Biological Wastewater Treatment – First results in developing a new biological cleaning method

The main problems in biological wastewater treatment

The big challenge in biological wastewater treatment (oxidation/nitrification) is the intensification of the natural cleaning process.

Further intensification can be achieved by offering the organisms surfaces (carrier materials) on which they can grow (biofilm formation). Ventilated and submerged fixed bed reactors (FBR) use this approach. In contrast to classic clarification processes such as activated sludge biology, higher bacterial concentrations can be achieved. Membrane bioreactors (MBR) are not suitable here because the immobilized microorganisms require permanently installed growth carriers, which ensure a stable and clog-free process as in FBR.

However, none of the methods mentioned can be used to specifically influence the composition of the biomass and thus the metabolic performance. On the other hand, wastewater contaminated with nitrogen, where the nitrogen content is disproportionately high compared to the carbon content, presents sewage treatment plant biology with an unsolvable task.

These requirements are particularly required for waste water from agriculture (liquid manure, digestate, surface waste water). Because of the saturation of the agricultural areas with nitrogenous compounds, farmers and plant operators lack the options for disposing of this waste. The fertilizer ordinance limits the nitrogen input per area.

Clearfox BioComps research project – new biological wastewater treatment technology in the development

The aim of this research project is therefore the development and production of an intensive nitrification module. This module allows the implementation of an innovative biological purification process, especially for such wastewater due to an unfavorable composition of the waste. That wastewater is insufficient or inadequate due to the natural clarification biology and cannot be processed by usual procedures. The process is based on the decoupling of the limiting metabolism, so that it can easily be integrated independent of the other clarification technologies. This innovative approach is made possible by a biocomposite technology developed at the University of Bayreuth. It is based on the embedding of specifically metabolically active microorganisms in an adapted polymer matrix in the form of fibers. As a result, the active microorganisms are stably fixed. They are optimally supplied with nutrients in the matrix, but are protected against harsh environmental influences such as high salt loads.

In combination with the proven FBR, a completely new cleaning technology is developed.

First results of Clearfox Biocomps research project

The first results from the tests in the PPU laboratory system are available. This involved working out relevant parameters such as loading, concentrations, discharge and ventilation for the operation. Different wastewater compositions based on synthetic wastewater according to DIN 38412 part 26 were used. Various nitrite concentrations were set to test the nitrite treatment rate of the fixed bed compared to the bicomponent fiber.

Industrial sectors in which this new biological wastewater treatment technology will be revolutionizing

In a next step, the implementation of the process in a pilot plant will be checked. The entire wastewater treatment process is to be examined here on the basis of the laboratory tests. The results from this can later be scaled up for large-scale applications. In addition to agricultural businesses, these are industrial sectors in which complex wastewater is produced with a nutrient composition that is unbalanced for the microorganisms. Furthermore, the protective polymer fiber enables also to treat waste water with growth inhibiting contaminants, such as high salt content from oil drilling.