Ternary cycle treatment of high saline wastewater from pesticide production using a salt-tolerant microorganism

The material of this study is provided by biological aerobic treatment of high saline wastewater from pesticide production. The microorganism used for biodegradation has been identified by gene-sequencing as a strain of Bacillus sp. SCUN. The best growth condition for the salt-tolerant microorganism has been studied by varying the pH, immobilized microorganism dosage and temperature conditions. The feasibility of pretreating wastewater in ethyl chloride production containing 4% NaCl has been discussed. It was found that under the pH range of 6.0-8.0, immobilized microorganism dosage of 1.5 g/L, temperature of 30 °C, and NaCl concentration of 0-3%, the microorganism achieves the best growth for biodegradation. After domestication, the strain can grow under 4% NaCl. This salt-tolerant microorganism is effective in the pretreated high saline wastewater. With a newly developed ternary cycle treatment, the chemical oxygen demand removal approaches 58.3%. The theoretical basis and a new method for biological treatments in biodegradation of high saline wastewater in ethyl chloride production are discussed.