o ensure reclaimed water has the highest possible quality, a generally accepted criterion is to urban wastewater effluents, as first alternative, leaving industrial effluents for exceptional circumstances. According to this criterion, preference is given to wastewater effluents with the largest domestic fraction. To prevent unforeseen pollutants to reach reclamation faciliti disturbing the treatment process and deteriorating its effluent quality, it is important to establish an effective source control program that includes a municipal wastewater ordinance and a publ education program, as to prevent access to the sewer system of undesirable substances, either for the integrity of the sewer system, the treatment process or the reclamation project An essential requirement of a reclamation project is the need to ensure a high reliability of the treatment process and the overall management of the reuse system. Reclaimed water is frequently the only alternative water supply, without the eventual protection that dilution with other water sources may provide. Reuse of reclaimed water frequently implies the possibility of direct contact with persons, animals and plants, which can be affected in their health and development. In these conditions, water reclamation facilities must have a high reliability, which has to be incorporated both during their design and construction, as well as during their operation and maintenance Water reclamation is currently considered a process aimed at obtaining a quality product repurified water", " new water", or just reclaimed water. Production and marketing of this new product must be conducted in a larger framework than that traditionally adopted for water pollution control, and with a mentality different than that normally adopted in wastewater treatment, whose final effluent is normally considered a residue, either liquid or solid. This new way of approaching water reclamation has made planned reuse of reclaimed water an essential component of water resources management Reclaimed water is being used for numerous beneficial uses: urban reuse, industrial reuse agricultural and landscape irrigation, supply to recreational and landscape lakes, environmental rehabilitation and enhancement, and groundwater recharge(Pettygrove and Asano, 1984; Asano et al., 1991). The technical debate on the application and future developments of planned water reuse is currently focused on whether indirect potable reuse should be promoted, or planned water reuse should be restricted to non-potable uses. This technical debate has reached high controversial levels in the United Sates( Okun, 1999a, 1999b, Harris, 1999, DeSean, 1999), with obvious political connotations in many cases, and has indirectly cast an unnecessary shadow over a real fact: the great success reached by reuse of reclaimed water for non potable uses in numerous areas particularly in states like California and Florida, with the largest and more numerous reclamation and reuse projects in operation WATER REUSE CHALLENGES The gradual implementation of water reclamation systems based on join utilization of conventional treatment processes and others based on synthetic membrane(from microfiltration to reverse osmosis) will greatly contribute to further development of water reclamation and reuse(Mujeriego and Asano, 2000; NWRI, 1999). a key determining factor in promoting wastewater reclamation, recycling and reuse is the continued development of cost-effective treatment systems. While water supply reliability may justify the adoption of advanced treatment systems for industrial reuse, that bring the cost of reclaimed water to equal or higher levels than those of conventional water supplies, other potential beneficial uses may require the least cost reclamation alternatives before they may be considered for implementation
11 To ensure reclaimed water has the highest possible quality, a generally accepted criterion is to use urban wastewater effluents, as first alternative, leaving industrial effluents for exceptional circumstances. According to this criterion, preference is given to wastewater effluents with the largest domestic fraction. To prevent unforeseen pollutants to reach reclamation facilities, disturbing the treatment process and deteriorating its effluent quality, it is important to establish an effective source control program that includes a municipal wastewater ordinance and a public education program, as to prevent access to the sewer system of undesirable substances, either for the integrity of the sewer system, the treatment process or the reclamation project. An essential requirement of a reclamation project is the need to ensure a high reliability of the treatment process and the overall management of the reuse system. Reclaimed water is frequently the only alternative water supply, without the eventual protection that dilution with other water sources may provide. Reuse of reclaimed water frequently