Recycle and reuse, eco-friendly

Early in spring 2009, the City will bring a new Sewage Treatment and Water Reuse Facility online.  The City has completed construction of the facility and has begun “seeding” the plant which consists of introducing sewage to the facility in order to start the biological process which is the backbone of sewage treatment.  Once the seeding process is complete and the plant fully functional, the City will begin diverting flows from existing parts of the City via the Fowler Avenue sewer trunk main to the plant.

This project has been a cooperative effort between the City of Clovis, Fresno Irrigation District, Fresno Metropolitan Flood Control District, Fresno County, and the State Regional Water Quality Control Board and Department of Public Health.

The City selected the firm of CH²MHill to design, build, and operate (DBO) the facility.  The DBO process allowed the City to minimize risks and obtain the greatest efficiencies possible since the same firm who designed the project is also responsible for building it and then operating it.  The CH team has been key to the successful implementation of this project.

This facility is unique in two very important aspects.  First, it is a state-of-the-art treatment facility utilizing the latest technology to safely and effectively treat sewage.  Second, it will provide an additional water supply to the City that was not previously available.

The process selected for the City of Clovis Sewage Treatment Water Reuse facility was an advanced membrane bioreactor filter (MBR) for the liquids treatment and the USFilter Cannibal™ process for the solids handling.  The MBR uses a biological process to “digest” the organic material in the sewage and then remove the remaining nondigestable solids from the water. The solids removed are then further reduced and consolidated by the Cannibal™ process. The filtered water from the MBR process is then disinfected through the use of ultraviolet light (UV).  These processes create a wastewater facility design that combines the high-quality effluent benefits of MBR technology with the minimization of residuals production that is possible only with USFilter’s Cannibal™ process.  Use of UV for disinfection eliminates the problems that can result from chlorine disinfection byproducts.

• Responsible Innovation: The use of innovative technologies, such as membrane bioreactors and the Cannibal™ process provide a very high level of treatment at a reasonable cost.

• Beneficial Use of Residuals: The best strategy for residuals is to not produce them in the first place.  The Cannibal™ process minimizes the volume of solids produced which greatly reduces the cost of solids disposal, and reduces the capital cost of the plant.

• Minimize Footprint: A small footprint will reduce project capital and operating costs and minimize the impact on the surrounding environment.  The MBR process provides the smallest footprint of any of the secondary treatment options currently available.

• Good Neighbor: The Facility design will minimize the impact upon the surrounding neighborhood.  The design eliminates the impact of odors on the area outside of the Plant boundary.  Equipment was selected and arranged to minimize the visual and noise impact of the plant on the surrounding area.  Minimizing residual production also reduces truck traffic in the neighborhood.

• Lowest Life-cycle Cost: CH²MHILL’s integrated team focused on determining the lowest life-cycle cost by developing the optimum balance between process design, operations, and construction.

The benefits of a much reduced footprint, improved aesthetics, superb effluent quality, and reduced capital/operating costs significantly outweigh the minimal and well understood risks assumed by CH²MHILL for proposing these innovative approaches.

The MBR secondary treatment process provides many benefits for the final disinfection process.  The MBR effluent itself is essentially free of coliform as a result of the membrane barrier.  The very low turbidity of the MBR effluent vastly improves the effectiveness of UV disinfection.  The disinfection of the wastewater for reuse purposes is controlled by Title 22 of the California Code of Regulations.

The elements of this system work together to provide the City of Clovis with an effluent quality that meets or exceeds all regulatory requirements.

After disinfection, the tertiary treated water is discharged to a storage tank that is part of the recycled water distribution system.  Recycled water will be used to irrigate open spaces in the eastern areas of the City, replacing potable water that is currently used for this purpose.  The City is also negotiating with other potential users of recycled water including Clovis Unified School District, Caltrans, and CSUF.  The City is also exploring the feasibility of making the water available to farming operations east of town.

Besides the obvious benefit of treating sewage in a safe and environmentally responsible manner, this facility has the added benefit of keeping this water in the Clovis area.  This allows the City to rely less on the groundwater aquifer which in turn helps reduce regional overdrafting.  In addition, it will allow the City to make current potable supplies available to areas of the City that may not have adequate water to accommodate planned growth.

This facility has been designed not only to function well, but to also blend in with the surrounding neighborhood.  The architectural features of this facility along with the landscape surrounding the installation resemble a business campus which is the future planned land use in the area.  Noise and odor control have also been addressed as a part of the design.  When the facility is complete and operational, you won’t see it, smell it or hear it.