Economic Value

Thus, it is necessary in such a way the determination of its characteristics and the evaluation of its agronmico and economic value, as well as knowing the toxic potential for plants and/or animals. (IT HISSES, 2001). Beyond the ambient and social benefits, the management of biosslidos represents a market with good perspectives in the project areas, planning and management of services, equipment and insumos. Some acceptable alternatives for the treatment of the silt exist technical. Most common it involves the anaerobic digestion that can be followed by final destination in exclusive sanitary aterros, followed of alternatives as the disposal of surface, the oceanic disposal, lagoons of storage, the incineration or the agricultural recycling.

The silt can influence positively some characteristics of ground, improving its support with immediate ambient consequences, as the reduction of the erosion and the consequent improvement of the quality of the hdricos resources. The application of the silt in agricultural areas brings benefits to the physical properties of the ground, as the formation of added of particles of the ground and the consequent improvement of infiltration and retention of water and to the aeration. Its decomposition produces complexantes agents capable to solubilizar unavailable forms of match in the ground (OAK & BARRAL, 1981), as well as nutrients in composites of slow release. The positive effect on the physical and chemical factors of the ground, still provide, one immediate reaction increment of the edfica population. Of the economic point of view, the use of the organic silt as fertilizing represents the integral reaproveitamento of its nutrients and the substitution of part of the doses of chemical fertilization on the cultures, with incomes equivalents, or superiors to the obtained ones with commercial fertilizers (USEPA, 1979). The properties of the product become it especially interesting agricultural ground consumed by inadequate handling, as well as for recovery of degraded areas. 4 ALTERNATIVES FOR the FINAL DISPOSAL OF SILT DE ESGOTOSAs alternative more usual for the exploitation and/or final disposal of the silt of sewers have been the following ones, in countries of the first world (TSUTIYA et al, 2000): Uses agrcolas direct Application in the ground; Aplicao in reforestation areas; Produo of composition or fertilizer organo-mineral; Solo synthetic for agriculture; Aplicao of the daily pay-conditional pie of silt with calcareous rock; Secagem trmicCompostagem.