Volatile Organic Sulfur Compounds Research Articles

Odor removal by and microbial community in the enhanced landfill cover materials containing biochar-added sludge compost under different operating parameters

Odor problem has become a growing concern for municipal solid waste (MSW) operators and communities located close to landfill sites. In this study, nine laboratory-scale landfill reactors were used to simulate in-situ odor control by a novel landfill cover material consisting of biochar-added sludge compost under various operating parameters. Characterization of odor removal and microbial community in the cover layer under various operating parameters was conducted using gas chromatograph-mass spectrometry and 454 high-throughput pyrosequencing, respectively. Results showed that H2S (76.9–86.0%) and volatile organic sulfur compounds (VOSCs) (12.3–21.7%) were dominant according to their theoretical generated odor concentrations. The total odor REs calculated using the theoretical odor concentrations in the landfill reactors were different than using the measured odor values, which were ranked from high to low as: R6 > R5 > R7 > R4 > R8 > R9 > R3 > R2 > R1, showing the largest discrepancy of 25.3%. The optimum combination of operating parameters based on the theoretical odor concentration was different with that based on the measured odor concentrations. Moreover, although Firmicutes (12.21–91.48%), Proteobacteria (3.55–51.03%), and Actinobacteria (4.01–47.39%) were in general the three major bacterial phyla found in the landfill covers, the detailed bacterial communities in the cover materials of the simulated reactors varied with various operating parameters. Alicyclobacillus and Tuberibacillus showed positive correlations with the removal efficiencies (REs) of chlorinated compounds, H2S, aromatic compounds, volatile organic sulfur compounds (VOSCs), and organic acids. The correlations of Rhodanobacter, Gemmatimonas, Flavisolibacter and Sphingomonas were strongly positive with ammonia RE and relatively positive with REs of organic acids, VOSCs, and aromatic compounds. These findings are instrumental in understanding the relationship between the structure of microbial communities and odor removal performances, and in developing techniques for in-situ odor control at landfills.

Detection of volatile organosulfur compounds by hydrogen-bond acidic polymer: A combined experimental and theoretical study

Volatile organic sulfur compounds (VOSCs) pose serious threats to environment and human health, while detection techniques of VOSCs are expensive and complex. Here, this paper first-time reported a hydrogen-bond acidic (HBA) polymer-based surface acoustic wave (SAW) chemical sensor for the detection of four VOSCs (methyl mercaptan, dimethyl sulfide, dimethyl disulfide, and carbon disulfide). The results show that this sensor exhibited both excellent sensitivity (limit of detections ranging from 0.035 to 0.11 mg/m3) with fast response and recovery and high selectivity (2.23–49.6 times higher response than interference vapors) toward VOSCs at room temperature. The good performance is attributed to the hydrogen bonding between the sulfur atom of VOSCs and hydrogen atom of hexafluoroisopropanol (HFIP) groups in polymer chain. Fourier-transform infrared spectroscopy (FTIR) spectrum and first principle calculations were performed to further support this proposed mechanism.

Determination of four volatile organic sulfur compounds by automated headspace technique coupled with gas chromatography–mass spectrometry

Determination of four volatile organic sulfur compounds by automated headspace technique coupled with gas chromatography–mass spectrometry

Miniaturized point discharge-radical optical emission spectrometer: A multichannel optical detector for discriminant analysis of volatile organic sulfur compounds

In this work, we proposed a miniaturized point discharge-radical optical emission spectrometer (PD-RES) as a multichannel optical detector for discriminant analysis of various volatile organic sulfur compounds (VOSCs). Under appropriate experimental conditions, the unique molecular emission of CS radical in the vicinity of 257.6 nm was recorded, as well as the atomic emission lines of C at 193.1 nm and 247.8 nm, the molecular emission of C2 radical around 231.5 nm and CN radical nearby 384.8 nm. They were utilized as five optical channels for precise qualification and discrimination. Linear discriminant analysis (LDA) and principal component analysis (PCA) further demonstrated the robustness of this detector for discriminant analysis: 95 unknown samples from ten typical VOSCs were classified with accuracy of 98.9%. This proposed detector was further successfully applied to the discrimination of different concentrations of CS2 in air samples and two types of isomers (functional group isomer and carbon-chain isomer).

