Waste treatment carried out in the plant managed by Kyklos uses the best available techniques to reduce, as much as possible, the negative effects on the environment that could occur during the bio-chemical transformation operations for the production of compost.

Once waste reaches the plant, it can follow two lines: green waste (pruning) is received outdoors and shredded; wet waste (sewage sludge from wastewater and the organic fraction of municipal solid waste – OFMSW) is immediately discharged into a large barn, where air is drawn and purified before its emission in the atmosphere, in order to avoid the diffusion of odours. In this barn the most important operations take place, first of all, the optimal mix of the different kinds of waste. This is a critical step, because the right dosage of the different kinds of waste determines the quality of the final compost, that is its capacity to improve soils, especially when they are used for excellent crops.

The material resulting from the first mix is put into 8 bio-cells which constitute the heart of the composting plant. They are closed spaces, inside the main barn, where the biological process parameters (temperature, humidity, amount of oxygen, air flow rate) can be easily controlled through probes. Bio-cells are equipped with air insufflators and water sprayers, in order to reduce the temperature of the fermenting mass, to maintain the correct humidity level and to provide oxygen to the bacterial flora. 9 days later, the masses are extracted from the bio-cells and transferred to floors which are aerated from below, in the same barn. After approximately 25 days of controlled aeration, the masses complete their accelerated bio-oxidation phase and lose their initial odorous characteristics.

At this point, the masses are transferred to another barn, where forced air renewal and purification take place before being emitted into the atmosphere. They stay put for 65 days and then become compost; the following step is to transfer the compost into a specific storage area, from which it is eventually taken to be sold.

The possible emission of odours, as said before, is controlled through two different aspiration machines in the two barns: the main one, where the bio-cells are, and the second one where the maturation of the oxidised mass occurs.

In both gas flows the destruction of odours is obtained through a pre-treatment wash of the exhausted air in a container placed horizontally and in a scrubber where dust particles and ammonia are captured.

The gas flow is routed through a vegetal-material bio-filter (made of heather roots) upon whose surface special microorganisms metabolise the pollutants, in particular the substances responsible for the odours.

The liquid containing a high concentration of pollutants which is formed during the composting steps (leachate) is currently collected and treated in external authorised plants. However, it is foreseen that as of early 2014, processed water and most rainwater will be purified in-house in a reverse osmosis plant which is being finalised. The treated water will be completely re-used in different steps of the process, for example, to sprinkle the masses in the bio-cells or to feed the scrubbers. In this way primary source consumption will be reduced to zero.

During the year, the process for the implementation of an integrated environmental and safety management system continued, in accordance with the UNI EN ISO 14001 and OHSAS 18001 standards.

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