Emissions Of Sulfur Compounds Research Articles

Evaluating the carbon footprint of sulphur recovery unit: A comprehensive analysis

Desulphurising of oil based fuels and industrial gases is a widespread practice. The combustion process in the sulphur recovery unit (SRU) involves the reaction of H2S with oxygen to produce SO2, which is then converted to elemental sulphur through a series of catalytic reactions. Oxygen enrichment is a technique used to enhance the performance and efficiency of the SRU. By introducing a higher concentration of oxygen into the combustion process, the overall combustion reaction can be optimised, resulting in an increased sulphur recovery from sour gas and reduced emissions of sulphur compounds. The present study analyses the gate-to-gate comparative environmental impact of air versus oxygen enriched air used for combustion to recover 1.0 ton sulphur using GaBi software (8.5.0.79 version). The primary data was collected from the literature. The GaBi Indian extension database is used for the secondary data source. The results are reported using midpoint impact assessment methods CML 2001. The global warming potential for oxygen-enriched SRU is 232 kg CO2 eq. compared to 276 kg CO2 eq. for air enriched SRU. Similarly, the potential for abiotic depletion (elements + fossil), acidification, eutrophication, human toxicity, freshwater aquatic ecotoxicity, marine aquatic ecotoxicity, photochemical ozone creation and terrestric ecotoxicity are higher for air based SRU than oxygen-enriched SRU. The analysis concludes that oxygen enrichment technology is a highly effective way to reduce the environmental impact of the SRU.

Modeling the impact of sulfide ore processing waste disposal facilities on the environment and human health

After the completion of the exploitation of ore deposits, atmospheric migration of sulfur compounds remains an urgent ecological and hygienic problem. The aim of the study was to obtain scientifically sound ideas about the danger of waste from the extraction and processing of sulfide ores of non-ferrous and precious metals accumulated in mining regions for the environment and public health based on the methodology of integrated modeling. The emission of sulfur compounds was studied on a full-scale model of the Ursky dump of barite–pyrite bulk (Ursk settlement, Kemerovo Region), the nature of their combined action was studied in a model experiment on Wistar rats. According to the simulation results, the main components of harmful emissions from the Ursky dump include dimethyl sulfide, dimethyl sulfoxide and sulfur dioxide, the concentrations of which in the air exceeded the normative ones by 129–170, 119–127 and 1,7 times. When exposing experimental animals with a two-component mixture of dimethyl sulfide and dimethyl sulfoxide, a partial summation of the neuro- and hepatotoxic effects of the components was noted, while a three-component mixture of dimethyl sulfide, dimethyl sulfoxide and sulfur dioxide potentiated the irritating effect. The dependences of the qualitative and quantitative characteristics of the biological effects of the isolated mixtures on the sum of the concentrations of their components and time are investigated. The proven algorithm for modeling the effects of the impact of a sulfide-containing dump on the environment and public health makes it possible to expand the possibilities of environmental expertise of environmental protection measures and assessment of risks to public health in mining regions.

Kinetics of biodesulfurization of South African diesel using Pseudomonas aeruginosa

As a result of several environmental and health challenges associated with the emission of SOx during the direct combustion of diesel, stringent regulations have been issued by the Environmental Protection Agency (EPA) and the South African government to all refineries in South Africa. Therefore, the development of an effective, affordable, and less energy-intensive technique is therefore urgently required. In this recent study, real South African diesel (obtained after HDS, 120 ppm) was degraded by resting cells of Pseudomonas aeruginosa in a batch experiment. About 5 mL of diesel was measured into a 250 mL Erlenmeyer flask with 5 mL of resting cell in glycerol/NaCl (1:1) and 20 mL of Basal Salt Media (BSM). The mixture was incubated for 8 h, at 37 °C, and agitated at 130 rpm, with an initial hydrodesulfurized diesel concentration of 120 mg/L and cell mass of 1.2 gDCW/L. High-Liquid Chromatography and Gas/Mass (GC/MS) chromatography were used to determine the initial and final concentrations of the synthetic and real diesel samples. Findings showed about 70.54 % removal of DBT in 120 ppm desulfurized diesel. Meanwhile, Pseudomonas aeruginosa selectively converted sulfur atoms in DBT compound to 2-HBP. Michaelis-Menten for modeling the growth of the bacteria fitted well into the experimental data. Similarly, First-order kinetic fitted and described well the behavior of the bacteria for degradation of DBT in synthetic and real diesel samples. The findings of this investigation indicated that biodesulfurization would be a more effective method to complement the hydrodesulfurization (HDS) technique as opposed to the primary methods for desulfurizing organo-sulfur compounds in diesel oil. This will assist the refineries to meet up with the stringent regulation to minimize the emission of sulfur compounds, which cause environmental pollution and health problems in South Africa and all over the world.