A comparative study of the emission of volatile organic compounds (VOCs) from different sulfur content crude oils

ABSTRACTA new lab-made passive sampler method was employed to collect volatile organic compounds (VOCs) and volatile sulfur compounds (VSCs) which they were emitted from the spill of two different sulfur content crude oils. In this study, two different models have been used to represent of spill crude oil in two different areas, a laboratory and field model for spill crude oil on the surface area and pipeline leak respectively. The effective meteorological parameters such as rain, wind speed, and air temperature were controlled. The results show that the emitted VOCs were inversely proportional to the sulfur content crude oils.

Emissions of volatile sulfur compounds (VSCs) throughout wastewater biosolids processing

Volatile sulfur compounds (VSCs) are important contributors to nuisance odours from the processing of wastewater sludge and biosolids. However, emission characteristics are difficult to predict as they vary between sites and are likely to be affected by biosolids processing configuration and operation. VSC emissions from biosolids throughout 6 wastewater treatment plants (WWTPs) in Sydney, Australia were examined in this study. H2S was the VSC found at the highest concentrations throughout the WWTPs, with concentrations ranging from 7 to 39,000μg/m3. Based on odour activity values (OAVs), H2S was typically also the most dominant odorant. However, methyl mercaptan (MeSH) was also found to be sensorially important in the biosolids storage areas given its low odour detection threshold (ODT). High concentrations of VOSCs such as MeSH in the storage areas were shown to potentially interfere with H2S measurements using the Jerome 631-X H2S sensor and these interferences should be investigated in more detail. The VSC composition of emissions varied throughout biosolids processing as well as between the different WWTPs. The primary sludge and biosolids after dewatering and during storage, were key stages producing nuisance odours as judged by the determination of OAVs. Cluster analysis was used to group sampling locations according to VSC emissions. These groups were typically the dewatered and stored biosolids, primary and thickened primary sludge, and waste activated sludge (WAS), thickened WAS, digested sludge and centrate. Effects of biosolids composition and process operation on VSC emissions were evaluated using best subset regression. Emissions from the primary sludge were dominated by H2S and appeared to be affected by the presence of organic matter, pH and Fe content. While volatile organic sulfur compounds (VOSCs) emitted from the produced biosolids were shown to be correlated with upstream factors such as Fe and Al salt dosing, anaerobic digestion and dewatering parameters.

Methanethiol generation potential from anaerobic degradation of municipal solid waste in landfills.

Volatile sulfur compounds are the main odorants at landfills. In this study, methanethiol (CH3SH) was chosen as a typical volatile organic sulfur compound, and its generation potential was investigated during the anaerobic degradation of the organic fractions of municipal solid waste (MSW) including rice, flour food, vegetable, fish and pork, paper, cellulose textile, and yard wastes. Among the experimental wastes, gas generation was the highest in the fish and pork waste with a high CH3SH concentration of up to 2.5% (v/v). Sulfur reduction in the solid phase was mostly converted into gaseous sulfur compounds. During the whole experiment, the cumulative CH3SH generation from the fish and pork waste was 0.139Lkgdw-1, which was about 2 and 6 orders of magnitude higher than that from the other experimental wastes. The ratio of CH3SH-S to TS reduction was 31.56% in the fish and pork waste. These results would be helpful to understand the generation of volatile sulfur compounds during the anaerobic degradation of MSW and develop techniques to control odor pollution at landfills.

Effects of aeration and leachate recirculation on methyl mercaptan emissions from landfill

The issue of odorous volatile organic sulfur compound methyl mercaptan (MM) released from landfill sites cannot be ignored for its extremely low odor threshold and high toxicity. In this study, we focused on the formation and emission of MM in four lab-scaled simulated landfill reactors running in different operation modes, namely, R1 and R2, without leachate recirculation, running under anaerobic and semi-aerobic atmosphere, R3 and R4, with leachate recirculation, running under anaerobic and semi-aerobic atmosphere, respectively. From the perspective of odor abatement, the semi-aerobic operation mode can efficiently lower the emitted MM concentration by 87.4–94.9%, relative to the semi-aerobic operation mode. Furthermore, under semi-aerobic conditions, leachate recirculation substantially shortened the period of MM influence by 12.7%, thus reducing the risk of affecting the surrounding atmospheric environment. The formation of MM was dependent on the characteristics such as the volatile fatty acid concentration and chemical oxygen demand in the leachate and sulfide concentration of the refuse. Overall, MM release can be effectively controlled with semi-aerobic operation mode and leachate recirculation.

