Innovative Carbon-based Sorbents as an Efficient Way of Wastewater Treatment

The environmental impact of different groups of micropollutants, similarly to microplastics, is currently being intensively investigated. In particular, the main sources, such as urban wastewater, are being sought. Wastewater contains a variety of micropollutants such as pesticides, pharmaceuticals and drugs, which can have a dangerous impact on the aquatic environment and the organisms living there. Certain types of medicines, hormones and drugs and their metabolites are capable of affecting, for example, the behaviour of aquatic animals, their reproductive capacity, etc. in small quantities (even in tens or hundreds of ng/l). At present, a considerable part of foreign work focuses on the behaviour of these micropollutants in the environment. Scientific studies over the last five years have shown the presence of pharmaceuticals, in particular, not only in wastewater, surface water and groundwater, but also in the bodies of aquatic organisms. In addition, some of these substances have the ability to accumulate in the environment (in animal bodies or plants) and thereby enter the food chain.

There is also increased emphasis on monitoring the presence of antibiotics and the associated presence of resistance genes and pathogenic microorganisms in wastewater and surface water.

Municipal wastewater treatment plants are identified as the main sources of micropollutants and pathogenic microorganisms. However, it should be remembered that wastewater treatment plants treat wastewater from hospitals and various health facilities, nursing homes and especially households, and these are the dominant source of harmful substances in the sewage system. Wastewater treatment technology at municipal wastewater treatment plants is more than 100 years old and unable to effectively degrade some types of micropollutants and their metabolites. Thus, most treatment plants continuously discharge certain types of compounds into the aquatic ecosystem, where they gradually enter other elements of the environment.

Micropollutants such as pharmaceutically active compounds (PhACs) enter the aquatic environment from a variety of sources, with wastewater being the main source of contamination. The concentrations of PhACs in the sewer system are influenced by the activities of physicians in the area, supplies by the pharmaceutical industry, the specific per capita water consumption, the specific consumption of each PhAC, seasonal changes, the weather and the type of sewer system used. Antibiotic-resistant viruses or microorganisms found in wastewater can often be responsible for serious diseases. It is therefore important to pay close attention to their occurrence and subsequent removal during the water treatment process. It is important to remove not only micropollutants and pathogenic microorganisms, but also resistance genes. Their presence is often linked to the presence of antibiotics and their degradation products in wastewater and causes the transfer of resistance genes. According to the EU, microorganism resistance and their spreading is one of the fundamental problems that must be tackled today.

Biochar is a carbon-rich material prepared by pyrolysis of organic matter. It offers high affinity and sorption capacity for organic contaminants, including pharmaceuticals. The biomass or waste from which biochar is most commonly produced can come from a variety of sources, such as cow and pig manure, straw, fruit peelings, corn, wood waste, sewage sludge, etc. Biochar appears to be an excellent sorbent for the removal of most micropollutants found in wastewater.

This is a common goal for two facilities. TUO is responsible for the preparation of sorbents based on biochar and for the development of a technological unit for chemical syntheses, including complete sorbents analysis.

SUT focuses on the development of a semi-operational technology for treating wastewater from selected substances, including their determination, and the subsequent installation of the semi-operational unit. It will be installed in real conditions of wastewater treatment plant operation. The research also includes the possibility of using treated water for irrigation during the summer months.