NH4 Removal and Reactive Nitrogen Recovery

EPA Grant Number: SU836766
Title: NH4 Removal and Reactive Nitrogen Recovery
Investigators: Grimberg, Stefan J.
Institution: Clarkson University
EPA Project Officer: Sergeant, Anne
Phase: I
Project Period: September 1, 2016 through August 31, 2017
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2016) RFA Text |  Recipients Lists
Research Category: Sustainability , P3 Awards , P3 Challenge Area - Water

Description:

Develop a viable process to reduce and recover total ammonia nitrogen (TAN) from food waste by identifying the most promising process enabling higher biogas generation rates, designing pilot and full-scale recovery systems and quantifying benefits.

Objective:

Anaerobic digestion (AD) is the preferable strategy to reduce the 35 million tons of food waste (FW) sent to solid waste landfills annually in the U.S. while simultaneously transforming organic compounds into value-added products with significant economic and environmental benefits. Treated biogas can be used as a substitute for fossil fuels. The liquid digester effluent retains most of the nutrients and can displace commercial fertilizers. However, there is a trade-off: nitrogen in the effluent is valued as fertilizer, but its ammonia form is inhibitory to methane producing bacteria, thereby reducing biogas production. In previous research, we observed that reducing total ammonia nitrogen (TAN) from 4500 to 2500 mg/L increased methane production by 80%. 

The development of a viable process to reduce and recover TAN will significantly improve the efficiency and value of FW AD. We propose to develop a passive TAN removal system to increase biogas production, and recover ammonia to meet agricultural needs. The specific objectives of this study are to: (1) identify the most promising process for ammonia removal and recovery that enables higher biogas generation rates; (2) design pilot and full-scale recovery systems and plan for the next stage of R&D; and, (3) quantify benefits to People, Prosperity and the Planet.

Approach:

Two principle processes will be evaluated (1) ammonia stripping and (2) ammonia recovery through membrane separation followed by recovery. Literature review and experimental evaluation will identify the most promising process to be studied in more detail. For example, which membrane is most economical or resistant to biofouling. A detailed design process will be used to scale the laboratory system to pilot and full scale. These data then will be used in preliminary life cycle assessment to determine net environmental and economic impacts of the process.

Expected Results:

The transformational innovation of this research therefore is to recover TAN from AD liquids at a significantly higher rate than achieved previously, thereby improving energy generation during AD while maintaining the fertilizer value of the substrate. The use of digestate fertilizer will reduce environmental pollution while minimizing commercial fertilizer use. The research will be grounded in practical relevance through the continuous involvement of experts of the solid waste and wastewater treatment industry partnering with the student team. Staff and engineers from our external partners will meet with the project team quarterly to review project results, and proposed research plans.

Supplemental Keywords:

Anaerobic Digestion, Nitrogen Recovery, Ammonia Inhibition;