Wastewater Treatment Plant

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Technology Fact Sheet

The Central City Wastewater Treatment Plant (WWTP) was bid in 1998 and began operation in 2000. The project was completed by Eriksen Construction of Blair, Nebraska and engineered by Olsson Associates with a total project cost of $4,553,198.92. The Sequencing Batch Reactor (SBR) facility includes ultraviolet disinfection and a sludge dewatering belt press. This link provides a technical review of the SBR process.

One employee runs the WWTP with the assistance of a computer controlled system. Since the plant runs constantly, the computer can call the operator after regular hours to report any problems. The plant consists of 4 square tanks that are 55 feet x 55 feet x 18 feet deep each. Each tank can hold 407,000 gallons of liquids.

The water is cleaned through a natural process of introducing bacteria into the wastewater reaching the plant. These bacteria, which we call the “bugs”, eat the nutrients in the water. Over time the bugs multiply and begin to die off, creating what we call sludge. The sludge falls to the bottom of the tank and clean water accumulates on the top. The clean water can be discharged and the sludge is collected for further treatment. There are no filters or screens used in the treatment process

The WWTP typically treats about 240,000 gallons each day. The domestic volumes remain fairly constant. However, the total water treated can vary widely depending on the weather, groundwater levels, and illegal dumping of water into the system. Click Here to learn more about the serious issues of Sewer Surcharges.

If you were to visit the plant, you would first reach the Control Building as you drove in. This building includes our laboratory, restroom, mechanical room and control room. To the left is the Blower Building which includes 8 air blowers essential for introducing oxygen into the treatment process to keep the bugs alive. A very large diesel generator is housed here for emergency operations if power goes out.

On the north side of the hill our ultraviolet light building disinfects the clean water before it leaves our facility. We take our water samples from this point to ensure compliance will all State and Federal regulations. The water leaves our facility through a discharge pipe that goes east until it reaches the Platte River.

The tall building is our Dewatering Building which consists of a belt filter press, control room, electric room and pump and sludge loadout room. This building allows us to remove the water from the sludge, which is important for purposes of storage, transportation and future use of the sludge. Once the sludge is pressed, it falls into a dumptruck with a consistency very similar to moist dirt. The sludge is then transported to the drying beds to the west of the plant. Every year or so the City will contract for the land application of this sludge to a field for its beneficial qualities as a fertilizer.

Wikipedia explanation of the SBR process.