ELIQUO has developed a proprietary sludge technology, EloVac® - P, that provide simple and innovative solutions to the wastewater sector.
An interview with Ulrich Knörle of ELIQUO - the inventor of EloVac® - P.
EloVac®- P is the only vacuum degassing technology with simultaneous phosphate precipitation for digested sludge on the market.
Vacuum degassing is a process where a vacuum extracts residual gas from a media, in this case digested sludge. Anaerobically digested sludge releases residual methane and carbon dioxide to the atmosphere – methane emissions from sludge treatment make up 75% of the diffuse CO2-equivalent emissions (Gärtner 2017). With vacuum degassing, a pump continuously extracts the residual gasses inside a reactor tank for beneficial reuse such as additional biogas/electricity. The retention time of the sludge in the reactor tank is controlled. The special feature of EloVac®- P is the simultaneous phosphate precipitation in the reactor tank by dosing magnesium chloride directly into the tank.
For a long time, I worked in the field of anaerobic wastewater treatment. I was always amazed how these tiny anaerobic microorganisms can produce so much gas to generate Megawatts of electricity. The methane in the biogas is a valuable energy source, but it can also be a source of potent greenhouse gas emissions; that is where I started thinking ‘how can a water company contribute to reduce greenhouse gas emissions?’ I had the opportunity to investigate how much gas is still contained in digested sludge, and to my surprise, it was much more than I had expected. The answer was clear: we extract the gas from the liquid to make it available for utilisation without releasing it into the atmosphere.
From the aggregated benefits of better dewatering, reduced polymer consumption and additional biogas production; and because of the simplicity and compactness of the system, the payback for water companies can be between one to three years. Moreover, based on our experience with the full-scale implementation in Lingen Germany, plants can expect approximately a 25% reduction in their overall carbon footprint.
Currently, we are focusing on municipal anaerobic sludge digestion. Nonetheless, in addition to the benefits already mentioned, vacuum degassing can also improve the overall sludge digestion process. For example, one area we are currently investigating is how vacuum degassing can improve sludge density and thus increase digester capacity. Therefore, the benefits are not limited to municipal plants, but any type of anaerobic sludge digestion where a certain viscosity of the sludge is not exceeded.
The first full-scale plant is running at the wastewater treatment plant in Lingen, Germany. Outside of Germany, through our sister companies in the United Kingdom, the Netherlands and the United States, the technology will be available, as it has generated a lot of interest. A pilot plant will be available in North America by end of this year. We are in discussions with various water companies in the UK as well who are interested in piloting the technology.