CLOGGING INCIDENCE OF DRIP IRRIGATION EMITTERS DISTRIBUTING EFFLUENTS OF DIFFERING LEVELS OF TREATMENT

Four types of drip irrigation emitters from three manufacturers were used to distribute effluents of different qualities. The control emitters were embedded in commercial grade landscape dripline, which was not designed for use with treated wastewater. The experimental emitters included one non-pressure compensating, turbulent flow emitter and two pressure compensating diaphragm regulated emitters. The experimental emitters were specifically designed for use with treated wastewater and contained antimicrobial agents to prevent emitter clogging. The emitters distributed tap water, primary septic tank effluent and secondary sand bioreactor effluent. All three effluents were run through a 100-micron filter. Each effluent was distributed through each emitter type for ten minutes every six hours, seven days a week for twelve months. Emitter flow rates were measured each month to evaluate system performance and identify clogged emitters. The control emitters exhibited the greatest reduction in flow rates with an average reduction of 16 % for septic tank effluent and 3 % for sand bioreactor effluent. With experimental emitters, the average flow rates were reduced by as much as 11 % for septic tank effluent and 2 % for sand bioreactor effluent. By the end of the experiment, many of the clogged emitters had recovered t