Effects of feeding methods on ecological soil wastewater infiltration systems for sewage treatment

Abstract

Abstract Intermittent feeding method and continuous feeding method were adopted in two experimental form ecological soil wastewater infiltration systems (ESWISs), respectively. The results showed that COD, NH4 + and TN removal efficiencies were enhanced from 81.8%, 70.5% and 45.8% in continuous feeding ESWIS to 90.0%, 88.5% and 72.7% in intermittent feeding ESWIS. The same TP removal efficiency was achieved in two feeding mehtods. Matrix oxidation reduction potential (ORP) was enhanced through the intermittent feeding ESWIS, especially above 60 cm depth of the matrix, which encouraged nitrification. The metabolic activity and reproduction of microbes were improved by intermittent feeding method, such as actinomyces, bacteria, nitrifying bacteria, fungus. Meanwhile, denitrifying bacteria and nitrate reductase (NR), nitrite reductase (NIR) activities were also increased. PCR-DGGE analysis confirmed that intermittent feeding method improved bacterial diversity. These results suggest that intermittent feeding method is viable to heighten the performance of ESWISs in sewage treatment.