Publicly Owned Treatment Works (POTW) collect wastewater from homes, commercial buildings, and industrial facilities that is transported via a series of pipes, known as a collection system, to the POTW. Collection systems can flow entirely by gravity and can also include lift stations, which pump wastewater by force mains to a higher elevation from which it was pumped, that continues by gravity.
Generally, POTWs are designed to treat only domestic waste, not most toxic or non-conventional pollutants that are present in industrial waste. Consequently, discharge from both industrial and commercial sources can cause problems at the POTW and can have detrimental effects on the water quality of the receiving waterbody, in our case, the Rogue River. The act of treating the waste before discharging to the Collection System is referred to as pretreatment. The City's Pretreatment program prevents the following:
- Prevents the introduction of pollutants into the POTW that will interfere with the operation, including interference with its use or disposal of municipal sludge.
- Prevents the introduction of pollutants into the POTW that will pass through the treatment works into the receiving stream or otherwise be incompatible with such works.
- Improve opportunities to recycle and reclaim municipal and industrial wastewaters and sludge.
Pretreatment regulations apply to all nondomestic sources that introduce pollutants into the POTW. These sources are commonly referred to as Industrial Users (IUss). Many of the Pretreatment regulations apply to Significant Industrial Users (SIUss) opposed to IUs. The distinction is that a SIU is defined as of any of the following:
- An IU subject to federal categorical pretreatment standards.
- An IU that discharges an average of 25,000 gallons per day (gpd) or more of process wastewater to the POTW.
- An IU that contributes a process wastewater making up 5 percent or more of the average dry-weather hydraulic or organic capacity of the POTW.
- An IU designated by the POTW because of its reasonable potential to adversely affect the POTW's operation or violate any pretreatment standard or requirement.
A Pretreatment Operator is assigned to follow strict EPA and DEQ guidelines by submitting data, collecting samples, surveying industrial users, inspecting significant industrial users and industrial users. The operator also keeps up the City's inventory of IUs, as well as, any discharge permits required. The City's Pretreatment Department does the following to protect the POTW and the Collection System:
- Issues wastewater discharge permits to IUs/SIUs.
- Collects samples of the collection system, POTW, and from any industry with a discharge permit.
- Enforces Local Discharge Limits on SIUs.
- Enforces the City of Grants Pass Sewer Use Ordinance 8.50.