Evaluation of city refuse compost maturity: a review

Peer reviewe

Apparent availability of nitrogen in composted municipal refuse

The use of compostested municipal refuse on agricultural land requires prior knowledge of the interactions among compost, soil, and plants. Research into the availability of N in highly matured municipal refuse compost is particularly important considering the current concern about groundwater contamination by NO$- N. A greehouse pot bioassay was conducted to determine the percentage of short-term apparent bioavailable N of a highly matured refuse compost and its relative efficiency in supplying inorganic N to the soil-plant system in comparison with NH$NO$. Municipal refuse (after 165 days of composting) was applied at rates equivalent to 10, 20, 30, 40, and 50 t ha ' to a ferrallitic soil from Tenerife Island (Andeptic Paludult). NH$NO$was applied at rates equivalent to the total N content of the compost treatments. Perennial ryegrass (Lolium perenne L.) was grown in 3-kg pots and the tops were harvested at regular intervals after seedling emergence. The compost increased dry matter yield, soil mineral N, and plant N uptake proportional to the applied rate. These increases were significantly higher than the control at an application rate of 20 t ha '. After 6 months the apparent bioavailable N ranged from 16 to 21$-N contamination. However, applied at moderate rates in our bioassay (<50 t ha'), compost showed a low N-supplying capacity to ryegrass, i.e. a small fraction of the mineralized compost N was used by plants in the course of time. This was ascribed to a partial biological innobilization. This pattern of N availability in highly matured municipal refuse compost, positive net mineralization but partial immobilization, is similar to the pattern of N availability in biologically active soils and is therefore extremely interesting for the conservation of N in agro-ecosystems.Peer reviewe

Effect of pine bark and compost on the biological denitrification process of non-hazardous landfill leachate: Focus on the microbiology

In an attempt to optimize the cost-efficiency of landfill leachate treatment by biological denitrification process, our study focused on finding low-cost alternatives to traditional expensive chemicals such as composted garden refuse and pine bark, which are both available in large amount in South African landfill sites. The overall objective was to assess the behaviour of the bacterial community in relation to each substrate while treating high strength landfill leachates. Denitrification processes in fixed bed reactors were simulated at laboratory scale using anaerobic batch tests with immature compost and pine bark. High strength leachate was simulated using a solution of water and nitrate at a concentration of 500 mg l−1. Results suggest that pine bark released large amounts of phenolic compounds and hydroxylated benzene rings, which both can delay the acclimatization time and inhibit the biological denitrification (only 30% efficiency). Furthermore, presence of potential pathogens like Enterobacter and Pantoea agglomerans prevents the applicability of the pine bark in full-scale operations. On the other hand, lightly composted garden refuse (CGR) offered an adequate substrate for the formation of a biofilm necessary to complete the denitrification process (total nitrate removal observed within 7 days). CGR further contributed to a rapid establishment of an active consortium of denitrifiers including Acinetobacter, Rhizobium, Thermomonas, Rheinheimera, Phaeospirillum and Flavobacterium. Clearly the original composition, nature, carbon to nitrogen ratio (C/N) and degree of maturity and stability of the substrates play a key role in the denitrification process, impacting directly on the development of the bacterial population and, therefore, on the long-term removal efficiency

City refuse compost and sodium dodecyl sulphate as modifiers of diazinon leaching in soil

Spanish "Comisi6n Interminterial de Ciencia y Tecnologia" (Projet AMB94-0688). Consejo Superior de Investigaciones Científicas (CSIC.Peer reviewe

Composting of domestic refuse and sewage sludge. I. Evolution of temperature, pH, C/N ratio and cation-exchange capacity

Peer reviewe

Biocomposting process for utilization agro-industrial wastes

Biological treatment has played prominent roles in bioremediation of wastes and contaminants. Composting is one of the biological process that has been considered to be one of the most suitable ways of converting organic wastes into products that are beneficial for plant growth. The study of the bio-composting process by solid-state bioconversion utilizing palm oil mill effluent (POME) and empty fruit bunch (EFB) were studied in lab scale. From the study it is found that horizontal rotary drum bioreactor was the most suitable to run this study. In this project, four filamentous fungi were used; (i) Phanerochaete chrysosporium. (ii) Trichoderma harzianum. (iii) Aspergillus niger. (iv) Penicillium sp. The bioconversion of lignocellulosic materials by evaluating the C/N ratio and other parameters using horizontal rotary drum bioreactor were studied. The good and mature of the compost is reflected by C/N ratio, germination index and glucosamine assay. The result showed that the C/N ratio drop from days 10 onwards and in the range of 25 to 30. The germination indexes of 50 to 70% indicate that the compost produce was a phyto toxic-free product and merely achieved as mature compost. The composting period required to complete this process was two months. Thus, this study developed an effective and feasible composting technique of POME and EFB using horizontal rotary drum bioreactor by solid state bioconversion process

Composting od domestic refuse and sewage sludge. II. Evolution of carbon and some "humification" indexes

Peer reviewe

Utilization of refuse compost for soil improvement and crop production.

by Chu Lee Man.Bibliography: leaves 176-204Thesis (M.Phil.) -- Chinese University of Hong Kong, 198