Odor Treatment Research Articles

정화조 발생 악취저감을 위한 전기화학 산화시스템의 적용에서 전극소재의 영향평가

정화조 발생 악취저감을 위한 전기화학 산화시스템의 적용에서 전극소재의 영향평가

Development and assessment of plant-based synthetic odor baits for surveillance and control of malaria vectors.

BackgroundRecent malaria vector control measures have considerably reduced indoor biting mosquito populations. However, reducing the outdoor biting populations remains a challenge because of the unavailability of appropriate lures to achieve this. This study sought to test the efficacy of plant-based synthetic odor baits in trapping outdoor populations of malaria vectors.Methodology and Principal FindingThree plant-based lures ((E)-linalool oxide [LO], (E)-linalool oxide and (E)-β-ocimene [LO + OC], and a six-component blend comprising (E)-linalool oxide, (E)-β-ocimene, hexanal, β-pinene, limonene, and (E)-β-farnesene [Blend C]), were tested alongside an animal/human-based synthetic lure (comprising heptanal, octanal, nonanal, and decanal [Blend F]) and worn socks in a malaria endemic zone in the western part of Kenya. Mosquito Magnet-X (MM-X) and lightless Centre for Disease Control (CDC) light traps were used. Odor-baited traps were compared with traps baited with either solvent alone or solvent + carbon dioxide (controls) for 18 days in a series of randomized incomplete-block designs of days × sites × treatments. The interactive effect of plant and animal/human odor was also tested by combining LO with either Blend F or worn socks. Our results show that irrespective of trap type, traps baited with synthetic plant odors compared favorably to the same traps baited with synthetic animal odors and worn socks in trapping malaria vectors, relative to the controls. Combining LO and worn socks enhanced trap captures of Anopheles species while LO + Blend F recorded reduced trap capture. Carbon dioxide enhanced total trap capture of both plant- and animal/human-derived odors. However, significantly higher proportions of male and engorged female Anopheles gambiae s.l. were caught when the odor treatments did not include carbon dioxide.Conclusion and SignificanceThe results highlight the potential of plant-based odors and specifically linalool oxide, with or without carbon dioxide, for surveillance and mass trapping of malaria vectors.

Evaluating odour control technologies using reliability and sustainability criteria – a case study for water treatment plants

Technologies for odour control have been widely reviewed and their optimal range of application and performance has been clearly established. Selection criteria, mainly driven by process economics, are usually based on the air flow volume, the inlet concentrations and the required removal efficiency. However, these criteria are shifting with social and environmental issues becoming as important as process economics. A methodology is illustrated to quantify sustainability and robustness of odour control technology in the context of odour control at wastewater treatment or water recycling plants. The most commonly used odour abatement techniques (biofiltration, biotrickling filtration, activated carbon adsorption, chemical scrubbing, activated sludge diffusion and biotrickling filtration coupled with activated carbon adsorption) are evaluated in terms of: (1) sustainability, with quantification of process economics, environmental performance and social impact using the sustainability metrics of the Institution of Chemical Engineers; (2) sensitivity towards design and operating parameters like utility prices (energy and labour), inlet odour concentration (H2S) and design safety (gas contact time); (3) robustness, quantifications of operating reliability, with recommendations to improve reliability during their lifespan of operations. The results show that the odour treatment technologies with the highest investments presented the lowest operating costs, which means that the net present value (NPV) should be used as a selection criterion rather than investment costs. Economies of scale are more important in biotechniques (biofiltration and biotrickling filtration) as, at increased airflows, their reduction in overall costs over 20 years (NPV20) is more extreme when compared to the physical/chemical technologies (chemical scrubbing and activated carbon filtration). Due to their low NPV and their low environmental impact, activated sludge diffusion and biotrickling filtration are in general the most cost-effective, and probably the technologies to be considered first for odour treatment in a wastewater treatment or water recycling plant. When, in an economical and risk evaluation, the reliability is counted to be as relevant as the overall costs, a hybrid technology (biotrickling filtration with activated carbon polishing) would be comparable to biotrickling filtration and activated sludge diffusion as the most preferred technologies, when all technologies are designed to have a 99% reduction of H2S and a 95% reduction of the odour concentration.

