Ammonia emissions from a representative in-use fleet of light and medium-duty vehicles in the California South Coast Air Basin

We used Fourier Transform Infrared Spectroscopy (FTIR) to measure tailpipe ammonia emissions from a representative fleet of 41 light and medium-duty vehicles recruited in the California South Coast Air Basin. A total of 121 chassis dynamometer emissions tests were conducted on these vehicles and the test results were examined to determine the effects of several key variables on ammonia emissions. Variables included vehicle type, driving cycle, emissions technology, ammonia precursor emissions (i.e. CO and NOx) and odometer readings/model year as a proxy for catalyst age. The mean ammonia emissions factor was 46 mg km^?1 (σ = 48 mg km^?1) for the vehicle fleet. Average emission factors for specific vehicle groups are also reported in this study. Results of this study suggest vehicles with the highest ammonia emission rates possess the following characteristics: medium-duty vehicles, older emissions technologies, mid-range odometer readings, and higher CO emissions. In addition, vehicles subjected to aggressive driving conditions are likely to be higher ammonia emitters. Since the vehicles we studied were representative of recent model year vehicles and technologies in urban airsheds, the results of our study will be useful for developing ammonia emissions inventories in Los Angeles and other urban areas where California-certified vehicles are driven. However, efforts should also be made to continue emissions testing on in-use vehicles to ensure greater confidence in the ammonia emission factors reported here.     

RCRA Cleanup Reforms

The Environmental Protection Agency's (EPA's) administrative reforms offer results‐oriented cleanup guidance that emphasizes flexibility and practical approaches. © 2001 John Wiley & Sons, Inc.     

Sponge burrowing: Fine structure of Cliona lampa penetrating calcareous substrata

Cliona lampa Laubenfels (Porifera: Hadromerida), a common burrowing organism in Bermuda, has been used to study the method of sponge penetration into calcareous objects. To progress beyond the results obtained by previous authors, electron-microscope techniques, in addition to light-microscope observations, were employed. Burrowing patterns, fine structure of the tissue-substratum interface and of calcareous fragments removed by sponge activity are described on the basis of scanning electron microscopy. Cell types and cytological features have been identified by light and transmission electron microscope. One cell type of archeocyte origin is demonstrated; it carves out chips of calcium carbonate (and conchiolin) by means of filopodial extensions and etching secretions. The cells undergo plasmolysis during this process; the substratum chips are expelled through the exhalent canal system. It is calculated that only 2 to 3% of the eroded material is removed in solution.Supported by Smithsonian Research Foundation Fund 426242. Contribution No. 574, Bermuda Biological Station.     

Performance of an integrated system combining microalgae and vertical flow constructed wetlands for urban wastewater treatment

Environmental Science and Pollution Research - The present study investigated the performance of an integrated system, combining the sequential use of microalgae (MA) and vertical flow constructed...     

Improving nutrient removal while reducing energy use at three Swiss WWTPs using advanced control

Aeration consumes about 60% of the total energy use of a wastewater treatment plant (WWTP) and therefore is a major contributor to its carbon footprint. Introducing advanced process control can help plants to reduce their carbon footprint and at the same time improve effluent quality through making available unused capacity for denitrification, if the ammonia concentration is below a certain set-point. Monitoring and control concepts are cost-saving alternatives to the extension of reactor volume. However, they also involve the risk of violation of the effluent limits due to measuring errors, unsuitable control concepts or inadequate implementation of the monitoring and control system. Dynamic simulation is a suitable tool to analyze the plant and to design tailored measuring and control systems. During this work, extensive data collection, modeling and full-scale implementation of aeration control algorithms were carried out at three conventional activated sludge plants with fixed pre-denitrification and nitrification reactor zones. Full-scale energy savings in the range of 16-20% could be achieved together with an increase of total nitrogen removal of 40%.     

