Large Amounts Of Particulate Matter Research Articles

CSOs처리를 위한 응집침전시스템에서 슬러지 반송에 의한 고형물 처리효율평가

In this study, the sludge that occurs in the initial operation of coagulation system developed for the treatment of CSOs were returned to the flocculation reactor. The purposes of this study were to analyze the Characteristics of flocs that are generated through the recycling sludge and settling characteristics of sludge, and to evaluate the possibility that high concentrations of particulate matter in the initial inflow of CSOs could be used as an weighted coagulant additive. As a result, the concentration of treated CSOs pollutants at the beginning of the CSOs influent with a large amount of particulate matter over 20 was low, after gradually increasing the concentrations of them. The flocs generated from the sludge return were similar in size compared to flocs generated through injection of micro sands, and settling velocity in case of return sludge injection was decreased from 55.1 cm/min to 21.5 cm/min. SVI value of the sludge accumulated at the bottom of the sedimentation tank was 72, and settled sludge volume decreased rapidly due to the consolidation of sludge to the time it takes to 10 minutes. these mean that sludge used for recycling has good settling characteristic. A condition of returned sludge which is 0.1% return of 0.3% extraction was formed in the balance of settlement and extraction. In this case, This condition was to be adequate to maintain the proper concentration such as 100~200 mg/L of TS and 50~100 mg/L of VS in the flocculation reactor. The usage of the return sludge containing particulate matters of CSOs as an weighted coagulant additive was able to secure a stable treated water quality despite the change of influent water quality dynamically. Furthermore, it can be expected to reduce the alum dosage along with the sludge production.

Cytotoxic, phytotoxic, and mutagenic appraisal to ascertain toxicological potential of particulate matter emitted from automobiles

Vehicular air pollution is a mounting health issue of the modern age, particularly in urban populations of the developing nations. Auto-rickshaws are not considered eco-friendly as to their inefficient engines producing large amount of particulate matter (PM), thus posing significant environmental threat. The present study was conducted to ascertain the cytotoxic, phytotoxic, and mutagenic potential of PM from gasoline-powered two-stroke auto-rickshaws (TSA) and compressed natural gas-powered four-stroke auto-rickshaws (FSA). Based on the increased amount of aluminum quantified during proton-induced X-ray emission analysis of PM from TSA and FSA, different concentrations of aluminum sulfate were also tested to determine its eco-toxicological potential. The MTT assay demonstrated significant (p < 0.001) dose-dependent cytotoxic effects of different concentrations of TSA, FSA, and aluminum sulfate on BHK-21 cell line. LC50 of TSA, FSA, and aluminum sulfate was quantified at 16, 11, and 23.8 μg/ml, respectively, establishing PM from FSA, a highly cytotoxic material. In case of phytotoxicity screening using Zea mays, the results demonstrated that all three tested materials were equally phytotoxic at higher concentrations producing significant reduction (p < 0.001) in seed germination. Aluminum sulfate proved to be a highly phytotoxic agent even at its lowest concentration. Mutagenicity was assessed by fluctuation Salmonella reverse mutation assay adopting TA100 and TA98 mutant strains with (+S9) and without (-S9) metabolic activation. Despite the fact that different concentrations of PM from both sources, i.e., TSA and FSA were highly mutagenic (p < 0.001) even at lower concentrations, the mutagenic index was higher in TSA. Data advocate that all tested materials are equally ecotoxic, and if the existing trend of atmospheric pollution by auto-rickshaws is continued, airborne heavy metals will seriously affect the normal growth of local inhabitants and increased contamination of agricultural products, which will amplify the dietary intake of the toxic elements and could result in genetic mutation or long-term health implications.

