Wastewater Treatment Process
With modern equipment and experienced operators, PPV is able to treat wastewater in the most efficient, and therefore cost-effective, manner possible.
While PPV configures the system to best treat each individual waste stream that it receives, the following information provides a description of a typical treatment process.
Pre-Screening process
Each load that is received is put through a process which entails a liquid, solids separation, utilizing various screening processes.
Batch Treatment
Each load received at PPV is sampled, analyzed and batch treated.
Further Clarificaton
In order to meet some of today’s water quality criteria-based discharge limits, all water is processed through three optional treatment trains (centrifuge, dissolved air flotation and ultra filtration) before final discharge to city sanitary sewer.
Equalization & Clarification
After batch treatment, wastewater is transferred to equalization (EQ) storage tanks. Contaminants remaining in the water at this point are removed through an additional series of chemical reactions and physical separation. At this stage, the water is also conditioned for further treatment.
Quality Control
Before accepting any waste stream, PPV’s samples and performs extensive treatability testing to:
- Pre-screen incoming waste streams to establish influent levels of several contaminants, including metals, COD, TSS and PH.
- Determine whether the stream can be treated effectively enough to meet PPV’s discharge permit limits.
- Establish a treatment for each stream to be optimally batch treated.
Instrumentation & Control
All of the treatment processes described above are automatically controlled by a centralized programmable logic controller (PLC). Alarm points in the tanks notify operators whenever manual intervention is necessary. Similarly, the automatic controller continuously monitors the effluent discharge for pH and turbidity; the two primary indicators that the treatment process is under control.
Acceptance Criteria
PPV is able to accept water and wastewater that is not classified as hazardous by the Oregon Department of Environmental Quality (OR DEQ) or the US EPA, and that is treatable at our facility.
What is considered Non-Hazardous Wastewater?
Non-hazardous wastewater is defined as groundwater, construction/highway project water, industrial process water, or other wastewater that does not exhibit any hazardous characteristics (ignitability, corrosiveness, reactivity and toxicity) and is not a listed hazardous waste.
Treatability
Sometimes wastewater may qualify as non-hazardous, but may not be treatable at our facility, or may cause PPV to violate our discharge permits from the City of Portland. Therefore, in some cases, we have to look at the Material Safety Data Sheets (MSDS) of the known chemical constituents of a waste stream to evaluate toxicity and other properties that have the potential to cause problems with our discharge permit.
