In the 21^st century, w e should develop the Ecology technology that must realize the symbiosis between Town, Village and Forest.

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The photovoltaic (PV) is considered to be the most promising energy source in many applications, due to its safety and high reliability. But, the initial high cost of the PV arrays and the large areas that require necessitate the optimum use of them. One of the solutions that optimizes the array performance is to what extent the array tilt should be adjusted such that the incident insolation on the array becomes as large as possible. In this paper a new technique, which maximizes the incident solar insolation at solar noon on the tilted PV array, is proposed and developed The monthly mean values of the solar insolation incident on a horizontal surface is calculated using a statistical methods. Also, a comparison between the proposed technique and the most common one is studied. The results indicate the superiority of the proposed technique.

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In last APCSEET (in Hong Kong) solar aided power generation concept has been proposed. Although the thermodynamic advantages of using solar energy to replace the bled off steam in the regeneration system of Rankine cycle coal fired power stations has been proven theoretically, the practical techno/economic feasibility of the concept has yet to be confirmed relative to real power station applications. To investigate the concept further, computer modelling software “THERMSOLV” has developed to simulate the steam cycle to assess the techno/economic merit of the concept for various power station structures, locations and local electricity market conditions. Two case studies, one in Victoria Australia and one in Yunnan Province, China, have been carried out with the software. This paper reports the structure and functions of the software, and the results of the two case studies. Although technically the concept is sound in both case studies, it was found from the case studies that under different scenarios ie. emphasis on fuel/coal saving or additional electricity generated (from solar), that payback times of adapting to this concept by modifying existing power stations are quite different. This to some degree may effect the specific application of this concept/technology.

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In this study, for the purpose of clarification of mechanism and optimum condition of reforming CO₂ into fuel-like species which are CH₄, C₂H₄ and C₂H₆ with the aid of photocatalyst, the experimental investigation has been carried out. The acrylic tube reactor composed of the ultraviolet (UV) lamp and copper ring coated with TiO₂ by the sol-gel and dip-coating technique was used. After filling the mixture of CO₂ and saturated vapor into the reactor, UV lamp was illuminated for 48 hours continuously. The effect of the power of UV lamp and the coating number on the amount of produced fuel-like species was examined. As a result, CH₄ production is influenced stronger by coating number than by the power of UV lamp. C₂H₄ concentration is increased with increasing the power of UV lamp and coating number. The reaction scheme of CO₂ reforming into fuel-like species has been revealed.

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Performances of the top-convergent solar chimney are predicted with a new theoretical model which is different in significant ways from the models proposed in the literature in that it allows interaction of flows in the greenhouse portion and the chimney portion through the small, but significant, pressure difference traditional ignored in the literature. For the top-convergent solar chimney, the results obtained by the newly proposed theoretical model are qualitatively different from the results predicted by an established model in the literature in that the efficiency is predicted to remain the same as in the straight chimney. Numerical predictions are also made by numerically integrating the full, quasi-one dimensional Euler's equations using the finite volume method. Results of the numerical and theoretical predictions compare very well with each other, qualitatively as well as quantitatively.

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A small-scale incinerator system was developed in UTM for used in Malaysia's urban areas. It was built for easy operation, incorporated with mechanical features to provide efficient and environmentally friendly operation. It consist of several components among which are i) a main chamber, ii) a heat recovery unit and iii) a gas cleaning train. The system was tried in a well-equipped laboratory and was observed to be combustion-efficient. This paper in addition to these, highlights the developmental work and the trial bum conducted on the incinerator and reports its salient points.

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Environmental issues, over the last one-decade, have been getting increased popularity Large waste dumps off various kinds have generated a deep concern among the common this situation has compelled the scientists to develop techniques for waste management. This paper focuses on several geophysical techniques that can be applied to the environmental problems and suggests the development of an expert system for effective waste management.

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One objective in a part of the research and development of infectious waste incinerator in Thailand is to determine the optimum operating condition of the incinerator such as the operating temperature of primary combustion chamber. By the fact that combustion process in primary combustion chamber is principally controlled by the thermal destruction behavior of waste, consequently, thermogravimetry (TGA) tests have been conducted on the thermal decomposition of the major components of infectious waste which mostly found in Thailand's hospital, i.e., cotton, rubber glove and PE syringe. The results of these tests show that the decomposition of waste material significantly depend on the thermal destruction temperature. The tests are also done with the simulated infectious waste, with the composition similar to the real waste. The results show significant features between these materials. Energy engaged at the early stages of decomposed materials can be used as an accumulated energy to destruct the other portion of material at higher temperature. The TGA results also use to compare with the evolution of primary chamber temperature and carbonmonoxide gas emitted during the combustion of infectious waste in a prototype controlled-air incinerator. The understanding of combustion behavior from this study could be used for determining the optimum operating condition of the prototype incinerator.Thermogravimetry, infectious Waste, Controlled-Air incinerator, Combustion Behavior.

