The processes of cleaning water in wastewater treatment plants occur in three stages: primary, secondary and tertiary. The secondary, also known as biological, is based on aerobic and anaerobic degradation of microorganisms. This secondary cycle can be carried out in various executions, namely as a system with attached and as a system with dispersed biomass. The system with dispersed biomass (activated sludge) is comprised out of a sequencing batch reactor (SBR) and a membrane bio reactor (MBR), which is an upgrade of the classical or conventional.
The purpose of the master thesis is the comparison of cleaning technologies for wastewater treatment plants in size of 8000 people equivalent (PE). We compared SBR technology and MBR technology. We are familiar with the operation of wastewater treatment plants, basic principles and technologies of wastewater treatment based on the literature. Calculation parameters of designing the treatment plant followed the guidelines of ATV DVWK-A 131E. For the design, we used the program for designing wastewater treatment plants Aqua Designer by company BITControl GmbH, which uses the above-mentioned guideline. Technologies are already established and widely used. The paper presents the advantages and disadvantages of each technology and key differences in designing and calculations on the basis of the discussed wastewater treatment plant.
The paper presents the findings, namely, that the size of the biological reactor is dependent on the concentration of activated sludge. In MBR technology, the concentration of the activated sludge is greater compared to SBR technology and because of this, the volume of the biological reactor is significantly lower. The size of the pool depends on the amount and strength of blowers and mixers. The quality of the effluent is better using MBR technology, as the value of the limit parameters is significantly below the threshold value. Operating costs are higher using MBR technology because of the electricity consumption of blowers and pumps, which are necessary for cleaning the membranes. Furthermore, the membrane water treatment technology is increasingly gaining recognition due to the optimizing treatment, the membrane materials and the affordable prices of membrane modules.