The kinetics of the transformation of methyl parathion have been investigated in aqueous solution containing reduced sulfur species and small concentrations of natural organic matter (NOM) from different sources such as soil, river, and peat. It was shown that NOM mediates the degradation of methyl parathion in aqueous solutions containing hydrogen sulfide. After evaluating and quantifying the effect of the NOM concentration on the degradation kinetics of methyl parathion in the presence of hydrogen sulfide, it was found that the observed pseudo-first-order reaction rate constants (k(obs)) were proportional to NOM concentrations. The influence of pH on the degradation of methyl parathion in the aqueous solutions containing hydrogen sulfide and NOM has been studied. The rate of degradation of methyl parathion was strongly pH dependent. The results indicate k(obs) with a commercially available humic acid has a maximum value at approximately pH 8.3. Two main reaction mechanisms are identified to dominate the degradation of methyl parathion in aqueous solution containing hydrogen sulfide and NOM based on the products aminomethyl parathion and desmethyl methyl parathion. The two mechanisms are nitro-group reduction and nucleophilic attack at the methoxy-carbon. The reduction of the nitro-group is only observed in the presence of NOM. The results of this study form an important base for the evaluation and interpretation of transformation processes of methyl parathion in the environment.

Study of the inorganic chlorides in municipal solid waste (MSW) shows that the main source of inorganic chlorides in MSW is food. The main organic source of HCl emission from MSW is plastic. But wood, textiles, and food also produce a large amount of HCl when they are combusted. Each combustible shows a different HCl releasing temperature range. At 973 K, there are 30-70% of the total chlorine left in the char of each combustibles in MSW.

In this paper, our work is focused on the fundamental combustion characteristics of the combustibles in MSW and its kinetic model. The combustion reactivity of the different combustibles in MSW and their mixtures such as TG and DTA profiles were studied by thermogravimetry (TG) and differential thermal analysis (DTA). On the basis of the investigations of combustion and pyrolysis characters of the combustibles in MSW, kinetic parameters such as activation energy and preexponential factor of each combustible were determined. A kinetic model describing the combustion reactive processes of the combustibles in MSW was proposed. From the study, it can be concluded that:  (1) The combustibles in MSW can mainly be divided into two types of mattersone is fibrous matter, and the other is polymer matter. (2) The combustion process of combustibles in MSW mainly consists of two stages. At the first stage, the volatile contained in fibrous matter was released, and then the released volatile matter was combusted continuously; at the second stage, the fixed carbon of fibrous matter was burned, and pyrolysis and combustion of the polymer matter happened at the same time. (3) The combustion rate of the combustibles in MSW can be expressed by a weighted sum of rates of each combustible, and the complex combustion processes of combustibles in MSW can be described by simple kinetic model. The computed results of the kinetic model can mostly fit experimental data.

Pseudomonas sp. ZD8 isolated from contaminated soil was immobilized with platane wood chips to produce packing materials for a novel biofilter system utilized to control restaurant emissions. The effects of operational parameters including retention time, temperature, and inlet gas concentration on the removal efficiency and elimination capacity were evaluated. Criteria necessary for a scale-up design of the biofilter was established. High and satisfactory level of rapeseed oil smoke removal efficiency was maintained during operation and the optimal retention time was found to be 18 s corresponding to smoke removal efficiency greater than 97%. The optimal inlet rapeseed oil smoke loading was 120 mg/(m(3) x h) at the upper end of the linear correlation between inlet loading and elimination capacity.

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