Abstract

The use of organic waste as a source of plant nutrition and/or to minimize problems in agricultural soils is one possible use of these materials. The objective of this study was to evaluate the characteristics and some chemical properties of organic wastes from different processes and sources to know the potential for agricultural use and the risks associated with their use. Data were subjected to an analysis of variance (ANOVA) to examine the chemical differences between organic wastes with three replications. A statistical analysis was conducted using the software SAS. The comparison of means was performed using the Turkey’s test at the significance level of (P < 0.01), with three replications. The wastes were separated into acidic, neutral and basic classes. The Ca, Mg, P and N were characterized as an excellent source of these elements in organic and inorganic form, but the C/N ratio limited the use of some of these wastes according to the release time of nutrients expected. Micronutrients and heavy metals are below maximum allowable concentrations by environmental agencies and government.

Key words: Organic sludge, pulp mill sludge, sewage sludge, C/N ratio, trace elements