Day 10 – Friday 23/3:

For today’s morning outing we decided to again go for a drive along the River Meuse, this time in the opposing direction, towards the French border. Along the way I decided to point out that there was a geocache on our route that should be a quick find. Reading the description, it turned out to be located at the hilltop ruins of an ancient Roman Fortress. After circumnavigating the hill by car, we found the closest point to the cache and I proceeded to walk up the very steep hillside (good exercise), as a walking trail was not to be seen. Once at the top, the sprawling remains of the fort greeted me. The Geocache was found fairly quickly. 

Patsy (who had managed to make her way up) and I then found several viewing platforms from which offered pretty impressive views over the surrounding countryside, before making our way back down again. On completion of our drive, we headed back to Soulme for lunch. The Toussaints, on hearing about my year 12 studies, which included the construction of a methane digester, arranged a visit to a local farm in the village of Surice. Here, with EU funding, they have set up a continuous methane digester to produce both heat and electricity for use on the farm and the village. Methane digestion is a fairly tedious process (as I well know) that requires very specific conditions to produce a usable amount of gas. These include:

-      Temperature (~35°C)

-      pH balance

-      Type of biomass (biomass is any mass of organisms, the substance(s) broken down inside the digester producing flammable methane gas as a by-product)

If any of these are slightly off, very little methane will be produced and the mixture will likely be ruined.

The heart of their system is the 1500m^3 digester, constantly fed with the biomass mix and heated to the appropriate temperature. This is a dairy farm, so the principal biomass used in the digestion process is cow manure. However, they also add concentrated starch, a by-product from potato washing, waste corn and other wastes depending on season. The digester produces some 600m^3 of flammable methane gas per hour. This gas is then mixed with oxygen and burnt to produce electricity, approximately 2400kw per day, enough to power the farm and surrounding village. The waste heat from the electricity production is also captured using a thermal motor. This heat is used to warm the digester and a number of houses in the village, saving the equivalent of 40,000L in heating oil. In the summer, when the heat is not required, it is used to dry bark chips so they can be burnt. The waste from the digester is high in phosphates and nitrates, making it a very good fertilizer. It is spread on surrounding fields, alleviating the need to purchase such fertilizers.

The efficiency of this process is extremely high, as it effectively creates heat, electricity and fertilizer out of what would have been useless waste that would have needed to be disposed of anyway. Hopefully, more of these facilities will pop up both here and in Australia over the coming years.

Following this most interesting tour, we went off to find a geocache, to show the Toussaint’s what the hobby is all about. Unfortunately, this did not go as well as planned. The first cache was a soggy film canister beside a roadway and the second was nowhere to be seen…

Finally, Charles and Jacqueline showed us an experimental water purification system just out of the village of Doische. This uses a series of reed filled ponds to filter a  village’s grey water, so that it can be released into a natural creek system, as opposed to the sewer.

Back in Soulme, Pierre, Bea and Michael (son of Patsy and Philip’s Australian friends Peter and Caroline) later joined us for dinner. Needless to say it was an excellent evening.