Feasibility Testing of Biofiltration Technology for Remediating Air Contaminated by a Boat Manufacturing Facility

ABSTRACT

This research investigated and compared the use of both bench- and pilot-scale biofilters to determine the effectiveness of controlling styrene, methyl ethyl ketone (MEK), and acetone emissions from an industrial gas waste stream. Critical operating parameters, including contaminant loading rate, temperature, and empty bed contact time, were manipulated in both the laboratory and field. At steady-state conditions, the bench and pilot-scale biofilters showed a 99% removal efficiency for styrene when the contaminant loading rate was less than 50 g m^-3hr^-1 and 40 g m^-3hr^-1, respectively. Although few data points were collected in the pilot-scale reactor where the styrene load was greater than 40 g m^-3hr^-1, the total organic contaminant load including both MEK and acetone typically ranged between 50 g m^-3hr^-1 and 80 g m^-3hr^-1. Greater than 99% removal efficiencies were observed for acetone and MEK in the pilot-scale biofilter at all evaluated loading rates. Also studied were biofilter acclimation and re-acclimation periods. In inoculated bench and pilot biofilter systems, microbial acclimation to styrene was achieved in less than five days. In comparison, no MEK degrading microbial inoculum was added, so during the first months of pilot-scale biofilter operation, MEK removal efficiencies lagged behind those noted with styrene.     

1971～200O年间安大略省基拉尼公园里的甲壳类浮游动物群落从酸化水体中得到恢复:pH6作为恢复的目标

尽管大气中SO2- 4的沉降减少,地表水的酸度也因此降低,但尚未记录到广泛的生物从酸化中恢复过来.本文通过考察1971～2000年间加拿大安大略省基拉尼公园的46个湖泊甲壳类浮游动物种的丰富度(物种数目)和组成的时间变化趋势,来估计由于水质有了重大改善即pH现在＞6后湖泊中生物的恢复程度,并与其他两组(从未酸化的湖泊和仍然酸化的湖泊[pH＜6])作比较.在这三组湖泊中,物种丰富度的时间趋势无法加以区别,物种丰富度的变化也不能说明恢复的程度.对比之下,在pH值增加到6以上的湖泊中,其浮游动物群落的组成(以物种多度的多变量指数表征)则有所变化,从"损害"状态返回到了中性湖泊的典型状态.在酸性湖泊也记录到浮游动物组成有某些恢复.虽然仍为酸性,这些湖泊的pH水平已经升高.基拉尼省公园里甲壳类浮游动物恢复的程度和速度为北美和欧洲其他酸化地区的将来预示了光明的前景.     

The use of polymerase chain reaction for the identification of sciaenid eggs

Traditionally, sciaenid eggs have been identified based on morphological characteristics such as size, number of oil globules and/or pigmentation patterns. Identification of sciaenid eggs by these procedures is time consuming and often inaccurate due to considerable egg size overlap among species. The utilization of molecular techniques for the identification of economically important species has become a fundamental component in ecological studies involving fish eggs and larvae. This study reports the development of a series of both multiplex and individual polymerase chain reactions to identify the eggs of 11 sciaenid species commonly found in the Gulf of Mexico and estuaries near Port Aransas and Corpus Christi, TX, USA. Following method development, the discriminatory power of the assay was first determined with samples from adult fish collected from Aransas and Corpus Christi Bays, Galveston Bay and the lower Laguna Madre in northern Mexico. Most (97%) of these fishes were correctly identified to the level of species. To demonstrate the applicability of the assay, wild fish eggs were collected and analyzed from the Aransas Pass tidal inlet from September through December 2005. During this period, the eggs of four target species were positively identified which was in keeping with current knowledge regarding the spawning areas and seasons of these sciaenids based on the presence of mature females, eggs and/or larvae. Future use of this method can provide valuable information to better discriminate spawning sites and seasons of these species.     

Iterating Masuyama’s method to reduce sampling variation

Masuyama in Sankhya 14(3):181–186, 1954 gave a method for addressing the boundary overlap problem that arises when sampling in a delineated study region. Here we propose a general sampling framework that allows one to iterate Masuyama’s method in a way that provides a smaller sampling variance. Results of simulations comparing the proposed method to existing approaches for addressing the boundary overlap problem are given. Variations, including systematic sampling, are also discussed.     

NEW METHODS OF MODELING WATER AVAILABILITY FOR AGRICULTURE UNDER CLIMATE CHANGE: THE U.S. CORNBELT1

ABSTRACT: This paper reports on new methods of linking climate change scenarios with hydrologic, agricultural an water planning models to study future water availability for agriculture, an essential element of sustainability. The study is based on the integration of models of water supply and demand, and of crop growth and irrigation management. Consistent modeling assumptions, available databases, and scenario simulations are used to capture a range of possible future conditions. The linked models include WATBAL for water supply; CERES, SOYGRO, and CROPWAT for crop and irrigation modeling; and WEAP for water demand forecasting, planning and evaluation. These models are applied to the U.S. Cornbelt using forecasts of climate change, agricultural production, population and GDP growth. Results suggest that, at least in the near term, the relative abundance of water for agriculture can be maintained under climate change conditions. However, increased water demands from urban growth, increases in reservoir evaporation and increases in crop consumptive use must be accommodated by timely improvements in crop, irrigation and drainage technology, water management, and institutions. These improvements are likely to require substantial resources and expertise. In the highly irrigated basins of the region, irrigation demand greatly exceeds industrial and municipal demands. When improvements in irrigation efficiency are tested, these basins respond by reducing demand and lessening environmental stress with an improvement in system reliability, effects particularly evident under a high technology scenario. Rain-fed lands in the Cornbelt are not forced to invest in irrigation, but there is some concern about increased water-logging during the spring and consequent required increased investment in agricultural drainage. One major water region in the Cornbelt also provides a useful caveat: change will not necessarily be continuous and monotonic. Under one GCM scenario for the 2010s, the region shows a significant decrease in system reliability, while the scenario for the 2020s shows an increase.     

