Key-words: composting, solid waste, agriculture Compostagem is the recycling of the organic substance of animal and vegetal origin, that is easily putrescveis, as, for example, vegetable leves, rinds and fruits, remaining portions of food, prunings of trees and weeding etc., which are transformed into a composed called product after its decomposition. The compostagem is controlled for microbiological activity, that is influenced by the composition of the departure material (relation carbon/nitrogen? C/N, ideally 30/) (second fundacentro), (Figure 1), aeration (oxygen supply) and humidity. The nutritional substances, as amino acids, proteins and lipdios, carboidratos quickly are decomposed by microrganismos. In this reaction the set free energy in heat form (thermal energy) leading to the formation of carbonic gas and water. In the decomposition of cellulose and lignina the hmico material is formed, that can be considered as end item of the compostagem, that is the proper composition. It is considered adjusted the ideal relation of C/N for the beginning of the process of 30/1.

Being different relation of this, the process of compostagem it will only occur that the compostagem time will be bigger. It is extremely important to know relation C/N, to favor a good aeration and to keep the humidity for 50% return. The compostagem is a natural and biological process where the microrganismos transform the substance organic, as estrume, leves, paper and remaining portions of food, in a similar material to the ground the one that if composition calls. To make the compostagem in house if saves transport and costs of the deposition of the residues which of another form could not have adequate the final destination. This process helps in the reduction of 60% of the volume of residues made use in lixes or sanitary aterros, beyond being beneficial to the environment. The main objective of the domiciliary compostagem is to reduce the amount of domestic residues that a person or family produces recycle it, if reduces these residues saves space and increases the useful life of the lixes or aterros, beyond reducing the taxes.