Application of biotechnology is an apparent trend in treatment of wastewaters. This primarily means the utilization of microorganisms to remove impurities from wastewater or to process sludge. However, biological processes have a limited or no use for several types of wastewaters and waste (mainly from the industrial domain) – e.g. due to toxicity or low biodegradability of the pollutants present or due to extremely low or extremely high concentrations. Such cases demand a different solution frequently consisting of physical-chemical processes (coagulation, clotting, membrane separation, oxidation processes etc.).
Modern oxidation processes
In removing the wastewater pollutants that are not readily biodegradable a great potential is displayed by so-called modern oxidation processes. (Advanced Oxidation Processes - AOP). Their mutual feature is their operation at common temperatures and pressure and the utilization of the outstanding reactivity of hydroxyl radicals. These radicals are the strongest oxidation agents known and are characteristic of their low selectivity, which means they are able to oxidize a wide range of compounds. There are several ways how hydroxyl radicals can be generated in wastewater – for instance by adding other agents (ozone, hydrogen peroxide) or applying UV radiation, ultrasound, etc. The procedures most readily applicable for this purpose are the Fenton reaction (radicals occur due to catalyzed degradation of hydrogen peroxide) and ozonization. Both the Fenton reaction and ozonization (or their possible modifications and combinations) can be applied effectively to degrade a range of pollutants in wastewaters (halogenated compounds, phenols, polycyclic aromatic hydrocarbons, etc.). These methods may also be utilized in the domain of sludge management – in the conditioning of sludges.
Currently, we are mainly engaged in the use of various modifications of ozonization for wastewater treatment. The main research topics include the use of AOPs for the removal of nitrogen compounds, with an emphasis on the possibility of oxidizing ammoniacal nitrogen to gaseous nitrogen.
Since 2020 we have been involved in the project FW01010142 - Combination of advanced oxidation processes (AOP) and membrane separation for industrial wastewater treatment (POV). The project is based on the use of a combination of AOPs and a membrane bioreactor (MBR) for the treatment of difficult-to-treat wastewater. Selected AOPs will be used as a pretreatment, which will increase the efficiency of the follow-up MBR-based biological stage. The aim is to achieve the quality of the treated wastewater enabling its recycling.