EFFECT OF TRYPTONE AND AMMONIA ON THE BIOGAS PROCESS IN CONTINUOUSLY STIRRED TANK REACTORS TREATING CATTLE MANURE

• Published in: Environmental technology Vol. 28; no. 8; pp. 905 - 914
• Main Authors: Nielsen, H.B., Ahring, B.K.
• Format: Journal Article
• Language: English
• Published: London Taylor & Francis Group 01.08.2007; Selper
• Subjects: Agriculture, rearing and food industries wastes; Ammonia - pharmacology; AMMONIA INHIBITION; Animals; Applied sciences; Bioreactors; Cattle; Chemical engineering; Exact sciences and technology; Fatty Acids, Volatile - metabolism; Manure; Methane - metabolism; Peptones - pharmacology; Pollution; PROCESS IMBALANCE; PROTEIN DEGRADATION; Reactors; VFA DYNAMICS; Waste Disposal, Fluid; Wastes; Methane; Thermophily; Biogas; Volatile organic compound; Farmyard manure; Continuous stirred tank reactor; Ammonia; VFA dynamics; process imbalance; Methanogenesis; Production; Volatile fatty acid; ammonia inhibition; Agricultural waste; Animal waste; Cattle manure; protein degradation; Organic compounds
• ISSN: 0959-3330; 1479-487X
• DOI: 10.1080/095933328086188485

Two thermophilic continuously stirred tank reactors, R1 and R2, were subject to pulses of tryptone and ammonia. R1 was operated at an ammonia-N concentration of 3.0 g l -1 and R2 was operated at an ammonia-N concentration of 1.7 g l -1 . Shock loads of tryptone (10 g l -1 , 10 g l -1 , 15 g l -1 ) had an immediate stimulating effect on methanogenesis for both reactors illustrated by significant peaks in methane production but also led to an organic overloading illustrated by a steep increase in volatile fatty acids (VFA) concentration. Three days after the pulses a second peak in acetate concentration and a decrease in methane production indicated an ammonia-inhibition of the acetoclastic methanogens. During the pulses of tryptone the performance of R1 was slightly more affected than R2. Pulses of ammonia (0.79 g l -1 as N) resulted in a decrease in methane production of both reactors but no immediate increases in VFA concentrations was observed illustrating that the ammonia inhibition during this experiment was an overall inhibition of the biogas process and not only an inhibition of the methanogens.