Wastewater for agriculture: A reuse-oriented planning model and its application in peri-urban China

The benefits of Integrated Water Resources Management (IWRM) are widely known but its recommendations remain thinly implemented. Designing wastewater treatment plants for reuse in irrigation is a particularly underutilized IWRM opportunity that could potentially increase agricultural yields, conserve surface water, offset chemical fertilizer demand, and reduce the costs of wastewater treatment by eliminating nutrient removal processes. This paper presents a novel planning model, consisting of a reuse-centric performance assessment and optimization model to help design wastewater treatment plants for reuse in agriculture. The performance assessment and optimization model are described, and their coupled application is demonstrated in the peri-urban district of Pixian, China. Based on the results of the performance assessment, two reuse scenarios are evaluated: wastewater to supplement business as usual (BAU) irrigation, and wastewater to replace BAU irrigation. The results indicate that wastewater supplementation could increase profits by $20 million (M) annually; alternatively, wastewater replacement could conserve 35 Mm³ of water in local rivers each year.     

A policy framework for trans‐boundary wastewater issues along the Green Line,the Israeli–Palestinian border

The annual discharges of municipal wastewater across the Green Line (the Israeli–Palestinian border) are causing a bi‐national conflict with political, environmental, and economic dimensions. This paper surveys the current scope of wastewater facilities in Palestinian communities and discusses the immense challenges to achieving sustainable wastewater treatment facilities. Current Israeli water policy hinders effective regional solutions to trans‐boundary wastewater issues. This paper proposes a less confrontational approach to solve common problems. The better management of bi‐national wastewater resources could establish sustainable trans‐boundary sanitation facilities. This would bring a range of benefits to health, the environment, and socio‐economic life.     

ENVIRONMENTAL FLOW SETTING IN ENGLAND AND WALES: STRATEGIES FOR MANAGING ABSTRACTION IN CATCHMENTS

This paper describes the evolution of methods to set environmental flows in England and Wales. Problems and challenges are reviewed in the context of recent legislative developments, and examples are given of different conceptual approaches. Scenario-based approaches have evolved as a pragmatic means to resolve competing uses of water; in contrast, approaches based on ecological objectives aim to meet more consistent goals. Where rivers or associated wetlands have been designated under national or European conservation legislation, broad ecological objectives are already under discussion. Furthermore, the European Water Framework Directive now requires good ecological status, or its equivalent, to be reached in all waters. Recently, the Environment Agency has developed a new process for managing abstractions in England and Wales; this includes a common methodology for the setting of environmental flows using objective methods.     

Water demand management: implementation principles and indicative case studies

Current practices for the efficient use and management of water resources are based on the conjunctive application of water supply and demand measures. Even though options for the augmentation of water supply are widely analysed and assessed, water demand management remains an open field for study, as it is highly dependent on the socio‐economic features of a region and has a site‐specific character. This paper summarizes the guiding principles of demand management and presents some successful application examples of demand management measures from regions that cover a wide range of socioeconomic and environmental conditions in an effort to identify the critical factors for the efficient planning and implementation of demand management plans.     

Cyanobacterial toxins: an emerging threat in South African irrigation water

The deterioration of water quality is a serious concern for a water scarce‐country like South Africa (SA). This article looks at the risks posed by the common practice of using surface waters to irrigate crops, as these are usually contaminated with harmful cyanobacteria and cyanotoxins which can be bio‐accumulated by plants. In addition to cyanotoxins, SA waters are also heavily impacted by other pollutants such as toxic metals, salts and high electrical conductivity. The consumption of food contaminated with cyanotoxins is a growing human health concern for countries like SA which are faced with surface water eutrophication‐related challenges. The country also lacks research on human exposure to cyanotoxins via irrigated crops and regulations to manage cyanotoxins in irrigation water. Such lack of data and policies thus prompts an urgent need for local evidence‐based research to guide policies and guidelines on cyanotoxins in irrigation water, food plants and water used for livestock.     