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Cellulose pyrolysate containing levoglucosan (1, 6-anhydro-β-D-glucopyranose) was hydrolyzed to glucose with 0.2 mol/l H₂SO₄ at 121°C for 20 minute. Such glucose in hydrolysate mixture was treated by neutralization with Ca(OH)₂ and adsorption with diatomite, and then was fermented to ethanol by S. cerevisiae and P sp. YZ-1. The ethanol of 0.45 g/g glucose was obtained with initial glucose of 41.9 g/l by S. cerevisiae. Furthermore, by training culture of S. cerevisiae 12 times in the hydrolysate medium containing 60.0 g/l glucose, the trained strain S. cerevisiae (R) could use 95.0% glucose and give 40.2 g/l ethanol in the fermentation with the hydrolysate medium containing 95.8 g/l glucose.

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Cassava waste from the starch factory was used as the raw material in this study. This project aimed to apply solid-state fermentation to enrich protein in cassava waste and use it after fermentation as nitrogen source for animal feed production. The optimum condition from the laboratory experiment was applied in the 5 liter drum fermentation. The experiment was carried out in the systems of using one fungus, Rhizopus oligosporus, and two fungi, Rhizopus oigosporus and Rhizopus sp. 26R. As solid-state fermentation has to take place in the rather dry condition, therefore, cassava waste was dried. After that the moisture content of cassava waste was adjusted to 50% (dry weight) and autoclaved at 121deg;C for 15 minutes before transferring to the drum bioreactor. After 84 hours of fermentation, % amino acid in above both fermentation systems was analyzed and compared. Totally 17 different types of amino acid were found in different concentration. The data showed that glutamic acid was the highest at 1.25% and methionine was the lowest at 0.15% in the two fungi fermentation system. Finally, % urea, % protein and % fibre were analyzed and used as data to formulate animal feed formulation. From the balances of energy, protein and fiber content shows that the fermented cassava waste can be used as the nitrogen source substitution up to 40% in cow meal, 24.5% in pig meal, 20.0% in chicken meal and 17.3% in duck meal.

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To minimize process energy consumption of absolute alcohol by distillation and the vapour recompression technique, the procedure was undertaken with computer simulation. The simulation of Azeotropic Distillation using Benzene, Cyclohexane and Carbondisulfide consisted of two distillation columns, mixer, decanter and heat exchanger. The vapour recompression with a compressor compressed the vapour from the first column to 2500 mmHg. The result pointed that the vapour recompression process can reduce the energy consumption by 22.16% compared to the conventional distillation. Carbondisulfide as azeotrope mixture consumes the lowest energy which is 16.76 MJ/kg-Ethanol 100%, while Benzene consumes 17.35 MJ/kg-Ethanol 100%. However, Benzene is the most favourable azeotrope mixture because of lowest cost and high availability. The economical analysis showed that the vapour recompression process reduces the cost of equipment up to 38.19% and the maintenance up to 44.04%, because of the smaller size of equipments. The net present value of this process is 338, 454.92 US whereas the other is 543, 887.17 US.

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To understand the behavior of the entrained-flow gasification of organic wastes, high calorie value polypropylene (PP) and low calorie value polyethylene terephthalate (PET) were examined in a down flow furnace. The behavior for operational factors of the gasifier, and the effect of auxiliary fuel were found as: High oxygen-carbon molar ratio of the raw materials were necessary in order to maintain the reaction temperature of 1300°C in these small gasifier of the capacity of 10 kg/h and such a high temperature could not be achieved under the low oxygen-carbon molar ratio. When methane gas was introduced as auxiliary fuel under the low oxygen-carbon molar ratio, reaction temperatures over 1300°C were achieved and higher carbon gasification conversion than 80 % was attained. The shift reaction equilibrium was conducted over 1250°C and the equilibrium constant was approximately 0.85.

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A cost-based method for determinicig optimum combustion air supplied to a 90 t/h industrial steam boiler is proposed to attain the highest thermal boiler efficiency with the minimum environmental impact. The total sum of “internal” costs (associated with the boiler fuel consumption) and “external” costs (or costs of damage done to the environment and humans by the gaseous pollutants from the boiler) representing the objective function for the optimization, is required to be minimized. The measurement of gaseous emissions (NO_x, SO₂, and CO) was carried out for 3 reduced boiler loads of 84 t/h, 70 t/h and 64 t/h. The optimum values of excess oxygen were found to be 1.2%, 1.8% and 2.7% for the above boiler loads, respectively. However, for higher boiler loads, the specified excess air should be selected taking into account fluctuations of the (excess) oxygen concentration in the boiler furnace. Fuel firing at the optimum excess air ratio ensures a noticeable benefit (energy saving) per unit boiler.

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The effects of operational conditions on the drying characteristics of porous materials immersed in the fluidized bed of fluidzing particles with superheated steam weae excamined experimentally and tbeoretically. A brick ball and the glass beads were used as the drying sample and fludizing particles, respectively. N₂ gas, which is substitute of air, was also used as the drying gas for the comparison. In calculation, heat and mass transfers in sample were considered. THe temperature of fluidiaed bed and mass velocity of drying gas were changed, respectively in experiment and calculation. There is the period when the temperature of sample center is almost constant in the fluidized bed drying with superheated steam and with hot air, and the temperature is ligber in the case with supertted steam than in the case with hot air. An inversion point of drying time between fltudzed bed drying with supertheated steam and that with hot air appears at about 473 K of bed temperature rathe calculation. The effect of mass velocity of drying gas onthe drying time is very slight when the mass velocity is sufficiently high.

