Removal of trichloroethylene (TCE) in up flow anaerobic sludge blanket reactors (UASB)

Abstract

Low concentrations of chlorinated aliphatic compounds may be found in wastewater and contaminated soils from different industrial sources and in the air arising from these sources. Low levels of Volatile Organic Compounds (VOC)’s can be removed by adsorption, incineration and biofi ltration methods. These methods have some disadvantages, such as low removal effi ciency or high operation costs. Chlorine has been removed from the chlorinated aliphatic compounds by anaerobic conditions. The aim of this research was the investigation of biological treatment of VOC’s in high fl ow speed reactors. The resistance capacity of micro-organisms was investigated in an upfl ow anaerobic sludge blanket reactor (UASB) with automated control system, by feeding with co-substrate additions, by loading different ratios of organic matter, varying hydraulic retention time (HRT), maintaining stable concentrations of COD and Volatile Fatty Acids (VFA), pH, alkalinity, temperature (35oC) etc. during the anaerobic treatment. Glucose, sodium sulphate, calcium chloride, ammonium bicarbonate, potassium phosphate and methanol were used as the co-substrates. In these studies the removal rates of TCE were approximately 86.4-90.0 %. The decomposition ratios were calculated for TCE as 0,231 mg g-1VSS d-1. The highest methane ratio in the obtained biogas was 67.8 % for TCE. Also, inhibition concentrations (IC) in 24 hours were determined as IC50; 31.1 and IC25; 9.9.