EUROPEAN COMMISSION
EURO-MEDITERRANEAN PARTNERSHIP
Development of Tools and Guidelines for the Promotion of the Sustainable Urban Wastewater Treatment and Reuse in the Agricultural Production in the Mediterranean Countries
(MEDAWARE)
Task 5: Technical Guidelines on Wastewater Utilisation
June 2005
Table of Contents
Table of Contents 1
List of Tables 2
List of Figures 2
1. Introduction 2
1.1 Objectives and Content of this report 2
2. The Wastewater reuse and the regulatory status 2
2.1 California-Wastewater Reuse Regulation 2
2.2 U.S.EPA Water Reuse Guidelines 2
2.3 The WHO Guidelines 2
2.4 Standards applied in various countries 2
2.4.1 Reuse standards in Cyprus 2
2.4.2 Reuse standards in France 2
2.4.3 Reuse standards in Italy 2
2.4.4 Reuse standards in Israel 2
2.4.5 Reuse standards in Jordan 2
2.4.6 Reuse standards in Lebanon 2
2.4.7 Reuse standards in Morocco 2
2.4.8 Reuse Standards in Palestine 2
2.4.9 Reuse Standards in Spain 2
2.4.10 Reuse Standards in Turkey 2
2.5 Comparison of reuse standards and standards for irrigation in various countries 2
2.6 EU environmental legislation on water quality 2
2.7 General conclusions and comparison 2
3. Pathogens and Public Health 2
3.1 Pathogenic Microoganisms 2
3.1.1 Bacteria 2
3.1.2 Viruses 2
3.1.3 Protozoan 2
3.1.4 Helminths 2
3.2 Survival of Pathogens on Food Crops 2
3.3 Survival of pathogens on non- food crops 2
3.4 Reduction of Pathogens through Wastewater Treatment 2
3.5 Removal of Parasites through Stabilization Ponds 2
3.6 Removal of Parasites by secondary and tertiary treatment 2
3.6.1 Removal of Pathogens by Primary Sedimentation 2
3.6.2 Filtration 2
3.7 Advanced Wastewater treatment 2
3.7.1 Reduction of Pathogens through Disinfection Processes 2
3.7.2 Disinfection with chlorine 2
3.7.3 Disinfection with Ozone (O3) 2
3.7.4 Disinfection with UV radiation 2
4. Groups of population at risk and epidemiological evidence of human health effects associated with wastewater irrigation 2
4.1 Groups of population at risk. 2
4.2 Human Health effects associated with wastewater irrigation 2
4.3 Effects of use of untreated wastewater 2
4.3.1 Effects on farm workers or wastewater treatment plant workers 2
4.3.2 Effects on consumers of vegetable crops 2
4.4 Effects of use of treated wastewater 2
4.4.1 Effects on farm workers or nearby populations 2
4.4.2 Effects on consumers of vegetable crops 2
4.5 Exposure to raw wastewater 2
4.6 Exposure to partially treated wastewater 2
4.7 Risks to consumers related to unrestricted irrigation 2
4.8 Effects on farm workers or wastewater treatment plant workers 2
4.9 Effects on consumers of vegetable crops 2
4.10 Evidence from microbiological studies of crops irrigated with treated wastewater 2
4.11 Studies on contamination of vegetable crops with nematode eggs 2
4.12 Human Safety and Control 2
5. Crops 2
5.1 Categorization of Crops 2
5.2 Restrictions on types of crops irrigated with wastewater 2
5.3 Crop selection considerations and criteria 2
5.3.1 Effects of salinity on crops 2
5.3.2 Toxicity hazards on crops 2
6. Irrigation Methods 2
6.1 Conventional Surface Irrigation methods 2
6.2 Modern Irrigation methods 2
6.2.1 Flood irrigation 2
6.2.2 Furrow irrigation 2
6.2.3 Basin Irrigation 2
6.2.4 Sprinkler 2
6.2.5 Drip systems 2
6.2.6 Bubbler Irrigation 2
6.2.7 Advantages and disadvantages of different methods of wastewater irrigation 2
6.3 Proplems with water quality in irrigation 2
6.3.1 Salinity 2
6.3.2 Specific Ion toxicity 2
6.3.3 Water infiltration rate. 2
6.3.4 Other problems 2
6.4 Steps to improve irrigation efficiency 2
6.5 Suitability of irrigation methods 2
6.5.1 Natural conditions 2
6.5.2 Type of crop 2
6.5.3 Type of technology 2
6.5.4 Previous experience with irrigation 2
6.5.5 Required labour inputs 2
6.6 Selection between Basin, Furrow or Flood Irrigation 2
6.6.1 Land Characteristics 2
6.6.2 Type of crop 2
6.6.3 Required depth of irrigation application 2
6.6.4 Level of Technology 2
6.6.5 Previous experience with irrigation 2
6.6.6 Required labour inputs 2
7. Storage of water (reservoirs) 2
7.1 The need for storage 2
7.2 Health impacts associated with storage reservoirs 2
7.2.1 Loss of disinfectant residual 2
7.2.2 Increase in pH 2
7.2.3 Corrosion and occurrence of hydrogen sulphide 2
7.2.4 Iron and Manganese. 2
7.3 Microbiological Problems 2
7.4 Physical problems 2
7.4.1 Sediment buildup 2
7.4.2 Contaminants 2
7.4.3 Temperature 2
7.5 Open and enclosed reservoirs 2
7.5.1 Storage reservoirs open and closed 2
7.5.2 Inlet/Outlet Designs 2
7.6 Problems with storage open reservoirs 2
7.7 Guidelines for avoiding problems in enclosed reservoirs 2
7.8 Disinfection of tanks 2
7.8.1 Reservoir maintenance and inspections 2
7.8.2 Other useful points in storage tanks 2
References 2
List of Tables
Table 2-1: Representative uses, application methods for reclaimed water and conditions in which use is allowed in California 2
Table 2-2: California water recycling criteriaa 2