Bio-preservative and Therapeutic Potential of Pediocin: Recent Trends and Future Perspectives

Bacteriocins produced by lactic acid bacteria are of keen interest to the food industry for their bio-preservative potential and antimicrobial properties. The increasing demand for high quality 'safe' foods which are not extensively processed has created a niche for natural food preservatives. The bacteriocins (produced by bacteria) derived their name after the genera that produce them, hence bacteriocins produced by genus Pediococcus are known as Pediocin. Pediocins are antimicrobial peptides which show a strong activity against food spoilage and pathogenic bacteria, also are thermostable in nature as well as stable over a wide range of pH. Pediocin produced by Pediococcus acidilactici, has been generally recognized as safe (GRAS). The current review summarizes about the progress made on the Pediocin research from patent perspective along with the immense potential of these Pediococcus derived bacteriocins not only as antimicrobial, biopreservative and probiotic agents but also for the treatment of cancer, body odors and other health promoting actions. The relevant patents have been listed and briefly analyzed to upgrade and benefit food industries by prolonging the shelf life of various products.

Is H2S a suitable process indicator for odour abatement performance of sewer odours?

Odour abatement units are typically designed and maintained on H(2)S concentrations, but operational failures are reported in terms of overall odour removal, suggesting a wide range of malodorous compounds emitted from sewers that may not be efficiently removed by existing odour abatement processes. Towards providing greater insight into this issue, several activated carbon filters and biofilters treating odorous emissions from sewer systems in Sydney (Australia) were monitored by collecting and analysing gas samples before and after treatment. The monitoring studies were conducted by both olfactometric measurements and gas-chromatography-based chemical analysis. Single H(2)S assessment often failed to indicate the odour abatement performance for treatment systems in the abatement units studied, particularly when the incoming H(2)S concentrations were in the sub-ppm range (i.e. below H(2)S odour threshold). Chemical analysis indicated that some non-H(2)S odorous compounds were not removed efficiently during odour treatment. Additionally, when odour eliminations were correlated with the removal of individual compounds (Pearson's correlations) it was observed that the correlation (with a coefficient of 0.79) was best when the overall removal of all the measured odorous compounds that exceeded their odour threshold values was used for the analysis. These findings may help to further advance the design and operation of odour abatement processes to address the treatment of sewer odour emissions.

Comparative assessment of a biofilter, a biotrickling filter and a hollow fiber membrane bioreactor for odor treatment in wastewater treatment plants

A low abatement efficiency for the hydrophobic fraction of odorous emissions and a high footprint are often pointed out as the major drawbacks of conventional biotechnologies for odor treatment. In this work, two conventional biotechnologies (a compost-based biofilter, BF, and a biotrickling filter, BTF), and a hollow-fiber membrane bioreactor (HF-MBR) were comparatively evaluated in terms of odor abatement potential and pressure drop (ΔP) at empty bed residence times (EBRTs) ranging from 4 to 84 s, during the treatment of methyl-mercaptan, toluene, alpha-pinene and hexane at trace level concentrations (0.75–4.9 mg m−3). High removal efficiencies (RE > 90% regardless of the air pollutant) were recorded in the BF at EBRTs ≥ 8 s, although the high ΔP across the packed bed limited its cost-effective operation to EBRTs > 19 s. A complete methyl-mercaptan, toluene and alpha-pinene removal was recorded in the BTF at EBRTs ≥ 4 s and ΔP lower than 33 mmH2O (∼611 Pa mbed−1), whereas slightly lower REs were observed for hexane (∼88%). The HF-MBR completely removed methyl-mercaptan and toluene at all EBRTs tested, but exhibited an unstable alpha-pinene removal performance as a result of biomass accumulation and a low hexane abatement efficiency. Thus, a periodical membrane-cleaning procedure was required to ensure a steady abatement performance. Finally, a high bacterial diversity was observed in the three bioreactors in spite of the low carbon source spectrum present in the air emission.

