Process details and effluent characteristics of a rice mill in the Sambalpur district of Orissa
A work was undertaken to study the process details and effluent characteristics of a rice mill in the district of Sambalpur, Orissa. The milling capacity of rice mill was 10 MT/day. The rice mill generates effluent in an average 100 kl/day from the paddy soaking, parboiling and boiler blow down operations. The physico-chemical characteristics of the effluent revealed an alkaline pH (8.0), with low concentration of DO (0.9 mg/L), nitrate (0.5 mg/L), phosphate (21 mg/L) and sulphate (40 mg/L); and moderate concentration of COD (630 mg/L), chloride (140 mg/L) and TDS (670 mg/L). The total suspended solids (530mg/L) and BOD (450 mg/L) were much higher than the recommended standard set by ISI (1974) for the discharge of industrial effluent into inland surface waters as well as on land for irrigation indicating the presence of high amount of organic matter in the effluent. Moreover the effluent was rich in sodium (235 mg/L), total phenols (35 mg/L) as well as silica (58 mg/L). The treatment of the rice mill effluent is highly essential to render the effluent suitable for discharge into surface water or on land for irrigation.
Abanti Pradhan and Sanjat K. Sahu