Multi-dimension analysis of volatile sulfur compound emissions from an urban wastewater treatment plant

Long-term monitoring of volatile sulfur compounds (VSCs) released at the water-air interface from different treatment units of an anaerobic/oxic (A/O) wastewater treatment plant (WWTP) was carried out to assess the temporal and spatial emission characteristics of VSCs, to explore relationships between wastewater quality and VSC release. The VSC from non-aerated and aerated units were collected using dynamic and static chambers, respectively, and determined using gas chromatography. The VSC emission fluxes diminished in the order of primary sedimentation tank (PST) > anaerobic areas (ANA) > oxic section 1 (OX1). VSCs were not detected in the oxic section 2 (OX2), the oxic areas section 3 (OX3), and the final setting basin (FSB). Release capacities of VSCs descended in the order of summer > fall > spring > winter, with July, August, and September being the months with the highest VSC release capacities. VSC emission fluxes correlated well with wastewater temperatures, sulfate concentrations, and COD. VSC emission flux empirical equations based on wastewater temperature, sulfate concentrations, and COD were established. Based on the established VSC emission empirical equation, a control strategy to reduce the operating costs of deodorization facilities was proposed. This strategy is economically efficient and reduces the consumption of electrical energy.

Effects of self-produced lactic fermentation (SPLF) on GHG and VSC emissions during swine slurry storage

Self-produced lactic fermentation (SPLF) is a new valued utilization technology, but its impact on gas emission remains unclear. The objective of this study is to investigate the effect of replacing the H2SO4 additive with SPLF on greenhouse gas (GHG), and volatile sulfur compound (VSC) emissions from swine slurry storage in a laboratory-scale study. In this study, SPLF is directed toward producing lactic acid (LA) through the anaerobic fermentation of slurry and apple waste under the most suitable conditions, with the LA concentration kept at 10,000–52000 mg COD/L and the pH remaining within 4.5 during the following 90 days of slurry storage. Compared with that in the slurry storage treatment (CK), the GHG emissions decreased by 86% and 87% in the SPLF and H2SO4 groups, respectively. The low pH (i.e., less than 4.5) inhibited the growth of Methanocorpusculum and Methanosarcina and resulted in very low mcrA gene copies in the SPLF group, leading to a reduction in CH4 emissions. The methanethiol, dimethyl sulfide, dimethyl disulfide, and H2S emissions in the SPLF group were reduced by 57%, 42%, 22%, and 87% and increased by 2206%, 61%, 173%, and 1856% in the H2SO4 group, respectively. Therefore, SPLF can be an innovative bioacidification technology for effectively reducing GHG and VSC emissions from animal slurry storage.

Eutrophication levels increase sulfur biotransformation and emissions from sediments of Lake Taihu

