Sensory Measurement of Ambient Traffic Odors

Laboratory determinations of ambient traffic odors were conducted in the streets of Stockholm. The measurements were made with a sensory method based on signal detection theory. The occurrence of odors was expressed by an index of detectability (d′) which was compared to the ambient carbon monoxide concentration and the rhythm of the traffic. The results showed that the detection technique employed could well be adjusted to field conditions by use of a mobile odor laboratory. Also, the odor index (d′) was correlated with other parameters in the trafficked environment in the expected way. The odorous emissions are likely to be diluted quickly as distance from the street increases. However, the relevance of the index of detectability as a measure of dose and response needs to be studied further.     

Measurement of Ambient Odors Using Dynamic Forced-Choice Triangle Olfactometer

Certain odor control regulations specify use of the Scentometer for ambient odor measurement. This evaluation is usually performed by a single individual who is surrounded by the odorous environment to be measured. A method is desired where an ambient odor sample can be evaluated by an adequate size panel in an odor-free atmosphere. A dynamic forced-choice triangle olfactometer was designed and constructed to measure ambient odors. Teflon bags of 18 liter capacity collect a sample within 2-3 minutes which includes pre-flushing the bag. The sample is evaluated by a dynamic olfactometer equipped with 5 dilution levels (81×, 27×, 9×, 3× and undiluted sample). Three sniffing ports are provided at each dilution level to present dynamically one diluted odor stimulus and two odor-free air blanks. Each panelist is required to indicate which port contains the odor. Evaluation of one sample is routinely completed by a panel of 9 within less than 15 minutes. The odor threshold value (ED₅₀) for the panel is calculated by use of a simple table derived statistically. No significant loss of odor was observed in sampling and in storage of rendering odors up to 48 hours. Bags were reusable after flushing with odor-free air. Reproducibility of log ED₅₀ values by the same panel was within a σ = 0.10 log₁₀. Agreement in evaluating duplicate field samples by two different panels was within the same limits. Under controlled laboratory conditions, a Scentometer reading of D/T = 2 was equivalent to an ED₅₀ = 4.8; and D/T = 7 was equal to ED₅₀ = 9.5.     

The Economics Of Environmental Quality Measurement

With the increasing public concern over the environment, corporate management is now faced with the problem of first, organizing its efforts to be responsive to the public and legislation, and second, obtaining maximum value for its expenditures. This paper discusses how a firm can approach the problem of deciding when to use environmental consultants and when to perform tasks using an in-house staff organization.     

Odor Threshold Measurement by Dynamic Olfactometry: Significant Operational Variables

Abstract

Combustion flue gases of three different industrial boilers firing miscellaneous fuels were monitored for a twoweek period. Nitric oxide (NO), sulfur dioxide (SO₂), carbon monoxide (CO), carbon dioxide (CO₂), and total hydrocarbons (CxHy) were continuously measured using single-component gas analyzers in parallel with a lowresolution Fourier Transform Infrared (FTIR) gas analyzer. Hydrogen chloride (HCl) was measured continuously using the FTIR analyzer and semi-continuously using a traditional liquid-absorption technique. Nitrous oxide (N₂O), nitrogen dioxide (NO₂), and water vapor (H₂O) were continuously measured using the FTIR analyzer only. Laboratory tests were conducted prior to the field measurements to assess the detection limits of the different measurement methods for each gas component. No significant differences were found between the results of the low-resolution FTIR analyzer and the single-component analyzers or the liquid absorption method.     

制革行业环境影响因素及污染治理措施

按照ISO14001的要求，对制革行业主要环境影响因素进行了识别，并提出了控制这些环境影响因素的具体办法，使环境管理体系和污染防治措施得到有机的结合。     

The Odor Threshold of Phosphine

In the literature for odor threshold, values of phosphine are given which vary between 3 ppm^1,2 and 0.02 ppm.³ According to another paper phosphine is odorless even in concentrations up to 200 ppm.⁴ Since phosphine prepared from metal phosphides is used as a fumigant for foods, feeds, and processed food products, we carried out new investigations to clarify the discrepancy.     

Control of Odors from a Continuous Soap Making Process

Innovations in the use of lung and myocardial tissue in vitro have permitted continuous morphological observation of cells treated with a controlled gaseous environment. The mammalian tissues are covered with a dialysis membrane and cultured in a Rose chamber containing a large gas phase. Test gases can be flushed continuously through two hypodermic needles in the culture chamber wall. Cell movement and morphology have been recorded with time lapse cinematography in chambers containing cells washed from lung airways or organotypic lung cultures. Myocardial cell morphology and beating rate have been analyzed with the aid of a remote TV monitoring system. Histochemical and ultrastructural techniques were also applied. The beating rate of myocardial cells was found to be an objective and convenient endpoint for testing the characteristics of the exposure system. A comparison of the response of cells in the gas phase with that of elements in the fluid phase within the same chamber suggested that this system can serve as a model for evaluating the effect of an increasing diffusion barrier.     