Screening of 47 organic microcontaminants in agricultural irrigation waters and their soil loading

Reclaimed water usage for crop irrigation is viewed both as an excellent sustainable water source and as a potential entrance for emerging organics into the food chain. This concern is backed by the already documented pollutant crop uptake potential. In the present study, irrigation waters used in agricultural fields (Torroella de Montgri, NE Spain) were screened for 47 analytes in a two year study (2007-2008). A total of 26 contaminants belonging to different chemical classes namely, pesticides, pharmaceuticals, personal care products, phenolic estrogens, antioxidants and disinfection by-products, were detected. Marked differences in concentration trends for the different chemical classes were evidenced from 2007 to 2008, and attributed to a persistent drought endured by the region in 2008. Also, loading mass rates of chemical classes were estimated based on crop irrigation regimes and they ranged from 0.8 to 121.3 g ha⁻¹ per crop cycle. These values were contrasted with those obtained for other water sources from countries where crop irrigation is commonly practiced. Finally, crops grown under these irrigation regimes, namely alfalfa and apple, were analyzed and 5 anthropogenic compounds were identified and quantitated, whose concentrations ranged from 13.9 to 532 ng g⁻¹ (fresh weight).     

Establishing hydroecological relationships to manage the impacts of groundwater abstraction

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.     

Social preferences and economic valuation for water quality and river restoration: the Segura River,Spain

The Water Framework Directive (WFD) aims at improving the ecological status of the water bodies in Europe. In this context, some rivers are currently being restored and, in accordance with this Directive, the restoration actions have to be evaluated from a socio‐economic approach. This work applies the Choice Modelling method to the WFD provisions for river restoration. This method proves to be useful for the economic valuation of the restoration measures, as well as a very important tool for people's public participation. In this sense, the water quality improvement has been defined as a priority action from a social point of view. Moreover, the method used has provided answers to both basic questions included in the WFD: the calculation of the economic value of the Segura River's ecological flow, the decrease of which would pose an environmental cost, and the estimation of the environmental income generated by this river.     

Challenges in developing an integrated catchment management model

Directives and policies increasingly call for more integrated management of land and water. Frameworks such as integrated catchment management may address these calls, and yet their implementation requires decisions to be taken under conditions of extreme complexity and uncertainty. This paper summarises a participatory framework through which decision‐makers, experts and system modellers can collaboratively develop an integrated model to support such decisions. A feasibility study showed the potential of the framework. An operational version of the model, able to analyse the effects of 50 management options on 20 indicators, is estimated to require in the order of 225 man‐months from system modellers, alongside substantial inputs from stakeholders. The significant technical challenges confronting such an exercise may be overshadowed by the institutional challenges, including the fundamental question of whether organisations are truly committed. However, the reward for overcoming such challenges is the opportunity to achieve genuine improvements in the social, economic and environmental quality of our catchments.     

Successful wastewater reuse scheme and sustainable development: a case study in Adelaide

Freshwater availability to meet the growing needs of humankind has raised serious concerns in the recent past. Two immediate responses to counter this challenge are efficient allocation of the scarce resources, and development and use of alternative sources of water. While ‘water markets’ are seen as a means to achieve efficient allocation of the scare resources, treated wastewater and low‐quality water are now considered as potential sources of water to supplement the freshwater supplies. However, the latter option, that is use of reclaimed water as an alternative, imposes concerns regarding its suitability to sustain development. This is because of various issues related to wastewater usage and application. At the same time, it is also true that a successful and well‐planned reuse scheme can help achieve sustainability as evidenced in some isolated cases around the world. In line with this, the current paper adopts a case‐study approach to demonstrate how a successful reuse scheme in Adelaide, South Australia, has contributed to the sustainable development of the region. The paper looks into the socio‐economic and environmental dimensions of sustainability and arrives at a conclusion that properly planned and managed reuse schemes backed with effective regulatory and policy measures can lead to sustainable development.     

The assessment of a water budget of North Cyprus

Water scarcity in North Cyprus (NC) began in the 1960s and is still tremendously increasing. Thus far no serious measurements have been taken to address this problem. Increased water demands led to extraction of water from unrestricted groundwater resources. Extreme water extractions caused the salinization of coastal aquifers up to brackish waters and the consequent depletion of interior aquifers. Such a situation requires precise control of water resources through an integrated water resources management (IWRM). Although the situation has reached an alarming state, no detailed research has been performed to establish the present demands of water in order to anticipate the future demands. Hence, this study, based on the IWRM approach, examines water budget of the country.     

New goals and methods in connection with the reshaping of multi‐storey housing areas—The gellerup project

Despite the fact that many large housing estates of the 1960s and 1970s are well planned, they have run into a vicious circle of severe and mutually intensifying social, environmental, technical and economic problems. This article reports on an experimental project in one such area, Gellerupparken. Taking the everyday life and the resources of area residents as the point of departure, the project tried to develop residential life and resources through several sub‐projects involving the inhabitants of the area. A socio‐cultural and an environmental improvement project are described in some detail. The main experiences of the project are (a) that a flexible and integrated effort adapted to local conditions has the best chances of success in changing residential life and area image, and (é) that such changes will last and continue long after such an effort is finished.     