Alternative prey and the dynamics of intraguild predation: theoretical perspectives

A rich body of theoretical literature now exists focused on the three-species module of intraguild predation (IGP), in which a top predator both attacks and competes with an intermediate predator. Simple models of intraguild predation are often unstable, either because one consumer is excluded, or because sustained oscillations emerge from long feedback loops. Yet, many natural IGP systems robustly persist. Standard models of intraguild predation simplify natural systems in crucial ways that could influence persistence; in particular, many empirical IGP systems are embedded in communities with alternative prey species. We briefly review the key conclusions of standard three-species IGP theory, and then present results of theoretical explorations of how alternative prey can influence the persistence and stability of a focal intraguild predation interaction.     

EFFECTIVENESS OF WASTE MINIMIZATION PROJECTS IN REDUCING WATER DEMAND BY UK INDUSTRY1

ABSTRACT: There is growing interest in managing water demand in the UK. A series of waste minimization clubs have been set up within the country and this paper identifies the effectiveness of these clubs in reducing the demand for water within industry. Membership of these clubs is voluntary and the only incentive for industry to reduce water consumption, and consequently the production of effluent, is the almost immediate financial saving made by the company, often achieved by accounting for the water consumption and loss within site from the point of input from the water supplier to output in the form of effluent. On average, companies are able to reduce water consumption by up to 30 percent. If the entire industrial sector within the UK were to achieve this degree of savings, it is possible that approximately 1300Ml/d could be saved.     

Score averaging for alien species risk assessment: a probabilistic alternative

In many biological risk assessment problems and specifically those involving invasive alien species and quarantine pests, ordinal scoring systems are used as a basis for risk quantification. Frequently, the problem is disaggregated into a series of components to allow a more structured and systematic evaluation. Each component is then scored and an overall measure of risk calculated from the set of scores. No satisfactory method exists to compute an overall measure of risk and most practitioners have resorted to score-averaging. Here we describe an approach involving the linear mapping of scores to notional probabilities to allow the use of conditional probability to derive an overall measure. Initial results give better discrimination between high and low risk cases and closer correspondence with independent expert judgement than does score-averaging.     

RNA:DNA ratio during the critical period and early larval growth of the red drum Sciaenops ocellatus

Eggs from two separate spawning stocks of the red drum Sciaenops ocellatus (Linnaeus) were hatched, and the larvae were reared in the laboratory for 2 wk under closely controlled conditions. Total RNA, DNA, and soluble protein were measured in each population daily in triplicate pooled samples of larvae from each of three tanks. Growth rate in mm d^-1 was determined for each population at 2 d intervals. Growth rate explained 72 and 95% of the variation in the RNA:DNA ratios of the two populations individually, and 86% of the variation in the RNA:DNA ratio when data from the two populations were combined. The RNA:DNA ratio appeared to be most effective as an indicator of growth in rapidly growing larvae, and to lose some resolution when growth was intermittent. The rates of deposition of RNA, DNA, and protein into tissue were all highly correlated with growth rate and with each other. Mean population RNA:DNA ratios of red drum yolk-sac larvae decreased from Day 1 post-hatch until larvae initiated successful feeding behavior, and then increased steadily throghout the remainder of the experimental period. This pattern of change in the RNA:DNA ratios during the yolk-sac stage appears to be an intrinsic developmental pattern of red drum ontogeny. The lowest values for the RNA:DNA ratio were observed just prior to the initiation of feeding or during the critical period, indicating that red drum larvae experience a decrease in capacity for protein synthesis as they initiate feeding. Intrinsic variation in the RNA:DNA ratio during development suggests that caution be used when comparing the RNA:DNA ratios of yolk-sac larvae to a critical ratio calculated from Buckley's general model.     

Data requirements of GREAT-ER: Modelling and validation using LAS in four UK catchments

Higher-tier environmental risk assessments on “down-the-drain” chemicals in river networks can be conducted using models such as GREAT-ER (Geography-referenced Regional Exposure Assessment Tool for European Rivers). It is important these models are evaluated and their sensitivities to input variables understood. This study had two primary objectives: evaluate GREAT-ER model performance, comparing simulated modelled predictions for LAS (linear alkylbenzene sulphonate) with measured concentrations, for four rivers in the UK, and investigate model sensitivity to input variables. We demonstrate that the GREAT-ER model is very sensitive to variability in river discharges. However it is insensitive to the form of distributions used to describe chemical usage and removal rate in sewage treatment plants (STPs). It is concluded that more effort should be directed towards improving empirical estimates of effluent load and reducing uncertainty associated with usage and removal rates in STPs. Simulations could be improved by incorporating the effect of river depth on dissipation rates.