Sequencing batch reactor for treatment of chemical laboratory wastewater

The wastewater from academical chemical laboratories is generally composed of organic matter and a wide range of chemicals and heavy metals, being one of the most difficult wastewaters for treating. The treatment consisted of hydroxide precipitation and of a biological treatment using a sequencing batch reactor (SBR). Each cycle of the SBR system was operated for 24h with FILL/REACT, SETTLE and DRAW/IDLE periods in the ratio of 20:3.5:0.5. The reactor was fed with a mixture of domestic and laboratory wastewaters to minimize the inhibitory effect of laboratory wastewater on the microorganisms bioactivity. Kinetic studies conducted for the FILL/REACT and SETTLE periods showed that the effluent has difficult biodegradability, reaching a COD reduction of 11%.