Skip to main content
ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #346745
Research Project: Improvement of Soil Management Practices and Manure Treatment/Handling Systems of the Southern Coastal Plain

Location: Coastal Plain Soil, Water and Plant Conservation Research

Title: Nitrogen recovery from wastewater using gas-permeable membranes: Impact of inorganic carbon content and natural organic matter

Author
item DAGUERRE-MARTINI, SILVANA - Miguel Hernandez University
item Vanotti, Matias
item RODRIGUEZ-PASTOR, MANUEL - Universidad De Alicante
item MORAL HERRERO, RAUL - Miguel Hernandez University

Submitted to: Water Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2018
Publication Date: 3/15/2018
Citation: Daguerre-Martini, S., Vanotti, M.B., Rodriguez-Pastor, M., Moral Herrero, R. 2018. Nitrogen recovery from wastewater using gas-permeable membranes: Impact of inorganic carbon content and natural organic matter. Water Research. 137:201-210. https://doi.org/10.1016/j.watres.2018.03.013
DOI: https://doi.org/10.1016/j.watres.2018.03.013

Interpretive Summary: Conservation and recovery of nitrogen from animal wastes and municipal effluents is important because of economic and environmental reasons. This research determined the role of inorganic carbon (bicarbonate alkalinity) on the effectiveness of ammonia recovery using gas-permeable membrane technology and low-rate aeration. There were two distinct and interconnected mechanisms in this new approach. One was the release of hydroxide from the natural carbonates that increased the wastewater pH and promoted gaseous ammonia formation and membrane uptake. The other was the release of acidity and consumption of alkalinity by the nitrogen recovery. This acidification of the wastewater can completely halt the N recovery process. Therefore, an abundant inorganic carbon supply in balance with the ammonia in wastewater is needed for a successful operation of the technology. Fortunately, most swine manures contain ample supply of endogenous inorganic carbon and the process can be used to more economically recover ammonia using the natural inorganic carbon instead of expensive alkali chemicals. Finally, we found that the process was not inhibited by increasing levels of organic matter in the wastewater.

Technical Abstract: Gas-permeable membranes coupled with low-rate aeration are useful to recover ammonium from livestock effluents. In this study, the role of inorganic carbon (bicarbonate) to enhance the nitrogen (N) recovery process was evaluated using synthetic effluents with various ammonium to bicarbonate molar ratios of 0.5, 1.0, 1.5 and 2.0. The study also evaluated the effect of increased organic matter on the ammonium recovery using humic acids (3000 to 6000 milligrams per liter), and the N recovery from high-strength swine manure. The release of hydroxide from the bicarbonate with aeration increased the wastewater pH and promoted gaseous ammonia formation and membrane uptake. At the same time, the recovery of gaseous ammonia through the membrane acidified the wastewater. Therefore, an abundant inorganic carbon supply in balance with the ammonium is needed for a successful operation of the technology. Ammonium removal efficiencies higher than 96 percent (%) were obtained with ammonium to bicarbonate molar ratios less or equal 1. However, higher molar ratios inhibited the N recovery process resulting in lower efficiencies (less than 65%). Fortunately, most swine manures contain ample supply of endogenous inorganic carbon and the process can be used to more economically recover the ammonia using the natural inorganic carbon instead of expensive alkali chemicals. Finally, it was found the process was not inhibited by the increasing levels of organic matter in the wastewater evaluated.