This active treatment facility was contructed by the PA Dept. of Env. Active mining operations often still build similar systems because the technology is well understood and because the mining companies must comply with effluent standards or face stiff fines.
Passive technologies are still relatively experimental.
However, the science of passive treatment is becoming better understood, and the passive treatment system do not fail catastrophically. If power is lost to an active treatment site, or if a company goes bankrupt, active treatment stops. Except at very high flows, all of Rausch is diverted into the facility. There are two clarifiers which are followed by single thickener. The slurry from the bottom of the thickener is pumped either to the sludge holding tanks or to a belt filter press.