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ARAMARK Uniform & Career Apparel, LLC Wastewater Pretreatment System Operating Instructions Stockton, CA The wastewater pre-treatment system receives wastewater primarily from industrial washers, softener regeneration and small amounts of wastewater derived from floor drains and utility sinks. Wastewater from washers, floor drains and utility sinks drain by gravity to an existing black water holding basin. Rinse water or grey water from the laundering process is discharged to another holding basin for reuse back in the laundering process. Wastewater from the black water basin is pumped through a vibratory screen to remove coarse solids. The wastewater is then directed through a heat reclaimer to capture remaining heat from the wastewater. After heat reclamation, the wastewater is discharged into a 106,000 equalization tank. The equalization tank is equipped with a mechanical mixer and process wastewater pumps for delivering wastewater to the chemical mixing chamber and dissolved air flotation clarifier. After equalization, wastewater is pumped through a 185 gallon chemical mixing chamber or "tube bundle" where organic polymers and inorganic coagulant aids are introduced to demulsify pollutants from the wastewater and facilitate particle separation. A cationic coagulant, bentonite clay and cationic flocculent provide the make-up the wastewater chemistry. These products are introduced into the tube bundle which provides high energy mixing that allows particle flocculation to occur. A 6,595 gallon dissolved air flotation clarifier equipped with inclined plates provides physical separation of suspended solids from the wastewater stream. The unit combines the technology of dissolved air flotation and gravity clarification. Dissolved air, injected into the waste stream, adheres to flocculated particles and floats these solids to the surface of the unit, which are removed by a mechanical skimmer into a solids holding tank. Higher density solids contact the inclined plates of the unit and settle. These solids are removed by an air diaphragm pump and sent to the solids holding tank. Solids contained in the holding tank are transferred by air diaphragm pump to a sludge conditioning tank. The dissolved air flotation clarifier will reduce concentrations of conventional constituents, oil and grease, suspended solids and trace metals.