Fraunhofer Water Systems Alliance (SysWasser)Less sewage sludge, more energy
In comparison with conventional digestion processes, high-load digestion excels through
- shorter residence times (5–7 days instead of 20)
- higher organic volume load (8–10 kg/m3*d instead of 1–2)
- improved degree of degradation (up to 70% of organic dry matter)
- less foam formation
- increase in biogas yield
- improved drainage of residual sludge
- smaller amounts of sludge
- cost savings for sludge disposal.
The high-load process can also be used to treat other organic substrates such as agricultural biowaste or organic municipal waste.
Microfiltration
A combination of high-load digestion with microfiltration using rotating disk filters leads to additional increases in turnover and achievable quantities of biogas. The filtrate is free of particles but rich in nutrients which can be recovered for use as fertilizers.