Septic Systems can be used in large commercial applications as well as smaller residential ones. Sometimes, when a large corporate headquarters or off-site production facility is created in a rural setting or a location where municipal sewer facilities are not yet available, a large commercial septic system may be a viable solution. In essence, these systems resemble a mini-wastewater treatment plant, with screening, settling, removal of residual bio-solids, and redistribution of treated water into the groundwater or waterway system.