Bacteria prefer warmer temperatures and they do not reduce BOD (biochemical oxygen demand) or reproduce as effectively during the colder months of the year. Due to this, mill upsets are more problematic during the winter. While temperature is one of the eight growth pressures that affect your Wastewater Treatment, there are things you can do ahead of time to ensure your system is as healthy as possible when upsets occur.
Increase nutrient feed rates to maintain sufficient nutrient residuals. Typically these residuals should be 0.3-0.5 for both nitrogen and phosphorus in an aerated stabilization basin and 0.5-1.0 for an activated sludge system. Nutrient residuals must be measured in the active form of nitrogen and phosphorus or as ammonia with phosphate as orthophosphate. Nutrients are necessary for bacterial reproduction and thus nutrient requirements increase when BOD loading increases. With proper nutrient control, your system is more robust and won’t require as much time to gear up when an upset does occur. This is particularly important in the winter months when bacteria multiply at a slower rate. Increasing nutrient feed rates during an upset to maintain nutrient residuals is important in maintaining a healthy biomass. MacroGro™ blends of nutrient supplied by Environmental Business Specialists provide a customized blend of nitrogen and phosphorus to meet the specific nutrient percentage needs for your mill. Changes in the nitrogen to phosphorus blend percentage can occur due to seasonal needs or due to changes in the incoming Wastewater Treatment water as a result of furnish changes or other system/chemistry changes upstream.
Know your retention time. BOD reduction takes longer in the winter and thus ASB retention time becomes more critical. Knowing this retention time and its characteristics (channeling, aerator placement effectiveness, etc.) helps when responding to upsets during the colder months. The area of greatest BOD conversion will most likely occur at a point further downstream in your ASB.
Bioaugmentation. Since the bacterial population will struggle more in the winter, proactive bioaugmentation & the addition of supplemental bacteria can help maintain the strength of the
microbiology. EBS’s Bacterial Acceleration Chambers or BAC units are useful for these reasons. First, use of the BAC unit gives the dry bacteria in EBS’s BioStar™ P or MicroStar™ time to release from the bran and come out of their spore state. Moreover, the EBS BAC unit provides an opportunity for the bacterial population to multiply 100-1000 times before they are ever added to the secondary system because EBS’s bioaugmentation products are specifically formulated to work with our BAC units. These advantages have the benefit of creating a situation in that when the bacteria are dumped from the BAC unit into the secondary system, they start reducing BOD more quickly and closer to the front end of the system. This increased exposure to a system’s full retention time (as opposed to part of it which occurs when bags of bugs are thrown into a secondary system’s influent zone and take a day’s worth of retention time to finally start doing their job) helps further reduce BOD levels. Additionally, these advantages allow for higher levels of bacteria to enter the secondary system influent zone while reducing the quantity of dry bacteria used which reduces cost.
Other Growth Pressures. The other growth pressures: dissolved oxygen, type and amount of food (BOD), toxicity and inhibition, and pH will also impact the Wastewater Treatment. Recovery from these upsets will be slower during the winter.
EBS is uniquely capable of responding to your winter upset issues because of our experience and ability to mobilize personnel. To learn more about the EBS BAC unit, the bioaugmentation products BioStar P or MicroStar, or discuss how you can be proactive for your unique mill, contact us at firstname.lastname@example.org