Innovative sewerage solutions for small rural towns.

The development and implementation of alternative wastewater servicing approaches in rural communities in Australia appears more feasible than in larger urban developments as many rural centres rely on septic tanks and surface discharge of greywater. This method of disposal creates many environmental, social and economic issues and is seen to limit potential for growth in many towns. This paper describes a generic methodology for the selection of innovative sewerage options for six regional towns in Victoria, Australia. The method includes consultation with stakeholders, multi-criteria assessment and concept design of the most favourable option. Despite the broad range of initial wastewater servicing options presented which included cluster-scale systems, upgrade of existing systems, greywater reuse and alternative collection, the outcome for five of the six towns was a modified centralised collection system as the preferred option. Lack of robust and reliable data on the human health risks and environmental impacts of alternative systems were identified as the primary data gaps in the sustainability assessment. In addition, biases in the assessment method due to stakeholder perceptions were found to be an additional issue.     

Climate Change Adaptation Indicators to Assess Wastewater Management and Reuse Options in the Mekong Delta, Vietnam

Climate change adaptation indicators have played a critical role in the increased understanding of potential climate change impacts. In this research, 6 climate change adaptation indicators were identified for Can Tho City in the Mekong Delta of Vietnam: (1) Rice production from wastewater during winter-spring crop; (2) % of irrigation water demand satisfied by treated wastewater; (3) % of nutrient demand satisfied by treated wastewater; (4) % remaining flow downstream of Can Tho in the Hau River; (5) environmental benefits; and (6) total investment cost for wastewater treatment. These indices were selected to assess various options/strategies for wastewater management and reuse in Can Tho City as a means to improve the City’s resilience to climate change. From an environmental perspective, this study shows the benefits for Can Tho City to set up a strategy to treat and reuse wastewater from catfish farming as the priority among four assessed scenarios with different climate change impact factors. It is concluded that adaptation can be assessed by the indicators because they can define whether adaptation policies and measures are implemented and whether vulnerability is reduced through effective actions.     

Strategic options for sustainable water management at new developments: the application of a simulation model to explore potential water savings.

Research on appropriate technologies and infrastructures to support water reuse has progressed rapidly over recent decades and there are now a wide range of source--treatment--reuse options for planners to choose from. Although the economics of water reuse schemes favours application to new developments rather than retrofit projects, there are few studies which have sought to address strategic option selection issues for large developments. The potential advantages of using treatment and reuse systems in new developments require an understanding of the relationships between a wide variety of social, environmental, technological, and operational factors. The operational effectiveness and economic efficiency of specific technology choices will vary as a function of network configuration, wastewater characteristics, how different technologies respond to dynamic loading (variability of feed strength and flow) and potential spiking, as well as equipment reliability, climate and household behaviour. Using a commercially available software package, the study reports the design and implementation of a low resolution simulation tool to explore sustainable water management options for a live case study site in the south of England (a peri-urban development of 4,500 new homes) with particular reference to opportunities for rainwater harvesting, and water reuse.     

A Framework for Wastewater Reuse in Jordan: Utilizing a Modified Wastewater Reuse Index

Pressing water scarcity in Jordan rapidly increases the demands of marginal water resources for the agricultural sector. Water management studies reveal that no single source could fully solve the nation??s water shortage and many integrated actions are needed to ensure water availability, suitability and sustainability. Yet, among these options treated wastewater has the largest potential to augment water supply in the near future, thereby narrowing the gap between available freshwater and total demand. Indeed, treated wastewater could be a valuable source for irrigation in the agricultural sector and an increasing percentage of irrigated areas, especially in the Jordan Valley, are currently using treated wastewater. With a fast growing population and expansion of the irrigated areas to meet food demand, the pressure on water resources in Jordan remains of imminent importance. Hence, an urgent call to analyze the current and potential role of treated wastewater seems justified. Under the umbrella of the project on the Sustainable Management of Available Water Resources with Innovative Technologies (SMART) funded by the German Federal Ministry for Education and Research in Germany, an investigation has been carried out in the Jordan Valley to estimate the current wastewater reuse quantities and the potential to increase its utility for agricultural production. In general, the reuse as percentage of total treatment is applied for national and international comparisons. Yet, this index is of limited use for policy decisions as it does not reflect potentialities of wastewater use. Therefore, this study introduces a wastewater reuse index (WRI) that reflects the actual proportion of wastewater reused from the total generated wastewater. We found that the WRI in Jordan steadily increased from 30% in 2004 to 38 in 2007. Efficient use of treated wastewater requires the application of new technologies in Jordan like dwellings connected to the sewer system, decentralization of treatment plants to rural and urban settlements and prevention of high evaporation rates from stabilization ponds.     

