Ion exchange-precipitation for nutrient recovery from dilute wastewater

Abstract

Regulated phosphorus (P) and nitrogen (N) discharges and the cost of fertilizer provide economic drivers for nutrient removal and recovery from wastewater. This study used ion exchange (IX) in dilute (domestic) wastewater to concentrate nutrients with subsequent recovery by struvite precipitation. This is the first tertiary wastewater treatment study directly comparing P removal using a range of Fe, Cu, and Al-based media followed by clinoptilolite IX columns for N removal and precipitation using the combined regenerants. Phosphate removal prior to breakthrough was 0.5-2.0 g P Lmedia −1 , providing effluent concentrations <0.1 mg L −1 PO4-P and <0.2 mg L −1 NH4-N for ≥80 bed volumes. Dow-FeCu resin provided effective P removal, efficient neutral pH regeneration and 560 mg P L −1 in the regeneration eluate (≥100× concentration factor). Exchange capacity of clinoptilolite in column mode was 3.9-6.1 g N Lmedia −1 prior to breakthrough. Precipitation using the combined cation and anion regenerants resulted in a maximum of 74% P removal using Dow-FeCu. Precipitates contained impurities, including Al 3+ , Ca 2+ , and Fe. Overall, the IX-precipitation recovery process removed ≥98% P and 95% N and precipitates contained 13% P and 1.6% N. This sequential process can NOT THE PUBLISHED VERSION; this is the author's final, peer-reviewed manuscript. The published version may be accessed by following the link in the citation at the bottom of the page.

Removal of antibiotic resistance genes in an anaerobic membrane bioreactor treating primary clarifier effluent at 20 °C

“…1,3 WRRFs provide a centralized opportunity to recover nutrients (particularly phosphorus), reduce energy demands or produce energy, and provide water for reuse. [4][5][6] To implement resource recovery, WRRFs may need to move beyond conventional activated sludge treatment that requires energy for oxygen transfer and biosolids disposal with limited opportunities for nutrient recovery. 3,7 Since anaerobic treatment is often a key technology for sustainable water resource recovery management scenarios of the future, anaerobic membrane bioreactors (AnMBRs) have garnered attention for multiple reasons.…”

“…11,12 Furthermore, AnMBR filtrate can be treated using processes such as ion-exchange to concentrate nutrients and recover valuable products such as struvite. 5,6 In addition to producing valuable products and recovering energy, sustainable water resource recovery must produce water having appropriate quality for reuse. Chemical micropollutants are prevalent in wastewater and pose a variety of ecological risks including fish feminization and the spread of antibiotic resistance.…”

Energy and nutrient recovery from agro-wastes: Rethinking their potential possibilities

“…. The only available technology to recover nitrate is anion exchange followed by precipitation as an inorganic salt of nitrate for application in agriculture [131]. Therefore, further research on less expensive promising technologies for nitrogen recovery definitely is considered on high priority.…”

Ion exchange nutrient recovery from anaerobic membrane bioreactor permeate

“…The effluent regenerant from the columns was collected in bulk for subsequent struvite precipitation tests. Regeneration was conducted until effluent PO 4 -P or NH 4 -N concentrations dropped below 10 mg/L, beyond which point a much larger volume of regeneration solution would be required to desorb a smaller fraction of the ions (Williams & Mayer, 2013;Williams, Zitomer, & Mayer, 2015). After regeneration, 5 to 10 BV of deionized water was pumped through the column to remove remaining regenerant solution and to prepare the media for another subsequent removal cycle.…”