Eutrophication can stimulate the emissions of volatile sulfur compounds (VSCs) accompanied by variations in environmental variables in lakes. However, the effects of eutrophication on VSC emissions from lake sediments as well as the underlying mechanisms remain unclear. In this study, depth gradient sediments at different eutrophication levels and seasons were collected from Lake Taihu to investigate the response of sulfur biotransformation in the sediments to eutrophication based on the analysis of environmental variables, microbial activity, abundance and community structure. H2S and CS2 were the main VSCs produced from the lake sediments, with the production rates of 2.3–7.9 and 1.2–3.9 ng g−1 h−1 in August, respectively, which were higher than those in March, mainly due to the increasing activity and abundance of sulfate-reducing bacteria (SRB) at high temperatures. The VSC production rates from the sediments increased with lake eutrophication level. Higher VSC production rates were detected in surface sediments in eutrophic regions but in deep sediments in oligotrophic regions. Sulfuricurvum, Thiobacillus and Sulfuricella were the main sulfur-oxidizing bacteria (SOB) in the sediments, while Desulfatiglans and Desulfobacca were the predominant SRB. Organic matter, Fe3+, NO3−-N and total sulfur had significant influences on the microbial communities in the sediments. Partial least squares path modelling showed that the trophic level index could stimulate VSC emissions from lake sediments by influencing the activities and abundances of SOB and SRB. These findings indicated that sediments contributed substantially to VSC emissions from eutrophic lakes, especially surface sediments, and sediment dredging might be an effective way to mitigate VSC emissions from eutrophic lakes.

Sonochemical transportation technology high viscous oil

The work is devoted to one of the urgent problems of the oil and gas complex - the transportation of high-viscosity oils. The object of the study was the high-viscosity high-sulphur mixed oil of the Ashalchinskoye field. The sonochemical treatment of oil made it possible to reduce the effective viscosity by 35-40% and the pour point by 15-20 °C. Pilot tests of the developed unit and sonochemical technology have shown the possibility of reducing the load on pumping stations of main pipelines, reducing the number of hot oil pumping stations, and reducing the amount of emissions of organic sulfur compounds into the atmosphere. Keywords: high-viscosity oil; petroleum dispersed systems; ultrasound; pour point depres-sants; sonochemical effect; effective viscosity; pour point.

Efficient Oxidative Desulfurization of High-Sulfur Diesel via Peroxide Oxidation Using Citric, Pimelic, and α-Ketoglutaric Acids

The widespread use of diesel fuel for transportation, industry, and electricity generation causes several environmental issues via an increase in the amount of sulfur compound emissions. Commercial diesel fuel must be free of sulfur-containing compounds since they can cause several environmental problems. Considering the currently available processes to eliminate sulfur compounds, oxidative desulfurization (ODS) is one of the effective means for this purpose. This work presented a simple, low cost, and efficient ODS system of high-sulfur diesel fuels using peroxide oxidation with the aid of citric, pimelic, and α-ketoglutaric acids. The aim of the study was to investigate the potential of these acids as hydrogen peroxide (H2O2) activators for ODS and to optimize the reaction conditions for maximum sulfur removal. The results showed that citric, pimelic, and α-ketoglutaric acids were effective catalysts for the desulfurization of high-sulfur diesel with an initial sulfur content of 2568 mg L−1, achieving a sulfur removal efficiency of up to 95%. The optimized reaction conditions were found to be 0.6 g of carboxylic acid dosage and 10 mL of H2O2 at 95 °C. The desulfurization efficiency of the real diesel sample (2568 mg L−1) was shown to be 27, 34, and 84.57%, using citric acid, α-ketoglutaric acid, and pimelic acid after 1h, respectively. The effectiveness of the oxidation process was characterized by gas chromatographic pulsed flame photometric detector (GC-PFPD) and Fourier-transform infrared spectroscopy (FTIR) techniques. The experimental results demonstrated that the developed system exhibited high efficiency for desulfurization of real high-sulfur diesel fuels that could be a good alternative for commercial application with a promising desulfurization efficiency.

Impact of Bacillus subtilis on manure solids, odor, and microbiome

A study was conducted to determine the effectiveness of supplementing swine manure with Bacillus subtilis (BS) to improve digestion of manure solids and lower odor emission. Large bioreactors (400 L) with manure (100 L) were treated with commercially available BS at a rate of 1% manure volume by either directly pouring or surface spraying the manure with inoculum. Manure physicochemical properties, gas emissions, and microbiome were monitored. Manures treated multiple times with BS or surface sprayed had significantly (P < 0.05) lower electrical conductivity, volatile solids, and chemical oxygen demand, by 3–5% compared to non-treated control manures. Volatile sulfur compound emissions (VSCs) were reduced by 20–30% in both experiments, while ammonia and volatile organic compounds were reduced by 40% and 15%, respectively, in surface spray experiment only. The manure indigenous microbiome remained relatively stable following treatment and BS were never detected in the raw or treated manure following multiple treatments. The reduction in manure organic carbon and VSCs emissions were a result of physical mixing during manure treatment and biological material in the microbial inoculum stimulating microbial activity and not growth of BS.

