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City of San Mateo Municipal Code.


(a) An industrial waste pretreatment system may be required to treat industrial flows prior to discharge to the sewer when it is necessary to restrict or prevent the discharge to the sewer of certain waste constituents, to distribute more equally over a longer time period any peak discharges of industrial wastewaters or to accomplish any pretreatment result required by the City. All pretreatment systems or devices shall be approved by the City but such approval shall not absolve the user of the responsibility of meeting any industrial effluent limitation required by the City, County, State, or Federal government. All pretreatment systems judged by the Director to require engineering design shall have plans prepared and signed by an engineer of suitable discipline licensed in the State.

(b) A gravity separation interceptor, equalizing tank neutralization chamber and control manhole will be required respectively to remove prohibited settleable and floatable solids, to equalize wastewater streams varying greatly in quantity and/or quality, to neutralize low or high pH flows and to facilitate inspection, flow measurement and sampling. Floor drains from commercial or manufacturing buildings, warehouses, multi-use structures, areas where any waste requiring pretreatment is involved shall not discharge directly into the sewer, but shall first discharge to a gravity separation interceptor.

(c) Food service facilities shall have a pretreatment system for grease removal designed to serve all drains that may discharge grease into the sewer, including floor drains. Such system(s) shall be located outside of the building. Only where available space on private property renders outdoor placement infeasible shall interior installation of hydromechanical grease interceptors be approved.

(d) Facilities that conduct steam cleaning of engines, chassis, and other oily parts; and facilities that conduct radiator flushing shall install closed-loop water recycling and reuse systems, and shall not discharge waste from these operations to the sewer system.

(e) Photo-process waste shall be discharged through an electrolytic recovery unit followed by two ion exchange cartridges in series and pH neutralization block, or equivalent.

(f) Dental Clinics. Dental clinics and other facilities that generate dental amalgam wastes shall have devices for capture of amalgam on equipment that might carry amalgam waste to the sanitary sewer system.

(g) The Director may establish minimum pretreatment system requirements not specifically referred to in this section. Such requirements shall be based upon commonly used and properly maintained pretreatment technologies for a given waste.