Hello! I could use any advice, guidance and thoughts anyone is willing to give on this. I have a potential SIU coming very soon to an already built industrial building. It will be a very large professional events company who will have batch days of extensive professional laundry, dishwashing and tent cleaning activities. The volume of pure process wastewater not including domestic will range on days between 20,000 and 35,000 gallons per day. The receiving wastewater treatment facility is a very small plant with an average flow of 1.2 mgd and already has trouble meeting Tphos and N0x limits. I have received all SDS for chemicals used. pH, temp, nitrogen and phosphorous will be obvious concerns. This will be by far the largest SUI for this facility. Also, once we set permit limits, is it our responsibility to guide them with the pretreatment equipment on how to meet those limits or is that their responsibility. Thank you so much!!!
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Hi Lori. Did the IWS or permit application of the potential SIU indicate that they have multiple locations? If so, it may be helpful to determine if they have any IU wastewater permits elsewhere and reach out to the corresponding control authority. This could give you a general idea of the IU's wastewater characteristics/concentrations and type of pretreatment used in their process, as well as help identify issues the WWTP has had (if any) with treatment of the user's wastewater. Outside of the pH/temp, nitrogen and phosphorous concerns, FOG will likely also need to be addressed in the IU's treatment of process wastewater. My knowledge of FOG is limited as there are separate positions for FOG and Pretreatment Coordinators at the City of Gastonia, but I am not certain a grease interceptor would be sufficient in the removal of FOG in this case, given their wastewater volumes and likely use of soaps/detergents and high temps, which could emulsify the FOG and cause it to pass-through the interceptor. Some type of DAF system may be more helpful in this case. In my experience, it is acceptable to educate IU's on the different types of treatment/reasons for treatment, but it is ultimately up to the IU to propose and submit plans for a treatment system, which then would need to be approved by the control authority.
Thanks so much Chris. There are multiple locations all over the state, but none permitted, as this will be the largest of all the facilities they own. I have asked them to fill out the Industrial User permit application long form using another facility using similar products and processes though. They sent it back incomplete without the lab information so I did not accept it. Thank you about mentioning the Oil and Grease/FOG, as I had not considered that but I agree an interceptor or DAF would be necessary (we also have separate FOG and pretreatment departments).