Estimation of sulfur fate and contribution to VSC emissions from lakes during algae decay

Algae decay is an important process influencing environmental variables and emissions of volatile sulfur compounds (VSCs) in eutrophic lakes. However, effects of algae decay on VSC emissions from eutrophic lakes as well as fate of algae-derived sulfur remain poorly understood. In this study, simulated algae-sediment systems were used to explore the flow and distribution of sulfur during algae decay. VSCs including hydrogen sulfide (H2S), methanethiol (CH3SH), carbon disulfide (CS2) and dimethyl sulfide ((CH3)2S) were detected during algae decay, which increased with algae biomass and eutrophic levels in lakes. During algae decay, the highest H2S, CH3SH and (CH3)2S emission rates of 10.45, 21.82 and 43.26 μg d−1 occurred in the first 1–2 days, respectively, while the highest CS2 emission rates were observed between days 8 and 11. The maximum emissions of H2S and CS2 from algae decay were estimated at 0.51 and 0.35 mg m−2 d−1 in Lake Taihu, accounting for 1.57% and 0.69% of the total H2S and CS2 emissions of in situ, respectively. Algae decay could significantly increase the contents of total sulfur and total carbon in sediments by 2.90%–21.11% and 4.23%–45.05%, respectively. The VSC emissions during algae decay could be predicted using the multiple regression models with the contents of total carbon, total nitrogen and sulfur-containing compounds in sediments. Partial least squares path modelling demonstrated that algae decay had a low direct effect on VSC emissions with a strength of 0.06, while it had a significant influence on environmental variables with a strength of 0.63, which could affect VSC emissions with a strength of 0.85, indicating VSC emissions from eutrophic lakes were affected by the environmental variables rather than the direct influence of algae decay. These findings illustrated the mechanisms of VSC emissions during algae decay and provided insights into VSC control and mitigation for eutrophic lakes.

Emission of volatile sulphur compounds during swine manure composting: Source identification, odour mitigation and assessment

This study aimed to identify the sources of volatile sulphur compounds (VSCs) and evaluate their mitigation by ferric oxide (Fe2O3) during swine manure composting. Four chemicals, including l-cysteine, l-methionine, sodium sulphite, and sodium sulphate, were further added to simulate organic and inorganic sulphur-containing substances in swine manure to track VSC sources during composting. Results show that sulphur simulants induced the emission of six common VSCs, including methyl sulphide (Me2S), dimethyl sulphide (Me2SS), carbonyl sulphide (COS), carbon disulphide (CS2), methyl mercaptan (MeSH), and ethyl mercaptan (EtSH), during swine manure composting. Of them, COS, CS2, MeSH and Me2SS were predominantly contributed by the biodegradation of methionine and cysteine, while Me2S and EtSH were dominated by the reduction of sulphite and sulphate. Further Fe2O3 addition at 1.5 % of total wet weight of composting materials immobilized elemental sulphur and inhibited sulphate reduction to reduce the emission of VSCs by 46.7–80.9 %. Furthermore, odour assessment indicated that adding Fe2O3 into composting piles significantly reduced the odour intensity level to below 4, the odour value of VSCs by 47.1–81.3 %, and thus the non-carcinogenic risk by 68.4 %.

Inhibitory Effects of the Addition of KNO3 on Volatile Sulfur Compound Emissions during Sewage Sludge Composting.