The Use of Fungi in Odorous Treatment—A Review

Most odorous compounds are toxic or hazardous for ecological environment and human health. Compare with the physical or chemical methods, the biological technologies can offer a cost effective and environment friendly alternative to odorous control. The microorganisms in the bioreactor were mainly the bacteria. But the removal efficient (RE) of pollutants by bacteria in the conditions of low moisture content and low pH seemed not so excellent. Recently, fungi were found that they could keep high activity and grew better in this condition than bacteria, and some characteristics of fungi were favor to the pollutions degradation, which showed the great potential to treat the hydrophobic compounds of the odors. Some scholars had paid their attentions in this field and did related researches. This review aimed to summarize the studies about the use of fungi in the odorous treatment and insight into the future research and development (R&D) needs of fungi in odorous control.

Study on Treatment of Odor Containing H<sub>2</sub>S and NH<sub>3</sub> by Industrial Scale Bio-Trickling Filters

The treatment of H2S and NH3 odor produced in sewage disposal process was carried out in industrial scale bio-trickling filters filled with different kinds of filler. The processing capacity per unit volume and the processing capacity per unit volume filler on odor removal performance for different bio-trickling filter were investigated. The results demonstrate that there are remarkable differences in deodorization performance between different kinds of bio-trickling filters.

Trapping ofEuropean buprestid beetles in oak forests using visual and olfactory cues

AbstractTrapping approaches developed for the emerald ash borer (EAB),Agrilus planipennisFairmaire (Coleoptera:Buprestidae), were adapted for trapping severalEuropean oak buprestid species. These approaches included the use of natural leaf surfaces as well as green and purple plastic in sticky trap designs. Plastic surfaces were incorporated into novel ‘branch‐trap’ designs that each presented two 5 × 9‐cm2rectangular surfaces on a cardboard structure wrapped around the leaves of a branch. We used visual adultAgrilusdecoys in an attempt to evoke male mating approaches toward the traps. Our first experiment compared the attractiveness of visual characteristics of the surfaces of branch‐traps. The second looked at the effect on trap captures of adding semiochemical lures, including manuka oil, (Z)‐3‐hexen‐1‐ol, and (Z)‐9‐tricosene. In total, 1 962 buprestid specimens including 14 species from the genusAgriluswere caught on 178 traps in a 22‐day time‐span. Overall, the green plastic‐covered branch‐traps significantly out‐performed the other trap designs. We further found that the presence of anEABvisual decoy placed on the trap surface often increased captures on these green traps, but this effect was stronger for certainAgrilusspecies than for others. The visual decoy was particularly important for the most serious pest detected,Agrilus biguttatusFabricius, which was captured 13 times on traps with decoys, but only once without a decoy. There were some small but significant effects of odor treatment on the capture of buprestids of two common species,Agrilus angustulusIlliger andAgrilus sulcicollisLacordaire. There were also 141Elateridae specimens on these traps, which were not influenced by trap type or decoys. The results suggest that small branch‐traps of this nature can provide a useful new tool for monitoring of buprestids, which have the potential to be further optimized with respect to visual and olfactory cues.

Characterization and Selection of Packing Materials for Biofiltration of Rendering Odourous Emissions

Robust and cheap, biofiltration is one of the most used methods for the biological treatment of industrial gaseous odours and VOCs emissions. The chemical, physical and microbial properties, as well as the economical impact of 11 organic and inorganic packing materials potentially suitable for biofiltration, have been investigated in order to select the most relevant for the treatment of rendering gaseous emissions. Fibrous materials such as peat and coconut fibres are predisposed to compaction. Moreover, according to their low expected running period, their implementation remains expensive, such as activated carbon which induce overweening costs (>100,000€ an−1 for the treatment of 40,000 m3 h−1 with a 60-s empty bed gas residence time). Considering economical aspects, physico-chemical and biological properties, pines barks, composted wood mulch and expanded schist seem fit for this application. The performance of these materials was therefore investigated in a pilot-scale study conducted on a rendering site. According to its appropriate pH (8.62) and water-holding capacity (1.41 g g−1) and its highest nutrients content and colonization at the biofilter start-up (93 g of ATP m−3, 29.1013 CFU m−3), composted would mulch show the best odour removal efficiency during the 134 days of operation. Performances ranged between 75 and 93 % for the treatment of odourous inlet load between 1.16 and 10.10 · 106 ouE m−3 h−1 with an empty bed gas residence time of 47 s. However, the pressure drop of the compost bed decreased, suggesting structural changes which may impact the performances in the long term.

