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INTRODUCTION I Mr. Jadi Singh is the owner of the Chevron Service Station Complex,which includes a Subway Sandwich Shop and a Hot Stuff Pizza Shop within the Chevron Mini-Mart Building. Wastewater from these food service facilities flows into an existing grease interceptor tank. Wastewater from the restrooms serving employees and customers flows into a small 1.2k gallon trash/surge tank before effluent from these two tanks enters the MicroSepTec Package Treatment Plant. This treatment system is composed of three separate treatment modules (a.k.a. EnviroServers). Only two of the three treatment tanks have been operational for the past several years. Effluent from the MicroSepTec treatment system is then pressurized for disposal to the adjacent leachfield, which has completely failed. For a number of reasons,the receiving leachfield has failed and effluent is surfacing. Failure can be attributable to: 1.) The receiving soils were never conducive to managing the wastewater flow volumes due to highly compacted,high density silt soils and an inadvertent compaction of a portion of the current leachfield area. 2.) The receiving silt soils have become inundated with biomat formation. 3.) The 1,200 gallon headworks trash/surge tank appears to have insufficient capacity to manage the high loading of trash and organic matter of the influent wastewater forcing the MicroSepTec treatment plant to not operate properly when wastewater flow volumes are at their highest. 4.) The grease interceptor tank has not been managed properly, which would have included pump-out service at regular intervals. Since the beginning of leachfield failure,portable toilets have been placed at the west side of the Chevron Building. Therefore,the current wastewater flows originate from restroom use by employees only, and the Subway and Pizza Shops. Chemistry on effluent after MicroSepTec treatment was conducted for this Report and found in Appendix G. Results indicate the system can currently treat flow volumes of comparatively low waste concentrations. Domestic water for the subject property is provided by the town of Thornton. Domestic wells surrounding the subject property do exist and are sufficient distance away from the Chevron Station Complex. Based upon the results if this investigation,the following changes to the onsite wastewater treatment system are proposed and discussed in further detail below: 1.) The trash/surge tank will be upgraded to a l Ok gallon,two compartment tank, 2.) A 1.2k gallon,two compartment pump tank will be installed after the l Ok gallon tank to equally distribute effluent among the three MicroSepTec EnviroServers, 3.)The headworks tanks will undergo regular pump-out intervals, and 4.) The existing leachfield will become the 100%replacement area, and the current 100% replacement area will now become the new primary leachfield. The new leachfield will be completely reconstructed using engineered fill due to extremely poor permeability characteristics of the native soils. i Page -1- Chesney Consulting