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Waste Water


Waste water refers to any water that is flowing out of a home, commercial structure and property after use.

These two photos are of Parshall Flumes, one is a newly manufactured flume, and the one on the right is the flume that is in use at the wastewater treatment facility, located in the Influent building. Parshall flumes are a fixed hydraulic structure commonly used to measure municipal sewer flows. They can vary in size depending on the design capacities of a plant. The plants flume is an 18 inch and at the time the photo was taken the flow was at 1,042 gallons per minute (gpm) or 1.5 million gallons a day.


Measuring the Flow

We have two ways of measuring flows with the Parshall flume one is by a staff gauge that is mounted inside the flume that shows inches of flow. These inches correspond with a chart, which cross references the inches with flow in gallons per minute (gpm) and million gallons per day (MGD). The other device is an Ultra Sonic flow measuring sensor that also measures the inches of flow and sends the data to our Supervisory Control and Data Acquisition (SCADA) system located in the operations building. The Ultra Sonic device is gray and is at the top middle of the right hand photo.


Waste Water Acronyms

Below are common terms used by waste water operators and laboratory personnel:

Mean Cell Residence Time (MCRT): The average time that a microbe is in the treatment process before being removed.

Sludge Volume Index (SVI): A measure of the ability of sludge to settle

Food to Microorganism Ratio (F/M): A ratio to determine the balance of food and microorganisms in the treatment process.

Mixed Liquor Suspended Solids (MLSS): Total amount of organic and inorganic material in suspension.

Mixed Liquor Volatile Suspended Solids (MLVSS): Fraction of MLSS that indicates organic solids

Total Suspended Solids (TSS): The sum of all insoluble particles suspended in water.

Biochemical Oxygen Demand or Biological Oxygen Demand (BOD5): Amount of oxygen used by organisms over a 5 day period.

Chemical Oxygen Demand (COD): Amount of oxygen used to oxidize all organic compounds.

Waste Activated Sludge (WAS): Sludge that is removed once its life cycle has ended.

Dissolved Oxygen (D.O.): Measurement of the amount of oxygen dissolved in water.