Wastewater Reuse Applications

Transcription

1 Wastewater Reuse Applications Prof.Dr. Göksel N. Demirer Department of Environmental Engineering Middle East Technical University Ankara, Turkey Turkish German Workshop on Sustainable Water and Wastewater Management 25 October 2010, Konya, Turkey

2 Motivation Conventional water supplies will not be able to satisfy the near future water demand Wastewater reuse practices do not only present a remedy to this problem but also a must for sustainability issues.

3 What is the Wastewater Reuse? To reclaim effluent from wastewater treatment plants and to reuse for beneficial uses. Potential areas of wastewater reuse: Irrigation (landscape) Agriculture (edible crops) Boiler feed water Cooling water make-up Process water Benefits of wastewater reuse: To mitigate water shortage problems To beneficially utilize nutrients in wastewater for crop production To reduce potential pollutant loadings To utilize wastewater as alternative water resources and reduce new water resources development To stimulate water industries by expanding wastewater reclamation projects Drawbacks of wastewater reuse: Health hazard risks and Food Safety Concerns High initial and operational costs

4 Wastewater Reuse Technologies and Constraints Almost any technology can be applied for water and wastewater reuse. Typical examples are: Precipitation & Sedimentation Biological Treatment Filtration Membrane Filtration Ion Exchange Reverse Osmosis Disinfection Goal Metals, Silica and Hardness Removal Disinfection Dissolved solids removal Dissolved organics and nutrients removal Technologies Solids contact clarifiers, hot and warm lime softeners, ion exchange softeners, and cross flow microfiltration Chlorination and UV disinfection systems Reverse osmosis, ion exchange and evaporators Biological processes + settling In order to determine which wastewater reuse technologies can be used, the relevant constraints must be considered: Environmental constraints Mechanical constraints (Corrosion, Scaling, Biological Growth) Cost constraints (Chemical and Capital costs)

5 Situation in Turkey Surface and Ground Water Supply The total, technically and economically usable surface and ground water potential of Turkey is around 110 billion m 3, with 95 billion m 3 (86%) coming from rivers located within Turkish borders, 3 billion m 3 (3%) from external rivers originating outside the country borders and 12 billion m 3 Dilek F., Imamoglu I., Surucu G. and (11%) from groundwater resources. Gokcay C.F., A Sustainable Waste Water Management Project: MEDAWARE, Conference on Environment: Survival and Water demand Sustainability, February 2007, Near East University, Nicosia-Northern Cyprus Turkey can be classified as a country facing potential water stress. The available amount of water per capita is 1735 m3, the overall potential around 3690 m3 per capita. The estimated sectoral distribution of annual water requirements realized for 2008 and estimated for 2023 are given below: Irrigation 34 billion m3 (74 %) 72 billion m3 (64 %) Drinking Water 7 billion m3 (15 %) 18 billion m3 (16 %) Industrial Use 5 billion m3 (11 %) 22 billion m3 (20 %) TOTAL 46 billion m3 112 billion m3

6 Situation in Turkey Waste Water Statistics and Waste Water Treatment in Turkey The total number of settlements with urban wastewater treatment plants (UWWTPs) serving for populations in excess of capita in Turkey is 138. Most of these treatment plants (70 %) employ secondary or biological treatment while only 7% employs advanced treatment or nutrient removal. The UWWTPs employing only physical treatment is about 1/4th of the total. In most cases, the effluents of these plants end up with sea discharges. According to the 2001 Turkish State Institute of Statistics (SIS) figures, 35% of the total population is being served by urban wastewater treatment plants in Turkey This figure is increasing year by year as it was mere 20% in Advanced, 10, 7% Physical, 32, 23% Fatta, D., Arslan-Alaton, I., Gokcay, C., Rusan, M. M., Assobhei, O., Mountadar, M., and Papadapoulos, A. (2005), Wastewater Reuse: Problems and Challenges in Cyprus, Turkey, Jordan and Morocco, European Water, 11/12, Biological, 96, 70%

7 Situation in Turkey Provinces of Turkey and distribution of the country s UWWTPs

8 Situation in Turkey Wastewater Reuse The reuse of treated wastewaters in agriculture is poorly practiced in Turkey. The wastewater reuse is accomplished through direct and indirect irrigation. Direct is to mean the reuse of effluents directly in agriculture for irrigation, whereas indirect indicates reuse through a receiving body. Eskisehir WWTP (24,820,000 m3/year) and Gaziantep WWTP (73,000,000 m3/year) effluents are directly being used in irrigation of farm land of 50,000 and 80,000 hectares, respectively. In the two reuse practices effluents do not conform with the recognized reuse standards. As a result the highest gastrointestinal disease rate is observed in Gaziantep province of Turkey as shown in below figure. Incident risk distribution related to waterborne diseases for Turkey

