Leachate from Brady Road Resources Management Facility (Manitoba, Canada) was evaluated to determine the most effective pre-treatment method to reduce the high concentrations of COD (1900 mg/L) and ammonia (640 mg/L) present. Four pre-treatment options were studied: (a) air stripping (b) chemical coagulation (c) electro-coagulation and (d) advanced oxidation with sodium ferrate. Each one of the procedures was evaluated under different conditions (pH, dose, contact time, etc.) to determine the operating conditions that best reduce the effluent COD and ammonia concentrations. Chemical coagulation exhibited the highest COD removal at 43% while in terms of ammonia removal, air stripping with 86% removal rate, was far superior to the other treatments. Electro-coagulation and advanced oxidation with sodium ferrate were found not suitable as pre-treatment options for this particular leachate, while combining air stripping and chemical coagulation removed approximately 50% COD and 85% ammonia, providing the highest removal percentages. Batch nitrification kinetics tests were used to assess the impact on nitrification performance of blending untreated and pre-treated leachate with municipal wastewater at varying percentages: 0.5%, 1%, 5% and 10% by volume. Pre-treatment was successful in allowing unhindered nitrification in the activated sludge bioreactor.
展开▼
