Recycling of poor quality urban wastewater by drip irrigation systems

Drip irrigation, combined with wastewater reuse, may offer the most effective and efficient way to cope with water shortage for crops and protect the environment receiving wastewater. Emitter and filter clogging are the main problems in the operation of drip systems in developing countries and small communities where treated wastewater is of poor quality. The main results of experimental trials on the behaviour of several kinds of filter and drip emitters using poor quality municipal wastewater are: the performance of the emitters and filters depends on the quality of the wastewater; Total Suspended Solids (TSS) influence the percentage of totally clogged emitters, the mean discharge emitted, the emission uniformity, and the operating time of the filter between cleaning operations; vortex emitters were more sensitive to clogging than labyrinth emitters; no significant difference was observed between the same kind of emitter placed on soil or sub-soil; gravel media and disk filters assured better performance than screen filters. The use of wastewater with a TSS greater than 50 mg l−1, did not permit optimal emission uniformity to be achieved.