Odor Treatment Research Articles

Evaluation of the performance of new plastic packing materials from plastic waste in biotrickling filters for odour removal

The gas emissions from wastewater treatment plants (WWTPs) contain multiple chemical compounds, such as H2S, NH3 and volatile organic compounds (VOCs), which can cause odour nuisance and health hazards. Biological technologies, such as biotrickling filters (BTFs), are preferred due to their cost-effectiveness and eco-friendliness. The selection of the packing materials in these bioreactors is crucial due to their high purchase cost, frequent replacement and impact on the gas-liquid mass transfer. This research aims at evaluating the NH3, H2S and VOC abatement performance of novel packing materials from plastic byproducts from the water cycle at different gas residence times (EBRT). The experimental set-up consisted of three BTFs of 2 L of working volume constructed with three different packing materials: commercial Pall rings (control), recycled plastic (from bottle caps), and extruded recycled plastic materials in the form of an optimised 3D-printed carrier. The three BTFs supported a complete removal of H2S and NH3 at EBRTs of 30, 15, 10 and 6 s, and VOCs removal above 90 % at EBRTs of 30 and 15 s. The extruded recycled plastic materials in the form of optimised 3D-printed carrier supported toluene and α-pinene removals of 100 % at EBRTs of 30 and 15 s. The genus Thiobacillus was identified in the three BTFs. This research confirmed the potential of reused and recycled plastics from the integral water cycle as a packing material in BTFs devoted to odour treatment.

Odour information enables patch choice by mammalian herbivores from afar, leading to predictable plant associational effects

Abstract Neighbouring plants can alter the susceptibility of high‐quality focal plants to herbivores by affecting herbivore patch choice. Herbivores can use plant odour to make patch‐scale foraging decisions from afar, but the actual information they rely on within complex plant odours is rarely defined. Revealing the information enabling patch choice by herbivores will provide the mechanistic link underpinning associational effects of plant neighbours arising from these foraging decisions. Here, our first aim was to test whether odour cues alone enable a mammalian herbivore to make patch choice decisions leading to predictable associational effects of neighbours on high‐quality focal plants. Our second aim was then to test whether artificial odour, designed to mimic the informative odour component within the whole odour profile of low‐quality neighbours, is as effective as real plants in influencing patch choice and associational refuge. We tested patch choice by African elephants, Loxodonta africana using a giant Y‐maze and real or artificial plant odours as the only cues for the neighbours of a high‐quality focal plant. We quantified the probability of various odour treatments being chosen in comparison with the odour of a focal plant alone. Compared with focal plants alone, we found that elephants were more likely to choose patches with the focal plant plus high‐quality neighbours of the same or different species, but less likely to choose patches with the focal plant plus low‐quality neighbours. We also demonstrated that an artificial subset of odours, designed to be informative, were as effective as real low‐quality neighbours in influencing patch choice and hence associational refuge to the focal plant. Our results demonstrate a key role of plant odour—and specifically informative components within complex odour profiles—in patch choice decisions by a mammalian herbivore, leading to plant associational effects on high‐quality focal plants. Understanding what olfactory information herbivores use when deciding which patches to visit or avoid, and how it affects focal plant susceptibility is important ecologically. Non‐random patch choice will not only affect individual fitness of herbivores, but also shape plant community dynamics through impacting plant survival and recruitment. Furthermore, artificially re‐creating odour information could offer a new tool to influence herbivore foraging decisions, with implications for wildlife management and conservation, including plant protection. Read the free Plain Language Summary for this article on the Journal blog.

PSLBII-6 Measuring greenhouse gas emissions from biogas facility as manure treatment and comparing with 2006 IPCC guideline calculation

