Fermentation of biogas, slurry, manure and food residues with biogas preparation and feed-in

SWISSWATER was the general planner for one of Switzerland's largest biogas plants for biogenic waste in Inwil, Canton Lucerne. Liquid manure, manure, green waste and biogenic waste from food processing are used as substrates.

The plant consists of a mesophilic wet fermentation and a thermophilic solid fermentation. The biogas produced is processed and fed into the natural gas grid. The fermentation residues are dewatered, whereby the liquid phase is processed into a nutrient-rich fertilizer via ultrafiltration and reverse osmosis. The solid digestate is composted and used as a nutrient supplier and soil conditioner for agricultural purposes.

Special features:

• The plant is very demanding in terms of process and structural engineering.
• The realized plant combination was unique at the time of construction.

In addition to the technical challenges, the needs of the plant owners also had to be met. The plant is supported by 75 farmers, several energy producers and the most important agricultural cooperative in Switzerland.

The plant has been awarded several prizes:

• Prix Pegasus from Energie Schweiz 
• Watt d'Or from the Swiss Federal Office of Energy

The amount of energy produced corresponds to approx. 3,000 natural gas cars at 15,000 km/year.

As general planners, we provided the following engineering and planning services:

• Civil engineer and structural planning/statics
• Process and machine technology
• E I&C planning
• HVAC planning
• Building physics
• Building services engineering
• Local construction supervision/construction management
• Construction management. (SIA 103 LP 1–6, HOAI LP 1 - 9).

In the run-up to the project, SWISSWATER worked out the new procedure and demand planning together with the client.