Can any one tell me the response they get by using a product called QUAT-LOCK? We started using this product based on recommendations from the company but have yet to see any response but maybe I am looking in the wrong spot. Thought from the company that I would see some response throughout the system but as of yet no changes. Been using the product for over two weeks. Wondering if anyone else has experience with this product.

We are being told that we have very high levels of quat like compounds in the waste stream (100 to 200ppm). We have anaerobic laggoons producing methane for our plant boilers and flare off the balance. Our treating efficencies out of the anaerobic is about 70% to 80% in COD and BOD values. We are trying to locate the source of quat but have not been able to find that source as it equates back to 800 to 1000 pounds per day and or typical use by chemical inventories at the plant are only 100 to 200 pounds per week at most. We were told that this would help our anaerobic treatment and drop our nitrogen levels on our discharge. Haven't seen any decrease and thought our current treatment in the anaerobics was fairly good. The company recommending Quat Lock says it should be closer to 90%.

Quaternary ammonium compounds can be inhibitory to anaerobic treatment down to low ppm in the wastewater.  Therefore, I do not think you have 100 to 200 ppm quat and still have good treatment. How are you measuring quats?   Even if you have 10 to 20 ppm quat, that is still an issue.

Please provide your lagoon effluent soluble and total COD.  Perhaps your less than ideal removal is due to solids exiting the lagoon?

I am not familiar with Quat lock but best solution is usually to replace quats in process with other less harmful chemicals.

I agree with Peter_McCarthy and DoctorBug that some quats are biocidal. Because you know the source of quats in your plant, it seems to me that you could determine the lethality of the products to your processes. In a previous post, you were concerned with a lack of denitrification in anoxic zones in your plant. You might want to consider that the quat discharges may not be uniform (hence the discrepancy between the difference in estimates of concentration) and the need to understand how the manufacturing process affects the influent concentrations. The MSDS for these products may also yeild some useful information.

I'm not familiar with the product Quat Lock and this may or may not be reactive with your quats. However, my opinion is that you need to segregate the waste quats first to see if your process improves. You might start with a SOUR test with various concentrations of the quats.

A description of your complete treatment process would be useful for the Forum Members. Investigation of the use of quats in the manufacturing process may also lead to a change in manufacturing operations (waste minimization or reduction possibilities).

Finally, (and this is just speculation on my part), the quats may be toxic to nitrifiers and you may not be nitrifying even though you are getting BOD and COD reduction without denitrification.

grrun

Thanks for the information about the treatment process. Have you considered phosphorus deficiency? I would check the soluble phosphorus in the effluent to see if there is an adequate residual.

See: http://www.fwrj.com/TechArticle05/0105%20tech2.pdf

I'll continue to look for other reasons that might contribute to your problem, but this one just occurred to me.

See: http://www.fvoa-illinois.org/EPA_Nutrient_Control.pdf

grrun

I'm curious how lack of P would be possible problem in this case? perhaps there's something we don't know about?? It's always a good idea to know you left a little on the plate (so not bad advice in general). I'm just not sure why this would be the contributing cause here.

best regards,

Ryan

Actually our effluent P is nearly nonexistent so we quit testing some time ago. We are getting ready to throw in some bioaugmentation to the system to see if we can jump start that population to alleviate our nitrogen issues. I will take a shot at adding some trisodium phosphate to see if that would also help. Any suggestions as to the amount?