(347q) Ammonia Removal/Recovery Using Electrokinetic Separations

The water scarcity and resource shortage due to accelerated population growth and industrial development are the major challenges for the society. Managing available resources such as nutrients and new water in the municipal area become emerging practice. The municipal and industrial wastewater contains large amount of nutrients (i.e., nitrogen and phosphorous), which are deemed to the reusable resources in the future. The nutrient-rich wastewater discharging into the nature environment can result in the eutrophication in the water bodies and deterioration in ecosystem. From 30% to 55% severe eutrophic lakes and reservoirs were found around the world and it spends more than 2.2 billion UDS of potential economic loss with freshwater eutrophication in the U.S. However, nitrogen (especially for ammonia) resource is the most important indigents for human life. The ammonia production for fertilizer ironically accounted for 1.5~2.5% global energy consumption and 1.6% carbon dioxide (CO2) emissions annually. By 2018, the global ammonia production reached 140 million tons per year, in which China accounting for 31.4%, followed by Russia (10%), US (8.9%), and India (7.8%). The excess discharged nutrients (e.g., ammonia) in the wastewater has resulted in the environmental problem, thus, to recover ammonia from wastewater can remediate the contaminated environment and mitigate the greenhouse gas emissions by reducing the demand of traditional ammonia manufactures.
The US Environmental Protection Agency upgraded national criteria for ammonia nitrogen discharge to improve the water quality. The removal of ammonia nitrogen from wastewater streams is important in preventing eutrophication of water bodies. The biological nitrification and denitrification are the conventional wastewater treatment processes on removal of ammonia, followed by a combined processes, Anammox, which can anaerobically convert ammonia and nitrite to N2. However, the biological processes do not recover nitrogen resource but release it into the atmosphere; thus, recovering the valuable nitrogen such as ammonia from waste streams would be an high energy efficient approach instead of fertilized product from atmospheric nitrogen.

This presentation discusses the developing electrokinetic and stripping technologies for ammonia removal/recovery from wastewater. A brief summary of various state-of-art technologies such as air stripping, gas-liquid contactor using modified packed bed and membrane contactor for ammonia removal compared to the electrokinetic processes including electrodialysis (ED), electrodeionization (EDI), capacitive deionization (CDI), electrochemical cell (EC) and bio-electrochemical system (BESs) will be presented. We will discuss the experimental assessment of using an in-situ pH adjustable electrokinetic separation technolog to reduce the energy consumption and processing cost to remove/recovery ammonia from waste water.