The wastewater treatment plant is located on the north part of Peräjärvi. This is the only place where the player can legally dispose of septic waste that has been pumped into the Gifu from performing septic work to avoid a hefty fine for illegal dumping. The working hours of the plant are weekdays between 08:00 and 16:00.

The cost of disposing waste is 150 mk + 0.14 mk per litre. The sum must be paid in order to be able to dump the waste on the grate. To dump the waste, park the lorry/truck just enough inside so that the rear wheels are at the doorway, open the spill valve, and wait until no more sewage pours out.