Month: October 2020

QUESTION

Sour Water, Foaming and Aeration We have been dealing with an upset condition at our facility due to having to treat some stored sour water inventory. The water is high in sulfides (136 ppm) and sulfite (247 ppm). We are running all of our aeration equipment at full capacity. We are starting to see foaming issues and very low D.O. levels. We have added some totes of peroxide and can see that it is helping but are concerned adding too much could kill our biological population. Our aeration capacity is 5 million gallons. The sour water stream is about 50 gpm. Any recommendations on adding more peroxide?  Dan P, Wastewater Engineer.  

ANSWER

It is difficult to get enough aeration equipment in the right location to treat the added sulfide/sulfite load on your system. The result of over aerating the front of the plant is often foaming. Hydrogen peroxide can be added directly to the influent of your aeration basin to oxidize the sulfide/sulfite load. H2O2 is immediately catalyzed and provides a 100% transfer of oxygen to your basin. This is very efficient compared to most aerators that are transferring oxygen at around 25-40%. Sometimes lower if influent temperatures are above 100° F. There is no harm to your biology. The result is by adding enough h2o2 to treat the overloading of sulfide/sulfite, your aeration basin should see a rise in D.O. fairly quick and will be able to handle to normal plant load coming in. Dan, I hope this helps answer your questions about how hydrogen peroxide can be applied safely and reliably provide supplemental dissolved oxygen.  Give our Applications Team a call at  (877) 346-4262 if you want to discuss this in more detail or want one of our technical team to visit your site for a technology fit assessment. Sincerely, USP Technologies Wastewater Technology Group

QUESTION

Can H2o2 Treat Ammonia? We are experiencing high levels of ammonia at our wastewater treatment unit. Do you have any experience treating ammonia?  Jean – Lead Operator  

ANSWER

Hydrogen peroxide is a very powerful chemical and is able to treat a very wide range of compounds including sulfides, sulfite, phenols, benzene, etc. but unfortunately ammonia is not a compound hydrogen peroxide is able to treat.  Jean, I hope this helps answer your question.  If you have questions about other wastewater treatment issues, give our Applications Team a call at  (877) 346-4262.   Sincerely, USP Technologies Wastewater Technology Group

QUESTION

We have been having persistent issues maintaining dissolved oxygen levels in our aeration lagoons. We are looking at adding more surface aerators as a possible fix but heard hydrogen peroxide might be another alternative. We don’t have any experience with hydrogen peroxide. How would your system work? How will it compare to adding aeration equipment?  Louis – Wastewater Manager

ANSWER

Hydrogen Peroxide is an excellent way to deal with high plant loadings or inefficient aeration equipment at high temperatures. Whereas aerators are limited at transferring oxygen at high temps hydrogen peroxide is not. H2O2 is 100% efficient at transferring oxygen to your lagoon. Our full service systems can be installed on site and be used as needed. Whenever you see the dissolved oxygen levels in your lagoon dropping you can simply turn on the peroxide until the plant is back to normal. Our team of program managers and application engineers can help support your application to make sure performance targets are being met. We also provide inventory management and maintenance of the equipment as part of our service. Louis, I hope this helps answer your question.  If you have further questions, please give our Applications Team a call at  (877) 346-4262. Sincerely, USP Technologies Wastewater Technology Group

QUESTION

I have an activated sludge basin that I can’t keep the DO levels up and its now starting to affect both my BOD and ammonia levels exiting the plant.  I’ve heard about other refineries using hydrogen peroxide and would like to know more.  I have a concern about how to safely use hydrogen peroxide and how this is going to work any better than if I use a temporary blower on the system.    Thanks for your help.  –  Ryan, Refinery Process Engineer

ANSWER

You know, Ryan, the recurring problem of intermittent periods of low dissolved oxygen levels is the number one area where hydrogen peroxide can provide immediate relief to a refinery.  But before we get into the specifics of this application, let’s talk about how USP Technologies’s full service supply scope can address  any safety concerns with using hydrogen peroxide:

1. Equipment – USP Technologies’s wastewater treatment programs include state-of-the-art turnkey peroxide bulk storage and handling systems, which eliminate the risk of operator exposure associated with handling of drums or totes.
2. Product – For our refinery customers, USP Technologies typically supplies “Refinery Grade” 27% hydrogen peroxide.     This product grade is a Class 1 Oxidizer (compared to a Class 2 Oxidizer rating for 50% hydrogen peroxide), and has inherent safety benefits to the higher concentrations of product.
3. Service – Our experienced Field Service Teams handle the equipment system installation and maintenance – so your folks don’t have to.  We also provide wastewater sampling and testing to assist with hydrogen peroxide dose rate optimization.  We also support all aspects of process hazard analysis (PHA), pre-start-up safety (PSSR), and management of change (MOC) reviews as part of the pre-installation process at the refinery.

Now, as far as the use of hydrogen peroxide for supplemental dissolved oxygen (DO), this is a treatment area we have a great deal of experience and many successfully operating systems.  As you know, the treatment efficiency of aerobic biological treatment processes depends on a number of factors including (but not limited to): Influent BOD/COD loading, F:M ratio, temperature, nutrient levels and dissolved oxygen (DO) concentrations.  Many refineries use hydrogen peroxide to supplement dissolved oxygen levels when oxygen limited conditions in their aeration basins result in poor BOD/COD removal, including ammonia levels when nitrifying bacteria do not have enough oxygen to convert ammonia to nitrate.  These conditions can be brought on by unexpected peaks or seasonal variations in influent BOD/COD loading and hot weather – which reduces the efficiency of oxygen transfer by mechanical aeration equipment (i.e., O2 solubility decreases as temperature increases). When hydrogen peroxide is used to provide DO, it is metered in just upstream of the aeration basin of a biological treatment system to provide an immediate source of dissolved oxygen. The conversion of hydrogen peroxide to DO proceeds by the following reaction:

 2 H2O2 → O2 + 2 H2O

The decomposition of hydrogen peroxide occurs very rapidly due to the enzymatic decomposition of hydrogen peroxide.  Catalase enzyme is a natural decomposition catalyst for hydrogen peroxide, being produced by most aerobic organisms, and is found in all activated sludge mixed liquors.  Since the decomposition of hydrogen peroxide to DO is so rapid, the oxygen supplied by hydrogen peroxide is immediately available for uptake by the aerobic organisms.  Additionally, since hydrogen peroxide is a liquid, and infinitely soluble in water, the amount of DO provided is not limited by the mass transfer of oxygen from the gas phase to the liquid as is the case with mechanical aeration.  This last point is of significant importance to refinery wastewater treatment applications, when comparing the use of hydrogen peroxide to mechanical aeration for supplemental DO supply.  As you are aware, the temperatures of refinery activated sludge systems are often in excess of 95 F and many systems operate at temperatures above 100 F.  Henry’s law dictates that at these elevated temperatures it is even harder to transfer oxygen (gas phase) from a mechanical aeration device into the wastewater and since hydrogen peroxide is a liquid, this limitation does not exist.  Ryan, I hope this helps answer your questions about how hydrogen peroxide can be applied to a refinery’s activated sludge system to safely and reliably provide supplemental dissolved oxygen.  Give our Applications Team a call at  (877) 346-4262 if you want to discuss this in more detail or want one of our technical team to visit your site for a technology fit assessment. Sincerely, USP Technologies Wastewater Technology Group