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CdS/Titanate nanotubes (TNTs) were successfully synthesised by a simple, rapid, and reliable microwave hydrothermal method. The CdS nanoparticles synthesised using a 140-W microwave irradiation power at 423 K photodegraded 26% ammonia in water, while the photocatalytic efficiency increased to 52.3% using the synthesised CdS/TNTs composites. The results indicated that the CdS/TNTs photocatalysts possess improved photocatalytic activity than that of CdS or TNTs materials alone. [ABSTRACT FROM AUTHOR]

This research studied how the air pollutants of urban areas affect a neighboring reservoir and its water quality. Through the atmospheric dispersion process, air pollutants move from the Taipei metropolitan to the Feitsui reservoir and enter the water body through dry and wet depositions. ISCST3 (Industrial Source Complex Short Term Model), an air quality model, was used to simulate dispersion, dry deposition and wet deposition of the air pollutants. Then the nitrogen loadings to the Feitsui Reservoir were evaluated. The results indicate that wet deposition places a greater burden than dry deposition does on the water body. Wet and dry deposition of NH4+ together make up a rather large proportion of the total pollution. The ratio ranged from 21.9 to 25.2%. Those of nitrate make up a smaller proportion, ranged from 2.0 to 2.3%. If we take indirect deposition into account and calculate the NO3- and NH4- together, the proportion is 1 5.9-1 7.6%. [ABSTRACT FROM AUTHOR]

Both surface treatments, H2-reducing pretreatment at 400 °C and the deposition of copper as a catalyst, were attempted to enhance the removal of nitrate (40 (mg N) L-1) using zerovalent iron in a HEPES buffered solution at a pH of between 6.5 and 7.5. After the iron surface was pretreated with hydrogen gas, the removal of the passive oxide layers that covered the iron was indicated by the decline in the oxygen fraction (energy dispersive X-ray analysis) and the overlap of the cyclic polarization curves. The reaction rate was doubled, and the lag of the early period disappeared. Then, the deposition of copper onto freshly pretreated iron promoted nitrate degradation more effectively than that onto a nonpretreated iron surface, because of the high dispersion and small size of the copper particles. An optimum of 0.25-0.5% (w/w) Cu/Fe accelerated the rate by more than six times that of the nonpretreated iron. The aged 0.5% (w/w) Cu/Fe with continual dipping in nitrate solution for 20 days completely restored its reactivity by a regeneration process with H2 reduction. Hence, these two iron surface treatments considerably promoted the removal of nitrate from near-neutral water; the reactivity of Cu/Fe was effectively recovered. [ABSTRACT FROM AUTHOR]

The surface and bulk properties of Al(III)/SiO2 and Fe(III)/SiO2 suspensions were determined as a function of prepared pH. The TEM results showed that Al(III) tends to form Al(OH)3 coatings on the surface of SiO2 while Fe(III) tends to form the discrete Fe(OH)3 phase in bulk solution with system pH increase. The charge reversals (CR) observed in the Al(III)/SiO2 system represent, in order of increasing pH, the point-of-zero charge (PZC) on the SiO2 substrate (CR1), the pH of surface nucleation of Al(OH)3 (CR2), and, at high pH, the PZC of the Al(OH)3 coating (CR3). The observed electrophoresis mobility of Fe(III)/SiO2 is the overall result contributed by negatively charged SiO2 and positively charged Fe(OH)3. [ABSTRACT FROM AUTHOR]

Swine manure was comprehensively characterized with respect to Cu and Zn due to feed additives. Separated swine manure (SSM) composts were collected from five pig farms at Tainan County. The total content, base extractability, synthetic acid rainwater (SAR) solubility, and leachability at varying pH of Cu and Zn were determined to assess its environmental hazard. The influence of dissolved organic carbon (DOC) from compost on leaching of these elements was evaluated. The SSM composts were enriched with Cu (208-1380 mg/kg) and Zn (847-2840 mg/kg). The SAR and neutral pH leachable fractions of Cu, Zn, and organic C were generally low (< 6% of their total content). Copper leachability in F2 compost, however, was high (14%), resulting from immaturity and associated substantial dissolution of organic C (11%). Most of Cu (86% on average) while small portion of Zn (14% on average) were distributed on humic substances (HS) which comprised about 40% of total compost organic C. Extracted Cu increased rapidly and was highly correlated to the increase of organic C concentration as the pH raised above pH 8, while extracted Zn remained low. High leachability of Cu at alkaline pH and during HS extraction was due at least in part to complexation with DOC. [ABSTRACT FROM AUTHOR]

