Agronomic and public health assessment of reclaimed water quality for landscape irrigation

Abstract

The Mas Nou golf course has been using disinfected secondary effluent for irrigation since September 1989. Although adjusted-SAR values and EC of irrigation water have generally fallen in the non-restricted irrigation categories, EC values were initially higher than desirable for turf irrigation, due to high effluent chloride concentration. A definite solution was reached in the summer of 1993 with completion of a new surface water transfer. Since 1993, EC values in summer effluent range from 1.2 to 1.5 dS/m. A new water and storage pond management system has been proposed to optimize both water and nutrients application, using only the most adequate water source available at a given time. The relatively low iron contributions of reclaimed water have resulted in occasional spots of ferric chlorosis, which have been recovered with localized application of iron compounds. Fertilizer savings have ranged from 0.06 to 0.12 US $/m3 of reclaimed effluent. Weekly analyses of reclaimed water show that faecal coliforms and faecal streptococci concentrations lower than 100 cfu/100 mL can be consistently achieved. By mechanical mixing of top oxygen-rich waters with bottom oxygen-depleted waters in the storage ponds, odor problems have been totally eliminated. Close collaboration with the greenkeeper has resulted in a more favorable attitude to the water quality requirements of reclaimed effluent and a more effective and economical fertilization program. The greenkeeper perception has gradually evolved from a passive acceptance of the requirements of using reclaimed water to a positive recognition of its benefits.