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An optimization method based on a dynamic linear programming tool for determining “the best load distributions” over distinct units of a fuel oil-fired power plant is presented. Two approaches are analyzed in this work. In the first approach, the objective function is based upon a minimization of the fuel consumption by the power plant. The second approach aims to minimize the total operational costs, i.e. the sum of the "internal" (or fuel) boiler costs and the “external” costs (or costs of damage done by the power plant to the environment and humans). The model used as the basis of the optimization also takes into account the changes in key operating variables as well as boiler efficiency with load variations. A 1330-MW fuel oil-fired power plant is the focus of the study. The method is applied to data from the power plant for the three climatic seasons in Thailand and two fuel options (dependent on the fuel grade). The optimum time-domain loading of the power plant units is strongly affected by the objective function, thermal cycle efficiency of the individual units and grade of fuel oil fired in the boilers. It was shown that application of the optimization method can reduce the total costs by 0.3-0.9% depending upon the seasons and fuel options.

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A Ni-samaria-doped ceria (SDC) anode was employed in direct electrochemical oxidation of methane in a solid oxide fuel cell with yttria-stabilized zircoma (YSZ) as electrolyte to seek insights into the anodic properties and electrocatalytic activities of the anode. Compared with Ni-YSZ, the Ni-SDC anode exhibited higher open-circuit voltages and lower degree of polarization. The anodic polarization of Ni-SDC was shown to result from the effect of concentration polarization. The effects of nickel content in Ni-SDC on the performance and microstructure of the anode were studied. It was found that the anodic polarization and electrocatalytic activities strongly depended on the Ni content in the anode, and the optimized results were achieved with the anode of 60 wt% Ni content. The high performance of the Ni-SDC anode containing 60 wt% Ni appears to be attributable to the microstructure formed. In addition, the Ni-SDC anode at this Ni content was found to be stable in methane environments.

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Nanofiltration is considered one of the most promising technologies for the removal of hardness as well as disinfection-by-products precursors. In this study, we set up a benchscale nanofiltration apparatus to investigate the effect of the operational parameters (e.g., applied pressure and feed water recovery) on hardness removal and inorganic fouling. Synthetic aqueous solutions prepared by calcium sulfate are used in the nanofiltration experiments. Operating pressure is accurately controlled from 20 to 100 psi using a gear pump. It is observed that the hardness rejection remains relatively constant at low feed water recovery (< 70 %). At higher recovery (>70 %), however, the rejection decreases sharply with the increase of recovery. Increased operating pressure results in greater hardness rejection due to the increased permeate flux and greater concentration factor in the feed water. A transport model based on mass balance has also been developed to simulate the hardness rejection behavior under the typical operating conditions of nanofiltration. The model results are in agreement with the experimental observations.

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This study examines the water purification by cylindrical wetted-wall reactor using corona discharge in gas phase. In this reactor, a cylindrical anode and a wire cathode are set apart from each other coaxially in an atmospheric air to generate corona discharge. The cylindrical anode surface is covered with falling water film by overflowing treated water from its top, and the outlet water is circulated to the reactor. Some reactive species, O^-, O₂^-, O₃, O are produced by gaseous corona discharge, and the ions should arrive at the treated water flowing on the anode surface by electric force, and the uncharged radicals should arrive there by convection caused by ion wind. When these gaseous species reach the water film, they readily react with water to produce aqueous radicals, which contribute to decompose organic contaminants in the treated water. Phenol was chosen as target organic compound. Experiments were carried out in variety of conditions.

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The monosodium glutamate wastewater is very difficult to be treated in normal ways. A good result had been received treating the monosodium glutamate wastewater with HCR process, the COD removal rate was very high and the acid wastewater with high-concentration of SO₄^2- could be directly treated for the reactor. Ammonia, hydrogen ion, organic acid and NAD(p)H would combined into Glutamatic acid, then the ribose and bacterial protein were descended in the waste water. Finally, the Glutamatic acid, organic acid and ammonium combined into some new protein. The NH₄⁺-N of the wastewater was degraded about 10-20%, and the pH value was automatically increased from 2.0 to more than 6.0.

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Adsorption of phenol and two organic dyes, Black 5 and Red 31, from aqueous solution on mesoporous activated carbon prepared from waste tire was carried out and, for comparison, an imported commercial activated carbon was also investigated. Phenol adsorption capacity of the prepared activated carbon was nearly equal to that of the commercial activated carbon because the micropore volumes of both carbons are almost the same. In contrast, the prepared activated carbon showed definitely higher adsorption capacities of both representative organic dyes because it had larger mesopore volume. It can be concluded that mesoporosity in the activated carbon prepared from waste tire makes it more suitable for removal of bulky molecular adsorbates from wastewater than the commercial activated carbon.