Abstract To achieve global net-zero emission goals by 2050, Korea government announced 2050 carbon neutral scenarios. Substitution of fossil fuel power plants to renewable energy plants is the main strategic long-term vision. It included increasing the number of a biogas facility to retrieve methane (CH₄) for energy sources from manure. As increasing the biogas facility with using manure, it is important to quantify and monitor the greenhouse gas (GHG) such as CH₄ and nitrous oxide (N₂O). The objective of this research was to measure the GHG emissions from the biogas facility as the baseline to construct the country-specific emission factors, and to compare the emissions between site measured data and 2006 IPCC guideline (2006 IPCC GL). This facility was constituted with feedstock, anaerobic digestion, biogas storage, and liquid fertilizer storage. The facility treats 70 tons of swine manure from 20,000 pigs and 30 ton of food waste per day and generates 3,000 m3 /d of biogas. All gases were vented by negative pressure from the odor treatment tower, except the generator and its blowers. Quantification of the total GHG emissions from the biogas facility was conducted for 24 h every 2 wk, from July 2022 to October 2023, using CH₄/N2O Analyzer (Los Gatos Research, San Jose, CA). The total emissions of CH₄ and N2O were 12,545 ± 2,297 kgCH4/yr and 442 ± 1,123 kg N2O/yr. To compare total GHG emissions from the facility, it was changed by carbon dioxide (CO2) equivalent. The results showed that when the system of biogas facility operated normally, it can reduce the total GHG emissions by up to 60% compared with 2006 IPCC GL calculation. However, if the system does not circulate properly, it can result in 18 times greater emissions due to N2O, leading to significant increase in GHG emissions. To reduce GHG from biogas facilities, it is crucial to ensure continuous operation of organic matter in and out, and increase the amount of sufficient aeration in liquid fertilizer storage.

Dual roles of odor cleaners and pollutant producers for chemical scrubbing and biological treatment: Evidence in a food waste anaerobic digestion plant

The odor generated during municipal solid waste and wastewater treatment is a major source of public complaints worldwide. Chemical scrubbing and biological treatment are commonly used to control the odor. However, in this study, such odor control measures were found to produce derived odorous compounds and greenhouse gases, leading to reduced efficiency or uncertainty in odor treatment. In a food waste anaerobic digestion plant, a series of site and lab investigations were conducted on the odor control performance and mechanisms, as well as secondary pollutants of chemical scrubbing and biotrickling. Methanethiol, hydrogen sulfide (H2S), propanethiol, and acetaldehyde were identified as the top four odor contributors to the gas collected in the plant. The mechanisms of acetaldehyde and propanethiol removal in the chemical scrubbers were studied using gas-washing bottles. Acetaldehyde was mainly removed via physical absorption, whereas propanethiol could be completely removed via oxidation by sodium hypochlorite (NaClO). However, acetaldehyde was desorbed from the absorption solution and generated from the oxidation of ethanol by NaClO in the chemical scrubbers, leading to low, or even negative removal efficiency. H2S, methanethiol, propanethiol, and acetaldehyde could be abated by the biotrickling filters. However, H2S, methanethiol, propanethiol, and greenhouse gases could be also produced under anaerobic conditions, particularly when the packings were compacted. Furthermore, acetaldehyde could be produced from ethanol by bacteria possessing dehydrogenase under aerobic conditions. Both chemical scrubbers and biotrickling filters demonstrated the dual roles of odor removal and pollutant production.

Evaluation of three granular activated carbon filters for the treatment of collections foul air entering a water resource recovery facility.

The treatment of raw foul air that could escape to the atmosphere from the head space of the incoming wastewater sewer lines into a Southern California Water Resource Recovery Facility was evaluated by using a 1/20th scale pilot unit consisting of three different granular activated carbon filter technologies, operating side by side, under similar operating conditions, each having an average 3.8-s contact time. The three activated carbon filters contained each 0.07 m3 of coconut, coal, and coconut mixed with permanganate media. The foul air entering the granular activated carbon filters contained 82% to 83% relative humidity. No moisture removal mechanism was used prior to treatment. The removal of six different odor characters from eight chemical odorants present in the foul air were assessed. These were rotten egg (hydrogen sulfide), rotten vegetables (methyl mercaptan), canned corn (dimethyl sulfide), rotten garlic (dimethyl disulfide), earthy/musty (2-methyl isoborneol and 2-isopropyl 3-methoxy pyrazine), and fecal (skatole and indole). This is the first time a study evaluates the removal of specific odors by simultaneously employing sensory analyses using the odor profile method, which defines the different odor characters and intensities, together with chemical analyses of the odorants causing these odors. The results show that the three granular activated carbon filters, before hydrogen sulfide breakthrough, provided significant improvement in odor intensity and odorant removal. Breakthrough was reached after 57 days for the coconut mixed with permanganate, 107 days for the coconut, and 129 days for the coal granular activated carbon filter. Breakthrough (the critical saturation point of the activated carbon media) was considered reached when the hydrogen sulfide percentage removal diminished to 90% and continued downward. The coconut mixed with permanganate granular activated carbon filter provided the best treatment among the media tested, achieving very good reduction of odorants, as measured by chemical analyses, and reasonable removal of odor intensities, as measured by the odor profile method. The coconut mixed with permanganate granular activated carbon is recommended for short-term odor control systems at sewer networks or emergency plant maintenance situations given its shorter time to breakthrough compared with the other granular activated carbons. The coal and coconut granular activated carbon filters are generally used as the last stage of an odor treatment system. Because of the observed poor to average performance in removing odorants other than hydrogen sulfide, the treatment stage(s) prior to the use of these granulated activated carbons should provide a good methyl mercaptan removal of at least 90% in order to avoid the formation of dimethyl disulfide, which, in the presence of moisture in the carbon filter, emit the characteristic rotten garlic odor. The differences observed between the performances based on odorant removal by chemical analysis compared with those based on sensorial analyses by the odor profile method indicate that both analyses are required to understand more fully the odor dynamics. PRACTITIONER POINTS: Three virgin granulated activated carbon media were evaluated in a field pilot unit using raw collections foul air. Coal, coconut, and coconut mixed with permanganate were tested until breakthrough. Samples were analyzed both chemically (odorants) and sensorially (odors). Coconut mixed with permanganate proved to be the media that better reduced odorants and odors.

