DESIGN OF A DIVERSION SYSTEM TO MANAGE THE FIRST FLUSH1

ABSTRACT: To manage the first flush of storm runoff in urbanized areas, a diversion box and detention basin system has been proposed for a new storm sewer system or for retrofitting an existing system. A software package for a personal computer has been developed to facilitate the analysis and design of the system. Hydrographs and pollutographs are generated at the inlet and outlet of the diversion box and the detention basin. The peak outflow and peak pollutant concentrations are compared with the allowable outflow and pollutant concentration for urban stormwater quantity and quality management. The model is developed for both analysis and design purposes.     

Oxygen-enriched air for co-incineration of organic sludges with municipal solid waste: a pilot plant experiment

Pilot-plant experiments were performed to evaluate the effect of oxygen enrichment on the co-incineration of MSW and organic sludge from a wastewater treatment facility. Combustion chamber temperatures, stack gas concentrations, i.e., CO(2) and CO, and the residual oxygen were measured. The maximum ratio of organic sludge waste to total waste input was 30 wt.%. Oxygen-enriched air, 22 vol.% (dry basis) oxygen, was used for stable combustion. As the co-incineration ratio of the sludge increased, the primary and secondary combustion chamber temperatures were decreased to 900 and 750 degrees C, respectively, approximately 100 degrees C below the proper incineration. However, if the supplied air was enriched with 22 vol.% (dry basis) oxygen content, the incinerator temperature was high enough to burn the waste mixture containing 30 wt.% moisture sludge, with an estimated heating value of 6.72 MJ/kg. There are two main benefits of using oxygen enrichment in the co-incineration. First, the sensible heat can be reduced as the quantity of nitrogen in the flue gas will be decreased. Second, the unburned carbon formation is reduced due to the oxygen-enriched burning of the waste, despite an increase in the sludge co-incineration ratio.     

Kinetics of acetyl CoA: Arylamine N‐acetyltransferase from rapid and slow acetylator fish tissues

N‐acetyltransferase (NAT) activity was determined in 100 fish (Oreochromis mossambicus) livers using 2‐aminofluorene and p‐aminobenzoic acid as substrates. Overall, the liver NAT activity of the 50 females was higher than the liver NAT activity of the 50 males. The activities (mean ± SD) of NAT from kidney, blood, intestine, and liver of males was 0.42 ± 0.11, 0.12 ± 0.03, 0.12 ± 0.08, and 1.56 ± 0.54 nmol/min/mg protein for the acetylation of 2‐aminofluorene and 0.36 ± 0.09, 0.09 ± 0.01, 0.11 ± 0.04, and 0.46 ± 0.15 nmol/min/mg protein for the acetylation of p‐aminobenzoic acid. In kidney, blood, intestine, and liver from female fish, the activities obtained were 1.60 ± 0.12, 0.35 ± 0.07, 0.15 ± 0.09, and 1.89 ± 0.50 nmol/min/mg protein for 2‐aminofluorene and 0.95 ± 0.11, 0.27 ± 0.03, 0.13 ± 0.09, and 0.57 ± 0.12nmol/min/mg protein for p‐aminobenzoic acid. Kinetic constants for arylamine N‐acetyltransferase activity in kidney, blood, intestine, and liver from fish with rapid, intermediate, and slow acetylator activity were determined. Apparent K _m and V _max values for 2‐aminofluorene were 5.5 and 7‐fold higher for liver than for the other tissues. Apparent K _m and V _max values for p‐aminobenzoic acid were 3.5 and 4.7‐fold higher for liver than for the other tissues. Based on the 2‐aminofluorene NAT activity of liver, there appears to be a polymorphism in NAT activity with 16 rapid, 28 intermediate, and 56 slow acetylators among the 100 fish assayed. This is the first demonstration of acetyl CoA: arylamine N‐acetyltransferase activity in fresh water fish and could lead to the development of a fish model for monitoring the effect of pollution of water environments on native species.     

Paeonol promotes arylamine N‐acetyltransferase activity in human bladder tumor cells

Paeonol was used to determine effects of arylamine N‐acetyltransferase (NAT) activity in human bladder tumor cells. The NAT activity was measured by high performance liquid chromatography assaying for the amounts of N‐acetyl‐2‐aminofluorene (2‐AAF) and N‐acetyl‐p‐amino‐benzoic acid (N‐Ac‐PABA) and remaining 2‐aminofluorene (2‐AF) and p‐aminobenzoic acid (PABA). The NAT activity in human bladder tumor cells was promoted by paeonol in a dose‐dependent manner, i.e. the higher the concentration of paeonol, the higher the promotion of NAT activity. The data also indicated that paeonol increases the apparent values of K_m and K_max from human bladder tumor cells in cytosols and intact cells. This report is the first demonstration to show paeonol did promote human bladder tumor cell NAT activity.     

Measurement of traffic conflicts

Traditionally road accident statistics are used to assess the level of road safety and evaluate road safety programs. In some cases, the lack of good and reliable accident records have hampered proper analyses. A promising approach that overcomes this problem is the traffic conflict technique which relies on observations of critical traffic situations for safety analysis. However, despite the extent of work undertaken in traffic conflict research, there are still a number of issues on conflict measurement and application that have not been well understood by many safety analysts. This has resulted in a general lack of support for the wider application of the technique in safety analysis. This paper shows that one way of using the traffic conflict technique effectively is to ensure that conflicts are quantitatively defined, objectively measured and suitably applied. Before establishing the proposed framework for conflict analysis, the paper first discusses the problems and weaknesses often associated with conflict studies. Considerations for a conflict study based on the proposed approach are then presented and the case of an expressway merging is used to illustrate the method adopted.     

