Wastewater

25 years ago, urine-diverting toilets were no more than an idea, challenging the central paradigm of wastewater treatment plants. Since then, however, modular water technologies have become increasingly important. Using a new method, scientists at Eawag have mapped the dynamics of this transition.

Even though industrial wastewater is treated at state-of-the art plants, the sheer variety of synthetic organic compounds from the chemical and pharmaceutical industry which end up in surface waters are seriously underestimated. This is shown by a new study carried out by Eawag and ETH Zurich.

The biologically active, slow-flow sand filters of lake water treatment would remove nanoplastics from the raw water very efficiently. This was shown both in the laboratory and in larger, realistic tests and modelling.

What has been a purification process in wastewater treatment plants for decades can also be used decentrally or semi-centrally as a recycling process for nutrients. Early separation of "solid and liquid" plays a key role here. It allows for flexible solutions in terms of process technology, especially in the treatment of urine. New studies also show that the processes can be used not only for human urine, but also for that of cows or pigs.

Ozonation is an established treatment process to remove micropollutants from wastewater. However, since unstable toxic reaction products can be formed in the process, biological post-treatment is necessary. Results from the Ecotox Centre and Eawag show how well different post-treatment methods reduce ecotoxicological effects. The combination of ozonation and activated carbon proved to be the most effective.