Effect of Aeration Injection Technology Application on Dissolved Oxygen in Floating Net Cages in Cengklik Reservoir Waters, Boyolali Regency

Abstract

Eutrophication in the Cengklik Reservoir has become a problem that occurs every year which results in the faster growth of water hyacinth (Eichhornia crassipes) around the reservoir waters. This occurs due to increased utilization of the reservoir causing a large amount of waste input into the waters, one of which is from floating net cages aquaculture. Based on the analysis of satellite imagery in 2022, there are approximately 1.355 floating net cage units. The application of intensive aquaculture is considered not optimal because only 70% of the feed is eaten by fish and the rest settles to the bottom of the water. Therefore, there is also an increase in oxygen consumption by fish and microbes for the decomposition process of organic matter.This study aims to increase dissolved oxygen in the waters using injection aeration technology in floating net cages by pumping microbubbles with a diameter of 1 m-1 mm into the water. Aeration was carried out in one floating net cage with a size of 6 m × 6 m for 8 h with 3 stages of dissolved oxygen testing, namely 06.00 (before aeration), 10.00 (after 4 h aeration) and 14.00 (final aeration). The results showed that aeration injection in floating net cages could increase dissolved oxygen 42-58% higher than non-aerated cages. In addition, aeration also increases the appetite of fish in consuming feed. Aeration injection technology can be recommended to improve water quality in Cengklik Reservoir, especially when oxygen is low in the morning.