ISAFOM-CNR, Perugia has recently developed an innovative procedure that can easily turn the waste resulting from olive oil mills into an excellent soil conditioner/organic fertilizer.
It is realized through a simplified static composting procedure conducted in gas-permeable bags with passive aeration of the biomass.
The technology is especially suited to the treatment of the humid pomace produced by “two phases” modern olive mills, ideally working in line with it.
In a first step, ground olive pits is recovered from the olive pomace for energetic purposes; the wet residue is then mixed with proper organic waste materials chosen so as to obtain a homogeneous, porous and non-percolating mixture which is immediately transferred into the gas-permeable plastic bags and stored outdoor in a place protected from the rainfall; in this phase, inside of the bags starts spontaneously a natural process of aerobic biological maturation which proceeds for about two months without any external support.
Later on, bags (recyclable for the next year) are emptied and the content chopped, homogenized and slightly re-hydrated to allow a short phase of "curing" of the biomass arranged in a pile, able to ensure better chemical-physical and microbiological characteristics of the end product (compost) for the best agronomic use.
- It provides an alternative solution to the expensive procedures normally carried out by the olive millers for disposing olive mill waste (OMW), namely controlled soil spreading or purification of OMW in the wastewater treatment plants;
- Valorization of the OMW, overcoming issues especially related to the management of the humid pomace produced by two-phase olive mills.
- Ground olive pits (about 10% of the humid pomace) is a marketable product (about 150 €/ton) mainly sold as a fuel and/or for other industrial uses.
- SANSOIL compost, obtained through a short, controlled and certifiable chain, can be successfully used in agriculture, even in organic farming. In the plant nursery industry, it has proven suitable substitute for the use of peat, thus replacing a fossil product with a high environmental impact. In addition, it is characterized by a high content of humic substances (about 15%) and of elements of plant nutrition (about 3% of N and K, as well as trace elements) as well as by a high biological stability, low phytotoxicity and an interesting suppressiveness against some phyto-pathogens of agricultural interest, all features that make it similar to a stable and mature compost, according to the reference standard (DL 75/2010).