Epic Cleantec produces beer and compost from wastewater and will also use it to heat buildings

Wastewater can be used for climate-friendly heating or beer production (image: Epic Cleantec)

Showering and flushing are not wastes but valuable resources. The company Epic Cleantec shows how wastewater can be used in a climate-friendly way to heat buildings, to brew beer and to produce a compost-like soil conditioner.

Nicole Dominikowski (translated by Nicole Dominikowski), Published 02/21/2024 🇩🇪 🇨🇳 ...

Business Renewable

Epic Cleantec already uses wastewater to produce beer and a type of compost, but wants to use it to heat buildings in a more climate-friendly way. In a high-rise building in San Francisco, for example, grey water from showers is collected and fed into a tank in the basement so as not to waste this valuable resource.

There it is filtered and disinfected using chlorine and ultraviolet light before being piped to the building's toilets. Recycling the water helps to reduce the load on municipal treatment plants.

Filter system in the building basement (image: Epic Cleantec / Matt Simon)

Input versus output from the building in San Francisco (image: Epic Cleantec)

By regulation, we’re only reusing the water for nonpotable applications. Scientifically, we can produce drinking-water quality.

- Aaron Tartakovsky, Epic Cleantec founder and CEO

Last year, the company produced a tasty Kölsch-style beer from grey water, which is produced when people take a shower and is rich in valuable nutrients and minerals, according to Peter Grevatt, CEO of the Water Research Foundation.

Epic beer made from shower water (picture: Matt Simon / Epic Cleantec)

Heat recovery from wastewater

Water recycling is not the company's only experiment, however. For example, several kilowatt-hours are used for the heating of water before it is discharged into the sewer system with the excess heat energy.

The key is to use the thermal energy of wastewater while it is still warm, i.e. at building level. It is an important renewable energy technology that makes buildings more energy efficient. Epic Cleantec is experimenting with heat exchangers that extract energy from wastewater to heat the building in order to develop this area.

To prevent cross-contamination between the wastewater and the building's water supply, the process uses double-walled heat exchangers. The raw wastewater is stored in the building at around 80 degrees Celsius. The heat exchanger uses the heat from the tank and then transfers it to the incoming city water, which is typically between 55 and 65 degrees Celsius.

Compost from sewage sludge

The company also recycles blackwater with human and organic waste into a compost-like soil conditioner that can be mixed into soil in home gardens, for example. The final product is treated in such a way that it is free of pathogens and odours. This biosolids sludge, which also contains microplastics and various chemicals such as PFAS linked to cancer, is much harder to recycle.

Water recycling systems will need to be expanded in the future, as more regions of the world experience droughts due to climate change. Wastewater in cities is growing at a super-linear rate The volume of wastewater in large cities is growing superlinearly, faster than the population, according to a recent study.

This is in stark contrast to greenhouse gases. In densely populated regions, they grow sublinearly, or slower than the population, due to the well-developed public transport system. Solid waste, on the other hand, has a linear growth rate with population growth.

You look to the places that are already experiencing the greatest level of water stress, many of those places are the places that are most rapidly growing. Needing to figure out how we recover resources is incredibly important.

- Grevatt