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An experimental study on hydrogen production from biomass was conducted using a bench-scale fluidized bed gasifer. Parametric experiments were performed to determine the effects of reaction temperature, steam, equivalence ratio (ER) and catalysts. The catalysts used were dolomites and nickel-based catalysts and were located in gasifier and a downstream fixed reactor, respectively. Of the conditions tested, hydrogen yield ranges between 22 and 83g H₂ per kg of biomass (wet basis) and hydrogen yield potential ranges between 115 and 223g H₂ per kg of biomass (wet basis). The experimental results prove that higher reaction temperature; proper steam quantity and ER will contribute to more hydrogen production. Dolomites and nickel-based catalysts are very active and useful for increasing hydrogen yield and gas conditioning.

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Main art of bio-boneycombing birquet made in laboratory is described and the combustion test data are given.The result of test display that reduction of effluence of SO₂ and dust are more than 60%, The reduction of NO_x is more than 20%, Economy-coal is more than 10% by comparing with coal burning.

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The purification of biomass -derived syngas via tar and methane abatement by catalytic cracking over Ni catalysts using benzene, toluene and naphthalene as model compounds was investigated. The effects of temperature and steam to carbon ratio on conversion, and the tendency towards coke formation were explored. Three Ni catalysts were prepared by use of metallic nickel as active phase grafted on dolomite. Five catalysts, three Ni catalysts, dolomite and heavy oil cracking catalyst, were evaluated in a bench-scale reactor at 700°C with an S/C ratio of 4.5. The results indicated that the naphthalene was the most difficult compounds to steam reform; the tendency towards coke formation increased as the increasing molecular weight of the aromatic; heavy oil cracking catalysts had a role in cracking biomass tar, but the conversion was limited; Ni catalyst calcined at 900°C showed the best selectivity to H₂ and CH₄ (H₂ 68.3%, H₂+CO 92.3%, CH₄ 2.3%). The ageing test (100h at 700°C) indicated: the total content of H₂ and CO was unchanged approximately; the ratio of H₂/CO decreased with the reducing of catalyst activity; No sintering was observed on this catalyst by characterization studies after catalytic test.

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This paper presents the results of an experimental study of biomass combustion in a conical fluidized bed combustor (conical FBC) using silica sand as the inert bed material. Three biomass fuels (sawdust, rice husk and pre-dried sugar cane bagasse) were fired with the aim of determining combustion efficiency. Effects of operating variables (load and excess air) on axial temperature and gas (CO and NO) concentration profiles as well as on CO and NO emissions from the conical FBC were also the focus of study. Both CO and NO axial profiles were found to have a maximum whose location divides conventionally the combustor volume into formation (lower) and reduction (upper) regions for these pollutants. The excess air values of 50-60% ensure minimized CO and NO emissions from the conical FBC fired with these biomass fuels. The combustion efficiencies greater than 99% for firing sawdust and bagasse, and of about 86% for firing rice husk, were achieved in the experimental tests on this combustor.

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Using HPA (heteropoly acid), namely Na₂HPMo₁₂O₄₀, as absorbent in form of aqueous solution, a promising resolution to SO₂ containing gas purification was developed. In this study, experiments were conducted concerning the additive effect for maximizing the desulfurization efficiency of HPA absorbent system and the performance of absorbent regeneration. As a consequence, all additives including NaCl, H₃PO₄, MnSO₄, CuSO₄, ZnSO₄ and NH₄VO₃ were found to have positive effects on the improvement of the desulfurization efficiency of HPA solution. Among them, the effect of NaCl is the most significant. The following two couples i.e. NaCl vs H₃PO₄ and Zn²⁺ vs Mn²⁺, were found to have interactions. Based on orthogonal experiments, the optimum additive/HPA molar ratio in multi-component absorbent system was gained. The process of HPA regeneration by air stream is strongly influenced by operation temperature, whereby the optimum regeneration temperature was found to be ca. 51°C. The desulfurization efficiency of single HPA shows excellent reproducibility during long time operation of 6 absorption-regeneration cycles. The resultant solution of single HPA after desulfurization can also be effectively regenerated by gas stream containing NO_x, which shows better effect than that by air stream.

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Using as absorbent the aqueous solution of heteropoly compound, namely H₃PW₁₀Mo₂O₄₀, a new approach to low sulfur containing gas desulfurization and sulfur recovery was developed. The dependence of the desulfurization efficiency on factors including the absorbent concentration, absorption temperature and the feed gas H₂S concentration were experimentally investigated, whereby the favourable operation conditions were recommended. For the gas stream with H₂S concentration below 1000mg/m³, flowing at a rate of 0.368L/min, the favourable concentration of 200mL of H₃PW₁₀Mo₂O₄₀ is ca. 5&times;10^-3mol/L. Within the temperature range of beyond 30°C as investigated, the increase of the absorption temperature tends to decrease the desulfunzation efficiency of H₃PW₁₀Mo₂O₄₀ solution. However, within the temperature range of below 30°C, the reverse effect can be found. Hence, ambient temperature of around 30°C is favourable for desulfurization. The desulfurization efficiency of H₃PW₁₀Mo₂O₄₀ solution decreases with the increase of H₂S concentration in the feed gas stream, which can be found remarkably when the absorption time exceeds 20min. Some additives having positive effect on the desulfurization performance of H₃PW₁₀Mo₂O₄₀ solution were found, with the effect decreasing in the order CuS>NaCl>NH₄VO₃ at low dosage.