Table 2-3i: EPA Recommended Limits for Constituents in Reclaimed Water for Irrigation 2
Table 2-3ii: EPA Suggested Guidelines for Water Reuse 2
Table 2-4: Guidelines for Unrestricted Urban Reuse of reclaimed water in states of the US 2
Table 2-5: Guidelines for Restricted Urban Reuse of reclaimed water in states of the US 2
Table 2-6: Guidelines for Agriculture Reuse; Food Crops of reclaimed water in states of the US 2
Table 2-7: Guidelines for Agriculture Reuse; Non-Food Crops of reclaimed water in states of the US 2
Table 2-8: Guidelines for the use of treated wastewater in agriculture a 2
Table 2-9: Guidelines for the quality of reclaimed water used for irrigation in Cyprus 2
Table 2-10: Microbiological standards for irrigation with municipal wastewater: comparison of regional guidelines with national and WHO standards 2
Table 2-11: Proposed maximum levels for dissolved and suspended elements and compounds and for different parameters in effluents for unrestricted irrigation and discharge to rivers 2
Table 2-12: Allowable Limits for wastewater reuse and criteria for reuse in irrigation 2
Table 2-13: Jordan Standard numbers 893 (JS #893) of the year 1995 for treated wastewater disposal 2
Table 2-14: Guidelines for Reuse in Irrigation 2
Table 2-15: Environmental limit values for wastewater discharged into seawater 2
Table 2-16: Environmental limit values for wastewater discharged into surface waters 2
Table 2-17: Use of wastewater criteria in Morocco 2
Table 2-18: Quality standards of water in order to be used for irrigation in Morocco 2
Table 2-19: Draft microbiological quality guidelines and criteria for irrigation in the proposed Spanish national regulation (1995) 2
Table 2-20: Turkish water quality criteria for irrigation, according to classes 2
Table 2-21: Classification of irrigation water with respect to resistance of plants to boron mineral 2
Table 2-22: Maximum allowable concentration of heavy metals and toxic elements in irrigation, water in Turkey 2
Table 2-23: The technical limitations and related basis on reuse of water in irrigation 2
Table 2-24: Suitability of treated domestic wastewater in irrigation without disinfection 2
Table 2-25: Summary of Water Recycling Guidelines and Mandatory Standards in the United States and Other Countries 2
Table 2-26: Parameters given in Directive 98/83/EC 2
Table 2-27: Quality requirements for bathing water 2
Table 2-28: Characteristics of surface water intended for the abstraction of drinking water 2
Table 2-29: General conclusions and comparison between the available reuse guidelines of WHO, recycling criteria of California, U.S.EPA and the following Directives (76/160/EEC, 75/440/EEC, 98/83/EC) 2
Table 3-1: Epidemiological characteristics of enteric pathogens in terms of their effectiveness in causing infections through wastewater irrigation 2
Table 3-2: Microbial pathogens detected in untreated wastewaters 2
Table 3-3: Microorganism Concentrations in Raw Wastewater 2
Table 3-4: Microorganisms Concentrations in Secondary Non-Disinfected Wastewater 2
Table 3-5: Survival of viral particles and bacteria in soil and groundwater 2
Table 3-6: Typical Pathogen Survival Times at 20-300C 2
Table 3-7: Levels of wastewater treatment 2
Table 3-8: Characteristics of an ideal disinfectant 2
Table 3-9: Comparison of different disinfection treatments 2
Table 3-10: Removal or destruction of bacteria by different treatment processes 2
Table 3-11: Expected removal of excreted organisms in various wastewater treatment processes. Values are expressed as log10 units 4 log10 units (i.e.equivalent to = 10-4 = 99.9 percent removal) 2
Table 4-1: Summary of health risks associated with the use of wastewater in irrigation. 2
Table 4-2: Estimated risks from the use of untreated or treated wastewater in irrigation of viral infection per person per year for various concentrations of E. colia 2
Table 5-1: Groups of cultivated plants 2
Table 5-2: Categorization of crops in relation to exposed group and health control measure. 2
Table 5-3: Water requirements, sensitive to water supply and water utilization efficiency of some selected crops 2
Table 5-4: Salt moderately tolerant agricultural crops 2
Table 5-5: Salt moderately sensitive agricultural crops 2
Table 5-6: Salt sensitive agricultural crops 2
Table 5-7: Relative tolerance of selected crops to exchangeable sodium 2
Table 5-8: Chloride tolerance of some fruit crop cultivars and rootstocks 2
Table 5-9: Relative Boron tolerance of agricultural crops1 2
Table 5-10: Threshold levels of trace elements for crop production 2
Table 6-1: Conventional irrigation methods and suitable crops 2
Table 6-2: Advantages and disadvantages of different methods of wastewater irrigation in terms of disease transmission risks, water use efficiency, and cost. 2
Table 6-3: Basic features of some selected irrigation systems 2
Table 6-4: Evaluation of common irrigation methods in relation to the use of treated wastewater 2