Methoxysulfinyl Radical CH3OSO: Gas-Phase Generation, Photochemistry, and Oxidation.

Methylsulfoxide radicals CH3SOx (x = 1-4) are key reactive sulfur species (RSS) in the atmospheric oxidation of volatile organic sulfur compounds (VOSCs). Through flash vacuum pyrolysis (FVP) of trifluoromethanesulfinic acid methyl ester CF3S(O)OCH3 at 1000 K, the methoxysulfinyl radical CH3OSO has been generated in the gas phase and subsequently characterized in cryogenic N2, Ar, and Ne matrices by IR spectroscopy. Upon 266 nm laser irradiation, CH3OSO efficiently isomerizes to the less stable methylsulfonyl radical CH3SO2 in matrices without noticeable decomposition. In the gas phase, CH3OSO reacts with O2 and yields sulfinyl peroxyl radical CH3OS(O)OO, a new member in the CH3SOx (x = 1-4) family. This radical dissociates into SO3 and CH3O with the intermediacy of the sulfonyoxyl radical CH3OSO3 under the 266 nm laser irradiation. Additionally, the photoisomerization of CF3S(O)OCH3 to sulfenic ester CF3OSOCH3 was also observed.

Exchange fluxes of VOSCs between rice paddy fields and the atmosphere in the oasis of arid area in Xinjiang, China

Investigations about VOSCs (volatile organic sulfur compounds) have been received increasing attention for their significant contribution to the nonvolcanic background sulfate layer in the stratosphere and the earth’s radiation balance and as a potential tool to understand the carbon budget. In this study, COS and CS2 were always recorded throughout the entire rice cultivation season of 2014. COS fluxes appeared as emission in non-planted soil and as uptake in planted soil, the corresponding results were obtained as 2.66 and −2.35 pmol·m−2·s−1, respectively. For CS2, both planted and non-planted paddy fields acted as sources with an emission rate of 1.02 pmol·m−2·s−1 and 2.40 pmol·m−2·s−1, respectively. COS emission or uptake rates showed a distinct seasonal variation, with the highest fluxes at the jointing-booting stage. COS and CS2 fluxes increased with increasing N fertilizer use because of improved plant and microbial growth and activity. Plots treated with both N and S reduced COS and CS2 fluxes slightly compared with plots with only-N treatment. Light, soil moisture or temperature showed no significant correlation with COS and CS2 fluxes, but revealed the important impacts on the magnitude and direction of gases fluxes. The results also showed that the (available) sulfur contents in soil and roots had a certain effect on VOSCs emission or uptake. Our results highlight the significance of biotic and abiotic production and consumption processes existing in the soil.

Factors Affecting the Production of Volatile Organic Sulfur Compounds (VOSCs) from Algal-Induced Black Water Blooms in Eutrophic Freshwater Lakes

Volatile organic sulfur compounds (VOSCs) are frequently reported in eutrophic lakes during the process of algal blooms’ degradation. The algal-induced so-called black water blooms have been purported to be a big contributor to the production of VOSCs. However, the production mechanism of VOSCs in black water blooms and its influencing factors still remain unclear. In this study, a laboratory sediment/algal slurry experiment was carried out to investigate the formation process of black water blooms and factors such as temperature, microorganisms, and sulfate concentrations on the production of VOSCs in eutrophic lake sediments during the decomposition of algal blooms. The simulation study indicated that black water blooms can only be produced with the participation of sediment and algal together, which could be the result of low redox potential and the continuous release of ferrion irons (Fe2+) and hydrogen sulfide (H2S) into the lake’s ecosystem; however, neither of algal nor sediment can induce the formation of black water blooms. In addition, the sediment + algal treatment can produce more VOSCs than a single sediment or algal treatment. Higher temperature incubation and a higher concentration of sulfate additions can enhance the concentration of H2S and VOSCs in black water blooms. However, the addition of microbial inhibitors in the algal/sediment slurry indicated that sulfate reducing bacteria (SRB) can stimulate the production of VOSCs, whereas methanogen might consume some concentration of VOSCs and thus lower their concentration in black water blooms.

