Wastewater Use in Agriculture
Die Weltbevölkerung wächst immer weiter, und der Wasserverbrauch hält Schritt. Entsprechend groß ist der Informationsbedarf, wenn es um die Wiederverwendu
1. GENERAL ASPECTS.
1.1. Sources, composition and treatment systems and methods of sewage effluent.
Presentation of a detailed overview of the various sources of sewage water and their characteristics. A discussion of the different methods for treating the raw sewage (from simple oxidation ponds to the most recent technologies of activated sludge and sophisticated filtration), levels of treatment (i.e., primary, secondary, tertiary and advanced), and the considerations for selection of the required treatment.
1.2. Irrigation with treated sewage water Health considerations.
Sources for health risks associated with irrigation with TSW in relation to the level of sewage treatment and the presence of various risk parameters in the treated sewage. Means to minimize direct (via contact) and indirect (via crops and animals) risks to humans associated with the use of TSW. Health guidelines for safe use of TSW will be presented.
1.3. Regulations for irrigation with of treated sewage water.
Reviewof the quality parameters of TSW that may significantly affect health and agricultural activity and products. Overview of regulations imposed worldwide on the use of TSW for irrigation of cultivated lands.
1.4. Economic aspects of irrigation with treated sewage water.
Cost benefit analyses of treating sewage water to different levels of purity. Pricing of TSW. Selection of suitable crops for use with TSW based on economical considerations. Cost benefit analysis of using TSW in agriculture from both country and farm scale perspective.
2. IRRIGATION WITH TREATED SEWAGE WATER IMPACT ON SOIL ENVIRONMENT AND CROP.
2.1. Major Minerals.
Effects of irrigation with TSW on the availability of the major and trace elements in the soil. The concentrations and forms of the major and minor nutrients in treated sewage effluent will be presented in relation to the sewage source and the method and rate of purification. Reactions and transformations of nutrients in the soil and their availability to plants in TSW irrigated crops. Specific consideration for each nutrient in relation to the use of TSW will be discussed.
2.1.3. Potassium and Sodium.
2.1.4. Calcium, Magnesium, Carbonate and Sulfur.
2.2. Boron and chloride effects.
The presence of toxic ions in TSW and the range of their concentrations in relation to crops sensitivity will be presented. Interactions of the toxic ions originating from the TSW with soil constituents.
2.3. Heavy metals.
Overview of the frequency and reactions of heavy metals in soils and in TSW. Advers effects of.
heavy metals on plants, animals and food chain. Interactions of heavy metals with soil organic matter. Dissolution/precipitation processes and mobility of heavy metals in TSW irrigated soil.
Data on the salinity of TSW as affected by sewage source and treatment. Effects of irrigation with TSW of various sources and methods of treatment on the salinity in the field. The relation between crop yield and salinity will be discussed and the effects of the salinity of the TSW on crop yields will be evaluated.
2.5. Physical aspects.
Introductory comments on the importance of maintaining adequate physical properties in cultivated soils. Comparison of the components of TSW that may adversely affect soil physical properties with those of fresh water, and possible mechanisms. A detailed examination of the impact of irrigation with TSW on aggregate stability, soil hydraulic conductivity, and soil susceptibility to seal formation and erosion.
Technical and agronomical considerations involved with irrigation with TSW. Regional management of the irrigating water in relation to seasonal changes in the crops demands will be presented. Considerations pertinent to the selection of irrigation equipment for applying TSW and the management of the irrigation equipment on field scale.
2.7. Microbiological activity.
Changes in structure and functions of soil microbial community following the use of TSW for irrigation. Impact of these changes on soil productivity and on the soil environment.
2.8. Pesticides and other organic microcontaminants.
Soil and TSW carried organic micropollutants substances and process. Soil as a biological, chemical or mechanical filter for organic micropollutants. Impacts of TSW components (e.g., soluble humic substances or detergents) on the transport of pesticides and other organic micropoluttents.
2.9. Organic matter.
Origin, nature, characteristics and properties of organic matter (OM) in TSW. Impact of OM in TSW on the behavior of soil OM. Interactions of OM in soils irrigated with TSW with other soil constituents. Contribution of OM to mobility of contaminants in the soil.
2.10. Transport processes.
2.10.1 Transport of contaminants.
Water movement processes in soil. Processes involved in transport of dissolved contaminants.
Dispersion and distribution of contaminants in heterogeneous soil material. Effects of.
contaminants on soil water transmission rates. Modeling of contaminants flow phenomena.
2.10.2 Transport of micro organisms.
2.11. Management and suitability of different crop types.
The specific health, fertilization, irrigation, salinity, ion toxicity considerations for different crop types will be covered in this section. This section will include the following subsections: Field crops, Pastures, Orchards, Ornamentals and Forests.