Control of Odors and Aerosols from Spent Grain Dryers

The information contained in this paper is directed to research workers concerned with odor identification and the development of methods for removal of odorous components from hot, moist stack gases and to application engineers faced with the practical problem of selecting effective, yet economical, odor control equipment for industrial operations. The new techniques described here demonstrate the beneficial uses of gas phase reactions as a conditioning step preceding absorption in a chemically reactive solution. Cost comparisons show markedly lower costs for full-scale reactor-absorbers than for gas incinerators for equal contaminant removal. Other methods of removing odors at the source, e.g., injection of ozone, use of nonvolatile oxidizing agents in solution, and adsorption on activated charcoal, were found to be impractical, ineffective, or both. The application of reactor-absorbers to spent grain drying is discussed in detail and reference is made to the use of this technique for other food industry waste treatment processes including rendering and fish and poultry meal production.     

Soil Bed System for Control of Rendering Plant Odors

Biofilter technology has been applied recently to treating rendering odors. Soil beds are one class of biofilter but as yet have not been used for this application. Although wet scrubbers have been a traditional method of odor control, their capital and operating costs are impacting more severely. Soil bed systems are less expensive to install and operate.

A soil bed system was installed at a rendering plant in Arizona and has been in operation since September 1983. The soil bed treats 1100 m³/h (650 cfm) of cooker noncondensables with a surface area of 420 m²(4500 ft²). The pressure drop across the soil bed is 5 cm (2 in.) of water. Odor sensory testing with the MTRI forced-choice triangle dynamic olfactometer indicates an odor removal efficiency of 99.9 percent is obtained with the soil bed. Soil bed odor removal efficiency is equivalent to or superior than that for incineration or scrubbing of high intensity odors from the rendering process. Recent experience during this past winter indicates a soil bed is a viable method for operation in a northern climate with severe winter weather conditions. Also, monitoring of the leachate from a soil bed indicated no contamination.     

Review of Federally Sponsored Research on Diesel Exhaust Odors

The information presented in this paper is directed to persons concerned with control of exhaust odors from diesel-engine-powered vehicles. This paper summarizes projects sponsored by the Environmental Protection Agency (EPA) over the past years in the field of diesel-exhaust odor. These investigations have concentrated on developing measurement methods for quantifying different odor levels, evaluating various odor control methods, and evaluating public opinions of such odors.

A human panel method using odor reference standards has been found suitable to measure these odor levels. In addition to this technique, chemical characterization work has been sponsored under a project jointly sponsored by the Coordinating Research Council and the EPA to isolate and identify those species responsible for the odor.

Knowledge of these odorous compounds and the techniques necessary to isolate them should lead to development of a chemical method to measure this type of odor, in place of human panelists. Such basic information would also lead to developing control techniques to minimize this odor.

Several control techniques were evaluated for diesel exhaust odor. To date, the most effective method is an improved needle injector for use in the Detroit Diesel type E 6V-71 engine commonly used in buses.

Finally, public reaction to diesel-engine-exhaust odor has been measured. It has been found that a systematic relationship exists between increasing public objections and increasing diesel odor intensity.     

An Investigation of Odors and Volatile Organic Compounds Released during Composting

ABSTRACT

The emissions of odors and volatile organic compounds produced from a commercial composting operation have been studied using a laboratory-scale composting system. The composting activity of a typical commercial compost feed was followed by monitoring the composting temperature, as well as the respiratory rate. Using a controlled aeration system, the gaseous volatiles produced were tested for odors using the "dilution-to-threshold" method, as well as gas composition, as determined by gas chromatography-mass spectrometry.

The results indicated that while there may be a reasonable correlation between the release of volatile organic compounds (VOCs) and odors, care has to be taken when trying to identify offensive odors with specific chemical species. However, the data obtained suggests that offensive odors formed during commercial composting may be due to sulfurous and nitrogenous compounds, although their concentrations in the compost gases may not be very high.

The major release of VOCs occurred during the first two weeks of composting, after which the gaseous releases fell dramatically as the composting process proceeded and temperatures started to fall.     

