Keiko Katayama-Hirayama

University of Yamanashi · Department of Civil and Environmental Engineering

The advanced oxidation of aromatic compounds in aqueous solution has been investigated using a multi-gas, dielectric barrier discharge, and the degradation rate was measured by high performance liquid chromatography (HPLC). In the degradation experiment of 2,5 - DNP, an accelerated degradation pathway was suggested in the transient state, using the...

Dielectric barrier discharge was operated in the liquid-gas boundary and applied to the degradation of Dibromophenol (DBP). The brominated aromatic compound show acute toxicity to aqueous living and, occasionally, carcinogenic and hormone-disruptive effect for human. The plasma degradation provides the advanced oxidation process by charged species,...

The advanced oxidation of 2, 4 - dinitrophenol (DNP), 2, 5 - DNP, and 3, 4 - DNP in aqueous solution has been investigated using a multi-gas, dielectric barrier discharge, and the degradation was measured by high performance liquid chromatography (HPLC). The acceleration of the advanced-oxidation has been investigated by the combination of the anio...

Most bio-waste contains a high amount of moisture, but has high caloric value if dried. Effective drying could produce solid fuel from bio-waste. This paper discusses the effectiveness of drying with aerobic microbiological degradation similar to a composting process. Wood chips (WC) that show little bio-degradation and a mixture of WC and dogfood...

Organic solid waste composting is a complex process that involves many coupled physical, chemical and biological mechanisms. To understand this complexity and to ease in planning, design and management of the composting plant, mathematical model for simulation is usually applied. The aim of this paper is to develop a mathematical model of organic s...

We attempted to remove mono-chlorophenols (MCPs) with a slow sand filter and UV irradiation, and compared the removability and the structure. The phenols examined are 2-chlorophenol (2-CP), 3-chlorophenol (3-CP) and 4-chlorophenol (4-CP). MCPs were also examined for removal under ultraviolet (UV) lamp irradiation and the relationship between degrad...

We examined the degradation of dibromophenols (DBPs), i.e. 2,4-DBP, 2,6-DBP and 3,5-DBP by ultraviolet (UV) irradiation and estimated the relationship between degradability and molecular orbital properties of each dibromophenol. The removal of DBPs under a UV lamp system was successfully performed in an aqueous solution. After 5 min of irradiation,...

This paper presents insight into the benefits of organic waste recycling through composting over landfill, in terms of landfill life extension, compost product, and mitigation of greenhouse gases (GHGs). Future waste generation from 2003 to 2020 was forecast, and five scenarios of organic waste recycling in the municipality of Phnom Penh (MPP), Cam...

This paper presents a mathematical model of vertical water movement and a performance evaluation of the model in static pile composting operated with neither air supply nor turning. The vertical moisture content (MC) model was developed with consideration of evaporation (internal and external evaporation), diffusion (liquid and vapour diffusion) an...

The aims of these experiments were treating tapioca processing waste water to produce polyhydroxyalkanoates (PHAs) and removal of chemical oxygen demand (COD). The experiments were conducted in a sequencing batch reactor with a volume of 6 L. The entire experimental condition was anaerobic-aerobic-anaerobic. Experiment 1, 2 and 3 had the first 2 h...

This experiment aims to examine how much PHA is produced and how much COD is removed by treating tapioca processing wastewater. We examined using a sequencing batch reactor (SBR) with a volume of 6 L. The SBR was operated for 9 hours with the first 2 hours for feeding and the last 3 hours for settling and draining. The 4 hours between these periods...

This paper presents an overview of municipal solid waste management (MSWM) for both technical and regulatory arrangements in the municipality of Phnom Penh (MPP), Cambodia. Problems with the current MSWM are identified, and challenges and recommendations for future improvement are also given in this paper. MPP is a small city with a total area of a...

Recent technological development enabled non-thermal treatment over a large area and large volume at the atmospheric pressure. Along with industrial applications such as surface cleaning and fictionalization, applied research in biotechnology is also carried out, including treatment of living tissues in medical applications, inactivation of pathoge...

