Control of Emitter Clogging in Drip IrrigationSystem Induced by Biological Agents

摘要

The main problem/limitation concerning the performance of drip irrigation system (DIS)utilizing wastewater effluent is clogging of the drippers. The field study, involving a drip irrigationexperimental system was conducted in Tohaku irrigation project to identify/assess the emitterclogging factors, its affect on uniformity parameters, define of the best emitter structure andchemical management to prevention of emitter clogging. An experimental DIS included 2 similarsubunits for without (S1) and with chlorine injection (S2) into the irrigation water was connectedto the main line of irrigation network. The assessment also included different orifice area (OA),with or without pressure compensation (PC) system, and with or without in-built filtration area(FA) in emitters using the stepwise regression procedure. The emitters discharge variationsalong a lateral were evaluated using three statistical methods, the mean discharge ratiovariation (Dra), the coefficient of field performance variation (Vf) and the uniformity coefficient(Uc). The results of water quality under use indicated that BCA was the main cause ofreductions in emitters discharge in DIS for the Tohaku irrigation project. The reduction in BCAinduced emitter discharge depended on chlorine injection and emitter design characteristics.The chlorine reduced the emitter discharge variation induced by clogging particularly when thepH of irrigation water was < 7.0. The impact of BCA-induced changes on emitter discharge on alateral defined by Dra, indicated that the variations were high in S1 than S2 particularly inemitters with relatively small OA. Chlorine injection increased Uc in S2 than S1 for all emitters.The impact of BCA and manufacturing variations -induced changes on discharge variationsacross emitters on a lateral, as defined by the coefficient of field performance index Vf, indicatedthe variations were low to medium, particularly on the pressure compensated emitters. Theresults of this research are useful in design and management of DIS in Tohaku irrigation projector other irrigation projects with same water resource specification.