implies the possibility of direct contact with persons, animals and plants, which can be affected in their health and development. In these conditions, water reclamation facilities must have a high reliability, which has to be incorporated both during their design and construction, as well as during their operation and maintenance. Water reclamation is currently considered a process aimed at obtaining a quality product: “repurified water”, “new water”, or just reclaimed water. Production and marketing of this new product must be conducted in a larger framework than that traditionally adopted for water pollution control, and with a mentality different than that normally adopted in wastewater treatment, whose final effluent is normally considered a residue, either liquid or solid. This new way of approaching water reclamation has made planned reuse of reclaimed water an essential component of water resources management. Reclaimed water is being used for numerous beneficial uses: urban reuse, industrial reuse, agricultural and landscape irrigation, supply to recreational and landscape lakes, environmental rehabilitation and enhancement, and groundwater recharge (Pettygrove and Asano, 1984; Asano et al., 1991). The technical debate on the application and future developments of planned water reuse is currently focused on whether indirect potable reuse should be promoted, or planned water reuse should be restricted to non-potable uses. This technical debate has reached high controversial levels in the United Sates (Okun, 1999a, 1999b; Harris, 1999; DeSean, 1999), with obvious political connotations in many cases, and has indirectly cast an unnecessary shadow over a real fact: the great success reached by reuse of reclaimed water for non potable uses in numerous areas, particularly in states like California and Florida, with the largest and more numerous reclamation and reuse projects in operation. WATER REUSE CHALLENGES The gradual implementation of water reclamation systems based on join utilization of conventional treatment processes and others based on synthetic membrane (from microfiltration to reverse osmosis) will greatly contribute to further development of water reclamation and reuse (Mujeriego and Asano, 2000; NWRI, 1999). A key determining factor in promoting wastewater reclamation, recycling and reuse is the continued development of cost-effective treatment systems. While water supply reliability may justify the adoption of advanced treatment systems for industrial reuse, that bring the cost of reclaimed water to equal or higher levels than those of conventional water supplies, other potential beneficial uses may require the least cost reclamation alternatives before they may be considered for implementation
The impressive cost reductions and performance improvement experienced by advanced treatment process during the last two decades anticipates a most promising future for expanding their application. With a development progress driven by the cost margins of the industrial sector numerous advanced treatment processes are expected to be cost-effective for application in other potential beneficial uses of reclaimed water, such as urban use, and groundwater recharge Establishing the cost of reclaimed water is a determining factor of the feasibility and success of any water reclamation and reuse project(Asano and Mills, 1990). Defining the cost of reclaimed water is a complex process, mainly because proving reclaimed water is usually more expensive(dual distribution system) than expanding the existing drinking water distribution system, and also because reclaimed water quality is lower than drinking water quality. However, the long-term benefits of reusing reclaimed water have resulted in water reuse being promoted by many drinking water services. Recent evaluations of price rates applied to reclaimed water( Cuthbert y Hajnosz, 1999)indicate the need to adopt a larger economical and financial framework than that traditionally applied, as to include the abilities of the water reclamation system: 1)to cover its own expenses, 2 to prevent higher costs incurred by new water supply projects, 3)to provide a reasonable contribution of the total cost of the system once it reaches its design capacity SUMMARY AND CONCLUSIONS Planned water reuse is currently considered an essential component of water resources management, ularly in coastal and semi arid zones, where it may have a significant contribution in augmenting water resources, both for direct non potable reuse and for artificial recharge of groundwater. Water reclamation is considered a process for obtaining a quality product The production and marketing of this product must be conducted in a framework larger than the traditionally adopted for water pollution control, and with a new mentality in planning, design operation and maintenance of water reclamation processes, substantially different from that adopted in wastewater