ARS | Publication request: TREATMENT OF NITROGEN IN ANIMAL WASTEWATER WITH NITRIFYING PELLETS

Submitted to: Water Environment Federation
Publication Type: Proceedings
Publication Acceptance Date: March 22, 1999
Publication Date: N/A

Technical Abstract: Enhanced nitrification of ammonia (NH4-N) is an important consideration for improved systems of animal waste treatment. One of the most effective processes uses large populations of nitrifying microorganisms entrapped in polymer pellets. We evaluated whether this technology could be adapted for treatment of higher-strength animal wastewater. A prototype plant was set up in a swine operation in North Carolina for nitrification treatment of lagoon wastewater. The liquid contained, on the average, 330 mg NH4-N/L, 420 mg TKN/L, and 220 mg BOD/L. Pellets were successfully acclimated to swine wastewater during the first 3-month period in which the ammonia loading rate was increased by decreasing the hydraulic residence time (HRT). Performance of the unit was tested under a range of ammonia loading rates (237 to 1070 g N/m**3 tank/d) and water temperatures (4.9 to 33.3 deg C) during the subsequent nine months. Nitrification rates during winter months (Dec.-Feb.) were 40 to 80 mg N/m**3 tank/day and increased considerably when water temperature raised above 10 deg C. The nitrification rate obtained in March (20 deg C) was 380 g N/m**3 tank/day using HRT of 19 h and further increased during summer months. In August (30 deg C), the nitrification rate obtained was 650 g N/m**3 tank/day with a 12-h HRT. All the ammonia-N removed was nitrified without losses of N by volatilization. Our results indicate that immobilized pellets can rapidly nitrify animal wastewater. One of their first applications may be the retrofit of anaerobic swine lagoons for fast and efficient removal of ammonia.