Black carbon emissions in gasoline vehicle exhaust: A measurement and instrument comparison

A pilot study was conducted to evaluate the performance and agreement of several commercially available black carbon (BC) measurement instruments, when applied to the quantification of BC in light-duty vehicle (LDV) exhaust. Samples from six vehicles, three fuels, and three driving cycles were used. The pilot study included determinations of the method detection limit (MDL) and repeatability. With respect to the MDL, the real-time instruments outperformed the time-integrated instruments, with MDL = 0.12 mg/mi for the AE51 Aethalometer, and 0.15 mg/mi for the Micro Soot Sensor (MSS), versus 0.38 mg/mi for the IMPROVE_A thermal/optical method, and 0.35 mg/mi for the OT21_T Optical Transmissometer. The real-time instruments had repeatability values ranging from 30% to 35%, which are somewhat better than those of the time-integrated instruments (40–41%). These results suggest that, despite being less resource intensive, real-time methods can be equivalent or superior to time-integrated methods in terms of sensitivity and repeatability. BC mass data, from the photoacoustic and light attenuation instruments, were compared against same-test EC data, determined using the IMPROVE_A method. The MSS BC data was well correlated with EC, with R ² = 0.85 for the composite results and R² = 0.86 for the phase-by-phase (PBP) results. The correlation of BC, by the AE51, AE22, and OT21_T, with EC was moderate to weak. The weaker correlation was driven by the inclusion of US06 test data in the linear regression analysis. We hypothesize that test-cycle-dependent BC:EC ratios are due to the different physicochemical properties of particulate matter (PM) in US06 and Federal Test Procedure (FTP) tests. Correlation amongst the real-time MSS, PASS-1, AE51, and AE22 instruments was excellent (R² = 0.83–0.95), below 1 mg/mi levels. In the process of investigating these BC instruments, we learned that BC emissions at sub-1 mg/mi levels can be measured and are achievable by current-generation gasoline engines.

Implications: Most comparison studies of black carbon (BC) measurement methods were carried out in the ambient air. This study assesses the agreement among various BC measurement instrument in emissions from light-duty gasoline vehicles (LDGVs) on standard test cycles, and evaluates applicability of these methods under various fuel types, driving cycles, and engine combustion technologies. This research helps to fill in the knowledge gap of BC method standardization as stated in the U.S. Environmental Protection Agency (EPA) 2011 Report to Congress on Black Carbon, and these results demonstrate the feasibility of quantification of BC at the 1 mg/mi PM standard in California Low Emission Vehicle III regulations.     

Resin embedments of quantitative meiofauna samples for ecological and structural studies — Description and application

In enumerating data for systematic and ecological studies on meiofauna, an unfortunate diversification exists in the methods used for observation, identification, preservation and curatorial treatment of various taxa. The application of transmission electron microscopy resin embedment techniques to whole, quantitative, extracted meiofauna samples is described here as a new method, which overcomes most of these problems. Slide-shaped resin blocks are produced by this method; they contain the mass-embedded meiofauna on one side and sand from the sample site on the other side; the latter can be used in studying sand-grain epigrowth of Protista, Fungi and Monera. Examples for the applicability of these slides to various meiobenthic studies are given for most taxa, but especially for Turbellaria, Annelida and Mystacocarida. Using this resin-slide technique, whole quantitative transects can be deposited as “ecotype material” in museums.     

Teil V: Das Umweltinformationssystem der Universität Osnabrück

The basis for the first energy and flow analysis of the University of Osnabrück and the resulting ecobalance was an extensive data collection, preparation and processing. To simplify drawing up the balance in the following years and to facilitate an eco-controlling based on this data, a concept for a University’s Environmental Information System (EIS) was developed. It consists of three parts: the operative level includes the data bases of the individual administrative departments; at the central data base level, the ecobalance and the environmental characteristic values are computed; and the processing and presentational level serves as an interface between the data and users. The implementation of the EIS is intended within the framework of the general Management Information System, the development of which was started in 1998.