BEI provided sanitary engineering services to a the Pride of San Juan in San Benito County to design a treatment system to reclaim their process wash water for irrigation. The design flow was 150,000 gallons per day. The treatment system components consisted of a grit separator, sand filters, two pump stations, a treated water storage pond, and interconnecting piping and valves. The reclaimed water was pumped to an irrigation system to water vegetable fields.
Sonoma County, California
BEI provided sanitary engineering services to Sonoma County to design a wastewater treatment plant for the City of Monte Rio. The design flows were an average dry weather flow of 100,000 gallons per day (gpd) and a peak flow of 140,000 gpd. The treatment plant components consisted of a drum screen, sequencing patch reactor, sand filters, UV disinfection, and sludge bagging. The treatment system was designed to fit into a building constructed to look like a barn. The treated effluent was pumped to an infiltration system consisting of trenches and subsurface drip irrigation.
City of Auburn, California
The City of Auburn has a 1.67 MGD activated sludge oxidation ditch treatment plant with wet weather storage and treatment ponds and a wastewater collection system with 12 lift stations. BEI has been consulting with the City in improving the compliance record at the wastewater treatment plant, improving the reliability and fail-safety of the lift stations, implementing the City’s pretreatment program and locating the sources of high coliform counts in the Auburn Ravine drainage basin. In addition, BEI successfully assisted the City in defending against a citizen lawsuit directed against the treatment plant’s compliance record and assisted the City in negotiating a new NPDES discharge permit. The new permit allowed the City to proceed with implementation of a much more cost-effective treatment plant improvement program than would otherwise have been allowed. BEI prepared the facilities plan addendum, design drawings and specifications, and office and field engineering services during construction for implementation of this project. The project consisted of installing a new influent headworks with a new screening system, upgrading one of the ponds to full secondary treatment to be operated in parallel or series with the oxidation ditch, optimizing wet weather storage in the ponds, and converting the existing chlorine disinfection system to ultraviolet disinfection to enhance protection of the environment, plus miscellaneous other plant renovation projects. The project was financed through the State’s Revolving Loan Fund.
City of San Juan Bautista, California
BEI is responsible for the monitoring of the sewer collection system and operation and maintenance of the wastewater treatment plant for the City of San Juan Bautista. The current collection system includes two lift stations. The treatment plant was originally an aerated pond system followed by chlorination prior to discharge to a drainage ditch. BEI was responsible for the planning and design of improvements required to reduce the potential impacts on downstream water supplies. The improvements consisted of conversion of the ponds to one aerated pond followed by an engineered duckweed (Lemna) system, nitrification using fixed film growth media, pressure filtration, and UV disinfection. During the design process, pilot studies were conducted to confirm that UV disinfection following dual media filtration could provide adequate disinfection. UV disinfection was selected to avoid potential impacts of disinfection by-products on downstream water supplies. The project was funded by the State through the Small Community Grant Program. Later , improvements were required to meet new chronic toxicity limits. BEI was responsible for the planning and design of improvements. The improvements consisted of converting the first aerated pond to a sequencing batch reactor and the second pond to sludge storage and flow equalization of the treated effluent from the SBR. A baffle was installed in the second pond to separate the sludge storage from the equalization.
City of Hollister, California
The City of Hollister had a pond treatment facility followed by land disposal. BEI’s project work included: the design of the original sewer outfall, the treatment plant, and the land disposal system; the preparation of a master plan for expansion of the treatment plant and sewer system; design and construction of treatment plant renovations; and design and construction of the expansion of the land disposal system. Additional project work has included several evaluations of the treatment plant’s capacity, reports on the impact of industrial wastes, reports on the capacity of the plant, micro computerization of the city’s public works data base (treatment plant operations data and sewer system model), and new revenue studies for the water and sewage systems.
Cielo Vista Subdivision, San Benito County, California
BEI is responsible for the contract operation and maintenance of the Cielo Vista Estates wastewater treatment system. This subdivision near Hollister, CA has a sequencing batch reactor followed by disposal to a leachfield. The effluent quality from the sequencing batch reactor is critical to continued performance of the disposal system. BEI operates this 100,000 gpd system under contract to San Benito County and is responsible for all monitoring reports to the Regional Water Quality Control Board and preparation and updating of O&M manuals and Emergency Spill Response Plans (ESRP) but is exempt from having to provide a Sanitary Sewer Management Plan (SSMP). The plant has consistently met all discharge requirements except salt levels due to water softener use by the homeowners.
Napa River Reclamation District, Napa, California
A complete wastewater collection, treatment, and disposal system was planned, designed, and built for the Napa River Reclamation District. The project involved review of bid documents, construction engineering and inspection services, as-builts, an O&M manual, sewer use ordinances, and a revenue program. The facilities constructed include community septic tanks, low pressure sewer lines, and a mound disposal system. The leachate from the mound system was collected and pumped to ponds which are designed to provide waterfowl refuge. The wastewater will ultimately be disposed of by evapo-transpiration from the mound system and by discharge to marshland during wet weather. The system has been in operation for over 10 years and has proved to be highly cost-effective and reliable.
City of Sunnyvale, California
BEI prepared a report on the best long term use of what was once a third sludge lagoon. The study involved evaluation of all algae and primary sludge production and disposal requirements and projection of the need for use of the third lagoon in future sludge storage to see if this land could be put to better use.
City of Sunnyvale, California
BEI, in conjunction with EOA, Inc., completed an evaluation of the reliability of the City of Sunnyvale’s municipal wastewater treatment facility. To protect the beneficial uses of the receiving water of the South San Francisco Bay, the objectives of the study were: determination of treatment process stability, identification of the reliability of the plant’s mechanical systems, and identification of the need for additional reliability measures. Key factors in the study were the associated costs and benefits, as well as consequences, on the beneficial uses of the receiving water of implementing or not implementing the measures. BEI was also responsible for developing a recommended program for improving plant reliability.
North Marin Water District, Oceana Marin, California
BEI studied and designed a shallow sand trench disposal system to maximize the effluent disposal capacity from the pond treatment system serving the Oceana Marin development. The system included a dosing siphon and a series of eight trenches following the contours of a hillside below the pond. Valving was provided to allow dosing to any one of the trenches individually and to isolate either half of any trench. Following installation, BEI assisted the district in testing to establish the significantly increased capacity of the system and to obtain approval of that capacity from the North Coast Regional Water Quality Control Board.