treatment and disposal The technical debated on the future of planned water reuse is currently focused on whether it appropriate to promote indirect potable reuse, or it is more adequate to restrict water reuse to non- potable uses. Among the technological advances that will contribute to further development of water reclamation and reuse there is the join use of conventional reclamation processes and new synthetic membrane processes, ranging from microfiltration to reverse osmosis. Water reclamation and reuse does depend not exclusively on technological factors. The existence of a solid legal and regulatory framework, and a clear political will to promote water reclamation and reuse, are critical factor for its future development The economical and financial analyses of a water reclamation and reuse project must be considered in a larger framework than that normally considered for water pollution control. Reclaimed water cost should be established considering its potential: to cover its own costs, to prevent higher costs associated to developing new drinking water sources, and to contribute to the overall cost of the project once it reaches full capacity. Demonstration projects for water reclamation and reuse clearly contribute to the development and acceptance of these technologies, offer new job openings and considerable prestige to the area, and provide a competitive edge in water management in semi arid areas
12 The impressive cost reductions and performance improvement experienced by advanced treatment process during the last two decades anticipates a most promising future for expanding their application. With a development progress driven by the cost margins of the industrial sector, numerous advanced treatment processes are expected to be cost-effective for application in other potential beneficial uses of reclaimed water, such as urban use, and groundwater recharge. Establishing the cost of reclaimed water is a determining factor of the feasibility and success of any water reclamation and reuse project (Asano and Mills, 1990). Defining the cost of reclaimed water is a complex process, mainly because proving reclaimed water is usually more expensive (dual distribution system) than expanding the existing drinking water distribution system, and also because reclaimed water quality is lower than drinking water quality. However, the long-term benefits of reusing reclaimed water have resulted in water reuse being promoted by many drinking water services. Recent evaluations of price rates applied to reclaimed water (Cuthbert y Hajnosz, 1999) indicate the need to adopt a larger economical and financial framework than that traditionally applied, as to include the abilities of the water reclamation system: 1) to cover its own expenses, 2) to prevent higher costs incurred by new water supply projects, 3) to provide a reasonable contribution of the total cost of the system once it reaches its design capacity. SUMMARY AND CONCLUSIONS Planned water reuse is currently considered an essential component of water resources management, particularly in coastal and semi arid zones, where it may have a significant contribution in augmenting water resources, both for direct non potable reuse and for artificial recharge of groundwater. Water reclamation is considered a process for obtaining a quality product. The production and marketing of this product must be conducted in a framework larger than the traditionally adopted for water pollution control, and with a new mentality in planning, design, operation and maintenance of water reclamation processes, substantially different from that adopted in wastewater treatment and disposal. The technical debated on the future of planned water reuse is currently focused on whether it is appropriate to promote indirect potable reuse, or it is more adequate to restrict water reuse to nonpotable uses. Among the technological advances that will contribute to further development of water reclamation and reuse there is the join use of conventional reclamation processes and new synthetic membrane processes, ranging from microfiltration to reverse osmosis. Water reclamation and reuse does depend not exclusively on technological factors. The existence of a solid legal and regulatory framework, and a clear political will to promote water reclamation and reuse, are critical factor for its future development. The economical and financial analyses of a water reclamation and reuse project must be considered in a larger framework than that normally considered for water pollution control. Reclaimed water cost should be established considering its potential: to cover its own costs, to prevent higher costs associated to developing new drinking water sources, and to contribute to the overall cost of the project once it reaches full capacity. Demonstration projects for water reclamation and reuse clearly contribute to the development and acceptance of these technologies, offer new job openings and considerable prestige to the area, and provide a competitive edge in water management in semi arid areas