Treatments of polluted emissions from incinerator gases: a succinct review

Due to the incomplete mineralisation of some organic compounds during the incineration of municipal solid waste, gaseous emissions are loaded with a large amount of particulate matter, undesirable elements and toxic molecules. Typically, an incinerator of urban solid waste produces large flows of hot gaseous emissions to be purified before being released into the atmosphere. In this paper, treatments of flue gas from a typical municipal waste incinerator are described. The first step is an energy recovery system through heat exchangers to make steam or hot water. Steam is used to produce electricity via a turbine. The economic balance of the total system is very often dependent on the heat recovery. The second step involves particle removal technologies. Different systems are available such as cyclones, scrubbers, electrostatic precipitators or baghouse filters. The third step is the removal of numerous molecule families such as acid compounds (SOx, HCl, HF), nitrogen oxides (NOx), metal species and many organic compounds. The latter include dioxins, furans and volatile organic compounds. Some treatment processes are described according to the pollutant family.

Identification of air pollutant sampling period using horizontal dilution potential

A new model is proposed for estimating horizontal dilution potential of an area using wind data. The mean wind speed and wind direction variation are used as a measure of linear and angular spread of pollutant in the atmosphere. The methodology is applied to monitored hourly wind data for each month of 1 year for wind data collected at Vadodara, Gujarat and monthly dilution potential is estimated. It is found that there is a gradual variation of horizontal dilution potential over a year with limited dilution during post monsoon period i.e., October and November and a high dilution in pre monsoon period i.e., May and June. This information can be used to design air quality sampling network and duration of sampling for source apportionment study. Air pollutant sampling during high dilution period can be carried out for identifying urban and rural dust and wind blown dust from mining activity. Air pollutant sampling during low dilution period can be carried out for capturing large amount of particulate matter from anthropogenic sources like elevated stack of furnace.

Polychlorinated naphthalenes and other dioxin‐like compounds in Elbe River sediments

Contamination of Elbe River (Germany) sediments with dioxin-like toxicants was investigated following the 500-year flood (flood that statistically occurs once in 500 years) of 2002. It was hypothesized that large amounts of particulate matter from river beds and associated dioxin-like toxicants were mobilized and transported during this flood event. The investigation focused on polychlorinated naphthalenes (PCNs) that have not been determined previously in the Elbe River. The in vitro H4IIE-luc assay was used as an overall measure for toxicants capable of binding to the aryl hydrocarbon receptor (AhR). The assay was combined with congener-specific instrumental analyses and fractionation to quantify PCN contributions to total AhR-mediated activity relative to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs). Penta- to octachloronaphthalene concentrations of 30 ng/kg dry weight up to 13 microg/kg dry weight were found in Elbe River sediments downstream of Bitterfeld. Concentrations of penta- to octachloronaphthalenes, however, were only approximately 3 microg/kg dry weight at a site in the vicinity of Bitterfeld, where a level of approximately 3 mg/kg dry weight was reported before the flood. Also, the congener pattern of PCNs at this site changed after the flood, and PCN patterns reported previously for Bitterfeld and assigned to chlor-alkali electrolysis with graphite electrodes could now be observed at the sites from downstream of Bitterfeld and Magdeburg. Whereas PCDD/Fs dominated the dioxin-like activity in the middle and lower Elbe River, PCNs contributed as much as 10% of the total AhR-mediated activity. The contribution of PCBs was less significant (maximum, 0.2%). Thus, in Elbe River sediments, PCNs should be considered as relevant contaminants and be included in future monitoring and risk assessment programs.

THE EFFECT OF RANDOMLY ORIENTED GEOFIBRE AND LIME ON THE CBR VALUE OF DADRI FLYASH: AN EXPERIMENTAL STUDY

ABSTRACT The purpose of this paper is to study the influence on CBR, Fly ash mixed with lime having varying percentage of geofibres. The volume fractions of geofibres were, 0. 00, 0.10, 0.15, 0.20 and 0.25 percent. Different types of ash residues and large amount of particulate matter and gases are generated by thermal power plants. Fly ash is the most abundant of all the residues and its disposal not only needs enormous land, water and power resources but it also causes serious environmental hazards. In India about 82 such Power Plants produce nearly 106 million tons of fly ash per year [9]and the figure is likely to soar. This alarming increase in the production of fly ash and its disposal in ecologically suitable manners has lately become a global concern. Efforts are being made to increase the use of fly ash in every possible way. In this struggle scientists and engineers especially civil engineers are playing a remarkable role. A number of studies have been carried out to determine the influence of geofibers on the physical properties of soil and fly ash. However, very few studies have been done to investigate the effect of randomly oriented geofibers on fly ash mixed with lime. In this paper, results of an experimental study have been presented to determine the effect of randomly oriented geofibers & lime on the value of CBR of Fly ash.