Simultaneous biofiltration of H2S, NH3, and toluene using compost made of chicken manure and sugarcane bagasse as packing material.

Offensive odors from wastewater treatment plants (WWTP) are caused by volatile inorganic compounds such as hydrogen sulfide and ammonia and volatile organic compounds (VOCs), such as toluene. To treat these pollutants, biofiltration is an effective and economical technology used worldwide due to its low investment and environmental impact. In this work, a laboratory-scale prototype biofilter unit for the simultaneous biofiltration of hydrogen sulfide, ammonia, and toluene was evaluated by simulating the emission concentrations of the El Salitre WWTP Bogotá, Colombia, using a compost of chicken manure and sugarcane bagasse as packing material for the biofilter. The prototype biofilter unit was set to an operation flow rate of 0.089 m3/h, an empty bed residence time (EBRT) of 60 s, and a volume of 0.007 m3 (6.6 L). The maximum removal efficiency were 96.9 ± 1.2%for H2S, at a loading rate of 4.7 g/m3 h and a concentration of 79.1 mg/m3, 68 ± 2% for NH3, at a loading rate of 1.2 g/m3 h and a concentration of 2.0 mg/m3, and 71.5 ± 4.0%for toluene, at a loading rate of 1.32 g/m3h and a concentration of 2.3 mg/m3. The removal efficiency of the three compounds decreased when the toluene concentration was increased above 40 mg/m3. However, a recovery of the system was observed after reducing the toluene concentration and after 7 days of inactivity, indicating an inhibitory effect of toluene. These results demonstrate the potential use of the prototype biofilter unit for odor treatment in a WWTP.

Detection of Sulfur Oxidizing Bacteria to Oxidize Hydrogen Sulfide in Biogas from Pig Farm by NGS and DNA Microarray Technique

A high concentration of hydrogen sulfide (H2S) released from pig farming is one of the major environmental problems affecting surrounding communities. In modern pig farms, the bioscrubber is used to eliminate H2S, which is found to be driven mainly by the sulfur-oxidizing bacteria (SOB) community. Therefore, in this study, molecular biology techniques such as next-generation sequencing (NGS) and DNA microarray are proposed to study the linkage between enzyme activity and the abundance of the SOB community. The starting sludge (SFP1) and recirculating sludge (SFP2) samples were collected from the bioscrubber reactor in the pig farm. The abundance of microbial populations between the two sampling sites was considered together with the gene expression results of both soxABXYZ and fccAB. Based on the NGS analysis, the members of phylum Proteobacteria such as Halothiobacillus, Acidithiobacillus, Thiothrix, Novosphingobium, Sulfuricurvum, Sulfurovum, Sulfurimonas, Acinetobacter, Thiobacillus, Magnetospirillum, Arcobacter, and Paracoccus were predominantly found in SFP2. The presence of Cyanobacteria in SFP pig farms is associated with increased biogas yields. The microarray results showed that the expression of soxAXBYZ and fccAB genes involved in the oxidation of sulfide to sulfate was increased in Halothiobacillus, Paracoccus, Acidithiobacillus, Magnetospirillum, Sphingobium, Thiobacillus, Sulfuricurvum, Sulfuricurvum, Arcobacter, and Thiothrix. Both NGS and DNA microarray data supported the functional roles of SOB in odor elimination and the oxidation of H2S through the function of soxABXYZ and fccAB. The results also identified the key microbes for H2S odor treatment, which can be utilized to monitor the stability of biological treatment systems and the toxicity of sulfide minerals by oxidation.