Analysis and pollution sources speculations of toxic gases in a secondary fiber paper mill

ABSTRACTThis paper quantitatively investigates the compositions of the gaseous pollutants in the ambient air of a secondary fiber paper mill. Total volatile organic compounds (TVOC), formaldehyde (HCHO), sulfur compounds (H2S), and hydrocarbon compounds (CxHy) were analyzed on six sampling sites with photo-ionisation detector, acetylacetone spectrophotometric method, and gas detector. The results revealed that, the high levels of TVOC and CxHy were detected at the wet end of paper machine and the office area, respectively; all the H2S contents on the six sites exceeded the limit (0.06 mg m−3) seriously; the HCHO concentrations at other five sites were out of the limit (0.10 mg m−3) except for the wastewater treatment plant. Furthermore, the necessary discussions about the possible pollution sources were considered on the process flow, the chemical agents used, and the ambient conditions in the paper mill. For the sake of air pollution control in paper mills, these remarkable results and analysis lay some technical basis in the following researches that should attract more attentions.

Effect of Stir Frying on the Antioxidant Capacity and Aroma Components of Bok Choy (Chinese Cabbage)

Bok choy, Brassica rapa subsp. Chinensis, is a type of Chinese cabbage. Stir frying could affect antioxidant activity and aroma composition of bok choy. Antioxidant activity such as diphenyl picryl hydrazinyl radical and ferric-reducing antioxidant power of the leave and stem samples were determined. The highest ferric-reducing antioxidant power activity was obtained at 1.5 min stir-frying under 160ºC for bok choy leaves (49.7 ± 2.1 µmol FeSO4/g dry weight). In ferric-reducing antioxidant power assay, antioxidant capacities of bok choy stem samples increased significantly after stir-frying. Dimethyl sulfide (DMS), a typical volatile organic sulfur compound with a characteristic cabbage-like odor, was only observed in leave groups. After cooking treatment, antioxidant activities of bok choy stems were higher than those of leaves in diphenyl picryl hydrazinyl radical assay. Odor-active compounds were identified using gas chromatography-olfactometry-mass spectrometry technique. Compared to stem sample data, more aroma components were quantified in leaves sample in 160, 180, and 210ºC, respectively. It was first time to detect and analysis the aroma components and antioxidant activity in different edible part of bok choy after Chinese domestic cooking.

Characterisation of volatile organic sulphur compounds release during coal pyrolysis in inert, hydrogen and CO2 atmosphere

The effects of CO2 atmosphere on the distribution of volatile organic sulphur compounds during coal pyrolysis and the effect of kaolin addition were studied. Sulphur compounds release was determined by atmospheric pressure-temperature programmed reduction “on-line” coupled with MS (AP-TPR/MS) and “off-line” coupled with GC/MS after thermal desorption (AP-TPR-TD-GC/MS). The results show that thiophene and methyl and ethyl substituted analogues were released between 400 and 500°C, while relatively more complex organic sulphur compounds such as benzothiophene and methyl benzothiophene evolved at higher temperature. In CO2, thiophenes evolved at lower temperature due to its more reactive and oxidative character. With kaolin addition, an increase in most registered volatile organic sulphur compound amounts was noticed both in inert and CO2 gas, due to the catalytic effect of kaolin.