Assessment of availability and characteristics of Greywater in Amman

Abstract:

The problem of water scarcity in Jordan has resulted in enormous pressures on the already limited renewable water sources. As a result, reuse of water is becoming an essential component of the water management trends being adopted. This study aims at evaluating the potential of greywater availability and the various components constituting sources of greywater generated in Amman, at investigating the different water quality parameters of the greywater in order to assess its reuse potential, and at gauging the public acceptance of greywater reuse for different applications. A survey was designed and administered in 38 areas of Amman. The survey covered a total of 233 houses and 1,514 people. Fifteen greywater samples, distributed equally, were collected and analyzed from showers, laundries, and sinks in some of these houses to determine their water quality parameters. The study concluded that per capita water consumption in Amman ranged between 51 and 115 liters per day, with an average of 84 liters per day. The quantities of greywater generated in Amman ranged from 39 to 80 Lpcd, with an average of 59 Lpcd, which constitute 70 percent of the total water consumption. Laundry, shower, and sink effluents comprised 16, 34, and 50 percent of greywater sources, respectively. The physical, chemical, and biological analyses of the grab samples revealed that greywater contains significant levels of suspended solids, inorganic constituents, chemical and biochemical oxygen demands, total Coliforms and Fecal Coliform bacteria. The public acceptance survey revealed that 21.6 to 67.6 percent of the public accepted the reuse of greywater for vegetable growing, irrigation of fruit trees, car washing, toilet flushing, or home laundry. Additionally, 2.0 to 91.8 percent of the public opposed greywater reuse due to cost, health hazards, groundwater pollution, or environmental impacts.     

Centralised urban wastewater reuse: what is the public attitude?

Public support is crucial for successful implementation of wastewater reuse projects. This paper analyses the findings of a questionnaire-type survey (256 participants) conducted to determine the attitude of Israeli urban public towards possible urban reuse options. The paper summarises the support/objection to 13 reuse options and the correlation between support and environmental awareness and perceptions. Results show that a high proportion of the participants supported options perceived as low-contact, such as irrigation of public parks (96%), sidewalk landscaping (95%) and use in the construction industry (94%), while higher-contact reuse options found less support (e.g. commercial launderettes, 60%). No correlation was found between biographical characteristics and support (education, gender, income, age). Based on the results, public campaigns in Israel should focus on disseminating information regarding wastewater treatment technologies, discuss health related issues, highlight the positive economic impact of water reuse and generate a positive public opinion, as these factors tend to influence individuals to support reuse projects.     

Towards sustainability in water recycling.

Those like us who believe in and spread the gospel of planned wastewater reclamation and reuse usually emphasize that this is a step towards sustainability in water resource management, but this is something that is very seldom analyzed. This paper discusses, from a critical point of view, issues such as goals in water reuse and influence on water demands, ecological analysis of the cycle of the main pollutants, health aspects and treatment requirements, energy consumption and measurable environmental benefits, in order to provide a set of criteria to assess sustainability in water recycling projects and to decrease the impact of the cultural water cycle on the environment.     

Ecosystem Service Impacts of Urban Water Supply and Demand Management

Utilities face the challenge of enhancing long-term water security while minimising undesirable economic, social and environmental impacts of supply and demand management options. This paper provides an example of how the ecosystem services concept can be used to enumerate and organise broad impacts of water supply options. A case study of Adelaide, South Australia, is used to examine costs and benefits associated with different sources of water and source-water mix scenarios. Ecosystem service impacts are estimated using estimates from the literature. Seven water supply and demand management options are considered for Adelaide: 1) the River Murray, 2) Mt. Lofty Ranges catchments, 3) wastewater reuse, 4) desalination, 5) stormwater harvesting, 6) groundwater and 7) water conservation. The largest costs are associated with sourcing water from conservation measures such as water restrictions on outdoor watering estimated at $1.87/kL. Salinity damage costs associated with residential uses are estimated at up to $1.54/kL. Salinity damage costs of wastewater reuse were estimated at $1.16/kL. The largest benefit is coastal amenity services associated with stormwater harvesting and treatment estimated at $1.03/kL. Results show that there is a trade-off between financial costs and ecosystem services impacts with source-water mix scenarios with the highest ecosystem services cost having the lowest financial O&M cost and vice versa. This highlights the importance of taking ecosystem services into account when evaluating water supply options.     

