Closed loop system for recovering ammonia from wastewater
NASA's Kennedy Space Center (KSC) seeks to license its Ammonia Recover System for Wastewater to industry. The Ammonia Recovery System for Wastewater was developed for potential use as part of the Environmental Control and Life Support Systems (ECLSSs) on the International Space Station. The system uses an affordable media that is highly selective for ammonia. Ammonia concentrations in wastewater as high as 100,000 ppm can be reduced to less than 1 ppm. Following treatment, the media is regenerated for reuse in the system and ammonia is captured as a by-product.
ECLSS conditions require low power usage and the avoidance of high temperature and pressure operations. State-of-the-art for ammonia removal techniques involve biological processes or ion exchange, and neither of these meets NASA's ammonia recovery needs. Biological processes have high complexity, high volume requirements, and introduce contaminants in the effluent. Ion exchange is not very selective for ammonia, and requires regeneration, which produces impure ammonia and other cation/regenerate effluent.
To address these challenges, NASA has designed a novel regenerable struvite-formation system for the capture of ammonia (traditionally, these systems have focused on capturing phosphorus not ammonia). This system has three primary functions:
1) Removal of ammonia from wastewater using a media that is highly selective for ammonia
2) Capture of the ammonia for later use (e.g., as a fertilizer)
3) Regeneration of the capture media for reuse in the system
Although the NASA system is being developed for smaller-scale, space-based applications, the technology is scalable for larger industrial and municipal wastewater needs.
* Higher capacity than traditional absorbents (multiple equivalents Ammonia/L substrate)
* Effective under varying influent ammonia concentrations (e.g., from 10s to 100,000s of ppm ammonia)
* Contact time of 2030 minutes needed for complete removal, with similar times needed for regeneration
* Easily regenerated media, which allows for repeated use in the system
* Ammonia captured/recovered during media regeneration phase (ammonia can then be reused or sold)
* Less expensive and more selective for ammonia than typical ion-exchange resins
* Agricultural wastewater (swine/dairy farms, etc.)
* Food processing plants
* Fertilizer plants (urea)
* Chemical plants
* Textiles (wool)
* Municipal wastewater
Figure 1: Media before treating an ammonia waste stream
Figure 2: Media after treating an ammonia waste stream