Qualitative Study of Compost Fertilizer Produced in Zahedan Factory, Considering Physical and Chemical Characteristics

Compost is extracted from the Latin word “Compositus”, meaning compound or mixture and sometimes it is known as mixed fertilizer in Persian language. Regarding the economic values of spoilable substances, producing fertilizer from waste not only will help to ues this value, but also in this way, the waste and its recycling can be controlled. Thus, construction of compost factories for hygienic repulsion and production of valuable fertilizer, are the main preferences of urban waste management in the country. Objective of this study is evaluation of physical and chemical quality of compost fertilizer, produced in Zahedan Factory, and its comparison with the standards in Iran and the world.
In this study, the compost fertilizer produced in Zahedan Factory was investigated during 9 months. To determine the physical and chemical characteristics of the compost produced in this factory, the factors such as pH, electrical conductivity, organic carbon, azoth, phosphor, lead, cadmium, zinc and copper were evaluated. Microbial specifications of the produced compost are also specified by determination of culiferoum, Salmonellae, and parasite zygote.
Evaluated factors are: average percentage of carbon (4.2 ppm), percentage of azoth (1.98 ppm), percentage of lead (89.98 ppm), percentage of cadmium (2.695 ppm). The microbial quality of the produced compost was in B level of Environmental Protection Organization of America.
Results demonstrated that the produced compost, in terms of heavy metals, was in the range of UN, America and Canada standards (AAFC, CCME, and BNQ) and was reasonable according to the National Standards of Iran. Carbon and azoth percentages meet the compost standards in most cases. However, considering that the ratio of carbon is higher than the ratio of azoth, it is necessary to add vegetable and fruit wastes - that contain higher nitrogen - to the compost ingredients. Amount of phosphor is placed in rank 2 of National Standards of Iran. pH is almost higher than standard levels; in this case adding a little sulfur will solve the problem. Compost fertilizer samples are applicable as soil reclamation factor. Waste segregation at source and establishment of thermophilic conditions in mass are two effective strategies that should be concentrated to improve the quality of compost fertilizer.