The removal and conversion of organic material is the important first step in wastewater treatment systems. Organic solids or particulate material could cause unwanted biological activity in other treatment processes and pose severe health risks. Anaerobic membrane bio reactors (AnMBRs) are a proven technology that can produce particle free water and biogas.
The research focus will be on ensuring optimal performance of the membrane filters that are prone to clogging. Methods such as below critical flux operation (i.e. filtrate flux above which irreversible deposits take place), periodic back washing, chemical cleaning and improving surface properties of the membranes will be investigated.
The energy that is contained in the biogas can be recovered using solid oxide fuel cells (SOFC). Biogas typically contains methane (CH4), nitrogen (N2) and carbon dioxide (CO2) along with other pollutants such as hydrogen sulphide (H2S), siloxanes and volatile organic compounds. These compounds can damage part of the SOFC and reduce long term performance. Initial research will focus on testing the SOFC with different biogas compositions and the removal of pollutants in the biogas. Another research focus is on making the biogas suitable for direct injection into the fuel cell.
To be able to cope with fluctuating water flows and solids concentrations, water and (organic) particles, have to be separated. The separation technology, dissolved air flotation (DAF) will be used for this purpose. Since DAF uses air bubbles to separate organic solids from the water, oxygen toxicity might be a problem for the anaerobic (no oxygen) bacteria that live in the anaerobic reactor. For this reason research will focus on the effect of oxygen in anaerobic systems and developing alternative gas carriers such as biogas.
For the development and construction of a suitable pilot scale pre-treatment system several steps are needed. Initially, a small scale installation (up to 100 liters per day) is tested with Barapullah drain water. During this initial period, the main focus is on the interaction between the separation and conversion systems. The information obtained from the small scale installation can be used to develop improved process designs.
Next, the improved process designs from the initial phase are used to scale up to 10.000L per day installations. At this stage a robust and high rate anaerobic process combined with a system that can effectively separate solids and liquid will be built based on membrane filtration and or DAF.