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Oil, gas and coal represent about 90% of the commercial energy used worldwide, at current rates of consumption reserves are estimated for at least two centuries. Although advances in renewable energy technologies will continue to play a role in determining the world's energy mix, the global community will, however, rely heavily on the use of fossil fuels for the foreseeable future. This will be particularly important in developing economies, which, present some 605 of annual growth in energy demand.
In meeting this growing demand, the challenge for the fuels sector is to develop and provide global market affordable products while ensuring environmental quality and safety to human health. The environmental issues that the industry faces are numerous, potential impacts include, among others: loss of 1% crude oil while processing which goes to waterways and soil, solid waste and air emissions from refineries and vehicles due to the use of inadequate standard fuels. Among these, the air pollution, is most critical. In fact, the density of air pollutants in a given area depends on three factors, namely,
i) Concentration of pollutants in the crude and additives
ii) Fuel efficiency of the motor vehicles, and
iii) City traffic planning and air flow.
The common air pollutants related to oil refining curd automobile sector include, particulate mutter, hydrocarbon, aldehydes, sulphur dioxide, carbonmonoxide, carbon dioxide, nitrogen oxide, and lead. The particulate matter leads to several respiratory diseases, whereas lead once deposited in the body stays there forever.
Vehicular traffic is the largest source of lead exposure in urban aretrs, often accounting for more than, 90% of all atmospheric emissions. It severely effects the IQ level, and in severe cases heart attack and early death. Additionally, perennial exposure to lead effects on human fetus, resulting in reduced birth weight, disturbed mental development, spontaneous abortion, or premature birth. Generally, the population group most seriously affected by the exposure to pollutants is the urban poor. Furthermore, children are most affected because of their proximity to the exhaust level.
Many countries in the tleveloping world have changed the crude oil refining processes and have switched over to unleaded gasoline. In Pakistan, unfortunately all the gasoline usetl is leaded which is a constant threat to human health, especially to that of young children. Likewise, the diesel and furnuce oil used in Pakistan contain higher levels of sulphur dioxide.
The Government of Pakistan has taken a number of good initiatives to improve the ref ining process in refineries to minimize losses, developed a policy to promote the use of CNG instead of gasoline and increased prices of diesel to promote its jurliciotts use. It is also being considered to import better quality crutle oil to minimize sulphur emissions. However, the measures taker, are not adequate to show results in near future.
To minimize air pollution and consequently the health affects, policy action are needed to enforce production of clean fuels by refineries and at the same time taking actions to improve fuel efficiency by automobiles. Such actions could be improving traffic flow, enforcing vehicle road fitness standards and their carrying capacity limits Training/awareness of drivers angel workshop mechanics for proper tune up of engines.

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A study on the combustion of EVA waste with high sulphur coal was carried out in a fluidised bed EVA is used in the production of shoe soles and beach sandals and its waste is currently being disposed of by landfilling. Work was done to study the capability of this material to capture sulphur from coal as it contains 40% calcium. The results show that co-firing coal with EVA waste can result in a significant reduction of SO₂ emission. The reduction in SO₂ emission can be attributed primarily to the decreased sulphur content in the feed mixture and the increased amount of Ca in ash as EVA waste increased and acting as sorbents for sulphur capture. These results also indicate that co-firing of EVA waste with coal reduced SO₂ emissions beyond what might have been expected as simply a result of dilution alone. This work demonstrates that, in certain case, co-combustion can be used to reduce the need for land based waste disposal with the reduction of SO₂ emission as an added advantage.

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A non-linear κ-ε model, which includes effects of the strain parameter and the rotation parameter, is applied to 2-D computation of the turbulent flow field behind a backward-facing step. Model coefficients are carefully adjusted in turbulence modelling. Coefficients in non-linear terms are firstly tuned focusing on the anisotropy in a simple shear flow. For the tuning of Cμ realizability conditions are examined in three types of 2-D basic flow patterns, namely, the simple shear flow, the flow around a saddle point and the flow around a focal point. Then, Cμ is adjusted as a function of the strain and rotation parameters considering the restrictions of realizability. Numerical simulatio are performed under the conditions of the laboratory test by Larousse et, al. Model performance is discussed through the comparison of the numerical and experimental results. The numerical result shows that the present model can qualitatively reproduce the cousplex2-D flow with separation and reattachment.To evaluate the accuracy of the computer code, comparisons with observed data were made and fairly good agreements were found between them.

