Characterization of Local Mill Rice Husk Charcoal and Its Effect on Compost Properties

This new publication on rice husk char application and testing can be added to the extensive list of research papers and interest in using these crop wastes as a biochar soil amendment. A search on this website for 'rice' will provide links to 14 previous posts related to the subject of RHC.
ABSTRACT
"Rice husk charcoal (RHC) is a by-product of rice processing mills which can befound in very large quantities in these mills. This industrial waste is largely unutilized, causing environmental pollution especially in the state of Kelantan. In order to increase its utilization, RHC was characterized and investigated for its potential in enhancing the composting process. Physico-chemical properties of RHC such as pH, nutrient content, ash content, CEC, adsorption kinetics, surface area, functional groups, surface structure and pore sizes were studied. The composting treatments were carried out by mixing 4% (wt/wt) and 6% wt/wt) RHC with organic substrates and with no RHC amended as control. Parameters such as daily temperature, CO2 flux, nutrient content, pH, moisture and total microbial count were measured during the composting process. Results showed that RHC is a highly alkaline material (pH 8.9) with a carbon content of 16% (wt/wt dry basis), CEC of 17cmol kg-1soil, BET surface area of 401 mg g-1 and a methylene blue Adsorption capacity of 38.8 mg g-1. The presence of C=O carboxyl-C, ketones and ester, aliphatic C=H, C=C benzene ring and C-H aromatic hydrogen suggests that RHC mainly comprises amorphous char, a random mixture of thermally altered molecules and aromatic polycondensates. The addition of RHC to organic matter accelerated the composting process through higher decomposition rates due to higher microbial population at the thermophilic stage with RHC acting as a bulking agent, as well as higher moisture and nutrient retention during composting. N losses were found to be lower with RHC composting."

Theeba, M.1*, Robert T. Bachmann2, Illani Z.I1, Zulkefli M1, Husni M.H.A3 and Samsuri A.W3
1Water and Soil Management Programme, Malaysian Agricultural Research Institute (MARDI) Persiaran UPM-MARDI, 43400 Serdang, Selangor, Malaysia
2Universiti Kuala Lumpur, Malaysian Institute of Chemical and Bioengineering Technology (UNIKL-MICET), 78000 Alor Gajah Melaka, Malaysia
3Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia , 43400 UPM Serdang, Selangor, MalaysiaKeywords: Rice husk charcoal, composting, physico-chemical, decomposition, nutrient retention
http://www.msss.com.my/mjss/Full%20Text/Vol%2016/Theeba.pdf
(I got a link warning on the msss site which I ignored. But please contact me if you want a copy of the report by email)