Rapid startup of two-stage bio-purification of low temperature groundwater containing high concentration of iron, manganese and ammonia nitrogen

Poor operational stability and effluent manganese (Mn) concentration exceeding limitation were found during the same layer of purification process with the low-temperature (5~6℃) groundwater containing high ammonia nitrogen(NH3-N), iron (Fe) and Mn contents (TFe:9~15mg/L, Fe2+: 6~12mg/L, NH3-N: 1.4~2.0mg/L, Mn2+: 1.4~2.0mg/L). In order to achieve efficient purification, the start-up of two-stage aeration combined with two-stage filtration purification process was investigated in water plant purification workshop, and the two-stage bio-purification was started separately by using the differential filtration rate and the same filtration rate. Results showed that two startup methods were started successfully after 59 days and 106 days. The start-up with the same filter speed shortened the startup time effectively, and the efficiency of Fe, NH3-N and Mn were 110.69g/(m2∙h), 18.80g/(m2∙h) and 19.54g/(m2∙h) respectively. Fe was removed to trace level at 60cm of the primary filter column; NH3-N was evenly removed by 85.08% in the primary filter column, with the remaining 14.92% removed from the secondary filter column; the efficiency and the oxidation-removal active sites of Mn were obviously affected by the filtration rate as well as the influent NH3-N concentration. Mn was removed by 33.72% and 66.28% in the primary filtration columnand and the secondary filtration column, respctively. Mn removal remains a decisive factor in filter maturity. © 2019, Editorial Board of China Environmental Science. All right reserved.