Wastewater Plant History
The City of Fresno initiated its first sewer system in 1891 with the construction of a 24-inch outfall sewer to a 40-acre ‘sewer farm’ located southwest of Fresno, east of the existing treatment facility. The acreage proved to be inadequate for the town and an additional 40 acres was purchased to increase capacity. The sewage was used for irrigating alfalfa crops. Eight septic tanks were constructed in 1907 to provide partial treatment of the sewage prior to land spreading and irrigation.
By 1910 Fresno’s estimated population was 25,000, necessitating an expansion of the ‘sewer farm’ to meet the treatment needs of this burgeoning society. A major expansion began in 1909 with the purchase of an additional 812 acres and the construction of another 24-inch outfall sewer running parallel to the original outfall. This expansion is the current site of the Regional Wastewater Reclamation Facilities.
Expansion of the Sewer Treatment Plant kept pace with the demands of the City. In 1917 a 60-inch outfall sewer and eight additional septic tanks were constructed. An additional 500 acres of adjacent land, made available by dairies forced to vacate by the State Health Department due to sewage overflow onto their properties, were rented. This system proved inadequate resulting in an odor and fly nuisance.
In 1922, the City Council recognized the dire situation and commissioned a study, to recommend a solution to the sewage crisis. The study recommended lowering the groundwater elevation to increase percolation capacity. This would allow water to be extracted and used on local water irrigation systems. Construction began on nine extraction wells in 1924. The project was successful and temporarily solved the sewage crisis.
Sewer Farm Management began a new enterprise in 1933 to raise cattle feed (mostly alfalfa) irrigated by treated sewage. This operation ended in 1960 due to cost constraints. A major new treatment plant, Plant 1, was constructed in 1947 to provide primary treatment to sewage prior to continued land disposal and local irrigation. This plant consisted of a Headworks, Primary Clarifiers, Anaerobic Digester, and Sludge Drying Beds. The City’s increasing population required the construction of a second plant, Plant 2, in 1958.
In 1966, the City of Fresno was designated as the sewering agency for the local metropolitan area and assumed the role of developing a long-range, area-wide wastewater treatment and disposal plan. An engineering report recommended a five-stage program to meet long-range metropolitan needs. In 1970 construction began on the first stage of the wastewater treatment facility improvements. Due to odor problems from excessive winery wastes, the City set limits on winery waste discharge until a separate system was developed.
In 1972 the Regional Water Quality Control Board (RWQCB) imposed sanctions on the Treatment Plant because of past odor problems. New waste discharge limits were issued which required a higher level of treatment.
As a result, the Treatment Plant underwent major construction to meet RWQCB requirements. In 1975 a biological secondary wastewater treatment process was added to Plant 1. Additional anaerobic digesters and sludge drying beds were constructed which increased the treatment and disposal capacity to 46 MGD on 2,000 acres. A separate winery waste collection, transport, and disposal facility was also constucted to help the Treatment Facility meet RWQCB requirements. 1976 saw the addition of a flotation clarifier and trickling filter to Plant 2.
In an effort to reuse the raw material coming into and created by the facilty, a cogeneration facility was built to use the methane gas produced by the anaerobic digesters to partially meet the plant’s energy requirements.
In February of 1996, the RWQCB adopted a cease and desist order requiring the facility to increase capacity to meet demands. A major project that included the rehabilitation of the existing facilities, a new headworks, biosolids dewatering equipment, and additional process units to increase capacity were already under construction. The new facilities came online in the fall of 1996 with an increase in capacity to 68 MGD. By the time the 68 MGD project was started up, the flow to the plant was already in excess of 70 MGD. Another phase of expansion to increase capacity to 80 MGD began immediately after the 68MGD project was started up. The 80 MGD expansion was completed in February of 1998.