Developing of Air Pollution Control Engineering

Air pollution control engineering is a compulsory special course for students whose major is Environmental Engineering. Through leaning this course, the students should know air pollutants and environmental quality standard, air pollution and weather, air diffusion mode and estimation of pollutant concentration, chimney height design, air pollution factors and control principles, basic methods, foundation of dust-cleaning technology, performance of dust-cleaner, mechanic cleaner, wet dust-cleaner, filter cleaner, electric cleaner, adsorption, catalytic transformation, treatment of exhaust gas containing SO2, treatment of exhaust gas containing NOx, treatment of exhaust gas containing fluorine, treatment of organic exhaust gas, treatment of tail gases, treatment of odor. This paper first analyzes the characteristics and probes the problems of this course prior to construction. Then it proposes a developing plan for the course: description of teaching contents prior to construction, aim for this class and construction, improvement of teaching methods and modes, and etc.

Odours in sewer networks: nuisance assessment

As odour nuisance can affect the quality of life, the population is more and more demanding and in many cities sewers are a critical source of odours. Both factors can lead to increasing numbers of complaints due to the odour nuisance perceived by the residents, affecting also the public image of the sewer management companies. Odours associated with sewer networks are very heterogeneous, in as much as the different 'types of odours' encountered are sewer site specific. The state of the art indicates that there are three parameters that play an important role with the nuisance generated by an odour: hedonic odour tone, odour concentration and odour intensity. This paper presents the results of the study on odour nuisance carried out in different points of the sewer network, with the aim to assess the nuisance generated and identify which points of the sewer should be targeted to implement corrective actions. Considering the different parameters assessed, pumping stations have been identified as critical points of odour nuisance in the sewers, being recommended to implement an odour treatment system in order to guarantee the odour comfort of residents.

Topical 15% Zinc Sulfate Solution Is an Effective Therapy for Feet Odor

Background: Feet odor is a common sociomedical problem that affects the feet of human beings of different etiological factors. Multiple modalities of therapy have been used in the treatment of feet odor. Objective: To evaluate the efficacy and safety of topical 15% zinc sulfate solution in the treatment of feet odor. Patients and Methods: This single blind, placebo, controlled therapeutic study was conducted at the Department of Dermatology-Baghdad Teaching Hospital, from March 2010 to July 2011. A total of 108 (88 males and 20 females) patients with feet odor were enrolled and were divided into 2 groups: Group A: treated with 15% zinc sulfate solution. Group B: treated with distilled water as placebo control group. Full history and examination were carried out including all relevant points. Four scoring had been used to assess the severity of odor in patients with bared feet Score 0: no odor, Score 1: mild odor, Score 2: moderate odor and Score 3: severe odor. Zinc sulfate solution 15% was applied to sole and toe webs once daily for two weeks, three times per week for next two weeks and followed by single application weekly as maintenance after clearance of odor for two months. Patients were seen every two weeks to be examined and to score the odor again and to record side effects. Results: Group A: Fifty patients completed the study, their ages ranged from 8 - 68 (33 + 14.5) years, while the duration of the disease ranged from 1 - 180 (7.22 + 38.24) months. The complete clearance of feet odor after two weeks of therapy was 35 (70%) patients which was similar to two months maintenance therapy 35 (70%) and was highly statistically significant (p value = 0.0000001). Group B: Fifty patients received the placebo solution, their ages ranged from 16 - 75 (32.6 + 13.4) years, while the duration of the disease ranged from 1 - 180 (43.7 + 47.65) months. The complete clearance of feet odor was in 1 (2%) patient after two weeks therapy and after two months maintenance therapy. No side effects were recorded. Conclusions: Topical 15% zinc sulfate solution had an effective therapeutic and prophylactic action against feet odor.