City-wide sweeping a source for respirable particulate matter in the atmosphere

Most of the cities located in Northern India are afflicted with the presence of unusually high concentration of PM 10 in the ambient environment posing a serious risk to human health. To understand the reasons underlying the persistence of the high levels of PM 10 in the Delhi region, a novel experiment was designed by appropriating a well-known tracer-source—Diwali fireworks—emitting a large amount of particulate matter (PM) in the atmosphere. Sequential eight hourly PM 10 samples were collected and analyzed for the elemental signatures associated with the tracer and other sources. Principal component analysis was used to resolve the sources; their respective mass contribution to PM 10 load, in time sequence, was estimated using absolute principal component score method. The results suggest that the well-established practice of city-wide street-cleaning, resuspends the surface deposited PM 10 back to the atmosphere. We suspect that this practice resuspends about 25% of the sedimented PM 10 back into the atmosphere.

The influence of tropical cyclone Melor on PM 10 concentrations during an aerosol episode over the Pearl River Delta region of China: Numerical modeling versus observational analysis

In this article, numerical simulations and observational analyses have been made for the aerosol episode that occurred over the Pearl River Delta (PRD) region in China during 1–3 November 2003. An air quality modeling system that consisted of the mesoscale model MM5, chemical transport model MODELS-3/CMAQ, and air pollutant emission model SMOKE, was employed. Studies have shown that this particulate matter (PM) pollution episode was apparently associated with the activity of tropical cyclone (TC) Melor. Model simulations revealed that Melor spawned this PM episode through dynamic and thermodynamic processes. The strong compensating subsidence induced by Melor's peripheral circulations created favorable meteorological conditions that enhanced local aerosol pollution. This strong downward motion produced significant adiabatic warming (2–4 °C daily) and dramatic drying in the low-level troposphere over the PRD. As a result, the PRD region was blanketed with a dry and warm air layer that strengthened the static stability of the lower troposphere. The descending motion also tended to dramatically lower the heights of the planetary boundary layer (PBL) through its dynamic effect. The fair weather created by this synoptic pattern further intensified the nocturnal temperature inversions through enhanced radiative cooling. All of these factors promoted a stagnant local atmosphere with very light winds near the surface. The horizontal and vertical dispersions of locally emitted aerosol particles were largely suppressed, leading to the accumulation of large amounts of PMs near local emission sources in the PRD region. As Melor drew near, changes in surface winds strengthened the horizontal transport of aerosol particles from inland sources to the area of Hong Kong downstream. This horizontal advection greatly contributed to the high PM 10 (particulate matters less than 10 μm in diameters) concentrations in Hong Kong.

Investigation of Novel Incineration Technology for Hospital Waste

Conventional incineration systems for hospital waste (HW) emit large amounts of particulate matter (PM) and heavy metals, as well as dioxins, due to the large excess air ratio. Additionally, the final process residues--bottom and fly ashes containing high levels of heavy metals and dioxins--also constitute a serious environmental problem. These issues faced by HW incineration processes are very similar to those confronted by conventional municipal solid waste (MSW) incinerators. In our previous work, we developed a novel technology integrating drying, pyrolysis, gasification, combustion, and ash vitrification (DPGCV) in one step, which successfully solved these issues in MSW incineration. In this study, many experiments are carried out to investigate the feasibility of employing the DPGCV technology to solve the issues faced by HW incineration processes, although there was no MSW incinerator used as a HW incinerator till now. Experiments were conducted in an industrial HW incineration plant with a capacity of 24 tons per day (TPD), located in Zhenzhou, Henan Province. Results illustrated that this DPGCV technology successfully solved these issues as confronted by the conventional HW incinerators and achieved the expected results for HW incineration as it did for MSW incineration. The outstanding performance of this DPGCV technology is due to the fact that the primary chamber acted as both gasifier for organic matter and vitrifying reactor for ashes, and the secondary chamber acted as a gas combustor.

