 2000 methodology is adopted in which eight impact categories are considered. SBRs ranked highest in energy consumption and global warming potential (GWP) but also produced the best effluent with respect to organics and nutrients. Constructed wetlands have negligible energy consumption and negative GWP because of carbon sequestration in the macrophytes. Emissions associated with electricity production required to operate the WWTPs, emissions to water from treated effluent and heavy metal emissions from waste sludge applied to land are identified as main contributors for overall environmental impacts of WWTPs. This comparison of technologies suggests that results from LCA can be used as indicators in a multicriteria decision-making framework along with other sustainability indicators.

The use of United States Environmental Protection Agency (USEPA) Method 1623 for the detection of Cryptosporidium in water often results in low and variable rates of recovery. According to data disseminated in Method 1623, less than a quarter of tested surface water samples had Cryptosporidium recoveries of 60% or greater. This research explored various method modifications in order to produce a method with higher recovery and less variability. Once method modifications were implemented, recoveries of C. parvum in reagent water increased by greater than 20% to an average recovery of 76%. In surface water, a significantly higher (P = 0.049) mean recovery of 67% for C. parvum was achieved with the modified method. Giardia is simultaneously detected when using Method 1623. The method modifications significantly increased the recovery of Giardia in reagent water by 37% (P = 0.0002) while also allowing for a 17% higher recovery in surface water samples (P = 0.21).

Over a period of 18 months, the dissolved organic carbon (DOC) concentration of a series of four lakes in North Wales was measured monthly. The lake catchment profiles consisted of an upland thin peat/soil (Llyn Cwellyn), an upland thin peat/soil associated with an adjacent area of small bog (Llyn Teyrn), an upland blanket bog (Llyn Conwy), and large lowland fen and fertile agricultural area (Llyn Cefni). The results examine the indirect effect of temperature and precipitation on the DOC concentrations found in the lakes fed by the catchments. The lowest DOC of the four sites was observed for Llyn Teyrn, varying from 1.2 to 3.30 mg/L, and with the highest being recorded for Llyn Cefni (5.45–10.83 mg/L). Temperature and rainfall data were both collected. Correlations with the DOC exhibited significant relationships with temperature for three of the sampled lakes Cwellyn (r 0.490), Teyrn (r 0.640) and Cefni (r 0.472). Recomputation versus 30- and 60-day temperature lag times improved the correlation coefficients. The data showed weak and insignificant correlations for DOC versus rainfall for the three lakes, but the upland lake, Llyn Conwy, with its blanket bog catchment, did not demonstrate any statistical correlation with temperature, although it did show a significant correlation for DOC versus rainfall (r 0.553, P < 0.05). Over the sampling period, although tentative relationships were found among temperature, rainfall and DOC levels, an indirect association tempered by site hydrology is suggested.

During the past decades, several models that predict the concentration profiles after a discharge of pollutants in a river have been developed. A model that predicts nitrogen concentrations in a river has been developed and is presented in this paper. The developed model that determines nitrogen concentrations in a water stream is based on a dimensional analysis. Fundamentals of the modelling of the pollutant predictions in a water stream consist of a derivation of function dependency from expressed non-dimension arguments. Non-dimension arguments are stated from variables, which influence the occurrence of pollutants. The model for the prediction of nitrogen concentrations in water streams has been developed for the Laborec River (eastern Slovakia). The differences between the nitrogen concentrations predicted from developed models and measured concentrations in the river are also discussed here.