Biochemical Collaborative Remediation And Optimization Of Polluted Sediment

With the process of urbanization, great quantities of wastewater were discharged into urban rivers, so the rivers were seriously polluted. Contaminants were accumulated gradually in the sediment, and released again through certain exchange action, threatening water quality overlying. Therefore, sediment pollution remediation became the most difficult issue in environment protection field. In recent years, microbial technology was becoming the focus in the field of sediment remediation, due to its less cost and little ecological damage. However, single microbial technology had its limitations, such as slow efficiency and being influenced by environment greatly, and so on, and chemical technology could make up these deficiencies exactly, so biochemical collaborative remediation research of polluted sediment was carried out in this project.The reseach was carried out in reactors which simulated rivers, mainly to study biochemical collaborative remediation effect and the contribution of chemicals and microbial. It showed that, system oxidation environment was improved by chemicals, and microbial degradation was greatly promoted. Especially, Ca(NO3)2 was superior than CaO2 in pollutants control and degradation, and aerobic denitrifying bacteria (ADB) together with yeast was playing a better role. It also showed that, by the action of ADB, NO3- could be utilized as electronic receptors in aerobic environment, so transformation of ammonium nitrogen to nitrate nitrogen was promoted, accelerating water purification process.For another, orthogonal experiment was designed to optimize conditions of sediment remediation, providing scientific proof for practical application. It was showed that, chemicals and temperature played higher significance level on pollution remediation, and dosage of microbial inoculums (contain PO43-) only played higher significance level on phosphorus remediation. An economic and effective remediation method was presented in this paper, firstly Ca(NO3)2 was injected in sediment in the dose of 2.4g/L. After two to four weeks, ADB and yeast inoculums were prepared in a concentration of 108cfu/mL, and then injected in water and sediment separately in the dose of 0.15? and 0.45?. It should be emphasized that ADB would be injected firstly or simultaneously with yeast, and biological grow agent would be added at the same time (separately 0.35? and 0.70? in water and sediment).