EFFECTS OF AERATION ON WATER QUALITY IN WASTE-TREATMENT SECTIONS OF SPLIT-POND AQUACULTURE, A THREE YEAR SYNOPSIS

Split ponds have a fish cell and a waste cell, approximately 20% water surface area and 80% water surface area respectively, in which water recirculates to improve water quality as a more intensive management system than traditional ponds. This is a continuation of a study that focuses on the possible benefits of using mechanical aeration in the waste-treatment section of the split-pond culture system.

Work was conducted on a commercial catfish farm in west Alabama. The farm currently has eight split-ponds, each with a fish-holding section of about 8,000 m². Two, 10-hp floating, electric paddlewheel aerators were placed in the waste treatment section of each of four ponds; while four ponds - the controls - had un-aerated waste treatment cells. Water samples were collected biweekly at the inflow and outflow of the waste-treatment cells; once the water became cooler in the fall and winter, the samples were collected monthly. Analyses that were gathered include: pH, dissolved oxygen (DO), temperature, secchi disk visibility, Chlorophyll a, total ammonia nitrogen, nitrite-nitrogen, nitrate-nitrogen, total nitrogen, soluble and insoluble nitrogen, total phosphorus, soluble reactive phosphorus, chemical oxygen demand (total and soluble), biological oxygen demand, acidification, water circulation, aeration hours, and sediment carbon/nitrogen concentration. Year 1 (2014) produced no significant results. Year 2 (2015) produced differences between control and aerated ponds for secchi disk visibility, total ammonia nitrogen, total nitrogen, chemical oxygen demand (soluble and total) and DO. Year 3 (2016) will conclude in October. Data for all three years will be presented and interpreted.