Paul Henshaw

Biological conversion of hydrogen sulphide to elemental sulphur in a fixed-film continuous flow photo-reactor.

The green sulphur bacterium Chlorobium thiosulfutophilum was used to remove hydrogen sulphide from synthetic industrial wastewater and convert it to elemental sulphur in a fixed-film continuous-flow photosynthetic bioreactor. Twenty 150 mm x 3 mm ID Tygon tubes formed the active part of the reactor resulting in a total volume of 21.2 mL. Seven steady states were achieved under different experimental conditions using this tubular photo-reactor. Sulphide loading rates ranged from 111 to 328 mg/hL under influent flowrates of 9.0-42.4 mL/h and hydraulic retention times of 0.50-2.35 h. The irradiance at the reactor surface averaged 25.4 W/m2. The sulphide removal rates were found to be 82-100% and elemental sulphur recovery rates were found to be 75-95%. The maximum sustainable sulphide loading rate was found to be 286 mg/h L, which is 2.5 times higher than the previous reported highest value. Sulphide loading rate was found to be the function of radiant flux per unit reactor volume and the bacteriochlorophyll concentration as expressed by the van Niel curve.

Effect of tube size on performance of a fixed-film tubular bioreactor for conversion of hydrogen sulfide to elemental sulfur

A fixed-film continuous-flow photobioreactor was used for the removal of hydrogen sulfide from synthetic industrial wastewater and conversion of it to elemental sulfur using sixteen 150 mm length Tygon tubes as the active part of the reactor. Three different tube sizes (internal diameters (ID) 6.4, 3.2, and 1.6mm) were used to investigate the effect of tube size on reactor performance. The reactor with 1.6mm tube attained a higher sulfide loading (1451 mg/Lh) than previously reported in the literature. High bacterial concentration, light to volume ratio and intimate contact between attached bacteria and influent sulfide resulted in excellent performance of the 1.6mm tube reactor.

A fluctuating plume dispersion model for the prediction of odour-impact frequencies from continuous stationary sources

A fluctuating plume dispersion model has been developed to facilitate the prediction of odour-impact frequencies in the communities surrounding elevated point sources. The model was used to predict the frequencies of occurrence of odours of various magnitudes for 1 h periods. In addition, the model predicted the maximum odour level. The model was tested with an extensive set of data collected in the residential areas surrounding the paint shop of an automotive assembly plant. Most of the perceived odours in the vicinity of the 64, 46 m high stacks ranged between 2 and 7 odour units and generally persisted for less than 30 s. Ninety-eight different field determinations of odour impact frequencies within 1 km of the plant were conducted during the course of the study. To simplify evaluation, the frequencies of occurrence of different odour levels were summed to give the total frequency of occurrence of all readily detectable (>2 OU) odours. The model provided excellent simulation of the total frequencies of occurrence where the odour was frequent (i.e. readily detectable more than 30% of the time). At lower frequencies of occurrence the model prediction was poor. The stability class did not seem to affect the models ability to predict field frequency values. However, the model provided excellent predictions of the maximum odour levels without being sensitive to either stability class or distance from the source. Ninety-five percent of the predicted maximum values were within a factor of two of the measured field maximum values.

Extraction of elemental sulfur from an aqueous suspension for analysis by high-performance liquid chromatography.

A bioreactor is being developed that produces elemental sulfur suspended in aqueous bioreactor contents. The concentration of elemental sulfur must be measured explicitly in order to study the efficiency of the conversion of sulfide to elemental sulfur. Extracting the sample with ethanol gave erroneous results when sulfide was present in solution. The extraction of aqueous elemental sulfur into petroleum ether prior to colorimetric determination was tested. When the aqueous matrix was simply deionized water, the extraction was poor. The development of a method of extraction of the sulfur into chloroform prior to quantification by high-performance liquid chromatography is described. The efficiency of the extraction was found to be greater than 90% in all matrixes tested and linear for aqueous elemental sulfur concentrations up to 200 mg/L.

