PERFORMANCE ANALYSIS OF AIR INJECTION FOR CONSERVATION OF WATER BODIES

Abstract

Water by far is one of the most important/essential natural resources on our planet. All life forms depend on water for their survival and sustenance. Over the past few decades, the availability of fresh water sources is declining at an alarming rate. Human intervention since the beginning has been the cause for dyeing the water quality and dissolved oxygen levels. Low dissolved oxygen (DO) levels have been discovered to be a widespread concern in polluted rivers and lakes. Low dissolved oxygen levels have impacted aquatic life and is a matter of imminent concern. In aquaculture systems, the concentration of dissolved oxygen can occasionally drop below the threshold level (DO < 5 mg/L), resulting in the mortality of aquatic life. Water aeration can have an impact on a range of biological features in a body of water. Aeration is a process that raises the dissolved oxygen (DO) content in wastewater, allowing aerobic microorganisms to decrease the BOD of wastewater and so improve water quality. For decades, aerators have been widely utilized as oxygen transfer systems in biologically treating wastewater. To maintain the proper dissolved oxygen concentration in pond water, several aeration systems have evolved with time. This thesis aims to analyze the performance of remedial measures of introducing air/oxygen through existing aeration systems to raise DO levels. In Nainital lake, DO of the surface of lake was much less than 5 mg/l before aeration but after that DO increase to above 8 mg/l, DO of the bottom layer of lake also rise, that is approximately 0 mg/l before aeration that rise to 6 mg/l after aeration, and BOD decreases to 8 mg/l. In Dal Lake, it seen that DO of spots with aerators has 0.4 mg/l less than spot without aerators, and BOD level higher by 4 mg/l. Temperature of Nainital lake increased by 5 oC, whereas in Dal Lake, temperature has 6 oC lower value where aerators are than where aerators are not. Algal blooms in fresh water due to nutrient, mainly some phosphate. In both Nainital and dal lakes, no effect of aeration was observed on PO4-P. However, NO3-N decreases in Dal Lake whereas no such effect was seen in Nainital lake. pH slightly decreased in both lakes. Transparency of dal lake as no effect whereas, transparency of Nainital lake increased by 1.5 m.