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A bench-scale matrix isolation system coupled with an FTIR spectrometer has been established for investigating the formation mechanism of tropospheric ozone. Mixtures of NO₂, O₂, and Ar are prepared and deposited on the matrix chamber at 8-12 K under vacuum. The matrix is then photolyzed to verify the mechanism of tropospheric ozone formation. Results show that both O₃ and NO are produced during the photolysis experiments, which serves as the first verification of the reaction pathway using matrix isolation technique. The characteristics, temperature effect, potential applications and limitations of matrix isolation technique are assessed and summarized. It is concluded that the matrix isolation spectroscopy can be an effective technique for investigating atmospheric reactions involving highly reactive species with short atmospheric lifetimes.

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A [Fe] hydrogenase gene (hyd) was cloned from Clostridium paraputrificum in Escherichia coli using a probe of a conserved DNA sequence of clostridia hydrogenase genes amplified by PCR. The hyd consists of an open reading frame of 1, 749-bp, encoding 582 amino acids with a MW of 64, 560. The cloned hyd was ligated into a shuttle vector pJIR751 between E. coli and C. paraputrificum and was sequenced and expressed in C. paraputrificum. The hydrogen gas productivity of the transformant was increased up to 1.7-fold. Since hydrogenase encoded by hyd is the terminal enzyme of the sequential metabolism for hydrogen evolution, fortification of the enzyme in the cell might accelerate hydrogen release.

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Utilization of carbon dioxide is one of the most significant subjects in environmental technologies. A common idea is reducing carbon dioxide to carbon monoxide or methane, which are valuable in industry. Though it is rather easy technically, the problem is how hydrogen can be supplied more cheaply. Supplying pure gaseous hydrogen is easiest, but most costly. One solution is to supply hydrogen in the form of hydrocarbons. Even if the reactions work, some remaining questions need to be answered. The first is if the dehydrogenation products from the hydrocarbons used are valuable in industry. The second is how the products will be separated. This study may give an answer to both the questions. A cyclic operation experiment of catalytic cyclohexane dehydrogenation and carbon dioxide hydrogenation was carried out successfully using LaNi₅ particles as a catalyst and as a hydrogen reservoir. Five kinds of LaNi₅ particles ranging from 10 to 725 μm in mean diameter were used. After a 30-minute activation of LaNi₅ using hydrogen at 673 K, carbon dioxide and cyclohexane flowed through the LaNi₅ particles bed for each 30 minutes at 673 K alternatively. The cycle was repeated four times. When cyclohexane was fed, cyclohexene, benzene and hydrogen were detected as products. Cyclohexane conversion increased with decrease in the mean diameter of LaNi₅, ie., with increase in external surface area per unit mass of alloy. When carbon dioxide was fed, carbon monoxide formed Hydrogen also was detected in the outlet gas. Carbon monoxide yield also increased with decrease in the mean diameter of LaNi₅

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Since the main components of fly ash are SiO₂ and Al₂O₃, which exhibit a similar chemical structure of zeolite, this studied was concentrated on the used of fly ash as raw materials for synthesizing zeolite. The objective of this study was to define an optimum condition on fly ash synthesis, which would conciliate a high cation exchange capacity (CEC) of synthesized zeolite. To achieve this goal, the strategy relied on the use of experimental design methodology. The effects of five parameters including sieve size, activated temperature, NaOH concentration, reaction temperature, and reaction time were determined by using the two factorial design approach to specify the significant parameters on the formation of zeolite from fly ash. In the first step, the reaction temperature was found to be the most important parameter and two other significant parameters are activated temperature and reaction time. The second step of this studied, the three significant parameters were controlled at the various values and the cation exchange capacity (CEC) were determined for an optimum condition. Reaction temperature, activated temperature, and reaction time were in the range of 40 to 150°C, 800 to 1100°C and 12 to 96 hours, respectively. The results showed that the optimum condition, which exhibited the highest CEC (636 cmol/kg) of synthesized zeolite was at reaction temperature of 110°C, activated temperature of 800°C, and reaction time of 96 hours. Therefore, the development of a technique for the utilization of coal fly ash is essential to preserve the environment and to recycle the waste materials. Zeolite-like material can be use as an alternative adsorbent for the removal of heavy metals such as Cd, Zn, Pb from wastewater.

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In order to develop the performance of an ejector refrigerator, a better understanding in flowing and mixing characteristic through the ejector is significant. In this study, a 3kW steam ejector refrigerator was constructed. The static pressure profile along the ejector at various operating conditions was measured. The analyzed experimental results introduce three new parameters. Using these data, the flowing characteristic through the ejector was well understood and clearly explained.

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Technology, planning, and human behaviour are suggested to be the main approaches to sustainable development of our built environment. Single approach to sustainable issues has been conceived as not only being less effective but also potentially causing conflicts to other approaches. Integrating all the three aspects has been attempted for a holistic and effective approach to sustainable development. However, the current integration is a one-way and top-down relationship —from sustainable objectives, to technical and planning strategies, and finally to affected lifestyle. This imposed lifestyle is questionable on users' readiness and willingness to accept. The solving of these conflicts has often relied on social approaches —education and economic incentive —which are not always effective. Redefining the roles of the three approaches, at least conceptually, in order to form a truly holistic integration in our endeavour for sustainable development is needed.

