Plant brochure designed by Charles L. Woodruff 1999 and revised in June 2004

Search The Wastewater Site

Newly renovated in 1998 at nearly $10 million dollars the advanced wastewater treatment facility features state-of-the-art technology to enhance and protect the water quality of Richland Creek. The treatment process uses both gravity and natural biological functions to continually improve the waste stream as it passes through each phase of the facility. There are 6 basic phases of treatment. Phase 1 consists of lifting and gravity flow of sanitary wastewater from the collection system to the headworks. Phase 2 pre-treatment consists of screening and grit removal as well as flow control to Phase 3. Phase 3 the oxidation ditch and fine bubble aeration is the heart of our treatment plant, this biological treatment process, reduces the amount of organics as well as ammonia nitrogen of the effluent. Phase 4 consists of clarifiers, tertiary clarifier and biological return system. The quality of the water is further enhanced by Phase 5 disinfections by ultraviolet light and Phase 6 post aeration before discharging into Richland Creek.
 

From the phase 2 treatment, the removed material, called grit, is taken to approved landfills for disposal. The solids generated by the phase 3 process are called bio solids or waste activated sludge. This material is wasted from the treatment process to mainly control biological growth in the treatment process. The solids generated by phase 3 are removed for thickening with a gravity belt thickener prior to disinfection of the bio solids in the ATAD process. Following the disinfection of the bio solids the solids are further de-watered on a belt filter press prior to disposing in an approved landfill or recycling with land application on farm land. Our bio solids are currently being recycled.

Plant Layout With Process Flow

Process Flow Block Diagram

Princeton is the third wastewater treatment plant (WWTP) in the Midwest to employ phased oxidation ditch technology to produce a high-quality effluent. The east plant consists of a three - (3) stage anaerobic selector and two oxidation ditches operating in the BioDenipho modes of (PID) Phased Isolation Ditch Technology and (2) Clarifies. During the time in the oxidation ditches, the mixed liquor is aerated to add dissolved oxygen into the mixed liquor, and to provide mixing of sludge and wastewater. The equipment associated with the Ditches includes horizontal brush aerators, submersible mixers, motor actuated weirs and dissolved oxygen probes. All the equipment is monitored and controlled by PLC-based control panels and (SCADA) Advanced System Control and Data Acquisition computer system. The SCADA system also optimises plant performance and provides continuous monitoring of the treatment facility and will alert operating staff immediately, 24 hours a day if there is an equipment problem or malfunction via pagers.

Discharge requirements, the National Pollutant Discharge Elimination System requires that the all WWTPs meet certain effluent limitations as set in their permit. A NPDES permit will contain plant operation requirements, sampling procedures, limits for pollutants that must be monitored such as pH, Dissolved Oxygen, E. Coli, Ammonia Nitrogen, Total Suspended Solids, Oxygen Demand, Cadmium, Copper, Cyanide, Lead, Mercury, Nickel, Zinc, sampling and analysis of sludge, bio monitoring (the toxicity of the effluent on aquatic life down stream). The NPDES permits requires that a WWTP be under the direct supervision of a licensed operator.

 

The Kruger Oxidation Ditches

Management Tools:

The City of Princeton Wastewater Treatment Plant has one superintendent, over the treatment plant, storm and sanitary sewer collection system and he also serves as superintendent over Street and MVH. We also have a pre-treatment coordinator, a chief operator who is licensed by the state, three plant operators, two maintenance persons, three sanitary and storm sewer collection system employees and one secretary.
 

Plant Staff as of 2005