Degradation Kinetics of Biofilter Media Treating Reduced Sulfur Odors and VOCs

ABSTRACT

A lab-scale study was conducted to determine the rate and extent of decomposition of three biofilter media materials—compost, hog fuel, and a mixture of the two in 1:1 ratio—used in biofiltration applied to removal of reduced sulfur odorous compounds from pulp mill air emissions. The rate of carbon mineralization, as a measure of biofilter media degradation, was determined by monitoring respiratory CO₂ evolution and measuring the changes in carbon and nitrogen fractions of the biofilter materials over a period of 127 days. Both ambient air and air containing reduced sulfur (RS) compounds were used, and the results were compared. After 127 days of incubation with ambient air, about 17% of the media carbon was evolved as CO₂ from compost as compared to 6 and 12% from hog fuel and the mixture, respectively. The decomposition showed sequential breakdown of carbon moieties, and three distinct stages were observed for each of the biofilter media. First-order rate kinetics were used to describe the decomposition stages. Decomposition rates in the initial stages were at least twice those of the following stages. Carbon mineralization showed close dependence on the C/N ratio of the biofilter material. Media decomposition was enhanced in the presence of RS gases as a result of increased bioactivity by sulfur-oxidizing bacteria and other microorganisms, thus reducing the media half-life by more than 50%. At higher concentrations of RS gases, the CO₂ evolution rates were proportionally lower than those at the low concentrations because of the limited acid buffering capacity of the biofilter materials.     

The Past,Present, and Future of Environmental Insurance Including a Case Study of MTBE Litigation

Environmental insurance policies and the success of claims brought under them depend upon the intersection of both the legal and technical issues involved. The evolution of environmental insurance policies, from their origin in the Commercial General Liability policies up to the creation of new insurance products designed to cover specifically environmental concerns are addressed in this work. Both scientists and attorneys will have to develop a fuller understanding of environmental damage and assessments. The intent of this article is to provide a starting point for members of both disciplines in their quest for a fuller understanding of the legal and technical issues involved in environmental claims.     

The Past,Present, and Future of Environmental Insurance Including a Case Study of MTBE Litigation

Environmental insurance policies and the success of claims brought under them depend upon the intersection of both the legal and technical issues involved. The evolution of environmental insurance policies, from their origin in the Commercial General Liability policies up to the creation of new insurance products designed to cover specifically environmental concerns are addressed in this work. Both scientists and attorneys will have to develop a fuller understanding of environmental damage and assessments. The intent of this article is to provide a starting point for members of both disciplines in their quest for a fuller understanding of the legal and technical issues involved in environmental claims.     

Removal of Exhaust Odors from Solvent Extraction Operation by Activated Charcoal Adsorption

This report, published as Technical Data Sheet No. 1 of the Air Pollution Control Association’s TA-7 Odor and Gas Treatment Committee, has been in the 14 step approval procedure of APCA’s Technical Council and Board of Directors for over two years. The Committee is attempting a new departure in this report which would be reflected in future reports. It has attempted to write a brief summary of a typical case history in a concise fashion on one sheet. Comments made by members of the Technical Council and Board of Directors were considered in the preparation of the final report. It is now published as representing the “best thinking of the Association.”     

餐厨垃圾两相厌氧发酵产甲烷相恶臭排放规律

为了研究餐厨垃圾两相厌氧发酵产甲烷相恶臭排放规律,在中温（35℃）条件下,以餐厨垃圾为发酵底物进行中试规模的两相连续式厌氧发酵试验,并对一个周期内不同时间段产甲烷相产生的气体进行采样,分析其臭气浓度和物质浓度,结合各组分的阈稀释倍数,筛选出主要的恶臭污染物。结果表明,在发酵系统稳定运行阶段,产甲烷相产生的臭气浓度较大,都在23万以上;产甲烷相产生的恶臭物质主要包括硫化物、萜烯类、含氧类和芳烃类四类化合物,其中质量浓度最高的恶臭物质是硫化氢,超过了150 mg/m3;产甲烷相的主要致臭物质是硫化物,其中贡献最大的是硫化氢,其阈稀释倍数都在26万以上,其次为乙硫醇﹥甲硫醇﹥乙硫醚,这3种物质的阈稀释倍数都在4 000以上;除了这4种硫化物,丁醛对恶臭的贡献也比较大,其阈稀释倍数也在4 000以上。     

苯胺生物降解极限的研究

介绍了有机物生物降解极限浓度的理论,推导得到了极限浓度的计算公式。以苯胺为目标有机物,利用经过驯化的活性污泥,通过测定其生物降解动力学参数值Ks、μmax、qmax、Ymax等计算得到了其生物降解极限质量浓度为0．025mg／L,并通过摇床试验对极限浓度进行了验证。研究表明,作为微生物生长的唯一碳源和能源,有机物生物降解存在极限浓度。