When you flush water down a drain, either in a sink, tub, shower, or toilet, your water, with the help of gravity, flows through a network of pipes that increase in size the closer they get to the wastewater treatment plant.  GMD’s staff of skilled Collection System Operators inspect, clean, maintain, construct, and repair those pipes.  They ensure that the series of pipes is clear of blockages and has the capacity to meet the needs of you and your neighbors. They safeguard public health by preventing sewer overflows.

Once your water has taken a trip through our sewer system, it has made its way to one of our wastewater treatment plants.

First, the wastewater that you washed down your drains will go through a primary treatment process, which aims to remove all large particles and debris.

Then, for secondary treatment process, organic matter is removed with bacteria that break down pollutants before the water is disinfected with ultra-violet light to remove the bacteria.

Finally, your water has been made safe to be returned into the environment and local rivers and lakes. The treated wastewater could go on to become drinking water, be used to irrigate crops, and help sustain aquatic life.

Collection System Components

A wastewater collection system is a series of pipes that transport wastewater from homes, businesses and industries to a centralized treatment plant. Transport of the wastewater is either by gravity (the preferred method) or with the use of sanitary lifts or pump stations to either a location that gravity can be used or to another lift or pump station and finally to the wastewater treatment plant. In either case, the collection system has many functioning parts as shown and described below.

House Sewer (service Lateral) conveys the wastewater from a building to the sub-main (collection) lines. Typically, these are 4-inch diameter pipes.

Sub-main Sewers are collectors for numerous house laterals from an area of several hundred acres or a specific neighborhood or housing development. They convey the wastewater to larger trunk sewer lines, to lift stations. These lines are generally 8-inch to 12-inch diameter pipes.

Trunk/Main Sewers serve as the main arteries of the wastewater collection system. They collect and convey the wastewater from numerous main sewer lines to a wastewater treatment plant. In our system these pipes range from 15-inch to 72-inch diameter.

Lift or Pump Stations are utilized in gravity sewer systems to lift (pump) wastewater to a higher elevation when the route followed by a gravity sewer would require the sewer to be laid at an insufficient slope or at an impractical depth. Lift stations vary in size and type depending upon the quantity of wastewater to be handled and the height it must be lifted.