Treatment of Odor by a Seashell Biofilter at Lake Wildwood WWTP

Treatment of Odor by a Seashell Biofilter at Lake Wildwood WWTP

Evaluation of the Effectiveness of Five Odor Reducing Agents for Sewer System Odors Using an On-Line Total Reduced Sulfur Analyzer

Sewer odors have been a concern to citizens of the Metropolitan Seoul region, which has installed combined sewer systems (CSSs) in 86% of its area. Although a variety of odorants are released from sewers, volatile sulfur compounds (VSCs) have been recognized as major ones. A number of technologies have been proposed to monitor or control odors from sewers. One of the most popular strategies adopted for the control of sewage odor is by applying a commercial odor-reducing agent into the sewer. In this study, the effectiveness of five different commercial odor-reducing agents (i.e., an odor masking agent, an alkaline solution, two microbial agents, and a chemical oxidant) was evaluated by continuously monitoring VSCs released from the sewer with an on-line total reduced sulfur (TRS) analyzer before and after each agent was sprayed into CSSs at five different locations of the city. In short, when the effectiveness of odor treatment was tested in the sewer system using five commercial odor reducing treatments, only the chemical oxidant was good enough to reduce the odor in terms of TRS levels measured before and after the application (p < 0.01).

An Experimental Study of Social Attraction in Two Species of Storm-Petrel by Acoustic and Olfactory Cues

Abstract. Many birds, notably colonial nesting seabirds, use public information (the visual, auditory, and olfactory presence of breeding conspecifics) when selecting nesting habitat. When colonies are extirpated, social cues that indicate nesting sites' quality are lost. In the Aleutian Islands, Alaska, storm-petrel populations were destroyed by introduced arctic foxes (Alopex lagopus) and have been slow to return after the foxes' eradication. We tested various social-attraction techniques as a method to encourage recolonization of Leach's (Oceanodroma leucorhoa) and Fork-tailed Storm-Petrels (O. furcata) in Ulva Cove at Amatignak, a former fox-farming island. We tested attraction to playback of each species' calls by broadcasting them in various patterns adjacent to a mist net and attraction to their odors with a T-maze design. We combined these two cues to test whether birds were more likely to enter and inhabit artificial burrows depending on playback and odor treatment. Both species of storm-petrel w...

NORMACAT project: normalized closed chamber tests for evaluation of photocatalytic VOC treatment in indoor air and formaldehyde determination

The aims of the NORMACAT project are: to develop tools and unbiased standardized methods to measure the performance and to validate the safety of new materials and systems integrating photocatalysis, to develop new photocatalytic media with higher efficiency and to give recommendations aimed at improving the tested materials and systems. To achieve this objective, it was necessary to design standardized test benches and protocols to assess photocatalytic efficiency of materials or systems used in the treatment of volatile organic compounds (VOCs) and odour under conditions close to applications. The tests are based on the validation of robust analytical methods at the parts per billion by volume level that not only follow the disappearance of the initial VOCs but also identify the secondary species and calculate the mineralization rates. The first results of inter-laboratory closed chamber tests, according to XP B44-013 AFNOR standard, are described. The photocatalytic degradation of mixtures of several defined pollutants under controlled conditions (temperature, relative humidity, initial concentration) was carried out in two independent laboratories with the same photocatalytic device and with various analytical procedures. Comparison of the degradation rate and of the mineralization efficiency allowed the determination of the clean air delivery rate in both cases. Formaldehyde was the only by-product detected during photocatalytic test under standardized experimental conditions. The concentration of transient formaldehyde varied according to the initial VOC concentration. Moreover the photocatalytic reaction rate of formaldehyde in mixture with other pollutants was analysed. It was concluded that formaldehyde concentration did not increase with time. CONCLUSION-PERSPECTIVE: This type of experiment should allow the comparison of the performances of different photoreactors and of photocatalytic media under controlled and reproducible conditions against mixtures of pollutants including formaldehyde.

