Being proactive during cold weather can noticeably reduce wastewater treatment plant (WWTP) upsets.
A reduction in temperature can cause a well-running WWTP to have issues almost overnight. Bacteria do not remove BOD or reproduce as effectively during the colder months of the year and generally favor temperatures between 68 and 95° F (20 – 35° C). In fact, for every 10° C decrease in temperature from 35 °C, bacterial reaction rates decrease by half. This decrease in biological activity is why WWTP upsets tend to be more problematic during the winter. While temperature cannot be fully controlled within a WWTP, there are a few things you can do ahead of time to ensure your system is as healthy as possible during the winter to boost microbial activity.
Adjust nutrient feed rates to maintain sufficient macronutrient residuals.
However, lower residuals may be required based on permit limitations. When lower residuals need to be maintained, it becomes even more critical to monitor the BOD:N:P ratio of your system to make certain it is not nutrient deficient. Residuals must be measured in the active form of nitrogen and phosphorus, as ammonia and orthophosphate. There are many products available on the market to meet the macronutrient demands of your WWTP, but perhaps the safest and easiest to control are pH-neutral blends of nitrogen and phosphorous. These customizable blends can be tailored to meet the specific nitrogen and phosphorous ratio required for your system which ensures you don’t overspend or underfeed.