Water Reuse Technologies Research Articles

INDUSTRIAL WATER DEMAND WITH WATER REUSE1

ABSTRACT: This work establishes an industrial water demand (IWD) model for a short term estimate, which considers water reuse technologies and discharge regulations, for the integrated circuit (IC) industry in northern Taiwan. Based on the optimization of an industrial water cost system, a computerized system dynamics model (SD model) is developed to generate individual firm IWD using data from year 2000. A market IWD is further constructed for 25 1C firms in the study area and is approximated by an inverse logistic curve. Analytical results demonstrate that price elasticity varies with water price in cases involving water reuse.

Understanding the factors that influence domestic water consumption within Melbourne

This social research project investigated the factors that influence community receptivity to using alternative water sources and technologies at the household scale. Focused through the City of Bayside, in southeast Melbourne, it involved a survey testing receptivity to a series of proposed activities using rainwater, greywater and seawater. It also tested perceived barriers to installing water reuse technologies. Increasing population and potential implications of climate change are driving the need to substantially reduce Melbourne’s potable water demand. So far, there have been few investigations into how to improve community receptivity to potable substitution to support urban water reform initiatives. The results revealed that water reuse receptivity was highest for external uses, such as watering gardens and flushing toilets, and progressively decreased with increasing personal contact, with receptivity to greywater declining more rapidly. Retrofitting of domestic rainwater tanks and greywater reuse systems was identified at around 5%. Difficulty, cost and renter status were revealed as key barriers to widespread implementation rather than poor awareness and attitudes. This evidence suggests that it is imperative that future initiatives harness this strong receptivity. Dedicated incentives, combined with active skills transfer and implementation and operational knowledge-building, should be the core elements of future programs, which need to be facilitated by a ‘help-line’ type service.

Managing Sustainable Urban Water Reuse: Structural Context and Cultures of Trust

ABSTRACT Water scarcity in urban environments is an issue of increasing concern in Australia and many other parts of the world. Technological solutions include recycling municipal effluent, which can be treated to a standard suitable for nonpotable uses such as garden watering and toilet flushing. Successful operation of such solutions requires institutional arrangements for long-term management, as well as public awareness and cooperation to establish safe practices. This article reports on research undertaken at four case study sites in Australia and the United States and identifies the social and management issues important to the success of water reuse projects. The cross-national findings demonstrate that best practice in residential water reuse technology should be coupled with institutional and structural arrangements that inform and involve the public and provide transparent governance. It is suggested that this combination of technical and social structural elements will facilitate a sustained trust in, and acceptance of, water reuse.

RATIONAL INDUSTRIAL WATER REUSE RATIOS1

ABSTRACT: This work begins by defining rational water use, and then discusses important factors that most strongly influence it. A general model is then developed to enable factories to quantify the ratio of rational industrial water reuse based on the least cost method. The model is established to minimize the cost of water with reference to gross water use and three subsystems ‐ the intake, reuse, and discharge of industrial water. Discharge cost is determined using data from a 1997 survey of 38 factories, and reuse costs are ranked and expressed by a step function. The model is verified using data from a typical semiconductor factory in northern Taiwan's Hsinchu Science Based Industrial Park, whose effective rational water reuse ratio is about 38 percent. A sensitivity analysis shows that improving water reuse technology is the most important factor in determining the rational water reuse ratio, and the price of water is the second most important. When water costs over NT$30 (New Taiwan Dollar, US$1 = NT$34) per cubic meter, increasing reuse becomes significant. The model provides a step towards the scientific management of industrial water.

Ensuring water re-use projects succeed — institutional and technical issues for treated wastewater re-use

The increasing need for water in the arid areas of the world has resulted in the emergence of new water re-use technologies. The success of water re-use projects however, does not just depend on the effectiveness and suitability of the technology, but also on the presence of an institutional framework that ensures that the treated water can be distributed and used safely and efficiently. These two diverse issues were examined by MWH in projects carried out in Egypt and in the USA. One project in the East Bank of Cairo assessed the potential benefits of treated wastewater for irrigation in agricultural schemes. The project established a lack of clarity on ownership and management of the treated wastewater and outlined the institutional development and legislation necessary for the safe and controlled re-use of treated wastewater. The project demonstrated enhanced crop yields but that additional treatment of the wastewater was required to improve its microbiological quality to the standards required by both international and Egyptian legislation for safe re-use. Another project carried out in California, USA assessed the new technology of submerged membrane bioreactors (MBRs) for water re-use. MBRs combine activated sludge treatment with a membrane separation process. The project studied two commercially available submerged MBR systems at pilot scale. The project was designed to evaluate the feasibility of using permeate from the MBRs treating municipal wastewater as a feed source for thin film composite reverse osmosis (RO) membranes. The MBRs were examined in both nitrification and denitrification mode and both MBR systems showed good removal of BOD, TOC and microorganisms. They both produced a high quality effluent that could be used by the RO membranes for water re-use.

