Within CORNERSTONE’s case study 3: Chemical Industry the lab experiments have successfully started. In a first step, the biodegradability and the methane potential of the different organically rich waste streams that have been selected by Covestro for the project are being analysed at TU Darmstadt. These tests are carried out using an Automated Methane Potential Test System (AMPTS). The wastewater is treated anaerobically in batches of 0.5 litres for a period of one to two weeks. The biogas produced is passed through a caustic soda solution, which absorbs the CO2, so that only the methane production is measured. When no more biogas is produced, the test is stopped. During the running time, the production of methane is recorded and at the end of the test, the degradation of organic matter is determined.
Different configurations were tested, including different ratios of food (wastewater) to microorganisms (anaerobic biomass) and different biomasses for inoculation originating from different industries, to analyse the effect of adaption of the different biomasses on the test results.
Picture on the right: Sinem Kale-Fundneider
These batch tests provide valuable insights into the anaerobic biodegradability of the waste streams, their biogas potential, specific methanogenic activity (SMA) and possible inhibitory effects. In the next step, continuous laboratory tests will follow. In addition to the pre-tests, they allow the biomass to adapt to the wastewater and the test conditions. In addition, some inhibition effects only become apparent over time. Therefore, a lab-scale phase of several months is indispensable before starting pilot-scale tests.
The technologies used for the treatment of Covestro’s waste streams will be an anaerobic membrane bioreactor (AnMBR) and an expended granular sludge bed reactor (EGSB). The waste streams selected by Covestro differ in terms of flow rate and organic load. While streams with a very high organic load but lower flow rate are better suited for an AnMBR, an EGSB can handle higher flow rates but lower organic concentrations. The EGSB plant is an existing plant with three reactors with a volume of 4.5 litres each, which will be upgraded to meet CORNERSTONE’s goals for smart monitoring. The AnMBR is a new plant equipped with a submerged flat sheet membrane and as well the necessary technology for Smart Monitoring. The continuous lab-tests will be performed in 2025 and we are thrilled to evaluate their performance.
Picture (left): Sinem Kale-Fundneider
January 2025