The Operation of Anaerobic Lagoons
The operation of the anaerobic lagoon adjacent to Isfahan Wastewater Treatment Plant was studied over a 12- month period. The rate of organic loading, BOD and SS removal efficiencies and their relationships with organic reductions and ambient temperature were studied. A high correlation was found to hold among temperature, organic loading rate, and BOD 5 removal. A correlation coefficient of 87% was obtained for temperature and BOD 5 removal efficiency and that for temperature and organic loading was 83%. The lowest atmospheric temperature during the study period was 4°C ( per day ) when BOD 5 removal efficiency reached 25%. A model was developed to predict SS removal efficiency against atmospheric temperature variations in which small increases were observed in removal efficiency with increasing atmospheric temperatures. The BOD 5 reaction constant ( K t ) at 20°C was equal to 0.4895 d -1 . A model was also developed a correlation coefficient of 83% with a standard error of 6.3%. According to the observations and studies carried out, the quantity of per capita sludge in the anaerobic lagoon was estimated to be 0.06 to 0.08 per person/year.