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An alternative direct-contact heat transfer in ice formations has been proven for efficient ice production method of thermal storage for cooling purpose. It maintains constant thermal resistance during ice formation process, which has better performance than conventional indirect ice formation method. In this study, the experimental investigation in ice formation on pilot scale direct-contact heat exchanger was conducted with capacity of ice formation of 1.5 refrigeration ton. The HFC-134a has been used as contact refrigerant with a mass flux in the direct-contact column varying from 0.98 to 2.19kg/m²s. The results show that water was frozen as a porous small grain slurry at 8.5°C resulting in higher refrigerator's coefficient of perfermance (COP) than conventional ice produciton systems.

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On November 7, 1996, an accidental explosion of an oil storage site occurred in Thaptong village area of Pluank Daeng District, Rayong Province in the Eastern part of Thailand. More than 200, 000 liters of oil were released into an unconfined aquifer. Site characterization and natural attenuation were assessed after 4 years of spillage which purpose to develop the strategic guideline for soil and ground water in situ bioremediation treatment. The contaminated plume was located as far as 44 meters away from the accidental site. Hydrocarbons in range of C9-11 were found to contaminate in groundwater and C11-20 were trapped in the soil. No carcinogens were found in the plume at the point of exposure (POE). The main compounds of the stored fuel (BTEX) were also not found in the local ground water. EPA Hydrocarbon Spill Screening Model (HSSM) was used for site assessment and indicated that after 6 days of spillage the drainage flowed down to groundwater level. The lens forming was started after 6 days of spillage which rapidly spreading during 4 years through 23 m in distance. These simulated results are in line with DMR data and villager's interviewing data. By using and risk-based corrective action (RBCA) approach, one can be concluded that the NAPL plume is confined to the place of accident and it needs treatment during 1-3 years of spillage. After that the natural attenuation can manage by itself for treatment.

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Usefulness of coffee grounds as a carrier of microflora capable of decomposing garbage was investigated by using a middle-scale composting reactor (100 l in volume). When coffee grounds fermented with garbage and rice straw were used for composting of garbage as a seed culture, composting of garbage could be successfully continued for 160 days in fed-batch mode without increasing in the volume. During the operation, the pH of the composting garbage fluctuated between 5 and 7. An offensive odor due to sulfide compounds was not negligible at acidic pH range. When coffee grounds well-moisturized with phosphate buffer (pH 7.6), the pH of composting garbage were maintained at about 6.5 without increasing the problem of odor for more than 80 days. Changes in microbial consortium analyzed by denaturing gradient gel elecrophoresis indicated that some bacterial species found in fermented coffee grounds remained during the composting period . These results suggested that coffee grounds were quite useful as a habitat for microbial consortium capable of decomposing garbage.

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We all have an interest in the management of the environment since it affects all of us and our natural resources. At the same time, by our actions, we all also have an impact on the environment. Uncontrolled population growth and the rapid pace of agricultural, urban, and industrial development in developing countries, especially in Pakistan, are placing an increasing pressure on the local environment and in some cases to regional and global. In order to manage and mitigate the human impact on the environment there is an essential need of tools and method of analysis, which can help us in collating, analyzing, modeling and monitoring environmental data in a specific and sustainable manner. Geographic Information System (GIS) is one of such tool.
Geographic Information System (GIS) is computer -Based IS (using spatial references), designed to serve as a Management Tool for all phases of geographic data and its manipulation: Data acquisition, coding, storage, retrieval, analysis and display of geo-information. GIS is an effective data storage and retrieval system, having ability of portraying results on a map. Visualization is worth a “thousands words”. Since Environmental planners/Managers depend extensively upon maps for presentation and analysis. GIS can be very useful for carrying out studies and more effectively and with greater precision.

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A multi-mirror solar cooker using a new tracking mechanism having an integrated structure for collectively driving plural reflectors is discussed, and prototypes are prepared. The solar cooker consists of the reflectors having respective vertical bars for rotating the reflectors around respective fulcrums, driving plates for collectively driving the vertical bars, a guide plate which guides the vertical bars, and a central pole for holding a pan. Because the solar cooker can be easily assembled or dismantled by a user, it can be compactly packed for transportation. Sunlight is concentrated to the pan in the focal area above the center of the guide plate, in which the bottom part of the pan is mainly heated by the concentrated sunlight even when the altitude angle of the sun is low, which facilitates solar cooking in winter. The heating power or the temperature can be adjusted in a defocusing mode by shifting each driving plate. One target is a handy compact solar cooker. Another target is a high-power central-receiver multi-minor solar cooker, in which a number of reflectors are arranged in lines and rows.

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Acetaldehyde is one of the malodorous gaseous components emitted at high temperature crematory furnace. In this study a corona discharge reactor is employed to remove acetaldehyde (CH₃CHO) from N₂ and air from room temperature up to 300°C. First the effect of acetaldehyde inlet concentration (200, 400 and 600 ppm) is investigated. In contrast to conventional separation processes, the more dilute the inlet concentration, the higher the removal efficiency becomes because, when the discharged current is kept constant, the number ratio of discharge electrons to acetaldehyde molecules increases. Next the effect of oxygen and/or water vapor in the emission gas is investigated. Interestingly the presence of either oxygen or water vapor always enhances the removal acetaldehyde from N₂. When the reaction temperature is increased, the removal efficiency is to increase starting from room temperature up to 200°C, above which the tendency reverses 300°C. It is found that the smallest discharge current required for complete removal of 600 ppm of acetaldehyde from the air is only 0.2 mA at room temperature. To elucidate the effect of temperature, the discharge current is deliberately set at 0.05 mA in some experiments.

