Sand Interceptor Sector Control Policy For Automotive Shops, Car Washes, & Facilities with Significant Potential for Sand or Inert Debris Discharge

Transcription

1 Sand Interceptor Sector Control Policy For Automotive Shops, Car Washes, & Facilities with Significant Potential for Sand or Inert Debris Discharge For the Service Area of the Littleton/Englewood Wastewater Treatment Plant 3/10/08 1

2 Sand InterceptorPolicy For Automotive Shops, Car Washes, & Facilities with Significant Potential for Sand or Inert Debris Discharge For the Service Area of the Littleton/Englewood Wastewater Treatment Plant 1.0 Overview of Policy The Sand Interceptor Policy ensures consistent sand interceptor management throughout the service area of the Littleton/Englewood Wastewater Treatment Plant (L/E WWTP). The purpose of this policy is to minimize the loading of sand and petroleum hydrocarbons from entering the collection system and the wastewater treatment plant. 2.0 Sand Interceptor Applicability A sand interceptor is a device designed and installed to separate and retain sand, solids, petroleum hydrocarbons, and other related undesirable matter from normal wastes and permit normal liquid wastes to discharge into a wastewater collection system by gravity. Facilities that discharge any quantities of sand or other inert debris into the sanitary sewer service shall have a sand interceptor installed on the sewer service line. Examples of such facilities include but are not limited to: automobile service stations, fleet maintenance stations, mechanical repair shops, car washes, garden nurseries, warehouses, and parking garages with floor drains. Sand interceptors shall not be required for private residences or dwellings. 2.1 Appropriate Use of a Sand Interceptor Sand interceptors shall not be used as a means for disposal of spent or spilled chemicals, automotive or other commercial or industrial fluids, sludges, or other substances. Sand interceptor use is limited to wastewater generated during normal operations from facilities described in Section 2.0. Normal operations include but are not limited to: floor wash down, car or truck washing, and heavy equipment washing. 3.0 Best Management Practices The following Best Management Practices (BMPs) are to be implemented as part of operations at facilities with sand interceptors: Appropriate storage of chemicals and wastes, in accordance with the Accidental Discharge Prevention Policy (ADPP) to prevent these substances from entering the sand interceptor and sanitary sewer system; 2

3 Sweep floors prior to floor wash down to ensure there is no excessive oil or sand entering the sanitary sewer; Implement appropriate clean-up methods for spills washing/rinsing of spills into a drain is prohibited; and Implement appropriate waste management practices for both hazardous and nonhazardous waste, including recycling or off-site disposal. 4.0 Sump Pumps (Elevator Pits) Elevator pits or similar infrastructure requiring the installation of a sump pump shall be plumbed through a sand interceptor. The sump pump must be equipped with a shutoff sensor that detects hydraulic oil. The sensor design must be approved by the L/E WWTP. No wastewater containing hydraulic oil may be discharged to the sand interceptor or any other discharge point leading sanitary sewer. This wastewater must be collected and disposed of as hazardous waste, or the oil must be removed from the water and properly disposed of. Any spills or leaks of hydraulic oil from the elevator components should be cleaned-up immediately. 5.0 Sand Interceptor Sizing Criteria and Plumbing Requirements All cities and sanitation districts discharging to L/E WWTP shall be responsible for incorporating the sizing criteria and plumbing requirements into their rules and regulations. Refer to Attachment 1 for sizing criteria and Attachment 2 for plumbing and structure requirements. The maximum interceptor size shall be two thousand five hundred (2,500) gallons. If a facility is sized for a larger sand interceptor, a series of interceptors may be necessary to meet capacity needs while keeping pumping and maintenance compliance feasible. All sand interceptor installation activities shall meet International Plumbing and Building Codes. At a minimum, all sand interceptors shall be double chambered. A t-cap outlet is required in the outlet chamber plumbing for all new facilities in order to allow for sampling of the effluent if deemed necessary. Sizing each sand interceptor shall be evaluated separately. Common or shared sand interceptors for multiple facilities are prohibited. 6.0 Sand Interceptor Inspections The Cities and Sanitation Districts of the Littleton/Englewood Wastewater Treatment Plant shall establish an inspection program for sand interceptors in their service area. The cities and sanitation districts will develop a mechanism to inventory all sand interceptors in their service area and document the inspections of these interceptors. Once the sand interceptors in the service area are identified, the interceptors will be classified into two (2) categories: 1. Critical Sand Interceptors The facilities connected to these sand interceptors contribute significant amounts of oil, sand, or debris to the sanitary sewer system. These sand interceptors will be inspected at a frequency of every three (3) months. 2. Non-critical Sand Interceptors 3

