Effectiveness of Reducing Turbidity Levels of Tofu Industry Wastewater with Alum Coagulant

Abstract

Tofu industry liquid waste is one of the pollutants that can pollute the environment, especially can cause turbidity in rivers, lakes, and other waters. One of the countermeasures is to treat the liquid waste by giving alum coagulant. The purpose of this study was to measure the turbidity level of tofu industry wastewater before and after the application of alum coagulant and calculate the effectiveness or optimal dose/concentration of alum coagulant. This research is a type of quantitative research with a quasi-experimental research design. The research was conducted at the Public Health Laboratory of Universitas Muhammadiyah Surakarta in January 2024. The data analysis technique used was quantitative to determine the effectiveness of alum coagulant, the test used was anova test. The results of this study indicate that the level of turbidity in the liquid waste of the tofu industry after the coagulation process using alum is at a concentration of 2 ml which produces a decrease in turbidity levels of 22.93%, a concentration of 4 ml produces a decrease in turbidity levels of 26.24%, a concentration of 6 ml produces a decrease in turbidity levels of 29.08%, and a concentration of 8 ml produces a decrease in turbidity levels of 36.41%, so that the optimum dose / concentration of alum coagulant is 8 ml because it has the best effectiveness value in reducing turbidity levels in the liquid waste of the tofu industry.