Greenhouse gases at composting - Good management and the right technology helps the climate
Various emissions are produced during composting, which can have a different impact on the environment depending on the composting system. For example, anaerobic waste treatment produces different emissions than aerobic waste treatment. However, the various structural measures also play a role, such as the design of the aeration, the amount of material in the compost or the various covers or enclosures.
To compare different emissions, the impact of the emitter on the environment is calculated in terms of CO2. This gives a CO2 equivalent. CO2 equivalents can be used to compare the environmental impact of different emissions from different types of installations.
At only 12 kg/t, half of which is due to the pre-treatment of the material, the GORE® Cover System is far superior to the competition. This is why the system is listed in the current European Best Available Technology (BAT) reference document for waste treatment from 2018.
Assessments of the Environmental Institute (bifa Umweltinstituts GmbH) Augsburg proved that emissions of climate relevant gases are mainly influenced through operation and rotting control.
Technical measurements like e.g. biofilter cannot separate methane and nitrous oxide therefore the aim should be to avoid these gases during composting.
In addition to methane and nitrous oxide, ammonia also has an indirect climate-relevant effect, as it is converted to nitrous oxide in the atmosphere.
The emission factors analysed in the study were total carbon, methane, nitrous oxide, ammonia and VOCs excluding methane. The results of the comparison of the different composting processes are shown in the figure.
Composting under a semi-permeable membrane shows excellent results. Fundamental to avoid climate relevant gas emissions is among all the management of the aerobic rotting process. Required for this are a favourable C/N ratio, sufficient water content, the dimension and shape of the rotting heap, a corresponding structure material portion, active aeration, the turning processes for sufficient homogenization and the control of the rotting temperatures.
The complete study can be ordered as bifa-text No. 47 Ecoefficient utilisation of biowastes and green waste (in German) at bifa Umweltinstitut GmbH, Augsburg, Augsburg, www.bifa.de
Since many years the UTV Inc. is active in the area of regenerative energies. The latest project is the stand-alone solar plant “SunFlower” by EasyKomp which on the site of the UTV Inc. in Baden-Baden generates energy from sunlight.
The innovative photovoltaic plant – like the sunflower – automatically aligns the solar modules with the optimal position of the sun. A small power station with ca. 8.5 kW performance with 42 solar modules is shaped like a solar panel.
The electronic controls the direction adjustment and the collector slope of the panel and thus optimises the energy output which increases by over 50% contrary to traditional photovoltaic plants.
An area of less than 200 square meters is enough to install this power plant. There are numerous application possibilities. For private investors and municipalities, industry and trade. SunFlower is also attractive for managers of sewage and compost plants. One module of the UTV System is enough to generate energy for one compost plant with a capacity of 5000 t/a.