Automotive coatings with improved environmental performance

The automotive coating processes contribute significantly to the environmental burden compared to other stages of vehicle manufacturing. Efforts are being made to reduce this impact through legislation, resulting in the introduction of new coating formulations and application technologies. Water‐borne, powder and UV‐cured coatings are seen as alternatives to solvent‐borne coatings. It is not clear which type of coating is superior in terms of impacts on the environment. This paper discusses the stages involved in the automotive paint application phase, together with materials involved. Next, the composition and properties of water‐borne coatings are discussed briefly. A summary of developments in powder coatings and research related to their properties and application follows. Finally, emphasis is placed on life cycle assessment (LCA) studies conducted to identify and quantify the environmental impacts and trade‐offs in the use of alternative coatings.

PREMIXED AMMONIA-METHANE-AIR COMBUSTION

ABSTRACT The burning velocity and combustion products of premixed ammonia-methane-air flames at room temperature and pressure were measured using an adiabatic flat flame burner, and also simulated using CHEMKIN, for equivalence ratios of approximately 0.5 to 1.5 and for ammonia concentrations of 0% to 5% by volume in the fuel. Concentrations of NO, NO2 and CO were quantified using an electrochemical gas analyzer, while ammonia concentration was measured by wet chemical analysis. The measured burning velocities agreed well with the simulated results. The addition of 4% ammonia resulted in a 10% to 20% decrease in burning velocities. Both simulations and experiments showed that adding ammonia to methane-air mixtures results in an increase in NO concentrations, especially at stoichiometric composition, and a minimal effect on CO formation. Near the flammability limits, ammonia of less than 0.1% of the incoming amount broke through the flame.

The effects of basecoat bell application parameters on elements of appearance for an automotive coatings process

This research investigated the effects of basecoat (BC) bell application parameters on the appearance of automotive vehicles. A full factorial two-level DOE matrix was created to test the impact of four BC bell zone variables on appearance: flow rate, shaping air, voltage, and bell speed. Paint age was a covariate in the analysis. Panels were sprayed with waterborne BC followed by solventborne clearcoat and cured vertically at 144°C. The appearance was characterized by measuring the DOI, surface waviness, and multiangle color. Flow rate, bell speed, and shaping air were found to have the most impact on surface waviness. In addition, four interactive effects were also found to be significant. Three of these interactive effects included flow rate in combination with the other parameters. The results of this study indicate that particle size and fluid atomization play a key role in paint appearance. Decreasing the flow rate and/or increasing bell speed lead to a smoother finish, but are also correlated to a darker appearance at near specular angles, whereas the opposite is true at far specular angles.

Occurrence of Aluminum, Lead, and Trihalomethanes in Drinking Water from the Great Lakes

Abstract Existing data on the concentrations of aluminum, lead, and total trihalomethanes in raw lake/river water and treated drinking waters were collected for six cities in the Great Lakes basin. These values are compared to existing goals and standards for drinking water quality. Two communities have often exceeded the WHO drinking water guideline for aluminum of 200 μg/L, and all communities exceed 10 μg/L most of the time, even in the raw water. Raw water lead concentrations for five of the communities studied were

Effect of a Triangular Rib on a Flat Plate Boundary Layer

The flow structure downstream of a triangular rib over a thin plate placed in a wind tunnel was experimentally investigated using a boundary layer hotwire anemometer. Flow and boundary layer characteristics, such as thickness, shape, and turbulence parameters, were studied at different freestream velocities and streamwise locations corresponding to ReX of 1.7 × 104–2.8 × 105 for plates without and with a leading edge rib. It was found that the boundary layer of the flow over a ribbed wall was 3–3.5 times thicker and had higher turbulence intensity and smaller turbulence length scales compared to its smooth wall counterpart.

Enhancing Smart Grid realisation with accurate prediction of photovoltaic performance based on weather forecast

The energy conversion efficiency of photovoltaic (PV) panels depends on solar irradiance and cell temperature. The cell temperature is affected by ambient and sky temperature, wind speed and direction, in addition to solar irradiance. This study summarises relevant relationships in the literature and describes a method of calculating cell temperature and efficiency, based only on field-measured solar irradiance, ambient temperature and wind speed. These equations have been applied to a 500 kW PV site on a typical spring day and all results were within 1.6% of measured values, with an average error of 0.05%. This provides a predictive capability for solar PV to be efficiently integrated into a Smart Grid.