Odor released from the sewage sludge composting process often has a negative impact on the sewage sludge treatment facility and becomes a hindrance to promoting compost technology. This study investigated the effect of adding KNO3 on the emissions of volatile sulfur compounds, such as hydrogen sulfide (H2S), dimethyl sulfide (DMS), and carbon disulfide (CS2), during sewage sludge composting and on the physicochemical properties of compost products, such as arylsulfatase activity, available sulfur, total sulfur, moisture content, and germination index. The results showed that the addition of KNO3 could inhibit the emissions of volatile sulfur compounds during composting. KNO3 can also increase the heating rate and peak temperature of the compost pile and reduce the available sulfur loss. The addition of 4% and 8% KNO3 had the best effect on H2S emissions, and it reduced the emissions of H2S during composting by 19.5% and 20.0%, respectively. The addition of 4% KNO3 had the best effect on DMS and CS2 emissions, and it reduced the emissions of DMS and CS2 by 75.8% and 63.0%, respectively. Furthermore, adding 4% KNO3 had the best effect from the perspective of improving the germination index of the compost.

Regenerative One-Stage Catalytic Absorption Process with Cupric Ions for Removal of Reduced Sulfur Compounds in Polluted Air

Reduced volatile sulfur compounds emitted from e.g. livestock production and biogas production facilities contribute to general air pollution and local odor nuisance. Improved technologies are required to mitigate the emissions of both hydrogen sulfide and organic sulfur compounds. The present study examines the oxidative absorption of reduced sulfur compounds, i.e. hydrogen sulfide, methanethiol and dimethyl sulfide in a wet oxidation process with cupric chloride. It was found that this process efficiently removes both hydrogen sulfide and methanethiol with removal efficiencies >94% under all process conditions tested, while the removal of dimethyl sulfide was in the range 20-40%. The main products determined were dimethyl disulfide, dimethyl trisulfide and elemental sulfur. It was shown that the process was more efficient than the similar process with ferric ions and higher removal could be obtained with lower residence times. Furthermore, though employing cupric ion as metal catalysts results in the production of gaseous sulfur compounds, it is estimated that this process is efficient for deodorization due to the higher odor threshold values of the product compounds and the pH range is optimal for gas streams containing CO2.

Eutrophic levels and algae growth increase emissions of methane and volatile sulfur compounds from lakes

Eutrophic lakes are hot spots of CH4 and volatile sulfur compound (VSC) emissions, especially during algal blooms and decay. However, the response of CH4 and VSC emissions to lake eutrophication and algae growth as well as the underlying mechanisms remain unclear. In this study, the emissions of CH4 and VSCs from four regions of Lake Taihu with different eutrophic levels were investigated in four months (i.e., March, May, August and December). The CH4 emissions ranged from 20.4 to 126.9 mg m−2 d−1 in the investigated sites and increased with eutrophic levels and temperature. H2S and CS2 were the dominant volatile sulfur compounds (VSCs) emitted from the lake. The CH4 oxidation potential of water ranged from 2.1 to 14.9 μg h−1 L−1, which had positive correlations with trophic level index and the environmental variables except for the NH4+-N concentration. Eutrophic levels could increase the abundances of bacteria and methanotrophs in lake water. α-Proteobacteria methanotroph Methylocystis was more abundant than γ-Proteobacteria methanotrophs in March and May, while the latter was more abundant in August and November. The relative abundance of Cyanobacteria, including Microcystis, A. granulata var. angustissima and Cyanobium had significantly positive correlations with temperature, turbidity, SO42--S, and total sulfur. Partial least squares path modelling revealed that the algal growth could promote VSC emissions, which had a positive correlation with CH4 oxidation potential, likely due to the positive correlation between the CH4 and VSC emissions from lakes. These findings indicate that water eutrophication and algae growth could increase the emissions of CH4 and VSCs from lakes. Controlling algae growth might be an effective way to mitigate the emissions of CH4 and VSCs from freshwater lakes.

