Microplastics in the water cycle and
the occurrence in sewage sludge
The microplastic cycle begins and ends with humans. Whether tyre wear, cosmetics or synthetic fibres – everything ends up in the wastewater and later, through the consumption of fish and seafood, back in us humans.
Microplastics are removed from wastewater in sewage treatment plants – but the fact is that this happens only insufficiently.
Despite the installation of a pre-treatment stage in sewage treatment plants, the sewage sludge contains non-organic substances and impurities up to microfibres of polyester as well as microplastic components. In addition, an analysis by the TU Freiberg in 2021 showed that numerous white particles, which do not represent microplastics, are contained in the sewage sludge. The wax-like, organic agglomerates consist mainly of aliphatic hydrocarbons (paraffins, waxes), amines and alcohols.
Incineration capacities for sewage sludge are currently only available to a limited extent and at high disposal prices. Since the agricultural utilisation of sewage sludge is facing the “end” in the medium term, ReTech Resources Technology GmbH, in cooperation with research and development companies such as FAUDI, has set a goal to develop a sewage sludge treatment concept.
Sewage sludge treatment –
Our alternative to mono-incineration significantly increases the value added from sewage sludge and offers an innovative holistic technology for the treatment and reuse of municipal wastewater streams.
the pre-filter – RT-microplastic Separator
The first step in our overall process is pre-filtration with our specially developed RT-microplastic separator.
This enables us to separate a filter cake containing all non-organic components and impurities, including microfibres and microplastic particles. The discharged filter cake with all impurities can be disposed of in a regulated manner with a very good residual moisture content. The cleaned sewage sludge flows via the filter element into a so-called clean tank and is fed from this clean tank to a further dewatering process that usually takes place.
In our sewage sludge treatment, heavy metals, other pollutants, resistant germs and antibiotic residues are separated in advance by means of ultrasound disintegration, solid-liquid separation and filtration. By combining mechanical, chemical and biological process technologies, a high-quality, humus-like product is produced, which is established in the agricultural industry as a substitute for primary material-based products. Furthermore, targeted nutrient recovery in the form of nitrogen and phosphorus recycling is carried out. The phosphorus in the form of struvite from MAP crystallisation or calcination can either be added as a nutrient to the humus-like product or, in a further process step, phosphoric acid can be recovered and fed back into the process.
We consider a possible modular integration of the sub-processes of the intended retrofit concept of our RT-microplastic separator into existing systems as an important element of a sustainable adaptation strategy for future challenges.
Innovative and sustainable
the overall process
Environmental added value with sewage slduge treatment
The Re-Use Idea
Enormous reduction of harmful substances
(coarse disturbances up to microplastics)
Increasing the stability of the overall process
Due to dry substance values of approx. 40% of the separated non-organic components
By separation of the substances
no return to the environment
Improvement of the initial situation for the production of
humus soil & possibility of agricultural spreading
No carbon loss
Which is urgently needed in agriculture
Reuse of water from municipal wastewater treatment plants
For the irrigation of agricultural land
Dewatering without the use of synthetic polymers
Annual savings through the use of biodegradable flocculants, cost reduction as well as no environmental pollution
Start into your next project
with us and our partner now
ReTech Resources Technology GmbH is our cooperation partner and with our support is your contact in matters of sewage sludge processing for regional value creation and nutrient recovery.