Hydrated Oil Shale Ash And Mineralized Peat As Alternative Filter Materials For Landfill Leachate Treatment In Vertical Flow Constructed Wetlands

摘要

The main objective of this study was to determine the treatment capacity of hydrated oil shale ash and well- mineralized peat in vertical flow filters designed to reduce BOD_7 and COD values as well as nutrient concentrations in landfill leachate. The filter material combinations were: (a) peat, (b) hydrated oil shale ash, and (c) both materials in equal volumes. In a 1-year indoor experiment (El), effluent from activated sludge treatment plant was used, whereas in the 6-months outdoor experiment (E2), water from the aerobic-anoxic pond was used. The average reduction of P in peat filters during the first 6 months was 77 and 93% for El and E2, respectively. In ash filters, the average reduction was 46 and 68%, and in peat/ash sediment filters 71 and 88%, respectively. Phosphorus removal efficiency in peat filters decreased during the next 6 months, whereas in other filters it remained stable. The BOD_7 value fell, on average, by 67 and 66% in peat filters and 52 and 54% in the ash sediment filters, and the best results were obtained in peat/ash sediment filters (75 and 78%). It took two months to achieve favorable conditions for the reduction of NH_4-N, after which high removal efficiency was maintained throughout the experiments.