Relationship of Microbial Mass and Activity in Biodegradation of Solid Waste

Abstract

Limited landfill space and resistance to siting such facilities has spurred consideration of new approaches to increase the longevity of landfills. Such efforts have included exploring methods to enhance degradation rates of municipal solid waste (MSW) and subsequently, mining landfills to recover materials and landfill space.Microbial mass and activity of MSW incubated in lysimeters, with moisture content sustained with recycled leachate, were compared under anaerobic and aerobic conditions in this study. Bacterial biomass and number were quantified by adenosine triphosphate analysis and acridine orange direct counts. Viability, adenylate energy charge and cellulase activity were also assessed.Bacterial number and energy status were lower in the anaerobic system. Cellulase activity in the anaerobic lysimeter decreased to undetectable levels while activity in the aerobic system continued to increase throughout the 92-day experiment. The results indicated that aeration, even at a relatively low volume, with leachate recirculation, significantly accelerated degradation of MSW. Furthermore, the results demonstrated the potential of using cellulase activity as a surrogate parameter of relative microbial activity of MSW degradation.

Performance evaluation of a landfill leachate recirculation treatment system using quadric model

“…After that an increase in pH was observed. This increase in pH may be due to onset of methanogenic activity which results in increase in methane gas production and decrease in hydrogen, carbon dioxide and volatile fatty acid production (Murphy 1995). When methane production was stabilized, the pH ranged between 6 to 8 (Ehrig, 1983).…”

Enumeration and characterization of cellulolytic bacteria from refuse of a landfill

“…Previous studies which concerned cellulolytic bacteria of land¢ll have focused only on counting bacteria [8,10^11] or on measuring global cellulolytic activity [7,10,30,31]. To our knowledge, phenotypic studies of cellulolytic bacteria of MSW have been restricted to the identi¢cation of one strain of Cellulomonas [12] and to the characterization of nine anaerobic cellulolytic bacterial isolates [15].…”

“…(g dry wt.) 31 , respectively ( Table 2). Densities of cellulolytic bacteria were higher than those reported by Jones et al [10] who detected 10 4 to 10 6 c.f.u.…”

“…(g dry wt.) 31 . Cellulolytic bacteria were present in all refuse samples and ranged from 1.1U10 6 to 2.3U10 8 c.f.u.…”

“…(g dry wt.) 31 according to the sample ( Table 2). The proportion of cellulolytic bacteria to the total culturable heterotrophic bacteria varied accord- ing to samples, ranging from 3.7 to 75%.…”