Large size is necessary. One group of bacteria converts organic wastes to organic acids. The second group converts the organic acids to methane gas and carbon dioxide. The second group of bacteria, the methane formers, is very sensitive to upset. The management requirements of an anaerobic lagoon are primarily concerned with creating the right environment for the methane-forming bacteria.
Anaerobic lagoons work best in warm weather.
Even in warm weather, several months are required to fully stabilize manure in an anaerobic lagoon. As the temperature drops, more time is needed. Turnover occurs as the lagoon is heating up in the spring or cooling down in the fall. Agitating the lagoon can help shorten the turnover period. Methane formers are very sensitive to pH. If the first group of bacteria, the organic-acid formers, grows and multiplies faster than the methane formers, the pH of the lagoon can drop.