9 Wastewater Reuse Standards The Technical Aspects Bulletin (Official Gazette dated , no ), linked to the Turkish Water Pollution Control Regulation has been issued in 1991 to stipulate irrigation water standards for reuse of waters in agriculture. Summary of some of the most crucial parameters for reuse in Technical Aspects Bulletin Quality Criteria Chloride (Cl-), meq/l mg/l Sulphate (SO4-), meq/l mg/l Irrigation Water Class I. Class (very good) II. Class (good) III. Class (usable) IV. Class (usable with caution) V. Class (detrimental, unusable) > 20 > 710 > 20 > 960 Total salt concentration (mg/l) > 2100 Boron concentration (mg/l) > 2 NO3- or NH4+, mg/l > 50 Fecal Coliforms** (per 100ml) > 1000 BOD5 (mg/l) > 200 Suspended Solid Matter (mg/l) > 100 ph < 6 or >9 Temperature > 40

10 In Aegean and Mediterranean Regions, where touristic facilities are concentrated, treatment plant effluents are started to be used for irrigation. In residential areas, these effluents are used for garden and park irrigation, and also in some places, wastewater collected in the stabilization tanks is used for agricultural purposes. Also in some cases, treatment requirement for discharging to the receiving environment can be higher than those for irrigation. For instance, in Istanbul, although discharging the effluents to the Marmara Sea requires tertiary treatment (N and P removal), secondary treatment (biological treatment) will be enough in case of irrigation. Industrial wastewater reuse is applied as wastewater recovery. Recovered wastewater is used in the process. Especially, in industrial plants near Istanbul, due to the high water costs, wastewater recovery is also economically charming. Şahin R., Legal Issues Pertaining Wastewater Treatment and Reuse in Turkey, Innovative Processes and Practices forwastewater Treatment and Reuse in the Mediterranean Region October 2007, Ankara, Turkey.

11 Wastewater Reuse Related Work in Turkey Selected Examples Reuse of Treated Wastewaters in Central, Eastern, SouthEastern, Western Blacksea and Mediterranean Regions in Turkey Name of Treatment Plant Discharge (m3/year) Receiving Body Irrigation Status/Type Kozan Municipality WWTP Kozan Stream Indirect / Field Yumurtalik Municipality Packet WWTP (Winter) (Summer) Ayas Creek Indirect Aksaray Municipality WWTP Karasu Creek Indirect ASKI Ankara WWTP Ankara Stream Indirect / Field ESKI WWTP Porsuk Stream Indirect / Field GASKI WWTP S. Creek Indirect / Field Igdir Municipality WWTP Aras River Direct Kayseri WWTP Karasu Creek Indirect / Field and Feed Plant Ilgin Municipality WWTP Bulasan Stream Indirect / Field Kadinhani Municipality WWTP Drainage Canal Direct / Field Urgup Municipality Biological WWTP Damsa Stream Indirect Bor Municipality WWTP Emen Plain Direct / Field Celal F. Gokcay, "Water Information Systems of Turkey & EMWIS", Seminar on 15 December 2005, DSI Conference Hall, Ankara

12 Wastewater Reuse Related Work in Turkey Selected Examples Arslan-Alaton I. Et al, Reuse potential of urban watewater treatment plant effluents in Turkey: a case study on selected plants, Desalination, 215,

13 Wastewater Reuse Related Work in Turkey Selected Examples AGRICULTURAL REUSE OF WATER AND NUTRIENTS FROM WASTEWATER TREATMENT IN TURKEY Intensified Cooperation (IntenC): Promotion of German-Turkish Higher Education Research PARTNERS Middle East Technical University, Turkey Technical University of Braunschweig, Germany

14 Wastewater Reuse Related Work in Turkey Selected Examples United Nations (UN) Joint Programme MDG-F 1680: ENHANCING THE CAPACITY OF TURKEY TO ADAPT TO CLIMATE CHANGE Project Team UNIDO Eco-efficiency Programme Executing Agencies: Technology Development Foundation of Turkey (TTGV) United Nations Industrial Development Organization (UNIDO) Project Coordinator: Şenol Ataman (UNIDO) Project Consultant: Prof. Dr. Göksel N. Demirer (METU)

15 CONCLUDING REMARKS The current realized wastewater reuse practices are mainly for research purposes and represent a very limited part of the existing significant potential in Turkey. The WWTP effluent reuse potential has to be explored not only for agricultural reuse but also for industrial facilities as boiler feed, cooling and process water. The data required for wastewater reuse applications are rather limited and highly scattered among different institutions. A reliable database must be developed. Wastewater reuse standards should be investigated regarding its technological attainability through pilot and/or full scale demonstration projects.

16 Unlike the urban areas, a limited fraction of the population is connected to treatment plants in Turkey. This fact calls for decentralized and small-scale treatment plants with reuse facilities. Highly engineered systems are not economically efficient for all cases. Technology selection for wastewater reuse applications must consider local conditions. Institutional and social aspects of wastewater reuse projects are as important as their economical and technical aspects. All stakeholders must appreciate the positive impacts of this practice through dissemination activities. Focus on water demand management and water use efficiency opportunities must be exploited parallel to wastewater reuse opportunities.

17 Thank you Prof.Dr. Göksel N. Demirer Department of Environmental Engineering Middle East Technical University Tel: e.mail: