The Effect of Aeration on River Water Receiving Industrial Discharges to Its Quality and Toxicity

Citarum River in West Java Province was an important river that supported more than 25 million people in the region. It was considered highly polluted by many sources of wastes. This study was aimed to evaluate the effect of aeration process on river water quality and toxicity in Citarum tributary receiving industrial wastes as river restoration alternative. Three types of aeration methods namely mechanical, hydraulic, and diffused air were studied in laboratory scale. Water quality parameters analyzed were TSS, TDS, COD, nitrate, phosphate, nitrite, phenol, and acute toxicity LC50 96 hrs on Daphnia magna was tested to obtain TUa value. Results showed TUa of water samples collected at daytime was 0.467±0.12, whereas night time water samples resulted higher toxicity of TUa 1.36±0.3. Aeration of daytime river water by diffuser, mechanical aeration, and cascade aeration, reduced toxicity to TUa of 0.01±0.002, 0.08±0.04, and 0.30±0.2 respectively. On the other hand, aeration for night time river water samples still posed higher acute toxicity showing TUa respectively of 0.13±0.02, 0.44±0.13, and 1.04±0.13. These showed that aeration type has different capacity in lowering water toxicity and improving water quality. Study suggested that contaminated river water quality and toxicity could be improved by aeration processes.