Use of Moringa oleifera seed extracts to reduce helminth egg numbers and turbidity in irrigation water

Water from wastewater-polluted streams and dug-outs is the most commonly used water source for irrigation in urban farming in Ghana, but helminth parasite eggs in the water represent health risks when used for crop production. Conventional water treatment is expensive, requires advanced technology and often breaks down in less developed countries so low cost interventions are needed. Field and laboratory based trials were carried out in order to investigate the effect of the natural coagulant Moringa oleifera (MO) seed extracts in reducing helminh eggs and turbidity in irrigation water, turbid water, wastewater and tap water. In medium to high turbid water MO extracts were effective in reducing the number of helminth eggs by 94-99.5% to 1-2 eggs per litre and the turbidity to 7-11 NTU which is an 85-96% reduction. MO is readily available in many tropical countries and can be used by farmers to treat high turbid water for irrigation, however, additional improvements of water quality, e.g. by sand filtration, is suggested to meet the guideline value of ≤1 helminth egg per litre and a turbidity of ≤2 NTU as recommended by the World Health Organization and the U.S. Environmental Protection Agency for water intended for irrigation. A positive correlation was established between reduction in turbidity and helminth eggs in irrigation water, turbid water and wastewater treated with MO. This indicates that helminth eggs attach to suspended particles and/or flocs facilitated by MO in the water, and that turbidity and helminth eggs are reduced with the settling flocs. However, more experiments with water samples containing naturally occurring helminth eggs are needed to establish whether turbidity can be used as a proxy for helminth eggs.     

Environmental degradation in Nigeria: implications and policy issues—a viewpoint

Sustainable development has become a global issue which now requires moving from commitment at the conceptual level into a pragmatic operational framework. Hence, environmentally sustainable development practices and policies should be an integral part of the concern of planners and decision makers. In this regard, this paper assesses major environmental problems facing Nigeria and also discusses their socio‐economic and socio‐cultural implications for the quality of life of the people. A policy framework of strategies formulated to address these problems is hereby suggested.     

Sulfamethoxazole contamination of a deep phreatic aquifer

Groundwater samples were obtained from the water table region of a phreatic aquifer (unsaturated zone depth up to 28 m) under land irrigated with wastewater effluents for about 5 decades and a relatively deep pumping well (109 m), used as a drinking water source till 2007, located downstream (1300 m) of wastewater effluent and sludge infiltration facilities. Sulfamethoxazole (SMX) concentrations in secondary effluents varied between 90 and 150 ng/L. SMX was extracted using SPE and was analyzed by HPLC-MS/MS. SMX (maximum concentration of 37 ng/L) was detected in the water table region, in two monitoring wells, after an unsaturated zone transport period of about 16 years. The maximum SMX concentration detected in the pumping well was of 20 ng/L. These results question wastewater effluent disposal strategies including the suitability of irrigation with effluents on the replenishment area of an aquifer supplying drinking water.     

Projected water consumption in future global agriculture: scenarios and related impacts

Global stress on water and land resources is increasing as a consequence of population growth and higher caloric food demand. Many terrestrial ecosystems have already massively been degraded for providing agricultural land, and water scarcity related to irrigation has damaged water dependent ecosystems. Coping with the food and biomass demand of an increased population, while minimizing the impacts of crop production, is therefore a massive upcoming challenge. In this context, we developed four strategies to deliver the biotic output for feeding mankind in 2050. Expansion on suitable and intensification of existing areas are compared to assess associated environmental impacts, including irrigation demand, water stress under climate change, and the productivity of the occupied land. Based on the agricultural production pattern and impacts of the strategies we identified the trade-offs between land and water use. Intensification in regions currently under deficit irrigation can increase agricultural output by up to 30%. However, intensified crop production causes enormous water stress in many locations and might not be a viable solution. Furthermore, intensification alone will not be able to meet future food demand: additionally, a reduction of waste by 50% along the food supply chain or expansion of agricultural land is required for satisfying current per-capita meat and bioenergy consumption. Suitable areas for such expansion are mainly located in Africa, followed by South America. The increased land stress is of smaller concern than the water stress modeled for the intensification case. Therefore, a combination of waste reduction with expansion on suitable pastures generally results as the best option, along with some intensification on selected areas. Our results suggested that minimizing environmental impacts requires fundamental changes in agricultural systems and international cooperation, by producing crops where it is most environmentally efficient and not where it is closest to demand or cheapest.     

