Characteristics of Tofu Wastewater From Different Soybeans and Wastewater at Each Stage of Tofu Production

Abstract

Tofu wastewater is a liquid by-product of the tofu production process that typically contains high levels of organic matter, such as proteins, carbohydrates, and fats, as well as other compounds, such as nitrogen, phosphorus, potas-sium, and COD. Tofu wastewater COD levels can vary depending on the type of soybeans used in the production process and the stages of the production process. This study aimed to analyze the characteristics of tofu wastewater from various types of soybeans and the characteristics of wastewater at each stage of the production process. The research methods used were field research and laboratory tests. Field research was conducted by collecting samples from different types of soybeans and analyzing them in the laboratory. Meanwhile, laboratory tests were run by analyzing samples for various parameters such as Soybeans Protein, Chemical Oxygen Demand (COD), total suspended solids (TSS), Biochemical Oxygen Demand (BOD), ammonia, and fat oil. The results showed that Wonogiri Soybeans had the highest protein parameter, 19%. As far as the wastewater of seed samples, the Wonogiri Seed sample had the highest parameter results for TSS, COD, ammonia, and BOD, which are 444 mg/L, 4583.33 mg/L; 13.86 mg/L; and 3.481 mg/L, respectively. As for the fat oil parameter, the Red Seed sample achieved the highest result of 6264 mg/L. In the case of the samples from each washing stage, it is known that the washing sample parameter results are lower than the seed samples. The Red 1st Washing sample had the highest TSS, COD, fat oil, and BOD values, amounting to 316 mg/L, 4666.67 mg/L, 356 mg/L, and 2053.71 mg/L, respectively. In comparison, the highest fat oil parameter corresponded to the Wonogiri 1st Washing sample with a value of 11.78 mg/L. The B/C ratio of all samples is >0.1 and is in the biodegradable zone. Thus, the samples are not only able to be treated through biological processes, but also able to be treated through physical and chemical processes to avoid the length of time for biological decomposition due to the acclimatization process of microorganisms to the samples.