Evaluation of Urban Quality Improvement Based on the MABAC Method and VIKOR Method: A Case Study of Shandong Province, China

In the current stage of urbanization in China, urban construction has gradually shifted from incremental construction dominated by real estate to stock transformation based on improving urban quality. The evaluation of urban renewal projects is crucial for decision-making and resource allocation. However, there is no consensus on the evaluation indicators and methods. This study evaluates the current status of urban quality using the MABAC method based on numerical indicators. It evaluates the improvement of urban quality using the VIKOR method based on public satisfaction indicators. It is found that the comprehensive weights and subjective weights of the five first-level indicators in the evaluation index system of urban quality improvement in Shandong Province, namely blue–green space improvement, air cleanliness improvement, road traffic improvement, life service improvement, and governance capacity improvement, are quite different. The weight distribution of these indicators needs to be adjusted and optimized, especially for improving living services, as well as secondary indicators such as black and odorous water treatment, urban clean heating, the number of public vehicles per 10,000 people in the city, the 15 min living circle, the renovation of old residential areas, and the construction of urban intelligent management platforms. Based on the comprehensive evaluation results, an attempt is made to propose a more scientific evaluation index system, providing valuable references for urban renewal management.

Copper doped UiO-66@TiO2 heterojunction for highly efficient photodegradation of odors in broiler houses

Odor pollutants produced by broiler houses can significantly impact the quality of the life of residents and the ecological environment, so it is crucial to explore odor purification technologies. In this study, a defect-rich CuUiO-66@TiO2 photocatalyst was successfully synthesized for the photocatalytic degradation of five typical odors in broiler houses. CuUiO-66 and TiO2 in a 1:3 ratio was the most effective in removing odors, capable of removing 99% of methyl mercaptan, 99% of dimethyl sulfide, 99% of dimethyl disulphide, 86.47% of toluene and 63.09% of ethyl acetate in 60 min. After five cycles degradation, the photocatalyst can remain the crystal structure and keep the photocatalytic degradation rate at 95.2% of methyl mercaptan. Furthermore, the proposed mechanisms for the removal of five odors by CU1T3 have been discussed. Therefore, this study has developed a highly efficient photocatalyst that can effectively eliminate odors emitted from broiler houses. This is a promising solution to address the challenges of odor treatment in the near future.

Using artificial odors to optimize attractiveness of host decoy traps to malaria vectors.

Malaria vector surveillance tools often incorporate features of hosts that are attractive to blood-seeking females. The recently developed host decoy trap (HDT) combines visual, thermal, and olfactory stimuli associated with human hosts and has shown great efficacy in terms of collecting malaria vectors. Synthetic odors and yeast-produced carbon dioxide (CO2) could prove useful by mimicking the human odors currently used in HDTs and provide standardized and easy-to-use olfactory attractants. The objective of this study was to test the attractiveness of various olfactory attractant cues in HDTs to capture malaria vectors. We compared 4 different odor treatments in outdoor field settings in southern Benin and western Burkina Faso: the standard HDT using a human, HDT with yeast-produced CO2, HDT with an artificial odor blend, and HDT with yeast-produced CO2 plus artificial odor blend. In both experimental sites, the standard HDT that incorporated a real human produced the greatest catch of Anopheles gambiae s.l (Diptera: Culicidae). The alternatives tested were still effective at collecting target vector species, although the most effective included CO2, either alone (Benin) or in combination with synthetic odor (Burkina Faso). The trap using synthetic human odor alone caught the fewest An. gambiae s.l. compared to the other baited traps. Both Anopheles coluzzii and Anopheles gambiae were caught by each trap, with a predominance of An. coluzzii. Synthetic baits could, therefore, represent a more standardized and easier-to-deploy approach than using real human odor baits for a robust vector monitoring strategy.

