Recycling of domestic organic waste with the use of composting and vermicomposting

The increase of the world population associated to the concentration of this population in urbanized environments has caused the growth of the production of residues of organic solids, that in most of the times are discarded in inadequate places that can pollute the environment. Another factor that is also related to population growth is the demand for more food, mainly agricultural products, which need different inputs, such as fertilizers to increase productivity. Given this context, it is essential to use technologies that allow the recycling of nutrients from organic waste, which have the potential to condition soils and fertilize agricultural crops. This work has the objective of evaluating two already consolidated technologies for recycling solid organic waste, such as composting and vermicomposting, implanted in compact systems. Among these feasible systems were evaluated the humic compounds and the slurries generated, the parameters being evaluated the assimilable phosphorus (P), the active acidity, organic matter and the organic carbon. The results obtained indicate that the vermicompost presents a higher production of humic compound and less of slurry in relation to the composting process, and that the humic compound produced in the composting process and the slurry produced by the vermicompost process have higher P indices, organic and organic carbon, in relation to their corresponding, and the acidity index was practically the same for the slurries and humic compounds produced in both organic matter recycling processes.

The characterization of the humic complexes of soil organic matter

1. During the course of the alkali fractionation and the preparation of the humic precipitates, the qualitative characters of the fractions were followed by employing a standard hydrolysis with dilute acid. Humic acid itself was shown to be unhydrolysed by this reagent, and, therefore, the extent of hydrolysis of a humic fraction can be used as a criterion of purity.2. Studies on the fractionation of the humic precipitate with aqueous, anhydrous, and alcoholic bases, led to the following conclusions:(a) The humic precipitate as normally prepared i s always a mixture of true humic acid with varying amounts of co-precipitated material of a non-humic nature.(b) This non-humic material is not an integral part of the humic molecules, it is merely co-precipitated and adsorbed contaminants.(c) The non-humic material is differentiated from the humic acids by the following properties: (i) it is hydrolysable with acid; (ii) it does not give the characteristic nitro-humic compound on nitration.