In this era, environmental management is very important because of the increasing number of population has affected the increasing number of solid waste and liquid waste (waste water). Waste water from tofu industry contains contaminants that COD (Chemical Oxygen Denand) and TSS (Total Suspended Solid). High contaminants can cause environmental degradation in water, disruption of aquatic ecosystems, and aesthetic disruption. Therefore, pond - biofilm technology with fishing nets and bioball as biofilter media is needed to reduce COD and TSS concentrations by varying the contact time. The detention time used was 4, 6, and 8 hours. The effect of detention time on the efficiency is the longer the detention time, the bigger the efficiency. The result shows the efficiency of COD concentration in the pond and drum (biofilter reactor) at the detention time of 8 hours is 22.89% and 15.49%. Efficiency of TSS concentration in the pond and drum (biofilter reactor) at the detention time of 8 hours is 80.60% and 72.99%.