Antibacterial and deodorizing effects of cold atmospheric plasma-applied electronic deodorant

Axillary odor is a malodor produced by bacterial metabolism near the apocrine glands, which often causes discomfort in an individual's daily life and social interactions. A deodorant is a personal care product designed to alleviate or mask body odor. Currently, most deodorants contain antimicrobial chemicals and fragrances for odor management; however, direct application to the underarm skin can result in irritation or sensitivity. Therefore, there is a growing interest in technologies that enable disinfection and odor control without the antiperspirants or perfumes. The cold atmospheric plasma temporally generates reactive radicals that can eliminate bacteria and surrounding odors. In this study, cultured Staphylococcus hominis and Corynebacterium xerosis, the causative bacteria of axillary bromhidrosis, were killed after 90% plasma exposure for 3 min. Moreover, the electronic nose system indicated a significant reduction of approximately 51% in 3-hydroxy-3-methylhexanoic acid and approximately 34% in 3-methyl-3-sulfanylhexan-1-ol, the primary components of axillary odor, following a 5-min plasma exposure. These results support the dual function of our deodorant in eliminating bacteria and axillary odors without the chemical agents. Therefore, cold atmospheric plasma-applied deodorant devices have great potential for the treatment and management of axillary odors as a non-contact approach without chemical use in daily life.

Synthetic microbial consortia to enhance the biodegradation of compost odor by biotrickling filter

Composting generates odorous gases, including ammonia (NH3), hydrogen sulfide (H2S), and volatile organic compounds (VOCs). The Biological Trickling Filter (BTF) is effective for odor treatment, but it may have limitations with hydrophobic VOCs. In this study, a strain of Bacillus subtilis with ammonia-reducing ability, a strain of Bacillus cereus with desulfurization ability and a strain of Schizophyllum commune with the ability to degrade dimethyl disulfide were isolated and screened. The three strains were combined to create synthetic microbial consortia for enhancing odor treatment in the BTF. Compared to the activated sludge control, the BTF with synthetic microbial consortia removed 92.43% ammonia, 92.75% hydrogen sulfide. Furthermore, it demonstrated a significant improvement in the removal rates of p-methyl mercaptan, methyl sulfide, and dimethyl disulfide. High-throughput sequencing was conducted on the fillers of the synthetic microbial consortia-inoculated BTF to analyze the microbial community composition.

Microbial community evolution and functional trade-offs of biofilm in odor treatment biofilters

Biofilters inoculated with activated sludge are widely used for odor control in WWTP. In this process, biofilm community evolution plays an important role in the function of reactor and is closely related to reactor performance. However, the trade-offs in biofilm community and bioreactor function during the operation are still unclear. Herein, an artificially constructed biofilter for odorous gas treatment was operated for 105 days to study the trade-offs in the biofilm community and function. Biofilm colonization was found to drive community evolution during the start-up phase (phase 1, days 0–25). Although the removal efficiency of the biofilter was unsatisfactory at this phase, the microbial genera related to quorum sensing and extracellular polymeric substance secretion led to the rapid accumulation of the biofilm (2.3 kg biomass/m3 filter bed /day). During the stable operation phase (phase 2, days 26–80), genera related to target-pollutant degradation showed increases in relative abundance, which accompanied a high removal efficiency and a stable accumulation of biofilm (1.1 kg biomass/m3 filter bed/day). At the clogging phase (phase 3, days 81–105), a sharp decline in the biofilm accumulation rate (0.5 kg biomass/m3 filter bed /day) and fluctuating removal efficiency were observed. The quorum quenching-related genera and quenching genes of signal molecules increased, and competition for resources among species drove the evolution of the community in this phase. The results of this study highlight the trade-offs in biofilm community and functions during the operation of bioreactors, which could help improve bioreactor performance from a biofilm community perspective.

The influence of plant odours on sexual readiness in an insectivorous songbird.