Integrated urban drainage, status and perspectives

This paper summarises the status of urban storm drainage as an integrated professional discipline, including the management-policy interface, by which the goals of society are implemented. The paper assesses the development of the discipline since the INTERURBA conference in 1992 and includes aspects of the papers presented at the INTERURBA-II conference in 2001 and the discussions during the conference. Tools for integrated analysis have been developed, but there is less implementation than could be expected. That is due to lack of adequate knowledge about important mechanisms, coupled with a significant conservatism in the business. However, significant integrated analyses have been reported. Most of them deal with the sewer system and the treatment plant, while few incorporate the receiving water as anything but the object of the loads to be minimised by engineering measures up-stream. Important measures are local infiltration, source control, storage basins, local treatment and real time control. New paradigms have been introduced: risk of pollution due to system failure, technology for water reuse, sustainability, new architecture and greener up-stream solutions as opposed to down-stream concrete solutions. The challenge is to combine the inherited approaches with the new approaches by flexibility and adaptability.

Performance comparison of direct membrane separation and membrane bioreactor for domestic wastewater treatment and water reuse

Two pilot-scale wastewater treatment systems - direct membrane separation (DMS) and membrane bioreactor (MBR) systems - were designed and constructed in order to investigate the feasibility of membrane filtration technology for domestic wastewater treatment and water reuse. A submerged-type hollow-fiber microfiltration (HF-MF) membrane module with pore size of 0.1μm was employed to build each pilot system. The systems were tested using low- and high-strength domestic wastewaters and the system performance was continuously monitored for a long period to compare filtration characteristics and effluent quality in each system. The MBR system showed much better performance than the DMS system in terms of filtration characteristics and effluent quality. Even though the mixed-liquor suspended solid (MLSS) content in the MBR system was much higher than that in the DMS system, the MBR filtration resistance was much lower than the DMS filtration resistance. The DMS system was not able to remove dissolved organic matter, which seemed to be a major component of membrane fouling. The MBR effluent quality such as COD, BOD, TOC and T-N was more stable and better than the DMS. In the MBR process, the organic removal efficiency remained more than 95% regardless of fluctuation in influent qualities. The effluent quality of both systems was satisfying the legal standards for water reuse in Korea. Rejection of pathogenic microorganisms by membrane filtration was also investigated.

The design and operational characteristics of the CP&L/EPRI fish barn: a demonstration of recirculating aquaculture technology

The Carolina Power & Light Company, in conjunction with the Electric Power Research Institute of Palo Alto, California has developed a commercial fish production demonstration utilizing water reuse technology developed at the North Carolina State University Fish Barn. The fish production system is housed in a 39.6 m long by 9.75 m wide barn structure located on the campus of North Carolina State University in Raleigh, NC. Fish production activities began in the spring of 1998. The facility is designed to produce 45 tonnes of fish annually, with the first crop being tilapia. The project is being operated as a public demonstration of this technology, with biological, engineering and economic data being collected by research and extension personnel at North Carolina State University. This paper outlines the design of the recirculating system technology used to recycle water through the main fish production tanks.

Water recovery from and volume reduction of gray water using an energy efficient evaporator

Tests were made under a contract with VEDA Inc. of Alexandria, Virginia, for the United States Navy, Environmental Protection Branch, Annapolis, Maryland. The objectives of the tests were to demonstrate the use of vapor compression distillation to greatly reduce the storage volume of wastewater on US Navy ships during extended missions, examine the quality of the produced distilled water for reuse, and determine energy requirements for the process. Three 55 gal drums of gray wastewater, shipped from Annapolis, were used in the tests at The Water Reuse Technology (WRT) test facility, Alamo, California. The tests were made in a 3 gal/h vapor compression distillation unit using the energy efficient wiped film rotating disk (WFRD) evaporator. Data were collected to determine recovery, evaporator performance, and distilled water and blowdown qualities. The tests were run at an average temperature of 122°F in the evaporator. The results show that recoveries as high as 98.6% are possible. Measured energy consumption by the compressor and rotor (for this small unit) varied from 75 to 90 Wh/gal. Samples of the wastewater, distilled water, and blowdown were collected for analysis. The results of the analysis of the distilled water samples indicate that total suspended solids, fecal coliform, and biological oxygen demand were below the detection limits of the instruments used in the analysis. The chemical oxygen demand varied from below 10 mg/L (detection limit) to 30 mg/L.

Implementation of the Cracow municipal wastewater reclamation system for industrial water reuse

The water deficit in industrialized regions of the Republic of Poland, especially for cooling circuits and for heating purposes, led to the concept of application of water reuse from municipal wastewater in Cracow (Poland). Reasons for water reuse technology in Cracow's particular case have been presented. Cracow University of Technology together with the US Environmental Protection Agency has developed a reclamation technology for practical application. The first stage of experiments described was performed at the pilot wastewater reclamation installation operating with a capacity of 120 1/d. Experiences from the first stage were applied in construction of the water reuse demonstration plant with the capacity of 1680 m3/d, based on a multi-phase biological reactor. Operational results have been presented; they proved the applicability of the method. Due to low concentration of the organic carbon compounds in raw wastewater, various internal sources of organic carbon were tested, with the special emphasis on easy biodegradable COD load in wastewater entering the reactor.