Mechanism of digestate-derived biochar on odorous gas emissions and humification in composting of digestate from food waste

Emissions of odorous gases and prolonged composting duration are the key concerns in the composting of digestate from food waste (DFW). In this study, different amounts of biochar derived from DFW (BC-DFW) were introduced in the composting process of DFW to decrease the emissions of ammonia (NH3) and volatile sulfur compounds (VSCs) and composting duration. The addition of BC-DFW increased the temperature and germination index during DFW composting. The group with 25% BC-DFW exhibited a 30% smaller composting duration. Significant amounts of NH3 and VSCs emissions were observed in the initial phase of DFW composting. Dimethyl disulfide (DMDS) was a prominent contributor to the odor associated with VSCs. The addition of BC-DFW facilitated the adsorption of NH3 and VSCs, and the corresponding contents decreased by 5–21% and 15–20%, respectively. Moreover,the BC-DFW accelerated the transformation of ammonium-nitrogen (NH4+-N) to nitrate-nitrogen (NO3--N), thereby alleviating the NH3 volatilization. The addition of 25% BC-DFW minimized the NH3 emission and enhanced the generation of humic-acid-like matter, thereby promoting humification. Therefore, the addition of 25% BC-DFW was optimal for promoting the degradation of organic matter and humification and odor emission reduction (e.g., NH3, DMDS).

CS2 increasing CH4-derived carbon emissions and active microbial diversity in lake sediments

Lakes are important methane (CH4) sources to the atmosphere, especially eutrophic lakes with cyanobacterial blooms accompanied by volatile sulfur compound (VSC) emissions. CH4 oxidation is a key strategy to mitigate CH4 emission from lakes. In this study, we characterized the fate of CH4-derived carbon and active microbial communities in lake sediments with CS2 used as a typical VSC, based on the investigation of CH4 and VSC fluxes from Meiliang Bay in Lake Taihu. Stable isotope probing microcosm incubation showed that the efficiency of CH4-derived carbon incorporated into organic matter was 21.1% in the sediment with CS2 existence, which was lower than that without CS2 (27.3%). SO42--S was the main product of CS2 oxidation under aerobic condition, accounting for 59.3–62.7% of the input CS2–S. CS2 and CH4 coexistence led to a decrease of methanotroph and methylotroph abundances and stimulated the production of extracellular polymeric substances. CS2 and its metabolites including total sulfur, SO42− and acid volatile sulfur acted as the main drivers influencing the active microbial community structure in the sediments. Compared with α-proteobacteria methanotrophs, γ-proteobacteria methanotrophs Methylomicrobium, Methylomonas, Crenothrix and Methylosarcina were more dominant in the sediments. CH4-derived carbon mainly flowed into methylotrophs in the first stage. With CH4 consumption, more CH4-derived carbon flowed into non-methylotrophs. CS2 could prompt more CH4-derived carbon flowing into non-methanotrophs and non-methylotrophs, such as sulfur-metabolizing bacteria. These findings can help elucidate the influence of VSCs on microorganisms and provide insights to carbon fluxes from eutrophic lake systems.

МАТЕМАТИЧЕСКОЕ МОДЕЛИРОВАНИЕ И УПРАВЛЕНИЕ ДВИЖЕНИЕМ ОДИНОЧНОЙ КАПЛИ ДОМЕННОГО ШЛАКА В ПОТОКЕ ГАЗА ПРИ СУХОЙ ГРАНУЛЯЦИИ

Dry granulation plants of blast furnace slag allow obtaining granulated slag and use heat of liquid slag. When introducing dry granulation of slag, emissions of harmful sulfur compounds into the atmosphere are excluded. When designing the granulation chamber, it is necessary to evaluate the main size of the chamber - its diameter to avoid slag sticking to the walls of the chamber. The slag droplets must solidify before colliding with the wall. In this work, the authors developed a mathematical model for the movement of a single droplet of molten blast furnace slag during dry granulation, which allows controlling the cooling process of a single droplet of molten blast furnace slag in the granulation chamber.