Many organisms rely on environmental cues to predict and anticipate the annual optimal timing of reproduction. In insectivorous birds, preparation for breeding often coincides with the time vegetation starts to develop in spring. Whether there is a direct relationship between the two, and through which mechanisms this link could come about, has rarely been investigated. Plants release Herbivore-Induced Plant Volatiles (HIPVs) when they are attacked by insects, and recent studies have shown that birds can detect and orient to those odours when searching for food. If those volatiles also stimulate sexual reproductive development and timing of reproduction remains to be discovered. We tested this hypothesis by monitoring gonadal growth in pairs of blue tits (Cyanistes caerueus) exposed to air from caterpillar infested oak trees or from a control, in spring. We found that while males and females grew their gonads over time, gonads grew at the same rate in both odor treatments. More exploratory (i.e. a proxy of personality) females did however have larger ovarian follicle sizes when exposed to the HIPVs than to the control air, which is consistent with earlier results showing that fast explorers have larger gonads in spring and are more sensitive to HIPVs. If HIPVs constitute powerful attractants in foraging birds, their influence on gonadal development prior to breeding appears to be relatively subtle and only enhance reproductive readiness in some individuals. These results are nevertheless important as they set olfaction as a new player in seasonal timing of reproduction in birds.

Effect of odor treatment systems on bioaerosol microbial concentration and diversity from wastewater treatment plants

Biofiltration, activated carbon and chemical scrubbing are technologies used for odor control in wastewater treatment plants. These systems may also influence the airborne microbial load in treated air. The study objectives were to 1) evaluate the capacity of three odor control system technologies to reduce the airborne concentration of total bacteria, Legionella, L. pneumophila, non-tuberculous mycobacteria (NTM) and Cladosporium in winter and summer seasons and 2) to describe the microbial ecology of the biofiltration system and evaluate its impact on treated air microbial diversity. A reduction of the total bacterial concentration up to 25 times was observed after odor treatment. Quantification by qPCR revealed the presence of Legionella spp. in all air samples ranging between 26 and 1140 GC/m3, while L. pneumophila was not detected except for three samples below the limit of quantification. A significant increase of up to 25-fold of Legionella spp. was noticed at the outlet of two of the three treatment systems. NTM were ubiquitously detected before air treatment (up to 2500 GC/m3) and were significantly reduced by all 3 systems (up to 13-fold). Cladosporium was measured at low concentrations for each system (< 190 GC/m3), with 68 % of the air samples below the limit of detection. Biodiversity results revealed that biofiltration system is an active process that adapts to air pollutants over time. Legionella spp. were detected in significant abundance in the air once treated in winter (up to 27 %). Nevertheless, the abundance of protozoan hosts is low and does not explain the multiplication of Legionella spp. The season remains the most influential factor shaping biodiversity. In summer only, air biofiltration caused a significant enrichment of the biodiversity. Although odor control technologies are not designed for bacterial mitigation, findings from this study suggest their potential to reduce the abundance of some genera harboring pathogenic species.

Key odorant identification and odor treatment technology evaluation during the chemical synthesis process of typical pesticide

Odor pollution has become one of the important environmental problems in China. In this study, Gas Chromatography Ion Mobility Spectrometry (GC-IMS), Gas Chromatography Mass Spectrometer (GC-MS) and Flame Ionization Detector (FID) were combined to obtain comprehensive information of the odor produced during the production of Captan, a common pesticide, and to evaluate the efficiency of the odorant treatment techniques utilized by the manufacturer studied. Based on our findings, refining, an important phase during the production process of Captan, was found to be the most important factor in determining the type and the concentration of the odorant produced. Of the odorants found during the production process, perchloromethylmercaptan (CCl3SCl) and other chlorine-containing compounds are the key odorants during the production process based on the calculation of odor activity value (OAV). The current odorant treatment utilized by the manufacturer studied showed about 40 % removal rate. However, the odorant treatment produced a new odorant, dimethyl disulfide. Therefore, a much more targeted odorant treatment technique without the production of new odorants is desired and should be utilized.

