diffusion tube Articles

  • Monitoring of nitrogen dioxide in and around an Oman liquid natural gas plant using passive diffusion tubes: exposure and ISCST model study

    Recognising that nitrogen dioxide (NO2) may be the primary air contaminant released from an Oman liquid natural gas (LNG) plant, this study has been designed with emphasis on this pollutant. The dispersion of NO2 was examined and compared with measured data during the period from 23 February to 1 April 2001. The observed concentrations were obtained by using NO2 ...


    By Inderscience Publishers

  • Assessment of diffuser pressure loss on WWTPs in Baden-Württemberg

    Aeration of activated sludge is a critical treatment step for the operation of activated sludge plants. To achieve a cost effective treatment process, assessing and benchmarking of aeration system performance are important measures. A simple means of gauging the relative condition of a fine bubble diffused aeration system is to evaluate the pressure loss of the diffusers as oxygen transfer tests ...


    By IWA Publishing

  • Sampling trace-level organic solutes with polymeric tubing. Part 2. Dynamic studies

    Parker and Ranney present the results of laboratory tests focused on investigation the potential positive or negative biases associated with using polymetric tubing to collect groundwater samples. This paper, the second in a series, focuses on the effects under dynamic (i.e., pumping) conditions. They show that negative biases are a function of the plymer material, the hydrophobicity of the ...


    By Solinst Canada Ltd.

  • Knotted in-tube and mini-column solid phase extraction of polycyclic aromatic compounds and nitroaromatics from aqueous samples for their determination by gas chromatography–mass spectrometry

    The selectivity of in-tube extraction by PTFE tubing vis-a-vis mini-column SPE has been evaluated for preconcentration and cleanup of PACs in their natural matrix, and has been found to effectively remove many polar analytes such as nitrogen containing aromatic heterocyclic compounds, anilines, phenols and certain organophosphorus pesticides. Knitting of tubings created a secondary flow pattern ...


    By Inderscience Publishers

  • Prairie farm rehabilitation administration paper

    The aeration efficiency of two types of aeration devices, air injection and mechanical surface aerators was evaluated in farm dugouts in the Peace River Region of Alberta. The air injection systems were tested using three types of diffusers; open-ended tubing, linear fine bubble diffusers and a membrane diffuser. Our results indicate that without aeration, anoxia can develop in the bottom of ...


    By EP Aeration

  • Lessons Learned from Startup of the Largest Tertiary Ballasted Settling System in the U.S.

     ABSTRACT In February 2005, Onondaga County (County) began operating a 492,000 m3/day (130 mgd) peak flow ballasted settling system at the Metropolitan Syracuse Wastewater Treatment Plant (Metro WWTP) for tertiary phosphorus removal. The system was designed to reduce the total phosphorus concentration in the BAF effluent from 0.75 to 0.12 milligrams per liter (mg/L). This ...

  • Residential Vapor Intrusion Evaluation: Long Duration Passive Sampling v. Short Duration Active Sampling

    Abstract Sampling indoor air for potential vapor intrusion impacts using current standard 24-hour sample collection methods may not adequately account for temporal variability and detect contamination best represented by long-term sampling periods. Mr. Henry Schuver of the U.S. Environmental Protection Agency (EPA) Office of Solid Waste staled at the September 2007 Air & Waste Management ...

  • Evaluating Leaks in a Soil Gas Sampling Train

    ABSTRACT The current advisory for active soil gas investigations in California requires leak tests to be conducted at eveiy soil gas probe while taking a sample. A leak may allow ambient ak into the sample train thus diluting the soil gas and underestimating the results. Also, the leak check compound itself may have impurities thereby contaminating the sample. The advisoiy suggests leak ...


    By Eurofins Air Toxics Inc

  • Fluorescent lighting case study

    Installed Measures: T5 OSRAM Fluorescent Lighting Refurbishment, New diffusers, New T5 vapour proof fittings, CP Electronics microwave absence & daylight detection, new switching arrangements. History: The Alun and Maes Garmon Schools combined is the largest school in Wales. They had a yearly issue with electricity consumption in that when the darker evenings came in and the colder ...


    By Elite Energy

  • A forward tracking scheme for solving radionuclide advective problems in unsaturated porous media

    In this paper we consider the numerical approximation of the problem of radionuclide contaminant transport in unsaturated porous media. The problem is modelled by a system of equations that describes the two-phase water?air flow and the radionuclide transport. We solve numerically the water?air flow equations combining mixed finite elements with a non-oscillatory central finite difference scheme. ...


