Agricultural Wastes

Abstract

The following review provides a summary of research activities related to the characterization, treatment, and management of agricultural wastes. The review has been divided into four major sections: (i) Waste Characterization, Analytical Methods and Measurement, (ii) Agricultural Waste Treatment, (iii) Reuse and Recycling of Agricultural Wastes, and (iv) Pollution Prevention and Minimization of the Environmental Impact of Agricultural Wastes. WASTE CHARACTERIZATION, ANALYTICAL METHODS AND MEASUREMENT Physical:Olive press cake (OPC) was composted with water and olive mill wastewater (OMW) over several temperatures (17ºC to 63ºC) and the metabolic activity and the respiration profile was monitored. Mari et al. (2003) proposed that composting OPC with OMW would have a two-fold benefit: compost of the solid waste would occur, and decomposition and detoxification of the wastewater would occur. More microbial activity was observed when OPC was composted with OMW than with water, and it was observed a temperature of 48.5ºC provided a better representation of the respiration profile on average. Biological: Inglis and Kalischuk (2003) studied the potential for direct identification of Campylobacter spp. in bovine feces using PCR, without the need 1480 for an enrichment step. Common measurement techniques require counting of colonies by technicians which introduces human error, while the PCR method can be influenced by PCR inhibitors found in feces, causing false-negative results. When inhibitors were removed before analysis, it was believed that the PCR method is more robust and allows for the detection of generally more species of Campylobacter. An intensive agricultural region in southern Alberta was studied over 2 years by Johnson et al. (2003) for the presence of Escherichia coli (E. coli) O157:H7 and Salmonella spp. in the watershed. E. coli O157:H7 was detected in 0.9% of surface water samples and Salmonella spp.was detected in 6.2% of the surface water samples. A statistical model did notshow an association between predicted manure output and pathogen occurrence, highlighting the need to include geographical and weather parameters into an analysis.A method for characterizing changes in a microbial community during the composting process was presented by Schloss et al. (2003). Automated ribosomal intergenic spacer amplification (ARISA) analysis was performed before and during composting, and it was found that the microbial community during composting did not represent the microbial community in the wastewater. The ARISA analysis provided a relationship between the variability in traditional compost variables (temperature, pH, effluent gas) and the composition of the microbial community. 1481 studies on the enterococcal flora from 6 faeces-containing samples. A phenotypic testing technique known as PhenePlate was used to discern enterococcal population diversity. This method provides a tool for determining the origins of faecal contamination. Gas/Volatile Emissions: Methane emissions were measured in a model storage...