Intermittent shallow aeration of anaerobic lagoons treating piggery wastes
Ginnivan, M.J.; Eason, P.J.
Effluent and Water Treatment Journal 23(3): 101; 103-104
Continuous shallow aeration capable of satisfying the oxygen uptake rate to a depth of 20 cm controlled odour emission from a column (186 cm) simulating an anaerobic lagoon for treating wastes. Maintaining dissolved oxygen (DO) values above critical levels to a depth of at least 20 cm via intermittent aeration, also provided effective odour control. Extending the interval of non-aeration to 2 hr allowed DO levels to fall to undetectable values; however odour control measured after 1 hr of reaeration was similar to other treatments. The continuously aerated system was consistently slightly better than the others. Although the percentage reductions were > 97%, the numbers of pollution indicator bacteria were high in all effluents. Volatile fatty acids in all effluents were < 0.01 g/l. Total fatty acid levels in the sludge and the untreated waste were approx. 0.2 g/l and 3.3 g/l respectively.