Sequencing Batch Reactor to Treatment Tofu Wastewater Using Impeller Addition

The characteristics of the wastewater produced by the tofu industry are high viscosity, slipperiness, and foaming resulting from the continuous fermentation of the tofu bacteria. This made it difficult to reduce the organic content of tofu wastewater, namely biological oxygen demand (BOD5), phosphate (PO4), and Total Nitrogen. A wastewater processor that is designed to handle dense and slippery tofu wastewater is known as a Sequencing Batch Reactor. The impeller is used to create turbulent flow, resulting in more evenly distributed DO, which is difficult to distribute due to the viscous tofu wastewater. The SBR was operated with a hydraulic retention time (HRT) of 24, 36, and 48 hours and an impeller stirring speed of 50, 100, and 150 rpm. The results of the research found that there was an effect on the stirring speed of the impeller and that the low stirring speed of the impeller was not optimal. HRT that was regulated in the SBR cycle has affected the performance of the bacteria. Pseudomonas sp. was found in this study and Bacillus sp., which can degrade up to 90% of phosphate and nitrate.