This article describes a study on the sterilization and high level disinfection using plasma oxidation and dehydrogenation process in high frequency glow discharge and an experimental comparison of an inductive energy storage pulse power source, from the view point of alternative method for ethylene oxide chemical disinfection process. Antibacteria...

This paper presents a current tapioca starch wastewater (TSW) management in Indonesia, for both technologies and regulations. Finding about the current TSW management is presented. Indonesia is the third largest tapioca starch producer in the world after Thailand and Brazil. As a result, tapioca starch wastewater (TSW) is increasing. TSW pollutes t...

The purpose of this paper is to present and compare disinfection effect of plasma by means of Atmospheric Pressure Glow plasma and streamer discharge. Geobacillus stearothermophilus was used as biological indicator for disinfection process. The effect of blades after irradiated in plasma was studied by SEM analysis. It was found that the disinfecti...

The purpose of this paper is to present and compare disinfection effect of plasma by means of Atmospheric Pressure Glow plasma and streamer discharge. Geobacillus stearothermophilus was used as biological indicator for disinfection process. The effect of blades after irradiated in plasma was also studied by SEM analysis. It was found that the disin...

IntroductionExperimental SchemesExperimental ResultConclusion AcknowledgmentsReferences

Tetrabromobisphenol A (TBBPA) is one of the widely used flame retardants in industrial products such as plastic polymers and electronic circuits, and has the potential to enter the water environment after disposal of these products. We tried to remove TBBPA in water by slow sand filtration and UV irradiation. The removal efficiency of TBBPA in rive...

A compensating effect in the reduction of bisphenols (BPs) has been shown using biodegradation in slow sand filtration and advanced photocatalysis. We tried to remove 8 kinds of BP by slow sand filtration. Removal rates of BPA, BPB, BPE, BPF, BPS, thiobisphenol (TBP), and dihydroxybenzophenone (DHB) indicated a high removal rate up to more than 90%...

Pyrene is a high molecular weight polycyclic aromatic hydrocarbon (PAH) that is found in water systems worldwide. It is harmful to living organisms, even when taken in very small amounts. The photocatalytic degradation of pyrene in porous Pt/TiO2-SiO2 photocatalyst (PPtPC) suspension under UV irradiation was investigated in this study. PPtPC was pr...

Novel inductive energy storage pulse power source was developed for the excitation of low temperature plasma at normal atmospheric pressure. Antibacterial effect of the pulse-excited atmospheric pressure discharge was compared with conventional high-frequency atmospheric pressure glow in He/O 2 , He/N 2 , and nitrogen mixture using biological indic...

Application of atmospheric pressure glow is spreading rapidly in Bio-Medical applications and exploration in new areas, micro-biology, organic chemistry and medicine needs collaboration with different fields. In this work, we present an experimental study on the antibacterial effect of high-frequency, atmospheric-pressure glow, against various micr...

Low-temperature plasma sterilization is studied in microwave plasma, 2.45 GHz, in He -N₂ -O₂ mixture gas based on the synergistic effect of oxygen radical and UV radiation. The performance of the antibacterial effect was demonstrated with biological indicators: Bacillus atrophaeus ATCC 9372 and Geobacillus stearothermophilus A...

Acinetobacter sp. strain ST-1, isolated from garden soil, can mineralize 4-chlorobenzoic acid (4-CBA). The bacterium degrades 4-CBA, starting with dehalogenation to yield 4-hydroxybenzoic acid (4-HBA) under both aerobic and anaerobic conditions, suggesting that the dehalogenating enzyme in the strain is not an oxygenase; the enzyme may catalyze hal...

We researched nitrate removal in water with high salt concentrations at low temperature using Candida sp. which was isolated from the upper layer of Lake Vanda in the McMurdo Dry Valleys, Antarctica. The strain was cultured in a synthetic medium that contained nitrate as the sole nitrogen source. The time course for the growth, and the nitrate and...

