Knowledge Base

Contaminants such as plastics, packaging, large or sharp objects, sand, and other inert materials should not enter the digester, as they do not contribute to biogas production and can damage equipment or disrupt the process. Packaging film and plastics from de-packaged food waste, for example, need to be removed upstream, since they neither digest nor settle in a useful way, and can interfere with mixing and pumping. Sand and grit, common in manure and some food residues, are abrasive and would otherwise settle and accumulate at the bottom of the tank, which is why HoSt applies slow-moving GiantMix® paddle mixers whose gentle motion keeps the grit moving so it is carried out with the exiting digestate rather than building up. Larger particles in liquid input streams are captured upstream by the HoSt Filter Basket®, protecting pumps and downstream equipment. Keeping contaminants out of the feedstock protects process stability, equipment lifetime, and the quality of the digestate as a fertilizer.