Penurunan Kadar BOD, COD, dan Total Coliform dengan Penambahan Biokoagulan Biji Pepaya (Carica papaya L) (Studi pada Limbah Cair Domestik Industri Baja di Surabaya Tahun 2020)

Domestic wastewateris wastewaterthat is from residential businesses or activities, restaurants, offices, businesses, apartments and dormitories. Preliminary test result against BOD, COD, Total Coliform in domestic wastewaterof steel industry Surabaya did not qualify which according to Regulation of Minister Environment Forestry Republic Indonesia Number 68 2016, the requirements were 63 mg/l, 189 mg/l 13,000 CFU/100ml. Treatment that could be conducted was coagulation-flocculation with addition biocoagulant papaya seed. Moreover, purpose this study order analyze reduction level by adding seed (Carica L). Type research a pure experimental pretest-posttest control group design. Object wastewater one industries Surabaya, East Java Province, Indonesia. The dosage variations 1 gram, 2 grams 3 0 gram as replication much 6 times. Thus, it obtained 24 sample size. results before after seed(Carica L)biocoagulant analyzed using paired t probit test. showed thatBOD, COD levels having treatment reduced. highest percentage dose gr reduce BOD until 93% 66%. optimum reducing 3,629 gr/l 3,109 gr/l. Furthermore, levels. for industry, necessary conduct pre-treatmentof being dumped into water bodies.