An Economical Solution for the Environmental Problem Resulting from the Disposal of Rice Straw

Abstract

The disposal of rice straw as a by-product resulting from the cultivation of rice is causing worldwide environmental and health problems. Farmers tend to randomly burn rice straw as the most economical method of disposal. This practice does not only generate smoke, but also breathable dust that contains crystalline silica and other health hazard substances. An environmentally friendly process that produces three valuable products is developed in this research. The process is based on a combustion technology using a special reactor manufactured in Canada. Significant amount of energy is released in the form of steam as a result from this process. The rice straw ash (RSA) resulting from this technology is rich in silica and can act as a mineral admixture that enhances the strength and durability of concrete. Liquid rich in potassium results from the hydrolysis of straw and can be used as a fertilizer. A simulation of the entire process, including hydrolysis, drying, chopping and combustion of the straw followed by grinding of the produced ash was conducted on a reduced industrial scale. A study to assess the enhancement in strength and durability of concrete and its resistance to chemical and corrosion attacks was also conducted. The paper also discusses briefly the main findings of a study funded by the Canadian International Development Agency “CIDA” that was carried out to assess the feasibility of such a project in Egypt.