Husk Ash Research Articles

■Enriched Coal Ash Utilization for Augmenting Production of Rice Under Acid Lateritic Soil

The use of industrial wastes such as fly ash (FA) or rice husk ash (RHA), along with paper factory sludge (PFS), farmyard manure (FYM), and chemical fertilizers (CF), under integrated nutrient management, was studied in acid lateritic soil on rice. Application of combined fertilization sources increased growth, yield attributes, and yield (up to 92.3 and 9.7% over control and CF, respectively) of wet season rice. The uptake of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and Co was increased under combined fertilization sources. The study also indicated that such integrated plant nutrition system improved physico-chemical properties of soil with respect to bulk density, pH, electrical conductivity, organic carbon, and available nutrient content. Utilization of these wastes saved chemical fertilizers to the extent of 37.8, 59.7, and 86.5% N, P, and K respectively, with an added advantage of minimizing environmental pollution. f 2010 The University of Kentucky Center for Applied Energy Research and the American Coal Ash Association All rights reserved. A R T I C L E I N F O Article history: Received 15 March 2010; Received in revised form 29 May 2010; Accepted 14 June 2010

Potential conflicts for the reuse of rice husk in Thailand

This study aims to investigate the impact of rice-husk power generation on agricultural uses of rice husk and its ash. We conducted case studies at a rice-husk power plant and organic farming groups in northeast Thailand. The case study on a rice-husk power plant showed that rice husk was useful in generating electricity without consuming fossil fuel, while husk ash, the by-product, could be utilized as silicate supplement for farmland soils. The case study on organic farming groups indicated that rice husk was one of the indispensable materials in conducting organic farming with locally available resources. On the basis of these findings, an analytical study on possible husk uses in Thailand was conducted, in which three potential major uses of rice husk were considered: i.e. (1) fuel use inside rice mills followed by husk-ash reuse, (2) fuel use at power plants followed by husk-ash reuse, and (3) direct reuse of husk for compost production. The result indicated that there would be conflicting demands for rice husk among those uses in the future. Therefore, there needs to be a strategy for balancing husk uses among them.

Metallic constituents in paddy husk

The status of the metals in the paddy husk which is a major agrowaste in India and other countries has been studied here from the points of view of environmental planning and utilization of this waste matter. Cu, Co, Ni, Pb, Zn, Cd, Mn, Fe, Ca, Mg, Na, K, Li, Sb and As were determined by atomic absorption spectrophotometry. Al was estimated spectrophotometrically, and SiO 2 gravimetrically. Cu, Co, Ni, Pb, Sb, As and Li were found to be below 10 ppm, Zn and Al below 25 ppm, Mn, Fe, Mg and Na below 200 ppm, Ca 213 ppm, K above 3000 ppm and Si above 9·4%. While Si is recoverable in semiconductor grade purity, K has its value as crop nutrient if the husk ash is applied to crop land. The uptake of some toxic metals (Cu, Co, Ni, Pb, Zn, Mn, Sb and As) by the paddy husk from the subsoil has also been indicated by the study.