Valorga develops biological treatment solutions (methanization, composting…) associating various technologies experimented for several years by start-up and operation teams and adapted according to the level of performances asked by our customers
The methanization by dry way is specifically adapted to the treatment of the solid fraction contained in the household refuse.
Anaerobic digestion is the natural decomposition of organic matter in an anaerobic environment (without air). This degradation is performed by anaerobic micro-organisms under controlled conditions, including temperature, and leads to the production of the so-called biogas.
This technology constitutes an interesting solution for the treatment of the biodegradable fraction of household waste (kitchen and garden waste and paper cardboards) as far as this fraction represents 60 to 65 % of the waste input to be treated.
Processing organic solid waste by anaerobic digestion leads to :
Energy production in the form of biogas containing around 55 % methane,
Recycling of residual organic material in the form of a stabilised soil conditioner.
New regulations, ecological requirements and available technologies lead the municipalities to consider more and more the waste treatment according to a multi-process approach.
If possible and considering economic requirements, this multi-process approach takes into account different techniques adapted to recovery and/or treatment of the different waste materials.
That is how simultaneous combinations can take place including the recycling of certain materials which are reintroduced in the industrial network (glass, metals, plastic, some types of paper), the biological treatment of the organic material (kitchen waste, garden waste, dirty paper), the incineration or the RDF (combustible) material (non recycled paper and plastics) and the dumping of non-valorisable materials or final residues from the previous treatments.
The biological treatment of the organic material is then naturally important in this multi-process approach in that non-stabilised organic material cannot be directly dumped. Furthermore, the incineration of the wet organic material cannot be considered as a recycling nor a valorisation process because of the destruction of the organic material and the low energy recovery by the combustion.
When a selective collection can be organised in order to obtain a source separated organic material almost free of refuses, a very high quality stabilised soil conditioner is available after treatment.
The aerobic composting can treat organic fraction of source sorted waste or bring a post treatment of the organic matter after anaerobic digestion.
Aerobic digestion is the decomposition of organic matter. This degradation is performed in presence of oxygen under the combined action of various micro-organisms. The increase of temperature of the order of 60 in 70°C during several weeks of biological degradation allows the production of a stabilized compost having the qualities of high quality organic amendment.
Valorga has developed several aerobic composting processes well adapted to the waste quality:
Aerated tunnels composting process
Ventilated swath composting process
Thermic drying composting
Biodrying tunnels composting process
It consists on solid, semi-solids or liquids waste anaerobic digestion treatment.
Usually they are industrials, agricultural waste or water treatment sludges.
They are directly input in the digesters or firstly mixed, with household waste.