SRI SUMIYATI, P. PURWANTO, AND S. SUDARNO
Abstract
Domestic wastewater if not processed will firstly cause pollution to the environment. Contaminants contained in domestic wastewater include BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), TSS (Total Suspended Solid), pH (potential Hydrogen) and temperature. The objective of this study was to analyze the effect of bio activator addition of local microorganisms and sludge from the waste treatment plant compared to the condition without the addition of bio activator (control). In this study the reactor was in anaerobic-aerobic conditions and operated continuously. The bio-film media used was derived from volcanic gravels. There were three research stages, namely: seeding, acclimatization and running. The results showed that the addition of bio activators of the local microorganisms and the sludge influenced the removal of COD concentration in domestic wastewater, especially in the anaerobic condition. In the reactor with the aerobic condition, the addition was not influenced significantly. In the Hydraulic Retention Time (HRT) of 24 hours, the decreasing pattern of COD concentrations tends to be almost the same, that is down by extreme, but at the HRT of 12, 6 and 3 hours the patterns were different. For the process added with the local microorganism bioactivator the graph tends to be flat and stable, but the process added with the sludge and the condition without addition tends to fluctuate irregularly. Under conditions without the addition of bioactivators the concentration of COD on HRT of 3 hours increased sharply. In the reactor under aerobic conditions with the HRT of 15, 7.5, 4 and 2 hours, respectively. The addition of bio-activator of local microorganisms influenced the removal of COD concentration in both anaerobic and aerobic conditions. It is significantly different when compared to the control and sludge. The HRT of 12 hours and 7.5 hours were the most appropriate retention times for anaerobic and aerobic conditions, respectively.