Immobilization of nitrifying bacteria in porous pellets of urethane gel for removal of ammonium nitrogen from waste-water

Abstract

The effects of immobilizing materials on the activity of nitrifying bacteria and removal of ammonium nitrogen (NH4-N) from waste-water by immobilized nitrifying bacteria were investigated using six urethane prepolymers. With a urethane prepolymer containing 2.27% free isocyanate, a high activity yield of nitrifying bacteria was obtained. There was a drastic improvement over the conventional method of immobilization by acrylamide in the activity yield. Inorganic synthetic waste-water was treated at a high loading rate of 0.24 kg N. m -3. d a y -1. The NH4-N concentration of the effluent could be reduced to 2 mg. l-1 or less and the removal was 90%. The life of the pellets in terms of activity was at least 120 days.

Chemolithoautotrophic Bacteria

“…The combined use of nitrifying bacteria and denitrifying bacteria is effective to remove ammonia; it produces nitrogen gas from ammonia (Sumino et al, 1992). The combined use of nitrifying bacteria and denitrifying bacteria is effective to remove ammonia; it produces nitrogen gas from ammonia (Sumino et al, 1992).…”

Preservation Property and Decay Kinetic of Polyurethane Immobilized Nitrifying Bacteria Pellets

“…How to effectively keep the high activity of nitrifying bacteria pellets for long-term storage is an urgent problem in its technology application [5] [6]. Because active decay of nitrifying bacteria in the preservation process is complex, it depends on lots of environmental factors [7]. Few studies on the decline of nitrifying bacteria and the research of immobilized nitrifying bacteria products preservation process have not been reported [8] [9].…”

Application of a novel Mass Bio System to remove low-concentration ammonia nitrogen from water bodies

“…Compared with the conventional processes, the embedding immobilization technology has several advantages [38][39][40] such as enhanced degradation rate, protection of microbes against toxicity, operation stability, protection from extreme conditions and economic. [41][42][43] A considerable number of previous studies on immobilized microbial technology are directed towards the treatment of high-concentration ammonia-nitrogen wastewater or wastewater containing toxic and harmful compounds.…”