Perchlorate and volatiles of the brine of Lake Vida (Antarctica): Implication for the in situ analysis of Mars sediments

AbstractThe cold (−13.4°C), cryoencapsulated, anoxic, interstitial brine of the >27 m thick ice of Lake Vida (Victoria Valley, Antarctica) contains 49 µg · L−1 of perchlorate and 11 µg · L−1 of chlorate. Lake Vida brine (LVBr) may provide an analog for potential oxychlorine‐rich subsurface brine on Mars. LVBr volatiles were analyzed by solid‐phase microextraction (SPME) gas chromatography–mass spectrometry (GC‐MS) with two different SPME fibers. With the exception of volatile organic sulfur compounds, most other volatiles observed were artifacts produced in the GC injector when the thermal decomposition products of oxychlorines reacted with reduced carbon derived from LVBr and the SPME fiber phases. Analysis of MilliQ water with perchlorate (40 µg · L−1) showed low level of organic artifacts, reflecting carbon limitation. In order to observe sample‐derived organic compounds, both in analog samples and on Mars, the molar abundance of reduced carbon in a sample must exceed those of O2 and Cl2 produced during decomposition of oxychlorines. This suggests that the abundance of compounds observed by the Sample Analysis at Mars (SAM) instruments in Sheepbed samples (CB‐3, CB5, and CB6) may be controlled by an increase in the reduced‐carbon/oxychlorine ratio of these samples. To increase chances of in situ detection of Martian organics during pyrolysis‐GC‐MS, we propose that the derivatization agents stored on SAM may be used as an external source of reduced carbon, increasing artificially the reduced‐carbon to perchlorate ratio during pyrolysis, allowing the expression of more abundant and perhaps more diverse Martian organic matter.

Optimum dredging time for inhibition and prevention of algae-induced black blooms in Lake Taihu, China.

Dredging, which is the removal of polluted surface sediments from a water body, is an effective means of preventing the formation of algae-induced black blooms. However, an inappropriate dredging time may contribute to rather than inhibit the formation of black blooms. To determine the optimum dredging time, four treatments were simulated with sediment samples collected from Lake Taihu: dredging in January 2014 (DW), April 2014 (DA), July 2014 (DS), and no dredging (UD). Results showed that typical characteristics associated with black blooms, such as high levels of nutrients (NH4 (+)-N and PO4 (3-)-P), Fe(2+), ∑S(2-) ([HS(-)] + [S(2-)]), and volatile organic sulfur compounds (VOSCs), including dimethyl sulfide (DMS), dimethyl disulfide (DMDS), and dimethyl trisulfide (DMTS), were more effectively suppressed in the water column by DW treatment than by UD treatment and the other two dredging treatments. The highest concentrations of NH4 (+)-N and PO4 (3-)-P in the UD water column were 4.09 and 4.03 times, respectively, those in the DW water column. DMS levels in the UD and DS water columns were significantly higher (p < 0.05) than those in the DW water column, but DMDS and DMTS levels were not significantly different between the treatments. After several months of dredging, surface sediments of the DW and DA treatments were well oxidized, and concentrations of Fe(2+) and ∑S(2-) were lower than those in UD and DS treatments because of material circulation between sediments and the water column. Water content, which is important for the transport of matter to the overlying water, was lower in the dredged sediments than in the undredged sediments. These factors can suppress the release of Fe(2+) and ∑S(2-) into the water column, thereby inhibiting the formation of black blooms. Black coloration occurred in the UD water column on the seventh day, 2days later, and earlier, respectively, than the DW and DS water columns and almost on the same day as in the DA water column. This phenomenon is mainly attributed to the oxidation of the new sediment surface in the DW and DA water columns, suppressing the release of sulfur into the water column, because of a long incubation period. Thus, dredging in the winter can prevent the formation of black blooms, while dredging in summer may contribute to them.

The Variation Characteristic of Sulfides and VOSc in a Source Water Reservoir and Its Control Using a Water-Lifting Aerator.

