study on high-strength anaerobic landfill leachate treatability by membrane bioreactor coupled with reverse osmosis

one of the most important concerns in tehran municipal landfill is the production of leachate and its potential for water resources pollution, this study was undertaken to examine feasibility of biological and physico/chemical treating of high-strength landfill leachate that was collected from tehran municipal landfill. average cod of the leachate in aerobic submerged membrane bioreactor is 68000 mg/l. the reactor with a working volume of 175 l, having membrane module (hollow fiber) with pore size of 0.1 μm coupled with reverse osmosis with pore size of 0.001 μm was used in this study. the dissolved oxygen (do) concentration was maintained at 3.2 mg/l and solid retention times (srts) and hydraulic retention times (hrt) were controlled at 55 and 15 days respectively. the average membrane bioreactor effluent cod was 1733 mg/l with average removal efficiency of 97.46%. the average nh 4 –n removal efficiencies was 99%. on the other hand, an almost complete nitrification was achieved during this period. po4 –p concentration in the effluent was low and its average removal efficiency was as high as 90%; especially during the operation period. the averages reverse osmosis (ro) effluent cod was 335 mg/l with average removal efficiency of 99.13%. po4-p concentration in the ro effluent was 0.86 mg/l and its average removal efficiency was 99.33%. the use of membrane technologies, more especially reverse osmosis offers the best solution of achieving full purification with average cod removal efficiency of 99% and solving the problem of water resources pollution.