Effect of Aeration on the Rate of Biochemical Oxygen Demand (BOD) in Floating Net Cages in Ir. H Djuanda Reservoir, West Java, Indonesia

Abstract

Aeration is an effort to improve dissolved oxygen when oxygen is in critical condition in water body. Ir . H. Djuanda Reservoir is utilized for fish farming activities by floating net cage culture impact on water quality, among others, an increasing of organic matter from the rest of wasted feed and fish feces and decreased oxygen waters. Increasing the organic matter will cause pollution if not balanced with sufficient oxygen to decompose the organic matter. The purpose of this study to determine the rate of BOD (k) in the treatment of water pre and post aerated for 8 hours. The study was conducted in floating net cage culture locations with aeration at a depth of 3.6 m (depth of hypoxia) with system pumps air through compressor with pressure about 3 atm for 8 hours . Sample was conducted in June - September 2013 and BOD subsequently measured daily for 7 days. k values was calculated by Least Square method. The results showed that the BOD5 was higher in pre- aeration (4.57 -8.74 mg/l) than post aeration (3.52 to 8.13 mg/l). The rate of BOD was higher post- aeration (0.2461 to 0.3335 per day) compared to pre- aeration (from 0.1262 to 0.2776 per day). This was caused post aeration oxygen supply gets larger than pre aeration so as to decompose organic matter.