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Home My WebLink AboutCOM2000-00129 CARWASH - COM Permit / Conditions - 3/1/2000 ATATg OPY f 18 8 ( 401 STATE OF WASHINGTON DEPARTMENT OF ECOLOGY P.O. Box 47775 • 01YInPia, Washington 98-504-777.5 • (360)407-6-300 June 28, 2001 Mr.Jack Johnson P.O. Box H 19 Belfair, WA 98528 i Ex E W I RE: "Vehicle Washwater Engineering Report and Construction Plan,Johnson Car Wash, Belfair, Washington",prepared by American Engineering Corporation,dated May 29, 2001 Dear Mr.Johnson: Pursuant to RCW 90.48.110 and WAC 173.240.630,the above-referenced engineering report and construction plan has been reviewed and is hereby approved. One copy of the approved document is being returned for your records. If you have any questions concerning this approval, please telephone Norm Schenck at(360)407-6290. Sincerely, �.v " Kelly Susewind, P.E. Southwest Regional Supervisor D3 229-23 dZZ Water Quality Program KS:NS:Imc(33/wq) Enclosure k�3 cc-. Terry Howard,American Engineering Corporation i ENGINEERING REVIEW of PLANS FOR CONSTRUCTION of WASTEWATER FACILITIES Document Name: "Vehicle Washwater Treatment Engineering Report" Document Date: May 29,2001 (Received May 30,2001) Document Type: Engineering report Industrial Activity: Johnson Car"Nash Prepared by: American Engineering Corporation Review Authority: State of Washington Department of Ecology Reviewed by: Norman K. Schenck,P.E. Date: June 21,2001 1 WA Cy�� t • 28682 IS9'i:�� E PIRES 12-15--01 —71 Pursuant to RCW 90.48.110, The Department jf Ecology must approve plans and specifications for the construction ofsewage treatment systems before construction may begin. WAC 173 240 has encompassed industrial wastewater in the term "sewage", and "engineering reports"in the term `plans and spectflcadons for construction', and further, has stipulated the required contents of an "engineering report". The review is in the context of these requirements. The technical scope of this review is limited to the design concepts for collection, conveyance, storage, treatment and disposal ofwastewaters, in terms ofstrategies, capacities and reliability to accomplish the regulatory discharge con at Yirrts. INTRODUCTION In accordance with the legal requirements,an engineering report was submitted for review and approval of proposed wastewater facilities associated with a proposed car wash in Belfair, Washington,an unsewercd community.The p i irpose of the review is to assure that the design is likely to reliably accomplish the intended purpose of collecting,conveying,storing,treating and discharging the wastewater,particularly with respect to compliance with minimum technology- based and water-quality-based standards as mny have been set by federal and state regulations and implemented through discharge permit cai iditions. L PROPOSAL SUMMARY The submitted engineering report describes the basis for the design and operation of proposed wastewater facilities in conjunction with the proposed Johnson Car Wash facility at Belfair in Mason County,Washington.The wastewater discharge from the proposed car wash would be directed to a treatment train consisting of grit removal,oil-water separation,clarification, OilTrap®"electro-pulse"treatment,activated carbon adsorption,and proprietary StormFilterO filtration prior to subsurface discharge via infiltration trenches. The stated purpose and intent of the proposed wastewater facilities is to assure that water discharges from these activities will comply with regulatory discharge limitations and receiving water standards by adhering to the requirements of the Department of Ecology's Vehicle and Equipment Wastewater Discharges—Best Management Practices ManuaL The initial receiving water of any pollutants from this discharge is presumed to be ground water. FEASIBILITY STUDY/ALTERNATIVE EVALUATION Several options for dealing with the wastewater were evaluated against the criteria of effectiveness,feasibility and implementability. Effectiveness was judged appropriately according to the following management priorities in descending order of preference,as laid out in the Manual: (1)no discharge(total recycle); (2)discharge to municipal sewer system; (3)treatment and discharge to ground;(4)discharge to surface water. The option chosen is a combination of(1)and(3),i.e.,partial recycle,with treatment and discharge to ground of the excess.Washwater would be treated and reused,but for spot-free cleaning,total recycle is not feasible.The rinse water is therefore taken from the potable supply, and discharged to the treatment and reuse system,causing an overflow, effectively a system "blowdown".This excess,approximately