A Sewer Discharge Station (SDS) is a point along the sewermain that can be legally accessed and used for discharging septage and sludge directly into the sewer so that it can be transported to a (Semi-) Centralized Treatment facility. SDSs are intermediate transfer points for sludge that cannot easily be transported to a dedicated treatment facility. Sludge can be dumped in a local SDS rather than either a) dumping it illegally or b) trying to travel to a distant collection point. Sludge is dumped into the SDS and then either released directly to the sewer or held in a temporary storage tank before being released to the sewer at a set time. Timed release can help prevent solids from building up in the sewer line and also help optimize the treatment efficiency of the treatment technology by reducing peak loading. A SDS consists of a parking place or discharge dock for the vacuum truck or sludge cart and a connection point for the discharge hose. The SDS may also have a storage tank and pumping system. The dumping point should be built low enough to minimize spills when labourers are manually emptying their sludge carts. Additionally, SDS should include a vent, a trash screen to remove large debris (garbage) and a washing facility for vehicles. The station should be well protected and maintained to prevent random dumping into the sewer and to ensure the safety of the users. A variation is a stand-alone Transfer Station that is not connected to a sewer main (for more information, refer to: Transfer Station (Underground Holding Tank). When the Transfer Station is full, a vacuum truck must empty the stored contents and take the sludge to a suitable treatment facility. If the municipality or sewerage authority is operating the Transfer Station they may charge for permits to dump in the Transfer Station to offset the cost of maintaining the facility.