Treatment of Rubber Thread Manufacturing Industry Wastewater

摘要

Wastewater from the rubber thread manufacturing industry has a pH range of 3.8 to 4.4 and contains high concentrations of COD, BOD, Total-N and Zn (5900, 5000, 222 and 286 mg/L respectively.) The high BOD:COD ratio (0.78 to 0.90) indicates that the wastewater is biodegradable, but the high Zn concentration would inhibit the anaerobic digestion process. Pretreatment using a would inhibit the anaerobic digestion process. Pretreatment using a combination of sodium sulphide (precipitant) and polyelectrolyte LT 27 (flocculant) at concentrations of 800 and 5 mg/L respectively is the most effective system for Zn removal. Subsequent treatment of the wastewater using an upflow anaerobic filter reduced the BOD and COD to within the Department of environment (DOE) standard for industrial effluent discharge. The optimum organic loading rate and the HRT obtained were 8g COD/L/d and 1.5 days respectively. Increasing the organic loading rate from 2 to 14g COD/L/d decreased the specific biogas yield from 0.250 to 0.069L CH_4/g COD added.