Sulfides and volatile organic sulfur compounds (VOSc) in water are not only malodorous but also toxic to humans and aquatic organisms. They cause serious deterioration in the ecological environment and pollute drinking water sources. In the present study, a source water reservoir—Zhoucun Reservoir in East China—was selected as the study site. Through a combination of field monitoring and in situ release experiments of sulfides, the characteristics of seasonal variation and distribution of sulfides and VOSc in the reservoir were studied, and the cause of the sulfide pollution was explained. The results show that sulfide pollution was quite severe in August and September 2014 in the Zhoucun Reservoir, with up to 1.59 mg·L−1 of sulfides in the lower layer water. The main source of sulfides is endogenous pollution. VOSc concentration correlates very well with that of sulfides during the summer, with a peak VOSc concentration of 44.37 μg·L−1. An installed water-lifting aeration system was shown to directly oxygenate the lower layer water, as well as mix water from the lower and the upper layers. Finally, the principle and results of controlling sulfides and VOSc in reservoirs using water-lifting aerators are clarified. Information about sulfides and VOSc fluctuation and control gained in this study may be applicable to similar reservoirs, and useful in practical water quality improvement and pollution prevention.

Marine Carbon-Sulfur Biogeochemical Cycles during the Steptoean Positive Carbon Isotope Excursion (SPICE) in the Jiangnan Basin, South China

Global occurrences of Steptoean Positive Carbon Isotope Excursion (SPICE) during Late Cambrian recorded a significant perturbation in marine carbon cycle, and might have had profound impacts on the biological evolution. In previous studies, SPICE has been reported from the Jiangnan slope belt in South China. To evaluate the bathymetric extent of SPICE, we investigate the limestone samples from the upper Qingxi Formation in the Shaijiang Section in the Jiangnan Basin. Our results show the positive excursions for both carbonate carbon (δ13C) and organic carbon (δ13Corg) isotopes, as well as the concurrent positive shifts in sulfur isotopes of carbonate associated sulfate (CAS, δ34SCAS) and pyrite (δ34Spyrite), unequivocally indicating the presence of SPICE in the Jiangnan Basin. A 4‰ increase in δ13Ccarb of the Qingxi limestone implies the increase of the relative flux of organic carbon burial by a factor of two. Concurrent positive excursions in δ34SCAS and δ34Spyrite have been attributed to the enhanced pyrite burial in oceans with extremely low concentration and spatially heterogeneous isotopic composition of seawater sulfate. Here, we propose that the seawater sulfur isotopic heterogeneity can be generated by volatile organic sulfur compound (VOSC, such as methanethiol and dimethyl sulfide) formation in sulfidic continental margins that were widespread during SPICE. Emission of 32S-enriched VOSC in atmosphere, followed by lateral transportation and aerobic oxidation in atmosphere, and precipitation in open oceans result in a net flux of 32S from continental margins to open oceans, elevating δ34S of seawater sulfate in continental margins. A simple box model indicates that about 35% to 75% of seawater sulfate in continental margins needs to be transported to open oceans via VOSC formation.

Research on an emergency treatment technology for black-odor water caused by macrophytes decaying

