History

Before we elaborate on the technologies used for farms, municipalities and industries, here is a little bit of history and explanation on the evolution of Biowaste treatment in Europe

Jan31-05Culbert Many years ago people realized that native-organic waste dumped on landfills was responsible for the majority of all the methane emissions from landfills. Together with all the well-known emissions to the groundwater and into the air, landfills also make a contribution to the greenhouse effect, too.

wetscrub1 Incineration of native organic is not supposed to be an intelligent solution because of their high water content. Therefore, as early as the seventies, people tried to remove all native organic from the waste and compost it.

compostboue From a technical point of view there has been no big problem. But detailed investigations demonstrated that there were large quantities of heavy metals within compost produced this way. As a result of this problem the compost produced got a bad image.

There was no chance to sell it either in landscape-gardening or in gardening or privately.

green_machine Somewhere in the mid-eighties first municipalities introduced a special bin for collection of so-called biowaste in each individual household. Biowaste is a mixture of garden and kitchen waste and was first collected for composting.

Although this path proved to be quite stony, it could be shown that this was what made the most sense and was best way. Meanwhile in most municipalities so called "biobins" are standard operating procedure now in many countries.

bga03 Parallel to the invention of biobins the first composting plants had to be engineered and constructed. It began with simple windrow composting.

Later on these old plants gradually became more automated. Still later on, these plants were enclosed to avoid, or more exactly, to minimize odor emissions. Nowadays enclosed composting plants, more and more working automated and on a high technical level are state of the art.

But only at the beginning of the nineties was digestion of biowaste initiated. Similar to developmental history of composting plants, the path to reliable and efficient digestion plants has been long and stony. Around the mid-nineties comparison of composting and digestion plants showed an equal development level. At this time it could be demonstrated that housed and automated composting plants and digestion plants with an identical throughput have similar investment costs.

The difference is that operation of digestion plants is cheaper - due to the production of electricity and heat. Again the Electricity Input Law was very valuable for the breakthrough. Comparison: Digestion and Composting.

Today composting and digestion plants are presumed to be equal in their technical level and costs. Rural municipalities which tend to have more garden waste inside their biobins prefer composting plants; cities that tend to have more kitchen waste inside the biobin prefer digestion plants.

Even today biogas technology is being improved day by day. But the basic problems have been solved. If there are still many more composting plants than digestion plants in Europe, the only reason for this is that composting started around 1985 and digestion about 10 years later. And there are some cities now that complain about their composting plant .....