Investigation of the self-heating and spontaneous ignition of refuse-derived fuel (RDF) during storage

Refuse-derived fuel (RDF)—RDF-5 according to ASTM guidelines—derived from municipal solid waste and other waste materials, has been prepared as a fuel source for power plants in Japan. RDF has been known as a stable and safe solid-fuel. However, some spontaneous ignition incidents occurred during storage of RDF in certain facilities. In the present study, the storage conditions, which might induce the spontaneous ignition in RDF samples, was investigated to understand and prevent this phenomenon. When the initial temperature of RDF sample was consistent, higher water content and shorter induction times was observed (e.g., the induction times of select RDF samples with 5.8% and 16.7% water content, was 446 and 270 min, respectively). Also, the induction time was affected by the size of a RDF sample. No relationship between bacterial fermentation and spontaneous ignition was observed. The linear relationship between the induction time and the inverse of the initial temperature of the RDF sample was obtained in the Arrhenius equation.     

Relation between odor and odorous components in solid swine manure

Odor similarity of the synthetically prepared solutions and the extract from solid swine manure showed that the main components for odor of solid swine manure are carboxylic acids and sulfides and that p-cresol increases the malodor and skatole modifies the nature of the malodor.     

Dechlorination of PCBs by electrochemical reduction with aromatic radical anion as mediator

Mediated electrochemical reduction was applied to the dechlorination of polychlorinated biphenyls (PCBs) in tetra-n-butylammonium perchlorate/dimethylformamide solution. Rapid and complete dechlorination was possible with biphenyl or naphthalene as the mediator, whereas the reaction was much slower with anthracene or 9,10-diphenylanthracene. The reaction rate was so high with naphthalene or biphenyl radical anion that differences in reactivity could not be observed between congeners. Side reactions, other than biphenyl formation, could occur depending upon the mediators and the substrates, but contributed less than 10% of the total products in the case of naphthalene-mediated dechlorination. Almost all chloride ion formed in the dechlorination remained in the cathode solution. The order of the reaction was determined to be 0.5 for the substrate and 1 for the mediator (naphthalene) in the dechlorination of 2-chlorobiphenyl; identical to results for the mediated dechlorination of 1-chloronaphthalene. The reaction rate in practical PCB dechlorination could be estimated with the use of the initial concentration of the mediator and chlorine content of the solution provided that the problem of the deactivation of the electrode surface could be solved.     

Formation of chlorodibenzofurans by thermal decomposition of vinylidene chloride polymer

This is the first reported measurement of four kinds of chlorodibenzofurans formed in the pyrolytic decomposition of vinylidene chloride, a polymer used as wrapping film. 3-Chloro isomer was the most abundant among four monochlorodibenzofurans.     

Large-scale evaluation of the current level of polybrominated diphenyl ethers (PBDEs) in breast milk from 13 regions of Japan

Polybrominated diphenyl ethers (PBDEs) were measured in 2004 in 105 breast milk samples collected from 13 regions of Japan (Hokkaido, Akita, Miyagi, Tokyo, Gifu, Fukui, Kyoto, Hyogo, Wakayama, Shimane, Yamaguchi, Kochi and Okinawa). Six congeners (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153 and BDE-154) were determined by gas chromatography /mass spectrometry (GC/MS). Total PBDE levels ranged from 0.01 to 23.0 ng/g lipid (geometric mean (GM), 1.34 ng/g lipid). BDE-47 (GM, 0.66 ng/g lipid, 59% of sigmaPBDE) was the most abundant congener present in breast milk and was detected in 99% of the samples. Total PBDE levels were higher in northern Japan than in other regions. We analyzed the effects of occupation, age, smoking status, alcohol consumption and number of deliveries on total PBDE levels. None of these factors were significantly associated with the level of PBDEs. The present study revealed that the current level of exposure to PBDEs in Japan is lower than that in the USA or Sweden. GMs (ng/g lipid) (GSD, geometric standard deviation) and medians (ng/g lipid) of PBDE levels in each district are as follows: Hokkaido 2.70 (1.70), 2.74; Akita 4.49 (2.19), 5.44; Miyagi 1.77 (4.37), 1.11; Tokyo 1.39 (2.09), 1.63, Gifu 2.83 (4.79), 2.23; Fukui 1.05 (2.34), 1.18; Kyoto 1.31 (2.95), 1.33; Hyogo 1.02 (2.69), 0.88; Wakayama 1.33 (3.80), 1.70; Shimane 0.83 (2.51), 0.66; Yamaguchi 1.74 (2.82), 1.76; Kochi 0.50 (2.69), 0.74 and Okinawa 1.91 (2.75), 1.22. This is the first large-scale study of current PBDE levels in breast milk in Japan.     

Gas phase equilibria for dibenzo‐p‐dioxin,dibenzo‐p‐furan and biphenyl in the C‐H‐O system

The gas phase equilibrium calculation for the C‐H‐O system at atmospheric pressure and temperature from 773 to 1773 K at intervals of 250 K was performed to understand the generation and decomposition behavior of dibenzo‐p‐dioxin (DD), dibenzo‐p‐furan (DF) and biphenyl (BP) in relation to the existing oxygen potential. It is possible to categorize these results into three regions from the viewpoint of this potential: region (A), region (B) and region (C) are that of the higher, modest and lower oxygen potential, respectively. In region (A), the equilibrium amounts of DD, DF and BP are nearly zero. In region (B), they increase once and then decrease with rise in temperature. In the most characteristic region (C), they increase uniformly with rise in temperature.     

High performance liquid chromatographic determination of pesticides in soluble phase and suspended phase in river water

A high performance liquid chromatographic method has been developed to determine pesticides in river water as both dissolved phase and suspended phase. The target pesticides were eight herbicides, asulam, diuron, flazasulfuron, linuron, MCPB, mecoprop, pyrazosulfuron‐ethyl and siduron, and two fungicides, oxine‐copper and thiram. The pesticides in filtered river water were extracted with styrene‐divinylbenzene copolymer and were eluted with acetonitrile. The pesticides on suspended solids were extracted ultrasonically with acetonitrile. Each eluate was concentrated and analyzed by HPLC with multiwavelength detector. Recoveries of the pesticides in the overall procedure of this method were 78–114% for filtered river water and 75–107% for suspended solids. The limits of detection in water and suspended solids ranged from 0.1 to 0.9 μg/L and 1 to 7 μg/g, respectively. Pesticide distribution between soluble phase and suspended phase in river water was measured by this method.