Isn't it Time to Outlaw Concrete?

March 30, 2016

I recently heard of an ordinance change in Springfield, Missouri, that surprised me. Effective February 2016 the jurisdiction no longer allows concrete interceptors. It isn't often in my dealings with pretreatment programs that I come across ordinance language that is clear and unambiguous about what interceptors can or cannot be made out of. Here's what the ordinance actually says now (bold and strike-through's are as-is in the ordinance):

"1003.3.4 Hydromechanical grease interceptors and automatic grease removal devices. Minimum required size of Hydromechanical grease interceptors and automatic grease removal devices shall be sized determined in accordance with ASME A112.14.3 Appendix A, ASME112.14.4, CSA B481.3 or PDI G101. Use of ASME A112.14.3 Appendix A shall be mandatory. Drainage period used in calculations to size hydromechanical grease interceptors and automatic grease removal devices shall be no more than 1 minute. Hydromechanical grease interceptors and automatic grease removal devices shall be designed and tested in accordance with ASME A112.14.3 Appendix A, ASME 112.14.4, CSA B481.1, PDI G101 or PDI G102. Hydromechanical grease interceptors equipped with manholes for access shall be equipped with a manhole for each chamber in the interceptor. Concrete grease interceptors will not be allowed. Hydromechanical grease interceptors and automatic grease removal devices shall be installed in accordance with the manufacturer's instructions. Where manufacturer's instructions are not provided, hydromechanical grease interceptors and grease removal devices shall be installed in compliance with ASME A112.14.3, ASME112.14.4, CSA B481.3 or PDI G101. This section shall not apply to gravity grease interceptors. Gravity grease interceptors shall be subject to the approval of the Authority Having Jurisdiction."

I contacted Sarah Limb, pretreatment inspector for the City of Springfield Department of Environmental Services, about the new requirement in their FOG ordinance and she was happy to share the details. Sarah has been with the jurisdiction for 10 years where she spent her first seven as a restaurant inspector and the last three managing the city's FOG program. Springfield has about 1150 Food Service Establishments and out of those Sarah says, "I have dozens of concrete interceptors that currently require immediate replacement."

Sarah stated that the jurisdiction does not like the 25% rule and has been seeking a more scientific approach to base interceptor maintenance frequency on. The jurisdiction started measuring pH in grease interceptors about a year ago and according to Sarah, "out of all the tanks that I sampled, every single GGI [gravity grease interceptor] had pH readings lower than 5.0." In fact she said, most were between 3.0 and 4.0.

Those of us who have worked in the life-science industries are fully aware of the corrosive effects of acidic media and should not be surprised with the jurisdictions findings regarding failing concrete interceptors and low pH readings.

Points to ponder:

  • What benefit does it serve a restaurant to have to pay thousands of dollars to purchase and install a giant concrete tank only to have it fail, forcing them to spend thousands of more dollars to replace it?
  • What benefit does it serve the jurisdiction to have a steady stream of acidic effluent discharging to the collection system from these tanks?
  • What benefit does it serve the environment when a GGI fails and its contents leech directly into the surrounding soil and how long will the leeching occur before anyone discovers that the tank has failed?

If we know that concrete GGIs are going to fail, and I'm pretty sure we all do know that, then why are we allowing them in the first place?

If your jurisdiction is interested in considering a ban on concrete you might wonder what the alternatives are. There are a variety of options for GGIs made from thermoplastics or fiberglass to choose from. Of course I recommend approving high-capacity hydromechanical grease interceptors (HGI) which have a smaller footprint but comparable grease storage capacities to much larger GGIs. Schier Products Great Basin series are made from a thermoplastic called high-density polyethylene and come with a lifetime warranty. Other's on the market use similar materials and are being offered with long-term warranty's as well.

When I asked Sarah about her jurisdictions experience with these high-capacity HGIs she said, "these units appear to be very efficient when being maintained at the correct frequency and when they have been installed correctly."

If you are wondering how the jurisdiction sets the maintenance frequency Sarah said, "We use the Schier grease production calculator to calculate the cleaning frequency for all of the GIs in town no matter the make or model. If the owners/operators maintain the interceptors at the frequency that we've set then they are incredibly efficient."

Bravo Springfield and the other jurisdictions that have taken the lead by eliminating concrete interceptors.

With all we know and all of the better solutions available, isn't it time to outlaw concrete interceptors everywhere?

Click here to see my Q&A with Sarah Limb.


  • Justin

    Apr 08, 2016

    My guess would be that since GGIs are large, if they are not pumped out on an adequate/regular basis, the contents will go septic and hydrogen sulfide will begin to form which results in more acidic effluent.

  • Steve Claybrook

    Apr 04, 2016

    Bullet #2 of your ‘points to ponder’ suggests that effluent from an HGI is not acidic, or as acidic as a GGI. Is that the case?

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