Sulfide Removal by Catalitic Oxidation From Rayon Waste

Catalytic oxidation of spent sulfidic caustic consist of SH- ion or NaHS compound by H 2 O2 in neutral or acidic solution to elemental sulphur may provide a convenient and economical method for the control of sulphide wastes and their associated odors at pulp, paper and textile industry. Oxidation of sulfide in rayon waste by hydrogen peroxide was investigated in the presence of ferric sulfate catalyst. Kinetic equations and activation energies of H 2 O2 and SH- ion to total sulphur and sulphate in rayon waste for catalytic oxidation reaction were calculated based on the experimental results. For the removal of sulfide from sulfide solution the most common process involves its catalytic oxidation to a more benign form sulfate. The rate of sulfidic catalytic oxidation was found higher at lower initial sulphide concentration and the rate of sulphide catalytic oxidation was found directly proportional to loading and hydrogen peroxide addition. Optimum total sulphide concentration was achieved when sulphide solutions in the presence of H 2 O 2 in the ratios SH-/H 2 O 2 1:4.2. The potential user of H 2 O 2 determine the optimal conditions for control of odor, corrosion and waste treatment cost due to sulfide consisting of sulphur ion, sulphate ion, etc. The catalytic oxidation of sulphides into sulphates by H 2 O 2 may be applied directly to aqueous wastes containing these odorants

Evaluation of aquatic phytoremediation technologies in urban black–odorous water remediation technology using a multi-level fuzzy analysis method

Abstract The comprehensive analysis and research on the selection and evaluation of technology for urban black and odorous water remediation have not yet formed a complete system, and the technical analysis and comparison of the remediation technology are not combined with the characteristics of the river and the pollution status, which often could not achieve the expected effect. Combining the multi-level index division and fuzzy weight matrix calculation method, this paper establishes a comprehensive evaluation method for urban black–odorous water treatment technology based on multi-level fuzzy analysis. The proposed method was applied to assess four kinds of in situ purification-aquatic plant remediation technologies. The results showed that the pollutants removal efficiency of a submerged plant was much higher than that of an emergent aquatic plant, floating-leaved water plant and floating plant. Meanwhile, according to the evaluation model, the comprehensive grading order of in situ purification-aquatic plants was as follows: emergent aquatic plant (84.2044) &amp;gt; submerged plant (78.838) &amp;gt; floating-leaved water plant (72.7596) &amp;gt; floating plant (66.4312). The calculations indicated that the ecological restoration project of black and odorous water should build an ecological restoration technology system based on in situ purification-submerged plant remediation technology, supplemented by other three types of aquatic phytoremediation technologies.

Термообработка слизистых субпродуктов под воздействием электрофизических факторов: разработка установки

Low efficiency of equipment for heat treatment, disinfection and removal of unpleasant odour of substandard mucous by-products urges the development of an installation that provides for the complex effect of ultra-high frequency electromagnetic field, ozone and bactericidal flow of ultraviolet rays. The paper presents the technology and describes the installation developed by the authors. The installation ensures electromagnetic safety and uniformity of loading according to the penetration depth of the wave. The duration of raw material treatment is matched with the specific power of the microwave generator, the power of the lamps and with the rotation frequency of the compartment disc. The electric field strength has been studied in the CST Microwave Studio program. The developed installation contains a resonator in the form of a flattened spheroid with diameters of the main axes multiple of half the wavelength. Magnetrons are placed on the upper surface of the spheroid along the perimeter. On the inner surface of the spheroid, where there are corona needles, ring electro-gas-discharge lamps powered from pulsed modeled high-frequency generators are uniformly installed along the perimeter through the gap. The source of radiation in the bactericidal lamp is an electric discharge in a mixture of mercury vapour and argon. A fluoroplastic perforated disc is installed at the level of the large diameter of the spheroid, on which mucous by-products are treated. The conducted research shows that the intrinsic factor of quality of the spheroid resonator is 9000. The heat treatment and disinfection of raw materials is most effective at the plant productivity of 50 kg/h, electric field strength of 3 to 4 kV/cm, disc rotation frequency of 0.17 to 0.2 rpm and a specific power of the microwave generator of 1.2 W/g. Power consumption amounted to 6.6 kW, while energy costs were 0.132 kW∙h/kg.

Application of screw stacker combined with plate and frame filter press for dewatering of ultra magnetic sludge from river suspensions

The black and odorous water body treatment projects promoted the application of various engineering solutions but also produced large quantity of solid waste, like the ultra-magnetic sludge (UMS) which is the river suspensions thickened and discharged by ultra-magnetic separator. Characterized by high concentration of water content, organic matter and compact structure, the dewatering of UMS will greatly benefit transportation and further use. In this study, the mechanical dewatering methods were tested and combined onsite in order to reduce the water content of UMS to 42~48%. The operating parameters and effects were discussed while the indexes of resultant UMS was analyzed shows promising use as land improvement agent.