Guidelines for food processors and preparers

Industrial Pretreatment Program - Guidelines for food processors and preparers 

  • The commercial facility must have separate exiting lines for their sanitary wastewater and process water.  The process wastewater would include all waters associated with food preparation and house keeping.
  • Additionally a sampling manhole must be available for inspection of the separate exiting sanitary and process lines.  The sampling manhole, if viewed from the top looking down to the bottom of the table, would contain two inverts (one for each of the separate lines) joining to one community line which would then tie into the main "trunk" line provided for the lot.  The overall appearance of this set-up would resemble the letter "Y".  The purpose of this manhole is to allow for inspection and/or sampling of the process wastewater line 24 hours/day if needed. 

The manhole allows for excess pollutants to be readily detected at the process invert, prior to dilution from other wastestreams.  Should excessive amounts of conventional pollutants be discharged to the sewer collection system, only the line servicing the kitchen would be impacted by this discharge (possibly blocked).   The sanitary lines would remain unharmed by a discharge of this nature.  Separate lines make for easier maintenance and readily allow for upgrades to the existing grease removal system.

  • Garbage grinders are not allowed in the commercial facility. Ground food materials suspended in your process wastestream most certainly will contribute to elevated TSS, BOD and COD loadings in your process wastestream. We recommend installation of a screening device at each of your sinks.  Removal of solids (as opposed to introduction of solids via garbage grinder) should enhance the quality of your process wastestream.
  • The facility must have a grease removal system in place.  Depending upon the size of the restaurant (seating capacity/revenue), kitchen components (dishwasher, sinks, rinse stations, floor drains) and process flow, the WSA may require grease trap(s) and/or grease interceptor(s).  Where grease interceptor(s) are required, they must be sized for > 24 hr. detention time.  Maintenance of the grease trap(s) and/or grease interceptor(s) is expressly the responsibility of the permittee.
  • Additionally, the facility should install water meters on their process flow lines.  This allows for more accurate readings for surcharging purposes.  Where flow measurements are unavailable, surcharges will be calculated at the discretion of the Warwick Sewer Authority.
  • According to our Intermunicipal Agreement with West Warwick, any company located within Warwick, that flows to West Warwick and meets any of the criteria below must meet with both municipalities, prior to issue of building permit/certificate of occupancy, for permitting purposes.

Restaurant with grease interceptor(s)
Significant/Categorical User

  • The WSA absolutely prohibits the use of enzyme products.  Bacterial additives, however, may be used.
  • Businesses must provide 3 sets of plumbing/floor plans and 3 sets of site plans (demonstrating connection) to the WSA for review prior to connection application sign-off/approval.
  • Businesses must obtain a wastewater discharge permit through the Pretreatment Division prior to Certificate of Occupancy.