The new plant is due to begin producing biomethane as early as autumn 2013 - the modular design of the plant allows for the realisation of the project within a short period of time. The biomethane will then be refined to natural gas quality making it suitable for all consumption paths including as fuel for the growing network of Finnish natural gas stations, Weltec Biopower said.
The company is working on the joint project together with Finnish renewables company, Doranova. The biogas plant will use “innovative strategies” to enable it to accept substrates which are normally difficult to process. The in-house constructed components such as the fermenter, pump and agitator technology will be put to use as well as separation and sanitation technologies, Weltec said.
For example, an in-house innovation for the feeding of substrate – the MULTIMix – has been integrated into the design, allowing fibrous input materials such as grass silage, straw or co-substrate to be disintegrated in the process. In this way, “these normally difficult-to-process substrates can be decomposed excellently into biogas by bacteria,” it said.
Similarly, there is the option to separate foreign bodies upstream of the pump and use the plant's stirring systems. Weltec said its new feeding system reduces the stress on the stirring system as well as wear on the Finnish plant. “Furthermore, the plant operator will, in the future, be able to flexibly choose input materials and can rely on cheap, but difficult-to-process substrates.”
This advantage will enable fox and mink excrements from a nearby fur farm to be processed in the future, although in the initial phase, just wastewater, grass and straw will be used as fermentation substrates. Additionally, manure from three nearby pig sties will enter the fermenters via pipelines.
Coordinated manure and fertiliser management will, after fermentation, supply high quality fertiliser for the region's farmers. It will also ensure adherence to statutory nitrogen limits so that the ground water is not overburdened with nitrate, Weltec added.
Edited By Josie Le Blond