1999 Volume 30 Issue 1 Pages 11-20
Ammonia, a major nitrogen source for methanogens, has toxic if it present in excess. Response of the reactor packed rock wool to ammonia in the methanogenesis with impulsive and continuous additions of ammonia in different HRT and acetic loading rate using chemostats was investigated. With impulsive addition, the reactors tolerated 20, 20, 12g-N/L of nitrogen concentration of ammonia at one day of HRT and 1.5, 4, 7g/L·day of acetic loading rate, while 20, 15, 8g-N/L of nitrogen concentration of ammonia could be tolerated at 5-day HRT. With continuous addition, at a 1-day HRT and acetic loading rate 1.5g/L·day, up to 16.5g-N/L of nitrogen concentration of ammonia added was tolerated, whereas at a acetic loading rate 4 and 7g/L·day 15 and 12g-N/L of nitrogen concentration of ammonia could be tolerated.
The change of concentration of methanogens in the effluent as changing the concentration of ammonia was determined. The recovery of methanogens inhibited by ammonia was investigated. The activity of acetoclastic methanogens which inhibited at 25 and 15g-N/L of ammonia was restored entirely after the ammonia was washed out within two weeks.