Rainwater and greywater harvesting for urban food security in La Soukra,Tunisia

This paper presents the findings of an integrated household water treatment and reuse system for agriculture in La Soukra, Tunisia. The researchers found that the system has an internal rate of return of 17% and a net present value range from USD 26,000 (at a 5% discount rate) to USD 11,000 (for a 10% discount rate). Benefits included more water for irrigation, reduced costs to service providers, increased agricultural production from greenhouses and expanded agricultural options. These results suggest that investments in rainwater harvesting and greywater treatment at the farm level can increase the financial feasibility of peri-urban farms, which are often faced with pressure from urban growth. The systems can also help build household resilience to broader environmental change by lowering the exposure of farmers to burdens associated with infrequent access to water and poor-quality soil.     

Alternative Water Resources for Rural Residential Development in Western Australia

Rainwater collected from residential roofs and greywater generated from domestic uses except toilets are viewed as possible substitutes for high grade water sources which supply nonpotable indoor uses and irrigation in Australia. This paper searches for alternatives by adopting roofwater and greywater in residential envelope as per Australian water standards. A water balance model Aquacycle was applied to determine storage capacities and to evaluate the percentage reduction in water supplying, stormwater run-off and wastewater disposal, as well as volume of rainwater use and greywater reuse. This study provides the results of greywater recycling, which contributes to the greater saving of mains water supply than rainwater use, and which reduces more than half of the wastewater to receiving waters in the rural township of Cranbrook, Western Australia. The results of this study provide greywater usage (maximum reduction 32.5%) more significantly reduces scheme water supply than rainwater harvesting (maximum reduction 25.1%). Use of greywater on individual residential lots has the dramatic effect for drainage system by reduction approximately 54.1% or 88.1 m³/lot/year. The results of rainwater use analysis show explicitly that rainwater tanks are much more effective in intercepting roof runoff, with the maximum stormwater reduction 48.1% or 68.3 m³/lot/year. This research endeavours to offer a typical paradigm for an integrated water system in the rural residential sectors.     

The application of economic-engineering optimisation for water management in Ensenada, Baja California, Mexico.

Mathematical optimisation is used to integrate and economically evaluate wastewater reuse, desalination and other water management options for water supply in Ensenada, Baja California Mexico with future levels of population and water demand. The optimisation model (CALVIN) is used to explore and integrate water management alternatives such as water markets, reuse and seawater desalination, within physical capacity constraints and the region's water availability, minimising the sum of economic costs of water scarcity and operating costs within a region. The modelling approach integrates economic inputs from agricultural and urban water demand models with infrastructure and hydrological information, to identify an economically optimal water allocation between water users in Ensenada. Estimates of agricultural and urban economic water demands for year 2020 were used. The optimisation results indicate that wastewater reclamation and reuse for the city of Ensenada is the most economically promising alternative option to meet future water needs and make water imports less attractive. Seawater desalination and other options are not economically viable alone, but may have some utility if combined with other options for the Ensenada region.     

An integrated assessment of options for rural wastewater management in Austria.

This paper reports a recently finished, interdisciplinary project on rural wastewater management in Austria. The objective of the project was to study alternative wastewater management options based on separation of the wastewater into its constituent parts, and to compare them with conventional ones. Thereby, a feasibility study of both conventional and alternative options for wastewater management in six model regions was carried out. Life cycle costs and social acceptance were analysed by using a case study-based assessment approach. However, hygienic and environmental risks were evaluated on a more general level. In order to complement the findings, a survey on urine separation system users in the Solar City of Linz was conducted. Based on these assessments and empirical findings, the paper concludes that options using a full separation of all wastewater fractions should be considered with care. Options based on a separation of only grey water and black water or in the liquid/solid phase can offer ecological and financial advantages over conventional options. Further, options combining wastewater management and regional biogas plants were identified as an interesting solution. However, legal constraints restrict this option currently.     

