Winter operation issues of wastewater pretreatment + biological treatment + advanced treatment

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During winter operation, for wastewater with high COD concentrations (above 10,000 mg/L), the biochemical reactions will cause the water temperature to rise to some extent. Additionally, due to the insulation and sealing of the biochemical treatment tanks, if the temperature of the water exiting the MBR exceeds 15°C, it can be sent to the membrane system for further treatment without the need for temperature elevation measures. If the temperature of the water fed into the membrane system for advanced treatment is reduced to below 10°C, it will affect the water production rate of the membrane system and cause irreversible damage to it. However, determining how much the temperature can rise in a biochemical system is a complex issue, involving factors such as the energy generated per kilogram of COD degraded, heat loss, and the temperature of the raw water – it’s quite complicated. Some sources indicate that 1 kg of COD can produce approximately 14 kJ of heat; it’s not clear whether this is reliable. I earnestly ask some expert to offer some good advice; I would be extremely grateful!