Water absorption and photocatalytic activity of TiO2 in a scrubber system for odor control at varying pH

The water absorption and photocatalytic activity of TiO2 in a novel scrubber system for odor control using CH3SH gas as target compound was investigated. It was found that the amount of absorbed CH3SH in water increased with increasing initial pH of water, especially in basic water, which was approximately four times than those in acid and neutral water. Adding TiO2 into water had little influence on the dissolved property of CH3SH in water with different pH. TiO2 exhibited excellent photocatalytic activity in the scrubber system for CH3SH removal and reaction solution with high pH facilitated the photocatalytic degradation of CH3SH. In basic TiO2 suspensions, 96.3% of dissolved CH3SH was degraded and the pseudo-first-order kinetic constant was roughly 1.5 and 2.7 times of those obtained in neutral and acid TiO2 suspensions, respectively. Role of TiO2 on CH3SH degradation in water was also discussed. Furthermore, the outlet concentrations of CH3SH all decreased to nearly zero after 60min of UV light irradiation in TiO2 suspensions with different pH. Varieties in the pH of water and TiO2 suspended solution after absorption and degradation process were measured. The absorption capacity of basic water with addition of TiO2 was relatively stable and TiO2 kept high photocatalytic activity for a long time (900min). This study provided helpful information on expanding the photocatalytic scrubber system for practical odor treatment.

Oxidation of CH3SH by in situ generation of ferrate(VI) in aqueous alkaline solution for odour treatment

This study demonstrated a new approach of odorous gas treatment in a wet scrubbing-oxidation system with in situ generation of ferrate(VI), in which gaseous CH3SH can be quickly absorbed by aqueous alkaline solution and rapidly oxidized by liquid ferrate(VI) generated through electrochemical synthesis in situ. In this study, the electrochemical generation of ferrate(VI) in aqueous NaOH solution was studied and the experiments demonstrated that a maximum current efficiency to generate ferrate(VI) occurred at 14M NaOH concentration, while an applied current density of 14.06mAcm−2 was applied. Then the self-decomposition of ferrate(VI) in such strong alkaline solutions was studied, and the results showed that ferrate(VI) behaved more stable in the stronger alkaline solution. Furthermore, the reactivity of ferrate(VI) with CH3SH in this highly-concentrated NaOH solution was investigated under different reaction conditions as the first time. The experimental results confirmed that CH3SH can be fully oxidized by ferrate(VI) to sulphate ion as a final product. The second-order reaction model is suitable to describe the kinetics of CH3SH reaction with ferrate(VI) in the strong alkaline solution. Meanwhile, stoichiometry of ferrate(VI) reaction with CH3SH in aqueous solution was determined with a minimum molar ratio of 2.20:1 (Fe(VI):CH3SH) to destruct CH3SH effectively and a higher molar ratio of 4.53:1 to convert CH3SH to sulphate ion completely. The experiments also demonstrated that the NaOH concentration in aqueous solution would be a key parameter and the best performance of CH3SH removal was achieved at the optimum NaOH concentration of 6M under our experimental conditions due to an optimum balance between the oxidation potential of ferrate(VI) and its generation rate in this wet scrubbing-oxidation system.

PAC Addition on Immersed Ultrafiltration Membrane for the Treatment of Raw Water Containing Taste and Odor Compounds

A hybrid process of conventional treatment UF-BPAC (biological powder activated carbon addition on immersed ultrafiltration membrane bioreactor) was evaluated for the treatment of taste and odor in algal-rich water simulated. The results confirmed that in the immersed ultrafiltration membrane bioreactor PAC had sufficient adsorption and long-term biodegradation of dissolved organic materials which cannot be removed by ultrafiltration membrane alone. UF-BPAC processes could intensify the conventional treatment. Through the advanced treatment of UF-BPAC, the average removal ratios of DOC and UV254 increased 19.6% and 30% compared with the conventional treatment process, respectively. Perfect ammonia removal ratio (82.5±5.5%) was also recieved through hybriding the conventional treatment process and UF-PAC process. The major taste and odor compounds from the raw water, 2-MIB and geosmin both fell below the odor threshold, which guaranteed the effluent quality.