We used intact cells and cell extracts to investigate the metabolic pathway of benzoic acid (BA) in Acinetobacter sp. strain ST-1, which dehalogenates 4-chlorobenzoic acid (4-CBA) hydrolytically and then mineralizes it via the β-ketoadipate pathway. Strain ST-1 degraded BA easily, yielding cis, cis-muconic acid and β-ketoadipic acid. A cell extract...

Acinetobacter sp. strain ST-1, isolated from garden soil, can mineralize 4-chlorobenzoic acid (4-CBA). The bacterium degrades 4-CBA, starting with dehalogenation to yield 4-hydroxybenzoic acid (4-HBA) under both aerobic and anaerobic conditions, suggesting that the dehalogenating enzyme in the strain is not an oxygenase; the enzyme may catalyze hal...

We designed a simple method that assesses the ability of aerobic microorganisms in soils to degrade 4-chlorobiphenyl (4-CB) to 4-chlorobenzoic acid. We screened bacteria in 46 soil samples collected from fields, paddy fields and gardens for strains that grew on biphenyl and degraded 4-CB. Sixty-five strains that utilized biphenyl were isolated from...

これまでに開水路で測定された酸素移動係数の値を整理し, 酸素移動係数と水面付近の乱れパラメータの関係を検討した. 乱れパラメータは水深や摩擦速度などのマクロな水理量から推定した.実験水路での測定結果を中心に考察したが, 再ばっ気現象に対するエネルギー逸散率モデルと乱れ強度モデルの適用性の比較をおこない, 乱れ強度モデルの有効性を示した. また, 自然河川を含む開水路の測定結果は, およそ3つのグループに分けられることを指摘した. そして, 撹拌槽での測定結果との比較もふまえて, 乱れ強度モデルにもとづいた, 河川での再ばっ気係数を求めるための関係式を導いた.

Biodegradation of phenol and monochlorophenols (CPs) by a yeast strain of Rhodotorula glutinis was examined. The strain completely degraded 5 mM of phenol and utilized phenol as a sole carbon source, The strain may degrade phenol by the 'ortho' type of ring fission because muconolactone was observed in the cultured broth. 3-Chlorophenol (3-CP) and...

Aromatic degradation by two yeast strains of Rhodotorula (R.) rubra was examined. Separation and identification of phenol and protocatechuic acid (PCA) metabolites were carried out using high performance liquid chromatography (HPLC) and gas chromatography/mass spectrometry (GC/MS). For HPLC analysis of β -ketoadipic acid, 2,4-dinitrophenylhydrazone...

The metabolic pathway of phenol was examined in the yeast strains of Rhodotorula (R.) rubra IFO 0892 and 1101. Changes in concentrations of phenol, phenol metabolites and dissolved organic carbon (DOC) in a medium were determined during incubation of phenol-grown cells with a phenol solution. A decrease in DOC concentration indicated that phenol wa...

The effect of phenol on the growth and oxygen uptake rate was studied in several strains in the genus Rhodotorula, and the degradation route of phenol by two yeast strains of Rhodotorula rubra was examined. Rhodotorula rubra IFO 0870, 0889, 0892, 1100 and 1101 grew well in medium containing 250 mg/l phenol. Rhodotorula rubra IFO 0870 still showed a...

Heavy metal inhibitions of the activities of β-galactosidase and dehydrogenases in activated sludge were studied.The activities of β-galactosidase and dehydrogenases were strongly inhibited by Cd and Hg. To produce 50% inhibition of β-galactosidase by Cd and Hg required 1.3 and 0.004 mmol g−1 MLSS, respectively. In the case of dehydrogenase, 50% in...

Nitrate removal in a medium (at /C) and the e#ect of culture tempera-ture on the fatty acid composition were investigated using Candida sp. which was isolated from the upper layer of Lake Vanda in the McMurdo Dry Valleys, Antarctica. The strain was cultured at /C aerobically, on a synthetic medium containing potassi-um nitrate (NO--N, +** mg l +) a...