Cooling and temperature control of wastewater
The temperature of the water in the different stages of treatment plays a very important role in the effective treatment of wastewater flows. However, we must also focus on the temperature limit value or on issues related to energy recovery and bad odors.
Waste water temperature
In addition to analyzing wastewater flows and their composition, monitoring wastewater temperature is an essential element in planning and optimizing your wastewater treatment plant. Partial flows of water that are too cold are a problem, especially for anaerobic reactors, such as, for example,
UASB (Upstream Anaerobic Sludge Blanket), EGSB (Expanded Granular Sludge Blanket) or IC (Internal Circulation), since the metabolism of bacteria depends on a minimum temperature. If the water enters too hot in the biological treatment stage, the biomass can be damaged.
Commercial relevance of wastewater cooling
Wastewater treatment plant operators are interested not only in the efficiency of their cleaning but also in the commercial aspects of their wastewater flows. To protect adjacent waters and the living organisms contained in them, there are regulations that establish direct discharge temperatures. The competent water authorities generally determine the temperatures to be observed in each case. In the province of Buenos Aires, for example, this limit is 45 ºC. In the City of Lima it is 35ºC.
Another aspect to take into account is the appearance of bad odors due to heat flows in the pipeline. According to the external temperature, this phenomenon can be increased and be a discomfort for the inhabitants.
Cooling and energy recovery from wastewater
Cooling towers, falling film coolers, and tube and plate heat recovery units have proven to be useful solutions in process water cooling. However, in practice other systems prevail. A viable solution is to use spiral heat exchangers, but these come with a high maintenance cost. With self-cleaning systems such as the E-Plate rotary heat exchangers we have solved this problem.