Wastewater Treatment using Oxidation Ditch Microalgae Chlorella sp.: Insight into the Effect of Intermittent Aeration and Characteristic of Effluent Organic Matter

Document Type : Original Research Paper

Authors

1 Environmental Engineering Department, Faculty of Engineering and Sciences, Universitas Pembangunan Nasional Veteran Jawa Timur

2 Department of Environmental Engineering, Faculty of Engineering and Sciences, Universitas Pembangunan Nasional Veteran Jawa Timur

3 Department of Environmental Engineering, Faculty of Engineering and Sciences, Universitas Pembangunan NAsional Veteran Jawa Timur

10.22059/poll.2024.365414.2075

Abstract

Wastewater treatment with microalgae such as oxidation ditch algae reactor (ODAR) could reduce organic matter, however, the process might produce by-products that are toxic when dissolved in water. Effluent organic matter and algae organic matter are by-products of the microalgae process, that are released as well in ODAR system.The presence of these compounds in water can be a precursor for the formation of disinfection by-products (DBPs). The aim of this study is to determine the characteristics of effluent organic matter contained in domestic ODAR using the microalgae Chlorella sp. under variations of oxic and oxic-anoxic conditions. Microalgae were applied in ODAR under oxic for 24 hours of aeration and oxic-anoxic through a brush aerator on for 7 hours and off for 3 hours with a ratio of waste volume to microalgae 1:1 with sampling time up to 5 hours. The results showed that BOD concentration tends to decrease up to 45% and 67% for oxic-anoxic and oxic, respectively. The UV254 value increased up to 110% and 147% for oxic-anoxic and oxic, respectively. Further, fluorescence excitation-emission matrix (FEEM) analysis identified the changing of four organic fractions as measured by the fluorescence regional index (FRI). The results indicate a decrease of aromatic protein-like significantly up to 62% and a decrease in soluble microbial products up to 30%. While humic acid-like and fulvic acid-like tends to increase by about 25-29% and 44-46%.

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