In drinking water treatment systems, the conventional process (coagulation, sedimentation and filtration units) cannot remove trace metals efficiently. Iron oxide is an excellent, regenerable adsorbent, and often controls free metals through adsorption. The utilization of heating process for coating iron oxide on sand surface allowed the media to be used in a packed column. The adsorbent media were investigated for removing copper ions from water using both batch and column experimental methods. A one-dimensional convective-dispersive transport model with a combination of second-order kinetic adsorption equation was adopted for predicting copper retention in a 80 cm depth filter bed. The concentration of copper ions in influent ranged from 0.64 to 3.2 mg/l. The experimental results indicated that the copper could be removed completely until the breakpoint. Once breakthrough occurred, the regeneration of the media could be achieved by soaking with acid solution (pH = 3.0). The simulation results of the transport-adsorption equation fit experimental data quite well. Consequently, the coated sand can be applied for the conventional rapid filtration process to remove copper ions from water. [ABSTRACT FROM AUTHOR]

A two-stage scouring-based model including two parameters for each stage, the ultimate scoured depth and rate of change of scoured depth, was developed to describe solute transfer to surface runoff. While the first stage is a quick decrease of mass loss of solute to surface runoff, the second stage is a slow one. An experimental flume with a medium packed bed was designed. Four different sizes of glass beads were chosen to be the media and saturated with uniform concentration (20000 ppm) of potassium chloride solution before runoff occurred. In a series of experiments, runoff was passed at varied flow rate, velocities, and depths over the medium bed. Runoff samples were taken at the end of flume and the concentration of potassium chloride analysed. By use of this model, the dimensionless ultimate scoured depth and the dimensionless rate ot change of each stage were investigated. The results showed that the Reynolds number within media and the relative length were two important factors affecting mass loss of chemicals. [ABSTRACT FROM AUTHOR]

Composting of separated pig manure (SPM) was studied to evaluate criteria indicating compost maturity and to determine the effect of composting on the fractionation of trace elements in SPM compost. Composting was performed in turn piles and the following parameters were measured in 10 samples during 122 days of composting: temperature, C/N ratio, ash content, metal contents, humic substance contents, and fractions (humic acid, fulvic acid, and nonhumic fractions - HA, FA, and NHF, respectively). A sequential extraction scheme was used to partition Cu, Mn, and Zn in SPM compost. The C/N ratio and ash content exhibited a typically high rate of change during the first 33 days and levelled off thereafter. The fresh SPM was enriched with Cu, Mn, and Zndue to feed additives. All metal concentrations increased approximately 2.6-fold in the final compost due to decomposition of organic matter. The HA content increased to a maximum at 80 days, representing the degree of humification and maturity of the compost. During the composting process, the major portions of Cu, Mn, and Zn were found in the organic, oxide, and carbonate fractions, respectively. Metal distributions in different chemical fractions were generally independent of composting age and, thus, respective total metal concentrations in the composts. (C) 1999 IAWQ Published by Elsevier Science. All rightsreserved. [ABSTRACT FROM AUTHOR]

Many studies have focused on heavy metal characteristics in sewage sludges and sludge-amended soils other than lime-stabilized sewage sludge (LS). Thus, the aerobically digested sewage sludge cake (13.61 % solids) sampled from the Min-Sheng Wastewater Treatment Plant in Taipei City, Taiwan was lime-stabilized for studying the effects of the lime treatment on fractionation and extractabilities of heavy metals (Cu, Pb, Cr, and Zn) in sewage sludge, using various extraction tests.For comparative objective, oven-dry sewage sludge without liming (unlimed sludge (S)) was also studied. The results of this study revealed that the percentages of the metals extracted from lime-stabilized sludge (pH = 12.05) and the amounts of the metals fractionated to the organically-bound fraction (30% H202 + 0.02 M HNO3 (pH2), 85 deg. C) in unlimed sludge were both in the order of Cu > Ph > Cr > Zn, meaning that the more the heavy metals (e.g., Cu) were fractionated to the organically-bound forms in unlimed sludge, the more unstable they were in the sludge after lime-stabilized. On the other hand, the metals (e.g., Zn) in lime-stabilized sludgewas more stable when they have less affinity for organics. Single extraction conducted at various pHs revealed that this effect was due to the irreversible dissolution of organics and some metals having a higher affinity for organics (e.g., Cu) at very high pH during processing and air drying of lime-stabilized sludge. Therefore, examining the fractionation of heavy metals in sewage sludge is useful for expecting heavy metal stability in the sewage sludges after lime-stabilized. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the application of waste minimization technology to electroplating plants and to evaluate the economic aspects of such an application. Waste minimization in electroplating plants can be classified into two categories: recycling and source reduction. Generally, source reduction takes priority beforethe other and is the most economic tool for waste minimization. Reduction of spent cleaning solutions and drag-out minimization are two major tasks, in which 86% and 60%. respectively, of the plants reviewed were involved, while 74% of the electroplating plants utilized purification equipment to recycle raw materials. In the electroplating process, some heavy metals and rinse water can be recycled. Most of theplants that were investigated recycle the effluent water to the rinse process for further use. From the results of the case study, the cost of the equipment and the utilization rate of the facilities have greater influence on the net present value (NPV) than other factors. Therefore, if the cost or the utilization rate of the facilities varies, re-evaluation will be needed. [ABSTRACT FROM AUTHOR]