水草腐烂加速水体耗氧和水体还原性物质的溶出进程,在夏、秋季高温条件下极易引发局部水体黑臭.以太湖沉水植物优势种马来眼子菜(Potamogeton malaianus)、苦草(Vallisneria natans)及浮叶植物优势种莕菜(Nymphoides peltatum)为受试材料,利用太湖原位底泥培养模拟水草腐烂形成的黑臭水体,考察不同的环境材料处置方式(壳聚糖(CTS)、聚合氯化铝(PAC)、聚丙烯酰胺(PAM)、CTS+PAC和PAC+PAM)对黑臭水体浊度、溶解氧浓度、挥发性硫化物等黑臭水体特征污染物的絮凝沉降规律及去除机理.结果表明:(1)絮凝处理24 h后,CTS+PAC组合对黑臭水体的浊度去除效果最佳,浊度去除率达70.3%,上覆水溶解氧浓度明显提高,增加率为261.5%;(2)加石英砂悬浊液加速絮体沉淀,形成絮体之后加石英砂使水体浊度稳步下降,4 h之后,浊度去除率达74.9%,显著高于与絮凝剂一起加入的处理组(29.8%);(3)植物腐烂释放的含硫特征嗅味物质主要为硫化氢(H₂S)、甲硫醚和二甲基三硫醚.不同植物体腐烂释放的含硫挥发性有机物浓度差异显著,马来眼子菜释放的4种含硫有机物总和分别为莕菜和苦草释放的319.8%和252.2%;(4)CTS+PAC处理后苦草及马来眼子菜腐烂水体中挥发性有机硫化物浓度较对照组分别降低了18.6%和44.5%.PAC+PAM组合絮凝处理组对莕菜腐烂水体中H₂S有较好的去除效果,去除率达到52.4%.CTS+PAC絮凝剂组合处理的H₂S浓度均低于对照组,苦草、马来眼子菜和莕菜腐烂后黑臭水体中H₂S浓度分别降低了27.4%、41.0%和28.6%.CTS+PAC组合对H₂S和二甲基硫醚类物质等致臭物释放的抑制效果优于PAC+PAM组合絮凝处理.;Aquatic plants decaying will accelerate the process of dissolved oxygen depletion and promote the dissolution of reducing substance, which can easily lead to partial water black-odor in a hot summer. In this study, dominant species of submerged plants Potamogeton malaianus, Vallisneria natans and floating-leaved dominant species Nymphoides peltatum in Lake Taihu were selected as test material. Then the macrophytes decayed in cylindrical sediment in the culture system in which simulated conditions in situ. The black-odor waters were formed to study the flocculation and sedimentation kinetics, removal mechanism of water turbidity, volatile sulfide, dissolved oxygen and other water and soil interface characteristics which were treated with different environmental material disposals(chitosan(CTS), poly aluminum chloride(PAC), polyacrylamide(PAM), CTS+PAC and PAC+PAM). The results suggest that:(1) After 24 h, the turbidity removal of black smelly water treated by CTS+PAC was optimal, when turbidity removal rate was 70.3%. The CTS+PAC combination can increase the dissolved oxygen in overlying water more significantly than other environmental material disposals, and the increase rate is 261.5%.(2) Taking flocculation experiments by joining flocculants in the black smelly water with different flocculants, the suspension of quartz sand was added at different timing. Quartz sand suspension can accelerate flocculant precipitation, adding quartz sand before flocculant is significantly better than after it with turbidity removal rate 74.9% compared to 29.8%.(3) Sulfur characteristic odor compounds released by decay aquatic plants are mainly hydrogen sulfide(H₂S), dimethyl sulfide and dimethyl trisulfide. volatile organic sulfur compounds(VOSCs) released by difference decayed plants was significantly different. The sum of the four forms of organic sulfur released from Potamogeton malaianus were 319.8% of Nymphoides peltatum and 252.2% of biter grass.(4) Volatile organic sulfur compounds contents of Vallisneria natans and Potamogeton malaianus decaying water treated by CTS+PAC was reduced by 18.6% and 44.5%. Treatment PAC+PAM has a good deodorizing effect on Nymphoides peltatum for the removal rate of H₂S reached 52.4% when treatment CTS+PAC affected both three kind of plants. The content of H₂S reduced by 27.4%, 41.0% and 28.6% in Vallisneria natans, Potamogeton malaianus and Nymphoides peltatum, respectively. The inhibitory effect of odorant(such as H₂S and dimethyl sulfide) in treatment CTS+PAC was higher than that in treatment PAC+PAM.

Removal of volatile organic sulfur compounds by aeration during algae-induced black blooms in shallow lakes

High levels of volatile organic sulfur compounds (VOSCs) have frequently been detected during algae-induced black blooms, which pose an ecological threat to water bodies and their surrounding residents. In this study, aeration was applied to remove the VOSCs after the outbreak of a black bloom. The removal efficiencies under different aeration rates (A1 (0.06 m3-air min−1 m−3), A2 (0.18 m3-air min−1 m−3), and A3 (0.54 m3-air min−1 m−3)) were compared. For treatments A2 and A3, the level of dissolved oxygen (DO) and the oxidation-reduction potential (Eh) increased sharply after 1 h of aeration, and about 70% of the VOSCs were removed from the water columns; however, for treatment A1, the increases in DO and Eh and the rate of removal of VOSCs were slower. The ultimate removal rate of VOSCs was >99% for all the aerated treatments after 24 h. The alteration of the oxidation-reduction conditions, induced by the aeration, could be the primary reason for the removal of the VOSCs. Thus, aeration treatment might be a feasible technique for the removal of VOSCs after the outbreak of black blooms in waterworks and some shallow lakes.