Abstract:
The Techno Park retention basin at the Faculty of Engineering Gadjah Mada University
was built for the purpose of restoring the water quality before it is allowed to return into
the Code river. The water entering the basin, especially in the dry season, is
characterized as domestic wastewater due to the dense settlements around the
university. Dissolved Oxygen (DO) is one indicator of healthy waters because it shows
the water’s ability to break down organic or nutrient loads in polluted water bodies
(Self-purification). The purpose of this study was to determine the effectiveness of
reaeration process using a Microbubble Generator (MBG) to increase DO, with the aim
of this leading to an improved water quality. A MBG aerator, with submersible pumps
and a horizontal nozzle was installation at a depth of 40 cm from the water surface in
the middle of the pond. The aerator was permenantly turned on. In situ monitoring of
DO was carried out using a Seri Lutron WA-2017SD DO meter. DO measurement
sampling was done around the aerator with a spread angle of 60o at each point and a
range distance of 0.5 m, 2 m, and 5 m from the aerator. Measurements were carried out
for 6 consecutive days. The increasing DO correlated with the changes of the
surrounding weather which impact on water and air temperature. At the time of DO
data collection, the water temperature ranged from 24.5oC - 27oC and the change in DO
measured at the inlet and outlet of the reservoir was in the range 0.3 - 1.1 mg/L, with
the DO directly surrounding the aerator reaching up to 2.4 mg/L from the inlet
