Stability and inhibition of anaerobic processes caused by insufficiency or excess of ammonia nitrogen
- 1.4k Downloads
Ammonia increases buffer capacity of methanogenic medium in mesophilic anaerobic reactor thus increasing the stability of anaerobic digestion process. Optimal ammonia concentration ensures sufficient buffer capacity while not inhibiting the process. It was found out in this paper that this optimum depends on the quality of anaerobic sludge under investigation. The optimal concentrations for methanogens were 2.1, 2.6 and 3.1 g/L of ammonia nitrogen in dependence on inoculum origin. High ammonia nitrogen concentration (4.0 g/L) inhibited methane production, while low ammonia nitrogen concentration (0.5 g/L) caused low methane yield, loss of biomass (as VSS) and loss of the aceticlastic methanogenic activity. It was found out that negative effect of low ammonia nitrogen concentration on biomass is caused not only by low buffer capacity but also by insufficiency of nitrogen as nutrient. It was also found out that anaerobic sludge with higher ammonia nitrogen concentration (4.2 g/L) tolerates even concentration of volatile fatty acids (160 mmol/L) which causes inhibition of the process with low ammonia nitrogen concentration (0.2 g/L).
KeywordsAmmonia inhibition Anaerobic digestion Buffer capacity Process stability Volatile fatty acids
This paper was supported by Ministry of Education project: “The study of chemical biological processes for the environmental protection, MSM6046137308” and from “Financial Support from Specific University Research (MSMT No. 21/2011)”. Authors would like to express gratitude to Lenka Vacková for her help.
- American Public Health Association AWWA (1998) Standard methods for the examination of water and wastewater. Water Environ FedGoogle Scholar
- Barredo MS, Evison LM (1991) Effect of propionate toxicity on methanogen-enriched sludge, Methanobrevibacter smithii, and Methanospirillum hungatii at different pH values. Appl Environ Microbiol 57(6):1764–1769Google Scholar
- Henze M, Harremoes P (1983) Anaerobic treatment of wastewater in fixed film reactors—a literature review. Water Sci Technol 15(8–9):1–101Google Scholar
- Horáková M (2003) Analytika vody. VŠCHT, PrahaGoogle Scholar
- Liu T, Sung S (2002) Ammonia inhibition on thermophilic aceticlastic methanogens. Water Sci Technol 45(10):113–120Google Scholar
- Takashima M, Speece RE (1989) Mineral nutrient requirements for high-rate methane fermentation of acetate at low SRT. Res J Water Pollut Control Fed 61(11–12):1645–1650Google Scholar