4 The facilities connected to these sand interceptors do not contribute significant amounts of oil, sand, or debris to the sanitary sewer system. These sand interceptors will be inspected at a frequency of every six (6) months. Classification of sand interceptors may be adjusted based on such factors as compliance history or change in facility operations. 7.0 Sand Interceptor Pumping Schedules Facilities are required to pump their sand interceptor at a minimum, annually, or when the accumulation of sand and debris in the secondary chamber is five (5) inches or less from the bottom of the outlet pipe. Pumping will include removal of entire interceptor contents. Partial removal of contents (i.e., removal of the oil layer or sludge layer) is not permitted. Contents removed from interceptors shall be hauled off-site and disposed of properly. Inspections of sand interceptors by the City or Sanitation District will determine if this frequency needs to be increased to control the amounts of sand or debris entering the sanitary sewer system or if the pumping frequency may be decreased. 8.0 Sand Interceptor Repairs All facilities are required to structurally maintain all components of the sand interceptors per design requirements. A t-cap outlet is required in the outlet plumbing in the secondary chamber for all facilities that are required to repair the outlet plumbing (Attachment 2). 9.0 Sand Interceptor Follow-Up Inspection Facilities that are required to pump and/or repair interceptors, as documented by inspections, shall be given written notices of violation. Pumping and repairs shall be completed within a maximum of 5 calendar days and 15 calendar days respectively upon written notice of violation. Facilities with violations shall be re-inspected following the elapsed time period to ensure compliance Existing Sources Not Connected to Sand Interceptors Existing sources not connected to sand interceptors that generate significant amounts of sediment and debris will be identified through inspection of the collection systems by the control authorities, which include the Industrial Pretreatment Division, cities of Littleton and Englewood, and the contracted sanitation districts. Once these sources are identified, they will be required to implement Best Management Practices (BMPs) identified in Section 3.0. If BMPs are not successful at the facility and the facility continues to contribute significant amounts of sediment and debris to the sanitary sewer, as documented by field inspections, then the facility will be required to install an adequately sized sand interceptor. 4

5 11.0 Records All records of maintenance of interceptors, removal of interceptor contents and of off-site hauling shall remain on-site and accessible for review for a minimum of one (1) year Enforcement All facilities must follow the requirements of the L/E WWTP Sand Interceptor Sector Control Policy. Failure to comply shall result in further notice of violation or enforcement actions. In accordance with the Enforcement Response Guide, the enforcement procedure is as follows: Notice Of Violation a. Repair deadline: 15 calendar days b. Pump deadline: 5 calendar days Specialist Meeting Administrator Meeting Directors Order 5

6 Attachment 1 Sand Interceptor Sizing Criteria Littleton/Englewood Wastewater Treatment Plant The maximum size for a sand interceptor is 2,500 gallons. If a facility is sized for a sand interceptor larger than 2,500 gallons, a series of interceptors may be necessary. The formula for sand interceptor capacity is: (Process floor space) / (Use category floor space) x (gal. of water) = sand interceptor capacity. The varying use categories are outlined below: Floor Space Use Categories 15 square feet Steam cleaning, Truck wash, Heavy equipment wash, Automatic car wash (car moved by chain) 50 square feet Automatic car wash (machine moves around car) 75 square feet Car wash (hand held spray) Automotive service garage 100 square feet Machine Shop Storage Areas/Warehouses 250 square feet Paint spray booths 300 square feet Printers 2,000 square feet Parking garages (where floors are washed) 3,000 square feet Parking garages (where tenant cars are washed) 4,000 square feet Parking garages (no water outlets, except for fire sprinklers) 6

7 Attachment 2 Sand Interceptor Plumbing and Structure Criteria Littleton/Englewood Wastewater Treatment Plant All sand interceptors shall be double chambered. A t-cap outlet is required in the secondary chamber outlet plumbing for all new facilities and any existing facilities that are required to repair the outlet plumbing. Sand interceptors are categorized into two types based on capacity such that the level of the base of the outlet pipe depends on the capacity of the interceptor: Type A Sand Interceptors: (<1,250 gallons) 7

8 Type B Sand Interceptors: (1,250 2,500 gallons) 8