REFERENCES Asano, T, Ogoshi, M. y Suzuki, Y.(2000). Lessons learned from the Japanese Water Reuse Experience. 3th International Symposium on Water Reclamation, Recycling and Reuse, Paris, 3 to 7 July 2000 Asano, T, Richard, D, Crites, R W. y Tchobanoglous, G(1991). Evolution of tertiary treatment requirements in California. Water Emvironment and Technology. Vol. 4, No. 2 Asano, T. y Mills,RA.(1990). Planning and Analysis for Water Reuse Projects. Journal of the American Water Works association Cuthbert, R W. y Hajnosz, A M.(1999). Setting reclaimed water rates. Journal of the American Water Works Association, Vol 91, No 8, pp 50-57 DeSena, M.(1999). Public Opposition Sidelines Indirect Potable Reuse Projects. Water Emvironment and Technology, Vol. 11, No 5, pp. 16-18 Harris, R (1999). Water Reuse Objection. Water Environment and Technology, Vol 11, No. 6, pp 8-9 Mujeriego, R. (1998). Evolution and perspectives of water reclamation in Spain. La gestio de A' Aigua Regenerada. Edited by R. Mujeriego y L Sala, Consorci de la Costa Brava, Girona Pettygrove, GS, and Asano, T(1984). Irrigation with Reclaimed Municipal Wastewater. Lewis Publishe Mujeriego, R y Asano, T (1999). The role of Advanced Treatment in Wastewater Reclamation and Reuse. Water Sciencie and Technology, Vo. 40, No 4-5, pp. 1-9 National Water Research Institute(1999). Non-Potable Water Recycling Report number NWrI-99- 02.E-mail:NWRI-1@worldnetatt.net Okun, D (1999a). Water Reuse Objection. Water Environment and Technology, Vol 11, No 6, pp Okun, D.(1999b). Potable Reuse: Public Education not the Issue. Water Environment and Technology, Vol ll, No. 7, pp 6-8 World Health Organization (1989). Public Health Guidelines for the Use of Wastewater in Agriculture and Aquaculture. Technical Report Series 778. Geneva, Switzerland United States Environmental Protection Agency and United States Agency for International Development(1992). Manual on Guidelines for Water Reuse. EPA/625/R-92/004, September 1992. Center for Environmental Research Information Cincinnati Ohio Water Pollution Control Federation(1989). Water Reuse(Second Edition). Manual of Practice SM 13. Virginia. United States
13 REFERENCES Asano, T., Ogoshi, M. y Suzuki, Y. (2000). Lessons learned from the Japanese Water Reuse Experience. 3th International Symposium on Water Reclamation, Recycling and Reuse, Paris, 3 to 7 July 2000. Asano, T., Richard, D., Crites, R.W. y Tchobanoglous, G. (1991). Evolution of tertiary treatment requirements in California. Water Environment and Technology. Vol. 4, No. 2. Asano, T. y Mills, R.A. (1990). Planning and Analysis for Water Reuse Projects. Journal of the American Water Works Association. Cuthbert, R.W. y Hajnosz, A.M. (1999). Setting reclaimed water rates. Journal of the American Water Works Association, Vol. 91, No. 8, pp. 50-57. DeSena, M. (1999). Public Opposition Sidelines Indirect Potable Reuse Projects. Water Environment and Technology, Vol. 11, No. 5, pp. 16-18. Harris, R. (1999). Water Reuse Objection. Water Environment and Technology, Vol 11, No. 6, pp. 8-9. Mujeriego, R. (1998). Evolution and perspectives of water reclamation in Spain. La Gestió de L’Aigua Regenerada. Edited by R. Mujeriego y L. Sala, Consorci de la Costa Brava, Girona. Pettygrove, G.S, and Asano, T. (1984). Irrigation with Reclaimed Municipal Wastewater. Lewis Publisher. Mujeriego, R. y Asano, T. (1999). The role of Advanced Treatment in Wastewater Reclamation and Reuse. Water Sciencie and Technology, Vo. 40, No. 4-5, pp. 1-9. National Water Research Institute (1999). Non-Potable Water Recycling. Report number NWRI-99- 02. E-mail: NWRI-1@worldnet.att.net. Okun, D. (1999a). Water Reuse Objection. Water Environment and Technology, Vol 11, No. 6, pp. 8. Okun, D. (1999b). Potable Reuse: Public Education not the Issue. Water Environment and Technology, Vol 11, No. 7, pp. 6-8. World Health Organization (1989). Public Health Guidelines for the Use of Wastewater in Agriculture and Aquaculture. Technical Report Series 778. Geneva, Switzerland. United States Environmental Protection Agency and United States Agency for International Development (1992). Manual on Guidelines for Water Reuse. EPA/625/R-92/004, September 1992. Center for Environmental Research Information, Cincinnati, Ohio. Water Pollution Control Federation (1989). Water Reuse (Second Edition). Manual of Practice SM- 13. Virginia, United States