The functional role of native freshwater mussels in the fluvial benthic environment

Summary1. Freshwater mussels are the dominant consumer biomass in many fluvial systems. As filter feeding grazers, mussels can remove large amounts of particulate matter from the water column and transfer these resources to the substrate as biodeposits (agglutinated mussel faeces and pseudofaeces). Mussel biodeposits are a nutrient rich and easily assimilated food source and therefore may have significant relevance to benthic community structure. This study examines the functional role of Margaritifera falcata in the South Fork Eel River, California.2. We addressed two main questions: (i) Do mussels increase benthic resources in this system? (ii) If so, does this alter macroinvertebrate community structure?3. Measurements and enclosure experiments in the South Fork Eel River show that mussels can play a significant role in local food webs by increasing available fine particulate matter (both organic and inorganic) on the substrate. We document increased benthic macroinvertebrate biomass for predators and collectors (Leptophlebidae) in the presence of mussels, but only in late summer.

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Variations in the source, metal content and bioreactivity of technogenic aerosols: a case study from Port Talbot, Wales, UK

Atmospheric aerosol samples were collected during different prevailing wind directions from a site located close to a busy motorway, a major steelworks, and the town of Port Talbot (Wales, UK). A high-volume collector was used (1100 l/min), enabling relatively large amounts of particulate matter (PM 10–2.5 and PM 2.5) samples to be obtained on a polyurethane foam [PUF, H 2N–C(O)O–CH 2CH 3] substrate over periods of 2–7 days. Four samples were chosen to exemplify different particle mixtures: SE- and NE-derived samples for particles moving along and across the motorway, a NW-derived sample from the town, and a mixed SW/SE-derived sample containing a mixture of particles from both steelworks and motorway. The latter sample showed the highest average collection rate (0.9 mg/h, 13 μg/m 3) and included a prominent pollution episode when rainy winds were blowing from the direction of the steelworks. Both NW and SE samples were collected under dry conditions and show the same collection rate (0.7 mg/h, 10 μg/m 3), whereas the NE sample was collected during wetter weather and shows the lowest rate (0.3 mg/h, 5 μg/m 3). Scanning electron microscopy (SEM) and energy-dispersive X-ray microanalysis system (EDX) analyses show all samples are dominated by elemental and organic carbon compounds (EOCC) and nitrates, with lesser amounts of sulphates, felsic silicates, chlorides and metals. ICP–MS analyses show the SW/SE sample to be richest in metals, especially Fe, Zn, Ni, and Mn, these being attributed to an origin from the steelworks. The SE sample, blown along the motorway corridor, shows enhanced levels of Pb, V, Ti, As, and Ce, these metals being interpreted as defining a traffic-related chemical fingerprint. The NW sample shows a very low metal content. DNA plasmid assay data on the samples show TM 50 values varying from 66 to 175 μg/ml for the adjusted whole sample and 89 to 203 μg/ml for the soluble fraction. The SW/SE-mixed metalliferous sample is the most bioreactive (both whole and soluble) and the soluble fraction of the metal-depleted NW sample is the least bioreactive. The metal content of the aerosol samples, especially soluble metals such as Zn, is suggested to be the primary component responsible for oxidative damage of the DNA, and therefore most implicated in any health effects arising from the inhalation of these particulate cocktails.

