Loading Rates on Waste Stabilization Ponds

Pond performance is affected by temperature, solar radiation, and wind-speed; therefore, facultative pond design should reflect the influence of local climatological conditions. Ponds located in mild climate areas are usually designed with higher loading rates than ponds in cold climate areas. Present recommended loading rates in the United States vary from an average of 26 lb BOD₅ per acre per day for the northern states (cold climate) to 44 lb BOD₅ per acre per day for the southern states (mild climate). In order to evaluate the effect of higher loading rates on organic matter removals, general pond performance, and selected pathogenic organism removals, model pond studies were conducted at Tulane University in New Orleans and Universidad del Valle in Cali, Colombia. Results indicate that with loading rates up to 100 lb BOD5 per acre per day in mild climate areas the BOD and COD removals will be greater than 90% and 80%, respectively; general pond performance will be satisfactory; and pathogen removals will exceed 99% after 24 days detention time.