RECYCLING OF TREATED WASTEWATER FOR AGRICULTURAL AND LANDSCAPE IRRIGATION TREATMENT OPTIONS AND CHALLENGES Gideon Oron Ben-Gurion University, Environmental Water Resources Center, The Institute for Desert Research, Kiryat Sde-Boker, Israel84990 Also at the department of Industrial Engineering and Management, Ben-Gurion University, Beer-Sheva, Israel and The Water Research Institute, Technion, Haifa, Israel. E-Mai: /<gidiabgumail bguacil The growing demand for water and increasing environmental awareness recalls for intensive efforts towards improving the treatment and disposal of the reclaimed wastewater. Water shortage problems can be solved by adequate reuse of treated domestic wastewater. The reuse of effluent primarily for irrigation has a series of advantages, which turn it into a valuable source Treated wastewater reclamation serves as solution for closing the gap between water supply and demand. The nutrients contained in the effluent replace artificial fertilizers requirements in irrigated areas, thus can increase productivity. The sludge generated during the wastewater treatment processes can as well be reused as a soil amendment. The sludge can as well be recycled as an alternative energy source by incineration processes. There are also attempts to use the sludge as a source for building material by using it for bricks construction Sludge is obtained in most treatment processes. Most of the carbon contained in the raw wastewater can be removed under anaerobic processes, generating biogas as alternative energy source. The sludge after the carbon removal has an elevated fertility value, due to the increased content of nitrogen hence, can be used as an improved fertilizer Aquaculture systems consist of combination of plants growing in the water body, living organisms (animals) and wastewater treatment principles. Aquaculture methods combine simple and low treatment techniques and natural processes taking place in nature. Links of the food chain are combined in the treatment process to yield simultaneously several by-products and thus improving the overall economic of the system. The main two by products are effluent for reuse and biomass for animal feed or energy generation. The main drawback of aquaculture systems is the high land requirements, the dependence of treatment on external uncontrolled conditions(environment)and the potential of loosing water due to evaporation. According to the conditions and constructed treatment systems, different species of plants are used Integrative research projects for optimal wastewater disposal and reuse with minimal environmental and health risks and elevated agricultural productivity are in progress. Secondary domestic wastewater can be disposed safely under conventional onsurface Drip Irrigation(DI)and advanced Subsurface Drip Irrigation(SDI)systems. Water and fertilizers accessibility supplied under SDI relatively high in comparison with di due to close location of the point water source to the main root zone. The soil under SDi performs as a complementary treatment biofilter, an extra stage in the conventional process of the domestic wastewater treatment
14 RECYCLING OF TREATED WASTEWATER FOR AGRICULTURAL AND LANDSCAPE IRRIGATION – TREATMENT OPTIONS AND CHALLENGES Gideon Oron* * Ben-Gurion University, Environmental Water Resources Center, The Institute for Desert Research, Kiryat Sde-Boker, Israel 84990. Also at the Department of Industrial Engineering and Management, Ben-Gurion University, Beer-Sheva, Israel and The Water Research Institute, Technion, Haifa, Israel. E-Mai :l <gidi@bgumail.bgu.ac.il>. The growing demand for water and increasing environmental awareness recalls for intensive efforts towards improving the treatment and disposal of the reclaimed wastewater. Water shortage problems can be solved by adequate reuse of treated domestic wastewater. The reuse of effluent, primarily for irrigation has a series of advantages, which turn it into a valuable source. Treated wastewater reclamation serves as solution for closing the gap between water supply and demand. The nutrients contained in the effluent replace artificial fertilizers requirements in irrigated areas, thus can increase productivity. The sludge generated during the wastewater treatment processes can as well be reused as a soil amendment. The sludge can as well be recycled as an alternative energy source by incineration processes. There are also attempts to use the sludge as a source for building material by using it for bricks construction. Sludge is obtained in most treatment processes. Most of the carbon contained in the raw wastewater can be removed under anaerobic processes, generating biogas as alternative energy source. The sludge after the carbon removal has an elevated fertility value, due to the increased content of nitrogen hence, can be used as an improved fertilizer. Aquaculture systems consist of combination of plants growing in the water body, living organisms (animals) and wastewater treatment principles. Aquaculture methods combine simple and low treatment techniques and natural processes taking place in nature. Links of the food chain are combined in the treatment process to yield simultaneously several by-products and thus improving the overall economic of the system. The main two by products are effluent for reuse and biomass for animal feed or energy generation. The