The Enduce energy recovery floor drain reduces hot water consumption at the application level, by using the thermal energy of used shower water to directly reduce the hot water demand of the shower mixer. The result is that less heat is washed out of the shower into the buildings' sewage system.
Of course, there are no regulations that govern that shower facilities should discharge gray water (used shower water) above a certain temperature, but there are rules in municipalities' General provisions for water and sewage systems (ABVA) that regulates that you cannot discharge colder wastewater from the property than the temperature of the cold tap water entering the property. There may also be rules specifying whether to install wastewater heat exchangers at the property level in the ABVA. These provisions are separate for each municipality, but do not apply to energy-saving technologies at the application level.
As regards the possible impact of colder wastewater on wastewater treatment plants, it is true that excessively cold wastewater can inhibit nitrogen removal in particular in wastewater treatment plants. In an article by R. Saagi et. al, City-wide model based analysis of heat recovery from wastewater using an uncertaty-based approach, published in 2022 by researchers at Lund University and RISE, provides an in-depth analysis of the impact of energy recovery on the incoming temperature of wastewater to wastewater treatment plants. The detailed study shows, among other things, that heat recovery at the application level in buildings generally has a negligible impact on the incoming temperature to wastewater treatment plants, as the energy losses to the surrounding soil around the sewer network and leaking groundwater have an overriding effect on the wastewater temperature.
In conclusion, there is no regulatory barrier to energy-efficient technologies in shower rooms, nor is there any evidence that energy efficiency improvements in showers can have negative effects on waste water treatment plants.
This article was updated on 2024-09-23.
