Renuka Gupta

Dye removal from aqueous solution by adsorption on treated sawdust

Formaldehyde treated and sulphuric acid treated saw dusts were used to adsorb malachite green at varying dye concentration, adsorbent dose, pH and agitation time. Similar experiments were conducted with laboratory grade activated carbon to compare the results. The adsorption efficiency of sulphuric acid treated sawdust (SD) was higher than formaldehyde treated SD. The adsorption followed first order rate expression and Lagergren equation. An initial pH in the range of 6-9 was favorable for the dye removal by both the adsorbents. Dilute solutions were effectively decolorized by the adsorbents. It is proposed that in batch or stirred tank reactors, both adsorbents can be an attractive option for dye adsorption.

Vermicomposting of Agro-Industrial Processing Waste

Agro-industrial wastes- wastes from agriculture, food processing or any cellulose based industries- remain largely unutilized and often cause environmental problems like dispersing foul odors, occupying vast areas, ground and surface water pollution etc. These wastes could be converted into potential renewable source of energy, if managed sustainably and scientifically. In the last few decades, vermicomposting technology has been arising as a sustainable tool for the efficient utilization of the agro-industrial processing wastes and to convert them into value added products for land restoration practices. The product of the process, i.e., vermicompost is humus like, finely granulated and friable material which can be used as a fertilizer to reintegrate the organic matter to the agricultural soils. The usability of the process depends upon several factors like raw material, various process conditions- pH, temperature, moisture, aeration etc., type of vermicomposting system and earthworm species used. The chapter briefly discusses with the process technology of vermicomposting and the present state of research in the vermicomposting of agro-industrial processing wastes.