equal to the rinse water usage,is the discharge stream. It would amount to about 35 —45%of the water used,according to the report. The selected management option appears to be a prudent choice,reusing water to the practical limit,discharging only a faction of the water used,and discharging a treated wastewater. ENGINEERING EVALUATION Discharge Quantity Design Data The treatment,re-use and partial discharge system proposed is intended to serve a facility with five self-serve,wand-type car wash bays(4 regular and one large)and one automatic car wash bay.Water use rate has been projected in the report based on 12 hours per day operation of the equipment and 19 days per month(to account for rainy days). The total water reused and treated is projected to be about 6600 gallons per day. Of that treated water,2,750 gallons per day are projected to be discharged to the infiltration trenches. Discharge Quality Design Data Data are presented,apparently from a one-time sampling,representing wastewater(influent and effluent)from a similar,existing operation and treatment train at another location. Oil and grease was reduced from 9 mg/L to less than the method detection limit of 5. TSS is reduced from 88 mg/L to 6. Seven metals were analyzed before and after treatment. Copper appears to have been significantly reduced(from 0.13 mg/L to<0.006)but nickel and zinc were only marginally reduced. Surfactants were present in the effluent at 21 mg/L.No other potential constituents(such as specific solvents)were analyzed. 5 ' s Treatment Unit Design Basis There is no design basis presented for the grit traps and oil/water separator.The clarifier has a detention time of 3.9 hours at peak day flow and,as such,is expected to remove at least 80%of silt-sized suspended solids.The design basis used is the Camp Hazen equation as presented in the Department of Ecology publication,Siormwater management in Washington State, Rungfj'' Treatment BMPs. There is no basis for the design of the OilTrap®"electro pulse"unit,with the explanation that is a proprietary secret.There is also no basis for design of the activated carbon adsorption unit,nor for the design of the another proprietary unit in the train,the StonnFilter®, except that it is said to be designed to treat 15 gpm,while the peak flow will be less than 10.No design basis for the infiltration trench is presented in the report. Compliance with Standards A Department of Ecology publication, Vehicle and Equipment Washwater Discharges Best Management Practices Manual(June 1995),has provided specific regulatory guidance for vehicle wash discharges.Where discharge to ground is proposed,this document recommends a treatment system incorporating gravity oil/water separation and a multimedia filter.Expected effluent quality associated with this system is defined as<75 ppm TSS and<10 ppm Oil& Grease. Allowance is made for installation of alternative treatment methods,if they provide equivalent or better treatment.The implication of the guidance manual is that if the recommended treatment(or an equivalent or better system)is employed,it may be constructed and operated without specific approval or discharge permit. The engineering review task in this case then,where the proponent has asked for approval of a different system,is only to assess whether or not the proposed treatment is equivalent to or better than the recommended system.It is not possible to make this assessment on a pollutant-by- pollutant comparison basis,since the recommended system itself has not been so characterized. However,in the judgement of the reviewer,the proposed system of grit removal,oil/water separation,clarification,carbon adsorption and filtration,would be at least equivalent to and probably superior to the recommended system in reducing all the potential pollutants of concern (generally speaking,solvents,surfactants and metals),and in any case capable of meeting the expected discharge quality criteria,and at least as likely to meet ground water quality criteria. Therefore,the system must be regarded acceptable in terms of meeting the requirements of the Department's guidance manual. Recommendation for Approval Approval of the engineering report is recommended. (The treatment system proposed is determined to be equivalent to or better than the recommended multi-media filter,based on professional engineering judgement about the unit operations and processes involved.Although the report is deficient in terns of design information and basis,there is no more design information and basis provided in Ecology's manual for the recommended system,and no report at all would be required if peat filters were being proposed.)