Utilization of a small soda pulp and paper mill effluent for rice field irrigation

Padalarang pulp and paper mill, a soda pulp and paper mill without chemical recovery, located near Bandung, Indonesia, discharges untreated effluent mixed with domestic waste water into surrounding rice fields. For more than 60 years, paddy has been harvested 3 times a year. An in-depth study to characterize the effluent, the soil and the biomass production was conducted to define the evidence. A field study using four experimental plots indicated that soil irrigated with effluent had a higher concentration of potassium, calcium, sodium ions and greater cation exchange capacity than near-by soil. Analysis of well water showed that the effluent had no effect on the ground water. A reduction of suspended solids and BOD occurred in the effluent while flowing through rice fields. The yields of paddy demonstrated significant positive effect of effluent either in dry or in rainy season, while zeolites as soil amendment did not give significant effect to the already high paddy crop yield.