钢铁生产废水处理与回用设计

介绍了某钢铁企业二期废水处理与回用工程的设计参数和运行情况.运行结果表明,采用MVFR-V型滤池工艺处理效果良好,出水可以达到厂区回用水水质标准和上海市《污水综合排放标准》(DB 31/199-2009)的一级标准,且具有较好的经济效益.     

Integrated Resource Planning for Water and Wastewater

Abstract

This paper describes the use of integrated resource planning for water and wastewater service provision by a major urban water utility. This methodology aims to meet the water and sewerage needs of the community at the least cost and includes an explicit analysis of the costs and benefits of measures that reduce the demand for water and the discharge of wastewater effluent. It therefore requires disaggregation of the demand for water into end-uses and a consideration of the linkages between the water supply and sewerage components of the business. This approach has significant advantages in economic, environmental, and social terms. The case study results indicate that significant investments in water efficiency programs are justified on economic grounds, particularly where augmentation of water and sewerage infrastructure is planned. Three studies undertaken as part of Sydney Water's efforts to integrate supply- and demand-side planning are described in this paper: first, a major integrated resource planning exercise designed to reduce demand for water by up to 35 percent, costing more than AU$25 million; second, a case study in a series of small towns where the benefits arise from reducing the capacity of sewage treatment plants by reducing wastewater flow; and third, in a major industrial region where water efficiency measures integrated with reuse measures reduce overall costs.     

Impacts of a participatory approach to assess sustainable sewage treatment technologies for urban fringe of Surat city in India.

This paper describes the assessment of the sustainability of a number of different sewage treatment technologies by means of a multi-criteria, participatory method for a scattered settlement of urban fringe of Surat. The special efforts have been made for the broad participation to achieve stronger democracy, better quality of the end product, and a more effective process. The mere participation of technocrats and bureaucrats certainly lead to the greater efficiency in working methods. However, the ultimate goal of sustainable developments of such technologies could not be reached in absence of democratic participation and social learning. Keeping this important aspect in view for assessment of sustainability, the detailed study was conducted in the presence of policy makers and stakeholders, academicians, technical experts, finance managers and NGO, to find out sustainability criteria and indicators for three different sewage treatment technologies: (A) Conventional Activated Sludge Process (B) Extended Aeration System, and (C) Upflow Anaerobic Sludge Blanket (UASB) Reactor followed by Aerated Lagoon and Polishing Pond. Technologies were compared according to four criteria subdivided into twenty operational indicators. Criteria and indicators were evaluated as in a weighted-scale matrix. In India, sustainability criteria used in this type of comparisons are often restricted to a limited set of environmental impacts and financial costs but in this study additional criteria were evaluated including economic, social, and technical aspects. Based on the values assigned by the panel, the Sustainability Index (SI) was calculated for each technology. According to the SI and a predefined scale, sustainability was medium for options A and B, whereas high for option C. The purpose of this study is to provide a basis for the selection of a particular technology based on a rational and democratic assessment of its contribution to sustainability in the local and global context.     

Incorporating Non-market Benefits of Reclaimed Water into Cost-Benefit Analysis: A Case Study of Irrigated Mandarin Crops in southern Spain

Maintaining a river system’s minimum water flow is a pre-condition for achieving the “good ecological status” prescribed by the European Water Framework Directive (WFD). In areas of water scarcity the reuse of treated water for agricultural irrigation is seen as a promising option to reduce the quantitative pressure on the resource. As part of assessing the viability of reclaimed water use in agriculture, and in accordance with the economic principles underpinning the WFD, a comprehensive economic analysis of this irrigation option is needed. This paper contributes to fill this knowledge gap by producing a cost-benefit analysis (CBA) of the use of reclaimed water in agriculture. The costs and benefits of reclaimed water use on an experimental mandarin farm in the south-east of Spain are compared with those of using surface water and a mixture of water sources. The novelty of this study is that non-market benefits are incorporated in the CBA. We thereby account for the increase in welfare that the environmental services of this supply option provide to society at large. These kind of “intangible” benefits are often ignored, but only the combination of market and non-market costs and benefits can produce a balanced assessment of water management options and lead to an efficient and sustainable allocation of the resource. Our results suggest that at the private and social level, when environmental benefits are included, the use of a mixture of water sources, including reclaimed water, seems the best option. However, at low mandarin prices (lower than 0.23 €/kg) the exclusive use of reclaimed water seems the most beneficial option.     