Agriculture: Sustainable Business – Sustainable Environment?

Irrigation is a small but important part of UK agriculture, accounting for about 150 000 ha of land and 160 000 Ml of water in a 'dry'year. By the year 2021, the irrigated area is predicted to increase by 14% and the volume applied by 50%. Irrigation is of significant economic importance to (a) farmers, (b) growers, (c) the food industry – improving crop yields, quality, consistency and reliability.
The environmental impacts of irrigation on river flows and wetland biodiversity are now receiving more attention. Irrigators are given advice on environmental impacts, voluntary agreements are secured between groups of irrigators and the Environment Agency, and on-farm reservoirs are constructed to reduce summer abstraction and provide more secure and flexible supplies. Better long-term planning and short-term management are essential.     

Decadal and seasonal scale changes of an artificial lake environment after blocking tidal flows in the Yeongsan Estuary region, Korea

Artificial lakes, initially built in estuaries for positive purposes such as flood prevention and providing irrigation water, have been found to have negative impacts including blocking tidal cycles, disappearance of brackish water zones, sediment increase, water pollution, change of microbial diversity inhabiting patterns, and a decline in fish diversity. In this study, multidisciplinary field studies including physical, chemical, and biological analyses were performed to demonstrate decadal and seasonal scale changes in the ecological environment in Yeongsan Reservoir (YSR), Korea, since the construction of a 4.35 km-long dam in 1981. The results of the study show that the volume of sediment accumulated in YSR was 75.2 million m³ since the dam was constructed, resulting in a 33.6% reduction of the total water storage capacity. Also, water quality in YSR was affected by complex physico-chemical and hydrological phenomena, including saline and thermal stratifications, and pollutant loadings leading to eutrophication. Subsequent sediment bacteria analyses showed microbial diversity according to different depths in sediment, indicating the environmental change of sediment ecology. Moreover, the fish diversity in this study (2006–2007) was found to be considerably reduced compared to a similar study in 1989 (42% reduction), and the ecological health was deemed to be in a “poor” condition based on the 10-metric Lentic Ecosystem Health Assessment (LEHA) model. Accordingly, these results indicate that aquatic ecosystems are detrimentally affected by estuarine dams that block tidal flows, and when applied to short/long-term management strategies for artificial lakes in estuaries, suggest that similar construction projects have to be suitably controlled.     

Social capital and profits of small firms in the French construction industry

The profitability of small businesses in the French construction industry depends partly on their social capital. However, social capital yields advantages as well as constraints. How and under what conditions do social networks improve a company's profit margins? From a socio‐technical perspective and strategic analysis, we defend the idea that return on social capital is conditioned by the nature of the tasks performed and by the interdependencies among firms. Comparing about 160 businesses from four various crafts, we show that loose networks profit relatively specialized businesses working independently on construction sites, while cohesive networks benefit those businesses that are most affected by socio‐technical uncertainties.     

Occurrence and suitability of sucralose as an indicator compound of wastewater loading to surface waters in urbanized regions

Urban watersheds are susceptible to numerous pollutant sources and the identification of source-specific indicators can provide a beneficial tool in the identification and control of input loads, often times needed for a water body to achieve designated beneficial uses. Differentiation of wastewater flows from other urban wet weather flows is needed in order to more adequately address such environmental concerns as water body nutrient impairment and potable source water contamination. Anthropogenic compounds previously suggested as potential wastewater indicators include caffeine, carbamazepine, N,N-diethyl-meta-toluamide (DEET), gemfibrozil, primidone, sulfamethoxazole, and TCEP. This paper compares the suitability of a variety of anthropogenic compounds to sucralose, an artificial sweetener, as wastewater indicators by examining occurrence data for 85 trace organic compounds in samples of wastewater effluents, source waters with known wastewater point source inputs, and sources without known wastewater point source inputs. The findings statistically demonstrate the superior performance of sucralose as a potential indicator of domestic wastewater input in the U.S. While several compounds were detected in all of the wastewater effluent samples, only sucralose was consistently detected in the source waters with known wastewater discharges, absent in the sources without wastewater influence, and consistently present in septic samples. All of the other compounds were prone to either false negatives or false positives in the environment.