Land Application Of Wastewater Research Articles

Aerosol production by irrigation equipment used for land application of wastewater

Aerosol production from sprays of four irrigation systems used for upland application of wastewater was studied over a range of operating and meteorological conditions by sampling particles from evaporated tracer droplets. Most aerosol-forming droplets were less than 100 mum in diameter with median number diameters from 1 to 3 mum and median mass diameters appreciably larger. More than 10(10) respirable sized particles were produced per minute by single nozzles. Actual wastewater sprays were similar. Diffusion calculations indicate decreases in concentration of 1 to 2 orders of magnitude in 1 km.

Design and Operation of Land Treatment Systems for Minimum Contamination of Ground Watera

ABSTRACTLow‐rate or irrigation‐type systems for land application of sewage effluent or similar wastewater are often used in humid areas because they have a small impact on the underlying ground water. In arid areas, low‐rate systems cannot be used to produce renovated water for ground‐water recharge, because the renovated water will have a much higher salt content than the effluent. Renovated water of relatively low salt content can only be produced with high‐rate systems. Such systems, which require permeable soil, can also be used in humid areas to reduce the land requirements. To minimize the impact of high‐rate systems on ground‐water quality, the system should be managed to remove as much of the pollutants (particularly nitrogen and phosphorus) as possible from the wastewater as it seeps through the soil, and to restrict the spread of renovated wastewater in the ground‐water basin. Nitrogen removal can be maximized by stimulating denitrification in the soil. Certain soils can store large quantities of phosphate. The spread of renovated water in the ground water can be controlled by intercepting the flow of renovated water with wells or drains for reuse or discharge into surface water. Techniques for predicting the underground flow system are presented.

Municipal Wastewater Reuse for Irrigation

Agricultural irrigation is the major use of water in the seventeen western Reclamation Act states. A small portion of the projected demand in 1980 and 2000 might be supplied through reuse of municipal waste water (respectively about 7,500,000 and 11,900,000 acre-ft per yr of the predicted withdrawals of 175,000,000 and 170,000,000 acre-ft per yr). Data on direct land application of municipal wastewater is discussed particularly for the western states and examples are cited. The estimate for 1962 is about 300,000 acre-ft per yr or not more than 5% of the available wastewater. Diseases associated with sewage irrigation are discussed, the most recent outbreak attributed to the practice in the United States having been reported as occurring in 1919. It is concluded that public health considerations pose no obstacle to crop irrigation with treated municipal wastewater but the trend seems to be toward higher-value uses such as ground-water recharge, golf course irrigation, and recreational lakes.