Treatability Study and Design Adequacy of Effluent Treatment Plant (ETP) of a Rubber Industry

Abstract

The stages of the entire study can be segregated as follows; firstly, site visit was conducted to study the effluent generation sources and the existing effluent management practices within the organization. Secondly, laboratory scale setup was made for studying and finding out the key parameters required for primary and secondary treatment of trade effluent from latex and rubber plant. Thirdly, based on the design data of each treatment unit provided by client, the adequacy assessment of the existing ETP was carried out with respect to the maximum existing and consented hydraulic load. Based on the findings, conclusion and recommendations were formulated. For primary treatment of latex effluent, the optimum dosage of coagulant (Alum, PAC or Ferric chloride) comes in the range of 600-800 ppm, optimum lime dose of 400 ppm and polyelectrolyte dose of 2 ppm. For rubber effluent, the optimum coagulant (Alum and PAC) dose comes to be in the range of 300-400 ppm. Optimum lime dose is 300 ppm and for polyelectrolyte it is 1 ppm. In the design adequacy study, all the treatment units of the effluent treatment plant except dual media filter were found to be hydraulically adequate to treat the consented volume of 435 CMD including trade effluent. The existing bio-reactor of the ETP has a capacity to handle a maximum of 435 CMD of effluent as per the treatability studies considering a range of 20-22 hrs HRT and operating at MLSS of 5000-6000 mg/l. However, theoretically considering an F/M ratio in the range of 0.1-0.15, the bio-reactor can adequately handle 435 CMD of trade effluent. In future, CLIENT is recommended to consider an additional STP of 40 KLD if the trade effluent generation goes beyond 400 KLD. As per the historic data & present data, CLIENT can utilize the existing bioreactor for trade & sewage effluent due to reduced hydraulic load on the existing ETP.