main drawback of aquaculture systems is the high land requirements, the dependence of treatment on external uncontrolled conditions (environment) and the potential of loosing water due to evaporation. According to the conditions and constructed treatment systems, different species of plants are used. Integrative research projects for optimal wastewater disposal and reuse with minimal environmental and health risks and elevated agricultural productivity are in progress. Secondary domestic wastewater can be disposed safely under conventional onsurface Drip Irrigation (DI) and advanced Subsurface Drip Irrigation (SDI) systems. Water and fertilizers accessibility supplied under SDI is relatively high in comparison with DI due to close location of the point water source to the main root zone. The soil under SDI performs as a complementary treatment biofilter, an extra stage in the conventional process of the domestic wastewater treatment
of the plants and fruits and the applied effluent. No specific problems of emitters clogg i e pang - m u Outdoor experiments are in progress in various commercial fields with different effluent qualities treatment methods and crops. The results indicate that improved agricultural yields are obtained under SDi, probably due to several agronomic advantages such as high nutrient availability an reduced salinity effects near the water irrigation point source. In addition, the health environmental risks are diminished due to minimal contact of the disposed effluent with on-surfac agro-technology activities. This includes as well no direct contact of the above surface foliage parts encountered due to adequate filtering of the effluent at the head control To enable optimal reuse, studies towards the examination of the content of pathogens(bacteria viruses and parasites)in the effluent and the related impact on the soil, plants that human or animal consumer, are in progress. The content of nutrients and the additional constituents in the effluent might have adverse effects on agricultural productivity, both on a short and a long-range time scale The long range effects are primarily related to dissolved solids accumulation in the soil, plants and the ground water Consequently, research has to focus simultaneously on several areas related to increase the available water potential. These include improved treatment of domestic, industrial and agricultural wastes, obtaining effluent quality with minimal health and environmental risks. The advanced treatment methods should be based on combined biological, chemical and mechanical processes, including methods of membrane technology and disinfection processes with minimal by-products. The residual by product generated during disinfection might be unsafe for consumption by the human and animal. Also should be examined technical methods for improved disposal and reuse of the effluent. The later include primarily drip irrigation for agriculture
15 Outdoor experiments are in progress in various commercial fields with different effluent qualities, treatment methods and crops. The results indicate that improved agricultural yields are obtained under SDI, probably due to several agronomic advantages such as high nutrient availability and reduced salinity effects near the water irrigation point source. In addition, the health and environmental risks are diminished due to minimal contact of the disposed effluent with on-surface agro-technology activities. This includes as well no direct contact of the above surface foliage parts of the plants and fruits and the applied effluent. No specific problems of emitters clogging were encountered due to adequate filtering of the effluent at the head control. To enable optimal reuse, studies towards the examination of the content of pathogens (bacteria, viruses and parasites) in the effluent and the related impact on the soil, plants that human or animal consumer, are in progress. The content of nutrients and the additional constituents in the effluent might have adverse effects on agricultural productivity, both on a short and a long-range time scale. The long range effects are primarily related to dissolved solids accumulation in the soil, plants and the ground water Consequently, research has to focus simultaneously on several areas related to increase the available water potential. These include improved treatment of domestic, industrial and agricultural wastes, obtaining effluent quality with minimal health and environmental risks. The advanced treatment methods should be based on combined biological, chemical and mechanical processes, including methods of membrane technology and disinfection processes with minimal by-products. The residual by product generated during disinfection might be unsafe for consumption by the human and animal. Also should be examined technical methods for improved disposal and reuse of the effluent. The later include primarily drip irrigation for agriculture