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This paper reviews our R&D activities on both thermal and non-thermal plasma technologies for pollution control and sustainable development. A novel method has been developed for generation of a single and/or multiple plasmas. The plasma reactors are energized in three stages with a solid-state pulsed power source. Pulsed corona plasma is generated with an ultra-short voltage pulse generator. Both single-switch and multiple-switch corona circuitries have been developed. Based on ions and radicals generated by pulsed corona plasmas, the next generation gas cleaning system - called zero emission system, will be developed in order to remove polluting gases, heavy metals, and particles simultaneously. Integrating the thermal and non-thermal plasma processes would lead to develop the next generation plasma technology for pollution control and sustainable development.

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Hydrogrossular injected in two types reactor of pilot plants was found to be capable of decreasing the HCl concentration from the effluent gas at high temperature that could not be captured by conventional sorbents suds as CaO and Ca(OH)₂. HCl gas was fixed as wadalite [Ca₁₂Al₁₀Si₄O₃₂Cl₆] at&gt;700°C under realistic gas phases including H₂O, CO₂ and so on.

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The experiment to decompose acetaldehyde and benzene in air was carried out using d.c. corona discharge and UV-254nm. It was found that the removal efficiencies of acetaldehyde and benzene by the simultaneous use of corona discharge and the UV-254 nm showed the significantly higher efficiency than by the use of UV-254 nm or the corona discharge independently. Additionally, the formation of the byproducts in the removal of acetaldehyde was significantly retarded by this simultaneous use. However, many reaction byproducts are formed when if UV-254 nm was replaced to UV-184 nm. As the mechanism of the synergetic effect by the hybrid use of corona discharge and UV-254 nm, the enhancement of ozone oxidation seems negligible from an experiment by ozone oxidation of the same concentration under UV irradiation. Instead, excitation of organic gas molecules induced by UV-254nm may cause the synergetic effect.

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A cylindrical d.c. corona discharge reactor was used to remove toluene from air. Using this reactor, the effect of electric field strength was investigated varying wire-cathode diameters in the elevated temperature which range from room temperature to 400°C. Electron energy depends on wire cathode diameters and gas temperature. When a thicker cathode was used, the required voltage to generate corona discharge increases. This voltage increase causes the higher electron energy. Also, when temperature is elevated, the accompanying gas expansion results in an increase at electron energy because the collision frequency of electron with gas molecules decreases. However, the gas expansion by temperature elevation causes the less resident time of the treated gas in the reactor. The experimental results show that in all temperature range examined here the removal efficiency is higher when the thicker wire-cathode is used at a constant current. When the removal efficiency based on consumed electric energy is considered, this energetic efficiency becomes higher when temperature is elevated.

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An optimization type energy model named ROSE (Refuse Option for Supplying Energy) was used to evaluate the energy use technologies of combustible waste in the city. A refuse energy system was proposed and examined from the perspective of system cost and CO₂ emission on electricity and heat supply to the 23 wards in Tokyo. Without increasing the system cost. CO₂ emission can be reduced by refuse energy systems (trash power generation. RDF generation, RDF cogeneration). RDF generation and RDF cogeneration were introduced by assigning constraints to the amount of CO₂ emission.

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The inability of existing process design and life-cycle analysis (LCA) methods to account for variability and uncertainty may contribute to misleading estimates of pollution prevention, performance, and cost of potentially promising new environmentally conscious technologies. The objectives of this research are to develop a novel assessment methodology for evaluation of the risks and potential pay-offs of new technologies that avoid pollutant production; and demonstrate the methodology via case study of solid waste gasification technology. A methodology for simultaneous characterization of both variability and uncertainty based upon previous work in emissions estimation, exposure assessment, and risk assessment is developed. To represent uncertainties in any process technology, a probabilistic modeling is applied to the case of solid waste gasification.

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As part of an ongoing project, a life cycle inventory (LCI) of aluminium high pressure die casting (HPDC) has been collected. This has been conducted from the view of an individual product and also the entire process. The objective of the study was to analyse the process and suggest changes to reduce environmental impacts. One modem aluminium high pressure die casting plant located in Victoria, Australia was evaluated and modelled. Site specific data on energy and materials was gathered and the process was modelled using a typical automotive component. The paper also presents our experience and methodology used in this inventory data collection process from the real industry for LCA purposes. The inventory data collected itself reveals that the HPDC process is energy intensive and as such the major emissions were from the use of natural gas fired furnaces and from the brown coal derived electricity. It is also found the large environmental benefits of using secondary aluminium over primary aluminium in the HPDC process. A detailed LCA is being carried out based on the inventory obtained.

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