Three cost functions of wastewater treatment plants in industrial districts were analyzed and discussed. From the results, the effluent charge rate can be proposed in order to internalize parts of the external cost of wastewater pollution. The charge base of the effluent charge shall be the total pollutant amounts in the effluent. The charge rate shall be set up according to the results of cost functions for various treatment efficiencies. The marginal cost of NT$790 (US$30.4) per noxiousness unit (F=1,000 m3/day, Q=5,000 noxiousness units/year, treatment efficiency = 90%) was recommended to be the initial charge rate. This cost should be updated regularly and the charge rate should be raised according annually. [ABSTRACT FROM AUTHOR]

Heavy metals were removed from industrial sludge by traditional and microwave-assisted acid extraction approaches. The effects of acid concentration, extraction time, sludge particle size and solid/liquid (S/L) ratio on copper-extraction efficiency were assessed. Leaching with increased acid concentrations increased the yield of heavy metals from the industrial sludge. In microwaveassisted acid extraction, reducing the S/L ratio and sludge particle size increased copperextraction efficiency. These experimental findings indicate that S/L ratio most strongly influenced microwave-assisted acid extraction. Both traditional and microwave-assisted acid extraction demonstrate that sulfuric acid was an effective extractant, and the copper fraction in extracted sludge shifted from being primarily bound to Fe-Mn oxides and organic-matter partition, to being mostly bound to organic matter, remaining as a residue during acid extraction. [ABSTRACT FROM AUTHOR]

Objective: To identify key nursing issues for paediatric patients suspected of severe acute respiratory syndrome (SARS) in relation to the family-centred model of nursing care and to develop a data-based model of paediatric nursing care to be better applied in situations of suspected SARS or where outbreaks of other infectious diseases occur. Methods: This is a retrospective descriptive case series, which analysed the medical and nursing records of all highly-suspected/suspected SARS patients admitted to a major acute hospital in Hong Kong. Key nursing personnel were also interviewed. Results: The study included a total of 17 highly-suspected and 49 suspected SARS paediatric patients (age: 1–16). None of the paediatric patients was eventually diagnosed of SARS. Most cases presented fever (highly-suspected: 76.5%/ suspected: 100%), cough (64.7%/71.4%), nausea and vomiting (35.3%/28.6%). Nursing care was provided to the patients as necessary. Both the children and parents experienced fear of SARS, as well as separation anxiety arisen from hospitalization in a strict isolation setting. Conclusions: Infection control overshadowed the family-centred nursing practices in the management of SARS paediatric patients. A major nursing care issue for SARS paediatric patients was to achieve a careful balance between attending to patients' physical and psychological needs and adhering to the infection control guidelines, while at the same time offering psychological support to family members. The current philosophy and practice of family-centred nursing model neglect the special needs of children with infectious diseases and predominantly apply to children with non-infectious diseases that family visits are allowed and nursing care by parents are encouraged. [ABSTRACT FROM AUTHOR]

This study was conducted to develop a process for coating hydrated iron oxide on the surface of quartz sand to utilize the adsorbent properties of the coating and the filtration properties of the sand. Three coating parameters were investigated: pH, Fe concentration at whichiron oxide was prepared, and the coating temperature. A Scanning Electron Microscope (SEM) and X-Ray Diffractometer (XRD) were used to observe the surface properties of the coated layer. Acid resistance wasused to evaluate the attachment strength of the coated layer. Batch adsorption tests were performed to compare the effects of each coating parameter on the adsorption of heavy metals on the coated layer. Energy Dispersive Analysis of X-ray (EDAX) was used for characterizingmetal adsorption sites on the iron-coated sand. The results indicated that the coated sand had more pores and higher specific surface area because of the attachment of iron oxide. The coated sand producedat higher pH(coating) had better adsorption efficiencies of metals but had worse acid resistance. A high-temperature coating process enhanced the stability of the oxide coatings. Comparing heavy metal removal by adsorption on iron-coated sand and chemical precipitation, adsorption was shown to be capable of removing heavy metalsover a wider pH range and to much lower levels than precipitation. The results from EDAX analysis showed that copper ions were chemisorbed on the surface of iron-coated sand. [ABSTRACT FROM AUTHOR]