Management of paddy soaking water: as a source for enriched compost making

Abstract

The effluents discharged from rice mills do not contain toxic compounds, but continuous discharge in to soil or surrounding water bodies cause adverse environmental effects. Hence, the aim of the research was selected as management of paddy soaking water with its composition of nutrients as source for preparation of enriched compost and also is useful for the control of wastewater pollution and make safe the environment with effective usage. The characteristics of the effluent generated from cold soaking were acidic pH of 4.0 with concentration of nitrogen as 98 mg/l, phosphorous (91mg/l), potassium (98 mg/l), and reducing sugar (76 mg/l) and high concentration of COD (2760 mg/l), total dissolved solid (2800 mg/l) and electrical conductivity of 6mS/cm. Wastewater from the paddy soaking was then used as a potential source to an anaerobic composting. The digester with organic solid waste of 5 kg was mixed with 30 lit of rice mill effluent and other with 30 lit of water as control. The experiment was conducted in complete randomize design with three replicates. The use of rice mill wastewater significantly increased the available nitrogen, phosphorous and potassium after completion of 42nd days. Chemical analysis of digestate revealed that nutrition profile for anaerobic compost making of paddy soak water with waste was better than that of water. The C/N ratio decreases with days of composting but the reduction rate was high in paddy soak water than the water treated. Therefore, the rice mill wastewater is useful for compost making in anaerobic condition with the production of enriched compost.