    By Inderscience Publishers

  • Oxygen, the fix for pond problems

    Aeration of a water feature should have three main considerations. These include preventing thermal stratification, balancing the dissolved oxygen levels throughout the water column from the sludge or benthic layer to the surface and balancing temperature levels throughout the water column. Although oxygen transfer from certain methods may be significant, the greatest amount of oxygenation takes ...


    By EP Aeration

  • TVOC measurement for LEED/green building evaluation

    Total Volatile Organic Compounds (TVOC) may be evaluated when building designers/managers are pursuing the Leadership in Energy and Environmental Design Green Building Rating System for New Construction (LEED-NC) EQ Credit 3.2. The latest LEED-NC guidance document specifies that the maximum allowed concentration of TVOC measured in a building (post construction, pre-occupancy) is 500 µg/m3; the ...


  • Air quality Monitors Track Pollution Hot-Spots

    Situated in the south west of Wales, in a largely rural area bordering the Brecon Beacons, Carmarthenshire’s air quality is predominantly good. However, there are areas of concern where major roads pass through some of the County’s larger towns, including Llanelli, Carmarthen and Llandeilo, where air quality is dominated by the effects of road traffic. The County Council is therefore ...


    By Air Monitors Ltd.

  • Hiden ESPion plasma probe measurements on a hollow-cathode based large-volume plasma source

    Vacuum-based surface engineering and coating processes require plasma sources generating a high charge carrier density in order to achieve enhanced sputter and activation effects. Fraunhofer FEP is providing a hollow-cathode based plasma source, which produces homogeneous large-volume plasmas of up to 1 m3 with maximum plasma densities of more than 1012 cm-3 at chamber pressures between 0.1 and ...


    By Hiden Analytical

  • What Are Solar Buildings Technologies?

    Solar buildings technologies use the non-polluting power of the sun to help heat, cool, and power our buildings. Because buildings now use one-third of the energy currently consumed in this country, the potential markets for using solar buildings technologies in place of conventional ones is substantial. Whether you're a home owner, architect, builder, business owner, or industry or utility ...

  • Ozone Artifacts and Carbonyl Measurements Using Tenax GR, Tenax TA, Carbopack B, and Carbopack X Adsorbents

    INTRODUCTION Sampling of airborne volatile organic compounds (VOCs) using thermally desorbable solid adsorbents has proven its usefulness in many environmental applications and has become a routine technique1 with compelling advantages over canisters, especially when a large sample volume or sample transport is needed.2 Many adsorbents are available, and users are faced with the difficulty of ...


  • ARCO Chemical - Case Study

    Custom Designed Furnace Reclaims $100,000 Condenser PCPC burn-off oven removed 4,240 lbs. of styrene polymer in compliance with local environmental laws. The Problem: ARCO Chemical Company's Beaver Valley plant in Monaca, PA, a manufacturer of styrene-based plastics, was experiencing severe problems and expense with the periodic cleaning of their ...

  • Water Based Damp Course Protection Chemicals: Tech-Dry Building Protection Systems

     Tech-Dry Building Protection Systems Pty Ltd has developed a range of water-based damp course chemicals for the building industry. These water-based formulations have replaced the solvent-based formulations previously used by Tech-Dry. Background Tech-Dry Building Protection Systems Pty Ltd was formed in 1982, and specialises in the development and supply of materials ...


  • Treatability Studies of Anaerobic/Aerobic Tomato-Processing Wastewater Treatment Systems: Pilot vs. Bench

    ABSTRACTTomato-processing wastewaters generated from food-canning industry are typically considered difficult to biodegrade since they contain seed, skin and high particulate and colloidal fractions. A bench-scale and a pilot-scale anaerobic/aerobic system were evaluated and compared for the treatment of high-strength tomato-processing wastewater. The pilot-scale and bench-scale systems had ...

  • AQMesh: a new option for flexible air quality monitoring

    AQMesh has an impressive collection of global users and performance results measuring ambient air quality in applications ranging from traffic planning and urban hotspots to industrial fence line monitoring, building ventilation management, or environmental lobbying. This pole-mounted unit comes with an independent power supply and communications, so offering the possibility of measuring air ...


    By AQMesh

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