Occurrence and emissions of volatile sulfur compounds in the Changjiang estuary and the adjacent East China Sea

Volatile organic sulfur compounds (VSCs) are key components of the oceanic and atmospheric sulfur cycle. Here, we investigated the distributions of three major VSCs, such as carbon disulfide (CS2), dimethyl sulfide (DMS), and carbonyl sulfide (COS), and estimated their sea-to-air fluxes in the Changjiang Estuary and the adjacent East China Sea from July 20 to August 3, 2017. The DMS, COS, and CS2 surface water concentration ranges were 0.22–18.62, 0.06–0.77, and 0.02–0.3 nmol L−1, respectively. The distributions of VSCs were related to environmental and biological factors. In contrast to DMS, COS and CS2 concentrations generally decreased from the estuary to offshore waters. A significant correlation was observed between chlorophyll a and CS2 concentration, suggesting that CS2 production may be related to phytoplankton growth. Moreover, a positive correlation was observed between CS2 and DMS, indicating that they might share similar production pathways. COS was the most abundant VSC in the atmosphere, with an average concentration of 422.9 ± 301.8 ppt, but its distribution was likely influenced by anthropogenic activities. The average COS, DMS, and CS2 sea-to-air fluxes were 0.98 ± 0.98, 4.38 ± 6.42, and 0.05 ± 0.05 μmol m−2 d−1. The Changjiang Estuary and the adjacent East China Sea are important sources of atmospheric VSCs. These results will help us to better understand global VSC cycling between the oceanic atmosphere and bodies of water.

Non‐Marine Sources Contribute to Aerosol Methanesulfonate Over Coastal Seas

AbstractMethanesulfonate (MSA) in the marine boundary layer is commonly considered to be solely contributed by the oxidation of ocean‐derived dimethyl sulfide (DMS) and often used as an indicator of marine biogenic sources. But whether this judgment is valid in coastal seas and how the validity is affected by air mass transport history have been less discussed. Based on multi‐year observations of aerosol MSA in the coastal East China Sea (ECS) and the Gulf of Aqaba (GA), as well as the analysis of air mass transport pattern and exposure to ocean surface phytoplankton biomass, we found that terrestrial sources made a non‐negligible contribution to MSA over the ECS but not over the GA. The abundant MSA in winter over the coastal ECS was likely associated with substantial emissions of volatile organic sulfur compounds from both anthropogenic and natural sources in eastern China and significant terrestrial transport influenced by the East Asian Monsoon. Good correlations between aerosol MSA and air mass exposure to surface phytoplankton biomass were established by removing the influence of terrestrial transport and confining the air transport height within boundary layer, which makes it possible to construct parameterizations for obtaining the spatiotemporal distributions of marine biogenic aerosol components using satellite ocean color datasets.

Improved effect of manure acidification technology for gas emission mitigation by substituting sulfuric acid with acetic acid

Animal manure is a significant source of ammonia, methane, hydrogen sulfide, and odor emissions. Manure acidification to pH 5.5 using sulfuric acid (H2SO4) is an approved method for reducing ammonia and methane emissions from barns and retaining bioavailable nitrogen in the slurry for subsequent field fertilization. However, the use of H2SO4 may increase the emission of malodorous sulfur compounds and reduces subsequent biogas production. In this study, we investigated if substituting a part of the H2SO4 treatment with acetic acid (CH3COOH) improves manure emissions. In two experiments, cattle manure was incubated for 11 days each and acidified daily with either i) H2SO4 (4M) or CH3COOH (4M), or ii) mixes of both acids (4M H2SO4 + 8M CH3COOH, in volume ratios of 75:25, 50:50, and 25:75) until pH 5.5. The emission of ammonia, methane, hydrogen sulfide, and volatile organic compounds (VOCs) was monitored continuously. At the end of both experiments, cumulative ammonia emission was reduced by 75% by H2SO4 and by 83% by CH3COOH, indicating that CH3COOH was more efficient. Acetic acid almost completely eliminated CH4 emission, while H2SO4 reduced CH4 emission by 89%. Furthermore, CH3COOH acidification resulted in lower odorant emissions compared to H2SO4. Based on the second experiment, we recommend using a high percentage of CH3COOH during the first days of acidification, followed by a mix containing at least 50% CH3COOH, to achieve a high mitigation efficiency with a lower emission of sulfur compounds compared to H2SO4 alone.