Table 6-5: Tolerance of selected crops to total dissolved solids in irrigation water, as determined by research in California, U.S.A 2
Table 6-6: Natural conditions and the choice of irrigation type 2
Table 6-7: Selection of an irrigation method based on the depth of the net irrigation application 2
Table 7-1: Water quality problems associated with storage water facilities 2
Table 7-2: Problems in the operation of open reservoirs used for the storage of reclaimed water 2
Table 7-3: Management strategies for open reservoirs used for the storage of reclaimed water 2
Table 7-4: Management strategies for enclosed reservoirs used for the storage of reclaimed water 2
Table 7- 5: Problems in the operation of enclosed reservoirs used for the storage of reclaimed water 2
List of Figures
Figure 1-1: / The role of engineered treatment, reclamation, and reuse facilities in the cycling of water through the hydrologic cycle / 11Figure 2-1: / EU Water Quality Standards / 57
Figure 3-1: / Bacterium / 66
Figure 3-2: / Procaryotic cell / 67
Figure 3-3: / Virus / 67
Figure 3-4: / Protozoan / 69
Figure 3-5: / Helminths (Roundworm) / 69
Figure 5-1: / Treatments for agriculture wastewater use / 111
Figure 6-1: / Flood irrigation / 123
Figure 6-2: / Furrow irrigation / 124
Figure 6-3: / Basin irrigation / 126
Figure 6-4: / Sprinkler irrigation / 128
Figure 6-5: / Center Pivot / 129
Figure 6-6: / Travelling Gun / 130
Figure 6-7: / Drip irrigation / 131
Figure 6-8: / Bubbler irrigation / 132
1. Introduction
Agricultural use of water resources nowadays is of great importance due to the high volumes that are necessary. Irrigated agriculture will play a significant role in the sustainability of crop production in years to come. However, in the future, further reduction in the extent of exploitable water resources, together with competing claims for water for municipal and industrial use, will significantly reduce the availability of water for agriculture.
The term wastewater reuse is often used synonymously with the terms wastewater recycling and wastewater reclamation. But they are three different terms:
Wastewaterreclamation / Involves the treatment or processing of wastewater to make it reusable (Asano, 1998).
Wastewater
reuse / Or water reuse is the beneficial use of treated water (Asano, 1998)
Wastewater
recycling / Or water recycling is the use of wastewater that is captured and redirect back into the same water use scheme (Metcalf and Eddy, 2003)
The U.S. Environmental Protection Agency (EPA) defines wastewater reuse as, «using wastewater or reclaimed water from one application for another application» (EPA, 2004). The deliberate use of reclaimed water or wastewater must be in compliance with applicable rules for a beneficial purpose (landscape irrigation, agricultural irrigation, aesthetic uses, ground water recharge, industrial uses, and fire protection). A common type of recycled water is water that has been reclaimed from municipal wastewater (sewage). The most common reasons for establishing a wastewater reuse program is to utilize new water resources to satisfy the increasing water demands and to attain this target with the lowest cost possible.
During the last two decades the use of wastewater for irrigation of crops has been substantially increased (Mara and Cairncross, 1989) due to:
- The increasing scarcity of alternative water resources for irrigation.
- The high costs of fertilisers.
- The assurances that health risks and soil damage are minimal, if the necessary precautions are taken.
- The high costs of advanced wastewater treatment plants needed for discharging effluents to water bodies.
- The socio-cultural acceptance of the practice.
- The recognition by water resource planners of the value of the practice.
In Figure 1-1 a general representation of the water usage in nowadays is shown. This important figure presents the cycling of water from surface and groundwater resources to water treatment facilities, irrigation, municipal, and industrial applications, and to water reclamation and reuse facilities. The major pathways of water reuse include irrigation, industrial use, surface water replenishment, and groundwater recharge.
Figure 1-1: The role of engineered treatment, reclamation, and reuse facilities in the cycling of water through the hydrologic cycle (Asano and Levine, 1996).
Surface water replenishment and ground water recharge also occur through natural drainage and through infiltration of irrigation and stormwater runoff. The potencial use of reclaimed water for a potable water source is also shown. The quantity of water that is transferred depends on the watershed characteristics, climatic and geohydrologic factors, the degree of water utilization for various purposes, and the degree of direct or indirect water reuse. The water used or reused for agricultural and landscape irrigation includes agricultural, residential, commercial, and municipal applications.