OPTIMIZATION OF N REMOVAL IN LANDFILL LEACHATES TREATMENT WITH MEMBRANE BIOREACTOR: PILOT PLANT AND FULL SCALE STUDIES

摘要

The treatment of leachates is a challenge compared to many other industrial effluents: the (N-NH4) content is frequently above 1 g/L, the C/N ratio is low (taking into account the biodegradable part of COD) and moreover, those ratios are changing with time from the beginning to the closure of the landfill site. It is thus not surprising that many types of systems have been tested to achieve this treatment, and among those, membrane bioreactors demonstrated excellent efficiencies (Praet et al, 2001). However, operating costs are rather high. Often much oxygen is injected in the system for nitrification, which can inhibit denitrification. This leads to an effluent with high nitrate concentration that is now focused by European disposal restrictions. Indeed nitrate could contribute to the eutrophication of aquatic environment (Jokela et al, 2002).