Comparison among three domestic Wastewater Treatment Plan in Semarang City

Background: water is a crucial element to uphold the existence of human beings, food production, organism, and economic growth. The wastewater treatment system in the city of semarang almost completely implements an on-site system in which every house has its own treatment facility in the form of a septic tank. Aim of this study is to find out the management system of the communal wastewater and its chemical and biological features.Method: the study topic about domestic wastewater treatment plan in semarang city which include simpang lima presented in kpp gunung asri i (rw ix, rt 0i), kpp gunung asri ii (rw ix, rt 04) and kpp cempaka (rw xiii, rt 06) using geospatial data. Variables in this study are, chemical (ph, bod, cod), and biological (e-coli) parameters. Statistical analysis spss and excel to display percentages and graphs.Result: the lowest tds is in inlet samples taken from kpp gunung asri i which is 152 ppm while the highest is middle samples taken from kpp gunung asri i which is 1114 ppm. The lowest turbidity is in outlet samples taken from kpp gunung asri i which is 8.2 ntu while the highest is inlet samples taken from kpp gunung asri i which is 159 ntu. The lowest ph is in inlet samples taken from kpp gunung asri i which is 7.02 while the highest is outlet samples taken from kpp cempaka which is 7.46. The lowest tss is in outlet samples taken from kpp gunung asri i which is 185 while the highest is middle samples taken from kpp gunung asri i which is 299. The lowest cod is in outlet samples taken from kpp cempaka which is 133.3 while the highest is inlet samples taken from kpp gunung asri i which is 1203.3. The lowest bod is in outlet samples taken from kpp gunung asri i which is 70.2677 while the highest is inlet samples taken from kpp gunung asri i which is 373.023. The lowest e-coli is in outlet samples taken from kpp gunung asri i and kpp cempaka which is 0 while the highest is middle samples taken from kpp gunung asri i which is 6400.Conclusion: the worst quality of wastewater is in inlet samples taken from kpp gunung asri i.