Degradation of aqueous carbon tetrachloride by nanoscale zerovalent copper on a cation resin

Nanoscale zerovalent copper supported on a cation resin was successfully synthesized to enhance the removal of carbon tetrachloride (CCl(4)) from contaminated water. The use of the cation resin as a support prevents the reduction of surface area due to agglomeration of nanoscale zerovalent copper particles. Moreover, the cation resin recycles the copper ions resulting from the reaction between CCl(4) and Cu(0) by simultaneous ion exchange. The decline in the amount of CCl(4) in aqueous solution results from the combined effects of degradation by nanoscale zerovalent copper and sorption by the cation resin; thus the amount of CCl(4) both in aqueous solution and sorbed onto the resin were measured. The pseudo-first-order rate constant normalized by the surface-area and the mass concentration of nanoscale zerovalent copper (k(SA)) was 2.1+/-0.1 x 10(-2)lh(-1)m(-2), approximately twenty times that of commercial powdered zerovalent copper (0.04 mm). Due to the exchange between Cu(2+) and the strongly acidic ions (H(+) or Na(+)), the pH was between 3 and 4 in unbuffered solution and Cu(2+) at the concentration of less than 0.1 mg l(-1) was measured after the dechlorination reaction. In the above-ground application, resin as a support would facilitate the development of a process that could be designed for convenient emplacement and regeneration of porous reductive medium.     

Effect of flue gas desulfurization (FGD) by-product on water quality at an underground coal mine

In this paper, a field study was carried out to examine the effect of flue gas desulfurization (FGD) by-product on water quality at an underground coal mine in central-eastern Ohio. Flue gas desulfurizalion by-product was injected into the down-dip portions of the Robert-Dawson mine in an attempt to seal major seeps exiting the mine and to coat exposed pyritic surfaces. Immediately following grout injection, significant increases in acidity, iron, aluminum, sulfur, and calcium were observed at most surface and ground water locations near where grouting was carried out. Following this initial flush of elements, concentrations of most constituents have decreased to near pre-grouting levels. Data from the site and geochemical modeling suggest that an increase in water level or rerouting of drainage flow resulted in the dissolution of iron and aluminum sulfate salts and ferrihydrite. Dissolution of the FGD grout material resulted in increases in calcium and sulfate concentrations in the drainage waters. Water within the mine voids was saturated with respect to calcium sulfate and gypsum immediately following grout injection. Based on an analysis of core samples obtained from the site, acid mine drainage (AMD) was in contact with at least some portions of the grout and this resulted in grout weathering. Subsequent transport of calcium and sulfate to the underclay, perhaps by fracture flow, has resulted in the deposition of gypsum and calcium sulfate solids.     

WATER QUALITY MANAGEMENT OF SKUDAI RIVER1

ABSTRACT: Urban runoff as well as industrial and agricultural discharges have seriously affected the water quality of the Skudai River, Malaysia. A water quality model is developed for simulating BOD and oxygen relationship. The simulated values agree relatively well with survey data taken during low flow conditions. Survey and simulated values show that a pollution abatement program is needed to prevent further deterioration of the river from organic discharges. A systems approach, involving complete analysis of water quality models and environmental control procedures, considering various water use patterns, water quality criteria, and waste input, is essential for solution.     

Conceptual frameworks and key questions for assessing the contribution of marine protected areas to shark and ray conservation

Marine protected areas (MPAs) are key tools in addressing the global decline of sharks and rays, and marine parks and shark sanctuaries of various configurations have been established to conserve shark populations. However, assessments of their efficacy are compromised by inconsistent terminology, lack of standardized approaches to assess how MPAs contribute to shark and ray conservation, and ambiguity about how to integrate movement data in assessment processes. We devised a conceptual framework to standardize key terms (e.g., protection, contribution, potential impact, risk, threat) and used the concept of portfolio risk to identify key attributes of sharks and rays (assets), the threats they face (portfolio risk), and the specific role of MPAs in risk mitigation (insurance). Movement data can be integrated into the process by informing risk exposure and mitigation through MPAs. The framework is operationalized by posing 8 key questions that prompt practitioners to consider the assessment scope, MPA type and purpose, range of existing and potential threats, species biology and ecology, and management and operational contexts. Ultimately, MPA contributions to shark and ray conservation differ according to a complex set of human and natural factors and interactions that should be carefully considered in MPA design, implementation, and evaluation.     

Status of Southeast Asia's marine sharks and rays

In Southeast Asia, elasmobranchs are particularly threatened. We synthesized knowledge from the peer-reviewed and gray literature on elasmobranchs in the region, including their fisheries, status, trade, biology, and management. We found that 59% of assessed species are threatened with extinction and 72.5% are in decline; rays were more threatened than sharks. Research and conservation is complicated by the socioeconomic contexts of the countries, geopolitical issues in the South China Sea, and the overcapacity and multispecies nature of fisheries that incidentally capture elasmobranchs. The general paucity of data, funds, personnel, and enforcement hinders management. Reduced capacity in the general fishery sector and marine protected areas of sufficient size (for elasmobranchs and local enforcement capabilities) are among recommendations to strengthen conservation.