 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
2009 E3 Design Honor
City of Clovis Sewage Treatment/Water Reuse Facility
Clovis, California
ENTRANT: CH2M Hill
ENGINEER IN CHARGE: Steven C. Patterson, P.E.
 |
 |
 |
 |
 |
 |
Entrant Profile
The City of Clovis was interested in building a city-owned Sewage Treatment and Water Reuse Facility (ST/WRF) in the Southeast area of Clovis, California. CH2M Hill was hired to design, construct, operate and maintain the facility for 10 years (including repair and replacement activities), and assist in obtaining permits and government
approvals for the new facility.
The design-build-operate contract was a departure from Clovis' customary procurement method and provided opportunity to consider investments over the life of the contract. The single-source alternative helped overcome current market conditions to finance the project at a competitive price.
The primary goal of the $37 million project was to design a ST/WRF to initially treat 2.8 million gallons per day (MGD) with the potential for expansion to 8.4 MGD as the City of Clovis grows. The project would also include the design and construction of a pump station to service the ST/WRF and the upgrade of a separate pump station to also service the new ST/WRF. Additionally, the process design had to reliably meet or exceed its goal for cost, effluent quality, aesthetics, and environmental impact.
CH2M Hill developed a solution to reliably meet the City's goals using proven process solutions in combination with innovative solids reduction technology. The ST/WRF will relieve the demand on underground and surface water supplies, will provide recycled water for irrigation, will use less energy, and is incredibly neighbor and environmentally friendly.
Project Description
CH2M Hill was hired to design, build and operate a Sewage Treatment and Water Reuse Facility (ST/WRF) for the City of Clovis. The project was the most complex the city of Clovis has ever undertaken.
CH2M Hill was chosen, in part, because of its innovative design that features a small plant footprint. The design allows for two future duplications of the plant being built without the need to procure additional land.
The primary goal of the program was to design a ST/WRF to initially treat 2.8 million gallons per day (MGD) with the potential for expansion to 8.4 MGD as the City of Clovis grows. The project also includes the design and construction of a pump station to service the ST/WRF and the upgrade of a separate pump station to also service the new ST/WRF. Additionally, the process design had to reliably meet or exceed its goal for cost, effluent quality, aesthetics, and environmental impact.
Integrated Approach
The new facility, featuring membrane bioreactor (MBR) technology and the patented Cannibal™ sludge reduction system, will reduce the area's impact on groundwater sources and provide recycled water for irrigation. To minimize environmental impacts, the facility was designed with comprehensive odor control and containment, as well as technologies that limit truck traffic around the facility by reducing chemical use and residuals hauling. This is the largest application of the Cannibal™ technology to date in California.
For disinfection, the plant uses low-pressure, high-output ultraviolet lamps that require one-third the amount of energy used by other ultraviolet options. Membrane bioreactors provide the opportunity for better automation, reduced facility size, improved treatment, and reduced environmental impact.
The Design-Build-Operate (DBO) turnkey delivery contract with CH2M Hill provides seamless delivery, resulting in a single point of contact and responsibility.
Quality
In 2008, the Clovis ST/WRF DBO project was honored with a Water/Wastewater Project Merit Award by the Environmental Business Journal in its yearly Business Achievement Awards. CH2M Hill was recognized for innovation in MBR and UV design features, as well as excellence in alternative project delivery.
The process is designed around a membrane bioreactor process delivering California Title 22 effluent water to the Fresno Irrigation District (FID) until the City's reuse delivery system is completed. The final stage of treatment includes the disinfection process provided by Wedeco, of which will be the first Low-Pressure High Output installation as approved by the California Department of Public Health regulations.
Originality/Innovation
First Tertiary Treatment Plant in Calif.: The facility is the first tertiary treatment plant in California completed by the DBO method.
The patented sludge reduction system can reduce the amount of biosolids by 90% and is the largest application yet to a California plant. The unique process is a two-step system that first involves physical separation using 250-micron screens-10 times finer than most others-to trap untreated organic material that passes through the upstream process. The second step relies on a biological stage that works much like a mini-digester.
Once again, the application to the plant was based on life-cycle considerations that will translate fewer truckloads of sludge to haul from the plant to land application sites or other disposal locations.<
The level of automation allows the plant to operate with one four-man shift daily. The shift is backed up during off hours by a SCADA that takes the plant's pulse 24/7 to ensure a quick response to any problems.
The system provides CH2M Hill the capability to remotely run and troubleshoot the plant via a laptop or central station in addition to simultaneous monitoring by the city.
Complexity
Although the city of Clovis treats its potable water with chlorine, the permit for the new sewage plant prohibited the discharge of any chemically treated effluent. Several options were considered over two years of negotiations before the city selected UV for the plant's process chain and earned approval. The low-pressure, high-output lamps will use one-third the amount of comparable energy, resulting in a projected savings of approximately 200 kW of power.
The MBR was not dictated by the city, but the system was justified by a life-cycle analysis over 10 years of operation. Although membranes are higher in initial cost than other options, they offered CH2M Hill better opportunity for automation, reduced facility size and more odor control. Unlike most wastewater treatment plants where the UV operates within exposed channels, the ST/WRF pumps the wastewater through the vessels in a fully enclosed piped system.
Social/Economic Advancement
Plant Aesthetics: The facility is designed to blend in with the local residential and business community. Architectural features include prairie-style architecture, water features, and extensive landscaping and screening to minimize visual impact.
Air Quality: Because the plant has many odor sources, CH2M Hill designed an aggressive, state-of-the art, plant wide odor control system to reduce aesthetic impacts on the community and contain and treat all odors. The odor control begins with physical enclosure of the treatment stream and is enhanced further by a two-stage treatment process. In the first stage, the foul air is passed through the membrane aeration system. In the second stage, foul air is directed to a non-chemical biofilter that uses organic compost media (wood chips) to treat any residual odor. The foul air passes up from the bottom through 4 ft of media used in this premium final treatment system whose performance can be monitored around the plant perimeter.
Biosolids Reduction: The patented sludge reduction system used can reduce the amount of biosolids by 90% and is the largest application yet to a California plant. The unique process is a two-step system that first involves physical separation using 250-micron screens-10 times finer than most others-to trap untreated organic material that passes through the upstream process. The second step relies on a biological stage that works much like a mini-digester. The application to the plant was based on life-cycle considerations that will translate to fewer truckloads of sludge to haul from the plant to land application sites or other disposal locations.
 |
 |
 |
 |