Pretreatment to remove ammonia from high strength wastewater with membrane aerated biofilm sidestream

Abstract

Wastewater with high ammonia concentration is pre-treated before discharging it into a wastewater treatment plant treating lower strength wastewater, for example an activated sludge plant treating municipal sewage. The high strength wastewater is pre-treated to oxidize ammonia by contact with a fixed film supported on gas transfer membranes in a membrane aerated biofilm reactor. The pre-treatment may be a batch or continuous process. The pre-treatment can be controlled to remove ammonia to about the point of material alkalinity depletion. One or more parameters such as alkalinity, pH, or membrane exhaust oxygen concentration can be monitored to determine if alkalinity depletion has occurred or is about to occur. In some examples, the high strength wastewater is blended with wastewater having less ammonia and more alkalinity, for example municipal sewage or primary effluent. In some examples, the high strength wastewater is a liquid fraction of one or more sludges.

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