Control of Mercury Emissions from a Municipal Solid Waste Incinerator in Japan

Abstract

The control of Hg emissions from a municipal solid waste incinerator (MSWI) is very important, because more than 78% of municipal solid waste (MSW) is incinerated. The Hg content of coal used in utility boilers is relatively low in Japan. In this study, recent trends in the Hg content of MSW in Japan and activated carbon (AC) injection as a control technology of Hg emission from an MSWI are discussed. The effect of AC injection on Hg removal from flue gas in an MSWI was investigated by pilot-scale experiments using a bag filter (BF). The injection of AC increases the Hg reduction ratio by 20–30% compared with cases without AC injection. The Hg reduction ratio increases as the flue gas temperature decreases. The Hg reduction ratio is closely related to the inlet Hg concentration and was expressed with a Langmuir-type adsorption isotherm.     

Novel enzymatic activity of cell free extract from thermophilic Geobacillus sp. UZO 3 catalyzes reductive cleavage of diaryl ether bonds of 2,7-dichlorodibenzo-p-dioxin

We characterized the ability of the cell free extract from polychlorinated dibenzo-p-dioxins degrading bacterium Geobacillus sp. UZO 3 to reduce even highly chlorinated dibenzo-p-dioxins such as octachlorodibenzo-p-dioxins in incineration fly ash. The degradation of 2,7-dichlorodibenzo-p-dioxin (2,7-DCDD) as a model dioxin catalyzed by the cell free extract from this strain implicates that the ether bonds of 2,7-DCDD molecule undergo reductive cleavage, since 4′,5-dichloro-2-hydroxydiphenyl ether and 4-chlorophenol were detected as intermediate products of 2,7-DCDD degradation.     

Molecular structure of extracellular poly(3-hydroxybutyrate) depolymerase fromAlcaligenes faecalis T1

The amino acid sequence of a peptide containing an active serine was examined with poly(3-hydroxybutyrate) (PHB) depolymerase ofAlcaligenes faecalis T1. The sequence Cys-Asn-Ala-Trp-Ala-Gly-Ser-Asn-Ala-Gly-Lys was obtained. This amino acid sequence around the active serine does not fit any reported sequence of other esterases and proteases. On the other hand, a segment of the amino acid sequence of PHB depolymerase ofA. faecalis was homologous to the type III sequence of fibronectin. Similar sequences have been reported in some type of bacterial chitinase and cellulases, and PHB depolymerase seems to have an overall similarity to these bacterial extracellular hydrolases.     

Formation of cyanide ion or cyanogen chloride through the cleavage of aromatic rings by nitrous acid or chlorine. XI On the reaction of purine bases with hypochlorous acid in the presence of ammonium ion

Cyanogen chloride was formed by the reactions of purine bases(adenine and guanine) with hypochlorous acid in the presence of ammonium ion. The origin of the carbon and nitrogen atoms of cyanogen chloride formed from adenine was investigated by use of synthetic adenines variously labeled with the isotope of nitrogen(¹⁵N) or carbon(¹³C).     

Effects of climate change on coastal disasters: new methodologies and recent results

Humanity faces an increasing possibility that unusual and extreme natural disasters will increase, compounded with climate change, including global warming. These compound events are designated as compounded natural hazards in this study. A methodology must be developed for predicting what events and risks will confront future societies, to propose countermeasures and adaptation strategies against these events, and to evaluate the influences of compound disasters on infrastructure which is particularly situated near coasts and rivers. Based on the above-stated background and demands, this study was undertaken with the intention of upgrading the methodology for estimating effects on infrastructure of compound events such as increased typhoon and rainfall severity caused by global warming occurring concurrently with a great earthquake in Japan. Such a methodology is expected to contribute to progress in the fields of natural disaster mitigation and land preservation, particularly benefiting coastal and river areas in Japan. Additionally in this study, risk and economic loss analyses for the possible occurrence of compound disasters for coastal infrastructure and foundations are produced for establishing environmental strategies at the governmental level. The authors further propose adaptation strategies and techniques as countermeasures against these events.     

Comparative study of microbial dechlorination of chlorinated ethenes in an aquifer and a clayey aquitard

In order to determine whether natural attenuation of chlorinated ethenes by microbial activity occurs in aquitards, sediments at a site contaminated with tetrachloroethene were vertically studied by drilling. The distribution of microbes (Dehalococcoides group and anaerobic hydrogen producers) and the ability of the sediments to sustain microbial dechlorination were determined in an aquitard as well as in an aquifer. Close-spaced sampling revealed the existence of large populations of Dehalococcoides and H(2)-producing bacteria, especially in the organic-rich clayey aquitard rather than in the aquifer. The vinyl chloride reductase gene was also detected in the clay layer. Furthermore, incubation experiments indicated that the clay sediment could sustain transformations of tetrachloroethene at least to vinyl chloride. In contrast, no significant transformation was observed in the aquifer sand. Our results indicate that dechlorination of tetrachloroethene by bacteria can take place in an organic-rich clayey aquitard, and that organic-rich clay may also be important in the natural attenuation in an adjacent aquifer, possibly supplying a carbon source or an electron donor.     

Comparison of general water quality of rivers in Indonesia and Japan

In Java and Kalimantan in Indonesia, river water plays important roles in human life; for example, for transportation, and economic activities of the inhabitants. However, industrial, agricultural and domestic water is discarded into rivers directly in many developing countries, including Indonesia, since drainage systems have not been completely constructed. In this study, to evaluate the water quality and to compare those levels of environmental contaminants in developing and developed countries, water quality and contents of endocrine disrupters were measured in a total of 64 water samples (Indonesia; 28 samples and Japan; 36 samples) from 53 sites. The results indicated that, rivers in both capital cities, Jakarta and Tokyo, were contaminated. Water in rivers in Indonesia was not so heavily polluted as in Japan. Pollution in the river water in Indonesia appeared to be caused by the lack of sewerage systems. In addition, the findings on endocrine disrupters indicated that the concentration of alkylphenol in water samples was large enough to affect living organisms.     

Effects of parabens on apoptosis induced by serum-free medium

Alkyl esters of p-hydroxybenzoic acids (parabens), an endocrine disrupter, are used as preservatives in cosmetics and foods. In this study, to understand the relationship between parabens and differentiation in infants, the effects of parabens on apoptosis induced by serum deprivation in PC12 cells were investigated. In addition, apoptosis-related factors were assayed. As results, a tendency toward enhancement of apoptosis was observed in the cells cultured in the serum-free medium with methylparaben, and this tendency was suggested to be related to the contents of BAD, a pro-apoptotic protein. Butylparaben did not show any tendency to enhance apoptosis.