The Removal Effect of Organic Pollutants by Different Fillers in Constructed Rapid Infiltration System

Abstract

AbstractIn recent years, the concept of ecological treatment of rural domestic sewage and tail water reuse has been strongly advocated by the Ministry of Ecology and Environment. Constructed rapid infiltration (CRI) system is a low-cost and suitable ecological sewage treatment measure in rural areas. There are many kinds of filter materials in CRI system, but there are few reports on the research of filter materials based on Farmland Irrigation Standard (GB18918-2002) as the effluent discharge standard. In this study, red sandy soil, black volcanic rock, red volcanic rock, slag and biological ceramsite were selected as the filter media of CRI system, and five CRI systems were constructed. Under the condition of hydraulic loading rate (HLR) of 1 m·d−1 and test period of 30 days, the removal efficiencies for chemical oxygen demand (COD) and five-days biochemical oxygen demand (BOD5) by each CRI system were studied, and the best filter media for organic pollutants removal was finally selected. The results show that red volcanic rock has the best removal efficiency for COD and BOD5. The effluent concentrations of COD and BOD5 are 43.8 mg/L and 30.2 mg/L, respectively, and the corresponding removal rates are 72.1% and 74.4%, respectively. The effluent can meet the standards of Class B and Class A vegetables in Farmland Irrigation Standard, respectively. This study provided a theoretical basis for the rational selection of filter material in practical engineering application of CRI system to improve the removal performance of organic pollutants.KeywordsConstructed rapid infiltration systemFillersCODBOD5