On-site greywater treatment and reuse in multi-storey buildings.

The paper presents a study of a pilot plant treating light greywater for seven flats. The pilot plant combines biological treatment (RBC) with physicochemical treatment (sand filtration and disinfection). The pilot plant produced effluent of excellent quality, meeting the urban reuse quality regulations, and was very efficient in TSS turbidity and BOD removal: 82%, 98% and 96%, respectively. COD removal was somewhat lower (70-75%) indicating that the greywater may contain slowly-biodegradable organics. The RBC (attached growth biological system) was able to retain most of the solids as a result of bioflocculation; further it was proven to have very stable and reliable performance. Faecal coliforms and heterotrophic reductions were very high (100% and 99.99%, respectively) producing effluent that also met drinking water standards. The combination of low organic matter, nutrients and microbial indicators reduces the regrowth and fouling potentials in the reuse system, thus ensuring safe reuse of the treated greywater for toilet flushing.     

Water reclamation, reuse and public health.

The number of people who have limited access to high-quality water has increased, and while this is a growing global crisis, water issues, problems and solutions are often seen as localised. Water reuse and reclamation will play a significant role in achieving sustainability and public health protection in the future. The wastewater and reuse community should be responsible for monitoring sewage impacts and improvements as demonstrated through pathogen reduction with appropriate treatment. Viruses, Cryptosporidium and Giardia can all be reduced during treatment anywhere from 99% to 99.9999%, achieving drinking water quality, if so desired. Recommendations to achieve better access to scientific information for decision making include: 1) developing a global data base for biological contaminant loading from wastewater and 2) defining the public health protection via reuse and reclamation.     

Treatment of petroleum production wastewater for reuse in secondary oil recovery.

Petroleum production wastewater is highly saline and contains large amounts of Ca, Mg, sulphides and hydrocarbons. The reuse of this wastewater in the secondary oil recovery can provide pollution prevention and water conservation benefits. Injection of water to the oil deposits is a frequently used method for secondary oil recovery. This operation is performed at high pressures and temperatures, because of which a suitable water quality is required to avoid deposit formation, scaling and clogging effects. The objective of this study was to select the best treatment system for the oil production wastewater, generated in one of the Mexican oil extraction facilities, for the implementation of this kind of reuse by injecting the treated water to sand formations with 12-15% porosity. A complete characterization of the petroleum production wastewater was done. Based on laboratory tests, three basic treatment options were suggested and evaluated in a pilot plant. The most suitable treatment was determined by injecting the different treated waters in samples of the real formations. The selected system consists in softening, followed by oxidation, decarbonation and filtration. This train allowed 99.8% hardness removal, a complete S(2-) removal, as well as 99% TSS, 78% TOC, 98% Sr, 86% Ba, 51% Si and 17% Fe removals.     

Greywater recycling systems in Germany--results, experiences and guidelines.

Although Germany is not considered a water-poor country, there exist regional differences in water supply and consumption. During the past 15 years, the greywater aspect has been dealt with in Germany with a greater interest and variable success. In addition to an increased environmental awareness, water costs also play an important role in increasing the demand for advanced greywater treatment plants nstalled in buildings. Under favourable conditions, the amortisation costs usually lie between 5 and 7 years. Systems that have been extensively tried and tested and have been shown to be most reliable are those employing an advanced biological treatment followed by an UV disinfection. Systems based on membrane technology are being developed and researched intensively in Germany for municipal wastewater treatment. However, so far they play no role in greywater recycling. Greywater systems operating under low energy and maintenance requirements without the use of chemicals are mostly favoured. In Germany, greywater recycling systems should be registered at the Health Office in order to guarantee that no cross-connections exist with the drinking water network and that pipes are labelled according to regulations. The hygienic requirements for recycled greywater, which is primarily used for toilet flushing, are oriented towards the EU-Guidelines for Bathing Waters. The use of recycled greywater for irrigation purposes is minor. As to the use of recycled water for laundry, the first promising investigation results are now available.