Implementation of the Cracow municipal wastewater reclamation system for industrial water reuse

The water deficit in industrialized regions of the Republic of Poland, especially for cooling circuits and for heating purposes, led to the concept of application of water reuse from municipal wastewater in Cracow (Poland). Reasons for water reuse technology in Cracow's particular case have been presented. Cracow University of Technology together with the US Environmental Protection Agency has developed a reclamation technology for practical application. The first stage of experiments described was performed at the pilot wastewater reclamation installation operating with a capacity of 120 1/d. Experiences from the first stage were applied in construction of the water reuse demonstration plant with the capacity of 1680 m 3/d, based on a multi-phase biological reactor. Operational results have been presented; they proved the applicability of the method. Due to low concentration of the organic carbon compounds in raw wastewater, various internal sources of organic carbon were tested, with the special emphasis on easy biodegradable COD load in wastewater entering the reactor.

HIGH-pH Coagulation-Adsorption: A New Technology for Water Treatment and Reuse

A novel high-pH water treatment technology with processed dolomite as coagulant is proposed. The technology has been developed on the basis of laboratory-scale experiments with model solutions and a variety of natural water samples. Treatment effects are assessed in terms of colour, turbidity, TOC and COD removal. The technology is successful when applied to the treatment of surface water, irrespective of the influent concentration of pollutants. The effluent is clear and colourless, displaying a high removal of organic matter and heavy metals, as well as a partial inactivation of viruses and bacteria. Following a single-stage recarbonation process, water treated via this technology exerts no corrosive action. The optimum dolomite coagulant dose depends exclusively on the influent alkalinity, provided that turbidity level and colour concentration are moderately high. The optimum pH for the treatment process approaches 10.5. The technology proposed is an advantageous combination of three unit processes: decarbonation, coagulation and adsorption.

MULTIDISCIPLINARY PLANNING AND MANAGING OF WATER REUSE1

ABSTRACT: This paper examines a rapidly expanding area of water supplies, specifically water reclamation and reuse, and provides a comprehensive planning methodology for developing and evaluating water reuse alternatives. The methodology uses five phases: goal setting, identification of reuse opportunities, development and evaluation of planning alternatives, assessment of water reuse linkages, and making decisions and recommendations. A tool called “input‐output modeling” is used in the third phase to present numerical data and choices. The methodology seeks to integrate the hydrologic and socio‐economic aspects of water resources planning in the area of study.Water reuse may satisfy some of the increasing demands for water in the world, but water quality, economics, public attitudes, and legal and institutional constraints may impose limits on the extent to which it can be employed. The challenge in planning systems is to maximize the utilization of water reuse in the fact of these constraints. The importance of multidisciplinary collaboration cannot be overemphasized.This paper assesses the potential for water reclamation and reuse in developing countries by considering the relationships among the pertinent technical, social, economic, and environmental parameters. Generally, the planning process for water reuse has focused on specific technological processes, but in order to ensure the efficient transfer of waste water reuse technology into the society, the methodology seeks to provide a conceptual model which integrates the hydrologic and socioeconomic aspects of water resources planning and water reuse within the study area. (KEY WORDS: water reuse; water reclamation; planning; methodology; model; reuse technology; socio‐hydrologic systems; socioeconomic systems.)

The application of solar energy in water reuse

AbstractThe application of photocatalysed oxidation in water reuse technology is described. Results with a sequencing batch reactor showed that 4 hours contact of the raw sewage with 0·5 mg dye sorbed g−1 fly ash in sunlight, under experimental conditions, significantly reduced the organic and bacteriological load and rendered it fit for use in irrigation or for discharge. The effect of variables such as contact time or amount of dye sorbed on COD, MBAS and MPN counts were investigated and the results interpreted in terms of enhanced photoactivity and biodegradation in the sorbed state. The process appears to be well suited to commercial exploitation as it is safe, quick and economical.

Applications of water reuse technology for overwintering threadfin shad Dorosoma petenense at northern latitudes

Two indoor water reuse systems which incorporated biofiltration were used to overwinter threadfin shad Dorosoma petenense in southern Illinois (latitude 37° N) during the winters of 1980–1981 and 1981–1982. Initially, 26 964 and 11 500 threadfin shad were stocked into the two systems, respectively. Survival rates were 33% for the first overwintering period and 63% for the second. Ground Tetra-SM80, Silver Cup Salmon Starter and Silver Cup Salmon No. 1 were readily accepted by the fish. No disease problem was encountered for either overwintering period, but a nutrient deficiency was suspected among some of the 1981–1982 overwintered fish.