MICROIRRIGATION OF WASTEWATER EFFLUENT USING DRIP TAPE

Abstract

Four different types of manufactured drip tapes were evaluated for use with secondary effluent from an activatedsludge wastewater treatment plant. Additional treatment within the irrigation system included sand media filtration,continuous chlorination to a free chlorine residual concentration of 0.4 mg/L emitting from the drip tapes, and screen filtrationto 100
m. Drip tapes used in this study had design discharge rates between 0.9 and 1.4 L/h/emitter at 60 kPa, emitter spacingsof 0.2 m, and wall thicknesses of 0.200.22 mm. During the first twomonth phase of continuous operation, none of the driptapes suffered flow reductions of more than 5%. One of the drip tapes, however, increased its flow by 30%, which wasattributed to a fault in its design. During the sixmonth second phase, one of the better performing drip tapes was used foradditional assessment. The statistical uniformity of emitter discharge for this latter drip tape ranged between 92.7 and 98.0%(mean value of 94.8%) during the second phase. This study indicates that drip tape technology has significantly improvedin recent years. Despite its low operating pressure and emission rate, relative to other microemitters, drip tape appears tobe a suitable product for use with activated sludge secondary effluent.