Report on green waste and sediment characterization

The deliverable presents the results of the activities related to AGRISED Action B1 from the start of the project (01/10/2018) until 29/02/2019 concerning the characterization of sediments and green wastes to use in a co-composting process. In fact, due to the delay in Italian authorization and some additional activities planned, the characterization activity was carried out for a longer period and it is not over finished yet. In particular, in this report, the sediment characterizations carried out by CNR-IRET and UNIFI-DAGRI of the following samples are reported: - two types of sediments collected from Navicelli canal in Pisa (Italy) -a sediment sample from Czech Republic - a green waste sample from Czech Republic These two last samples were characterized and used for a composting process that is taking place in Czech Republic, as additional activity. The green waste has not been collected in Italy yet because it must be taken immediately before the preparation of the compost, that needs the Regional authorization The first sediment collected, labelled NAVI A, showed some physical-chemical properties not suitable for composting process with green waste as planned in the Agrised project. This sediment, in fact, even if having a good nutrient content, no heavy metal contamination and hydrocarbon C>12 higher than the Italian legislation limit, as required by the project, it presented a low content in sand and a high clay content and salinity. This texture would be a problem for a composting process due to the presence of fine particle and low porosity that could create anoxic conditions not favorable for microorganism activity in organic matter transformation (mineralization and humification). In addition, the high salinity of NAVI A could affect negatively and drastically the biological activity in the composting process. For these reasons, another sediment was collected in a different area, and labelled NAVI B. The texture of NAVI B was suitable for a composting process, due to a high amount of sand in the sediment (62.42%). The salinity, even if still high, was reasonable, and after regular washing of the sediment and the mixing with green waste it would be further decreased. Furthermore, the good nutrient content and hydraulic property (high water availability), no heavy metal contamination, hydrocarbon C>12 higher than the Italian legislation limit and absence of toxicity makes the NAVI B suitable for the composting process The Czech sediment EPS had physical and chemical characteristics similar to the NAVI B sediment. In fact, it had a sandy texture, good hydraulic property (high water availability) and nutrient content (slightly lower content in Mg, Fe, K), no inorganic contamination, and no toxicity. The organic contaminants showed similar trend observed for the Italian samples. In addition, it has the advantage to present a very low salinity due to its origin coming from agricultural area, resulting very appropriate for a composting process to be carried out in Czech Republic. The good nutrient content, both in total and soluble forms, the absence in contaminants, the great enzyme activities, confirmed the suitability of these biomasses: corn cobs, wood chips, grass and leaves, for the composting process. These matrices, in fact, had the task to improve the content in organic matter and nutrients, other than to ameliorate the physical structure. The high salinity measured in the leaves and grass will surely decrease in the composting piles with the mixing with the other two green waste biomasses (corn cob and wood chips) and sediments, not compromising the composting process.