The Zeolite-Anammox Treatment Process for Nitrogen Removal from Wastewater—A Review

Abstract

Water quality in San Francisco Bay has been adversely affected by nitrogen loading from wastewater treatment plants (WWTPs) discharging around the periphery of the Bay. While there is documented use of zeolites and anammox bacteria in removing ammonia and possibly nitrate during wastewater treatment, there is little information available about the combined process. Though relatively large, zeolite beds have a finite ammonium adsorption potential and require periodic re-generation depending on the wastewater nitrogen loading. Use of anammox bacteria reactors for wastewater treatment have shown that ammonium (and to some degree, nitrate) can be successfully removed from the wastewater, but the reactors require careful attention to loading rates and internal redox conditions. Generally, their application has been limited to treatment of high-ammonia strength wastewater at relatively warm temperatures. Moreover, few studies are available describing commercial or full-scale application of these reactors. We briefly review the literature considering use of zeolites or anammox bacteria in wastewater treatment to set the stage for description of an integrated zeolite-anammox process used to remove both ammonium and nitrate without substrate regeneration from mainstream WWTP effluent or anaerobic digester filtrate at ambient temperatures.

Upscaling the Zeolite-Anammox Process: Treatment of Anaerobic Digester Filtrate

“…Following the partial restoration of aggregate surface materials in the second stage of the tank reactor study, we took advantage of the apparent layered bacterial biofilms (nitrifier over anammox bacteria on the zeolite aggregate) obtained from the prior flood-drain cycling to examine the nitrate scavenging potential of the zeolite-anammox reactor. As others using anammox reactors have noted (Mansell [6]; Grismer and Collison [7]), we found that the continuous submergence of the zeolite media in the tank favored anammox growth over nitrifiers, while the lack of a carbon source limited the growth of denitrifiers, likely promoting the DRNA reactions while efficiently cultivating bio-zeolite for use in seeding other zeolite-anammox reactors. Encouraging the apparent anammox DRNA reactions provided interesting results and has important ramifications for treating wastewaters subject to both ammonium and total nitrogen (TN) discharge limits.…”

“…Influent to both the barrel and Baker tank reactors was obtained from 3.4 m 3 (1000 gal) and 30 m 3 (8000 gal) AD filtrate storage-settling tanks, respectively. Both reactors were designed as recirculating trickling-filter reactors and operated as two-layer aerobic-anaerobic treatment systems to take advantage of the nitritation-anammox process described by Zekker et al [12] and the oxycline described in our review (Grismer and Collison [7]). In effect, the two-layer zeolite-anammox system within a single reactor enables the top layer to produce nitrite (equivalent to the Sharon process in a separate tank) while, presumably, a combination of denitrifying and anammox bacteria in the lower submerged layer converts nitrite and ammonia to nitrogen gas.…”

“…The zeolite-anammox system appears to overcome the relatively high temperature and ammonia concentrations required by anammox or partial nitritation reactors because we speculate that the zeolite immobilizes the influent ammonium ions at cation-exchange sites where the anammox bacteria can 'strip' these ions from the zeolite and, when combined with the available nitrite, eventually convert them to nitrogen gas. When maintained in anoxic conditions, some anammox strains (e.g., K. stuttgartiensis) are also capable of dissimilatory nitrate reduction to ammonium (DNRA) bypassing the ammonium-nitrite combination step (Mansell [6]; Grismer and Collison [7]).…”

Upscaling the Zeolite-Anammox Process: Treatment of Secondary Effluent

“…Similarly, treatment methods have emerged exploiting the large cation-exchange capacity of zeolite aggregates; however, some issues remain in upscaling their application in wastewater treatment due to media regeneration requirements. Grismer and Collison [6] provide a more detailed review of the use of zeolites and anammox bacteria in wastewater treatment systems and here we only briefly summarize their observations relevant to domestic wastewater treatment.…”

Optimum Design of Phosphorus and Nitrogen Removal from Domestic Wastewater Treatment Plant

“…The negative effects of nutrients (phosphorus-nitrogen) on the receiving water resources (rivers and lakes) have been shown and these effects have been covered by adequate scientific studies (Converti et al, 2009, Kong et al,. 2010, Mata et al, 2010, Bernard, 2011, Abdel-Raouf et al, 2012, Samorì et al, 2013, Kim et al, 2014, Mark and Robert, 2017, Ghawi, 2017and Ghawi, 2018. Therefore, the legislations that define the specifications of treated water for water sources have been established, thus ensuring the safety and preservation of these sources.…”