Cooler temperatures negatively impact biological treatment of wastewater systems. It is clear to see in the northern climates with icy roads, snow and temperatures below 32°F (0°C), but even in the Sun Belt states, lower water temperatures in the fall and winter months can contribute to poor biochemical oxygen demand (BOD) and solids removal in a biological system and increased filamentous bacteria activity, which can cause settling problems.
Studies show most microorganisms thrive between 77°F (25°C) and 113°F (45°C). A 10°F (12°C) drop in temperature reduces the effectiveness of the bacterial growth about 90%. However, there are some steps you can take to ensure optimal system performance when your wastewater temperature is slowly decreasing.
- Increase your return activated sludge (RAS) or decrease waste activated sludge (WAS).
- Maintain dissolved oxygen (DO) at optimal levels, a minimum of 2 parts per million (ppm).
- Supply hot air or hot water to your wastewater source to maintain an appropriate temperature.
- Implement a supplemental bioaugmentation program. Additional bacteria and micronutrients can increase biomass.
In many cases, a supplemental bioaugmentation program is the most effective and economical approach. Bacterial strains are isolated and selected based on their ability to thrive in colder water. The combination of these specialized bacteria and micro-nutrients mitigate the negative affect of lower water temperatures and offer the following benefits:
- Improved BOD and chemical oxygen demand (COD) reduction in colder wastewater
- Promotes system stability ensuring effluent compliance
- Aids biomass in improving cold temperature nitrification
Each biological system is unique. In most cases, a systematic approach with documented activity puts the system on the right track for improved performance.
Contact us today if you’re interested in learning more from one of our wastewater experts.