Abstract:The quantitative and qualitative composition of Chinese municipal solid waste (MSW) differs significantly from German waste. The focus of this paper is on whether these differences also lead to dissimilar qualities of leachates during storage or landfilling. Leachates ingredients determine the appropriate treatment technique. MSW compositions of the two cities Guilin (China) and Essen (Germany), each with approx. 600 000 inhabitants, are used to simulate Chinese and German MSW types. A sequencing batch reactor (SBR) is used, combining aerobic and anaerobic reaction principles, to test the biodegradability of leachates. Leachates are tested for temperature, pH-value, redox potentials, and oxygen concentration. Chemical oxygen demand (COD) values are determined. Within 8 h, the biodegradation rates for both kinds of leachates are more than 90%. Due to the high organic content of Chinese waste, the degradation rate for Guilin MSW leachate is even higher, up to 97%. The effluent from SBR technique is suitable for direct discharge into bodies of water.
Parts 1, 2 and 3 of this series of publications gave details of the development and application of a pilot in situ auger mixing treatment on a contaminated site in West Drayton, Middlesex. The treatment method employed was in situ stabilisation/solidification using cement-based grouts and applied using a soil-mixing auger. In these publications, details were given of the initial laboratory treatability study, the site trial and subsequent laboratory assessment of the treated contaminated made ground using samples cored at 55 days and tested at 0·2, 1·2 and 2·4 years after treatment. Recently, further coring of the treated ground took place at 4·5 years of in situ curing and the samples were tested at around 5 years after treatment. Hence this paper presents the longer-term behaviour of the in situ cured stabilised/solidified contaminated ground in terms of physical and chemical properties such as strength, leachability, leachate pH, permeability, freeze–thaw and wet–dry durability and microstructural analyses. The performance is presented of both soil types present, made ground and sand and gravel, from both single and overlap column mixes. The paper provides an insight into the effectiveness of the treatment at 5 years, a correlation between the performance of the different soils and mix conditions, and an assessment of the applicability of the available test methods and test criteria imposed.
The Anaerobic Digestion Model No. 1 (ADM) and the Activated Sludge Model No. 2d (ASM) have been combined in a sequencing batch reactor simulation using a FORTRAN ODE solver. Special attention has been paid to the interface definition between the two models which use different biological state variables. The simulation results demonstrate the alternating treatment characteristics resulting from the sequence of anaerobic and aerobic steps. A parameter study reveals the process optimization potential of the model. Some numerical issues of the ADM are discussed in detail. The Jacobian matrix is provided, and the error handling of negative gas-rates and negative concentrations is described from a numerical point of view.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.