Biogenic and lithogenic particle fluxes in the western region of the Sea of Okhotsk: Implications for lateral material transport and biological productivity

Sinking particles collected at two depths at two sites off Sakhalin Island in the western region of the Sea of Okhotsk were analyzed to determine their major chemical components (lithogenic material, biogenic opal, calcium carbonate (CaCO3), and total organic carbon (TOC)). The lithogenic and opal fluxes increased downward, indicating the lateral input of resuspended sedimentary particles into the lower traps, while the CaCO3 or TOC fluxes did not change greatly between the upper and lower traps. The lithogenic particle flux in the lower traps showed intermittent increase events frequently during periods when cold water masses penetrated into the intermediate layer at the mooring sites. This coincidence between the flux increase and the cooling of the intermediate layer clearly indicates that the cold and turbid Dense Shelf Water (DSW) is discharged from the bottom of the northwestern continental shelf to the pelagic intermediate layer, supplying large amounts of particulate matter onto the bottom of the slope and deep basin. After removing the effect of the lateral input, the time series of the opal export from the surface water at the mooring sites were reconstructed using the upper trap data. There were two predominant characteristics in the seasonal variations of the opal export, which is nearly equal to the diatom production, in the area off Sakhalin. One is the relatively large opal flux in autumn, and the other is the southward propagation of the spring diatom bloom, although the sea ice retreats northward every spring. Both of these characteristics suggest that the river water discharged from the Amur, together with the seasonal sea ice cover, regulates primary production in this area.

Properties of DPF System Using Perovskite Catalysts Supported on ZrO2/SiC Fibers

Diesel engine, which is widely used as a power plant for trucks and buses, is most efficient internal combustion engine. However, it generates a large amount of particulate matter (PM) and NOx. Diesel particulate filter (DPF) system is expected to be an effective tool to reduce PM and NOx emissions, but it is far from practical use because of clogging and low heat-resistance. In this work, ZrO2/SiC felt which supported perovskite oxide catalyst is employed as a filter material, and the performances of the new DPF system to reduce PM and NOx emissions were evaluated. As a result, La0.9K0.1CoO3 supported by alkoxide method exhibited promising performance to reduce PM and NOx emissions, and Pt on the perovskite oxide enhanced the PM oxidation performance at about 500°C.

Degradation of Macromolecular Organic Compounds in a Tropical Lagoon (Ciénaga Grande, Colombia) and its Ecological Significance

AbstractPrimary production and decomposition of organic substances were investigated in a tropical lagoon during the rainy season. Production and mineralization were measured using the oxygen method. Total bacteria numbers and biomasses were estimated with epifluorescence microscopy, and the enzymatic degradation capacity of model substrates was determined photometrically. These parameters were measured in the water and sediment of the lagoon itself and also in its effluents and incoming waters. The aim of the study was to determine the sites of highest microbial activity in the lagoon and to compare its activity with other coastal water bodies. Since the shallow water lagoon contains a large amount of particulate matter, it was of special interest to study the degradation of this material and its influence on the microbial population. It was found that up to 14 % of the bacteria colonized the particles and that 62 % of the respiration originated in the particle fraction &gt;8 μm. Highest exoenzymatic activities were measured in the sediment and water of the mangrove belt. It is concluded that decomposition and conditioning of particulate organic matter play dominant roles in the recycling of organic carbon in the lagoon.

A Roentgen-Ray Study in Absorption of Thorium Dioxide from Peritoneal Cavity of Albino Rat.

It has long been known that serous cavities have the capacity of absorbing certain injected substances, Cunningham showed that, when a mixture of erythrocytes, large unfiltered carmine granules, and fine lampblack granules, made up in isotonic NaCl solution, was injected into the peritoneal cavity of animals, all 3 types of material reached the anterior mediastinal glands shortly after injection. His results indicate that most, if not all, of the transfer of granular material from the peritoneal cavity into the diaphragmatic lymphatics, during the first 30 minutes, takes place by means of a type of phagocytosis. His important findings give a clearer understanding of the high phagocytic capability of the lymphatic endothelial cells to remove large amounts of particulate matter from the peritoneal cavity. The diaphragm is rich in lymphatics and its lymphatic vessels anastomose with the lymphatic vessels of the pleura and the peritoneum, which, in turn, connects with the right and left lymphatic ducts. The thoracic duct, terminating in the internal jugular vein, conveys the great mass of lymph and chyle into the blood. It is the common trunk of all lymphatic vessels below the diaphragm. The right lymphatic duct receives lymph from the right upper extremity, the right thorax, right lung, right side of the heart, and from parts of the convex surface of the liver. It opens into the junction of the internal jugular and the subclavian veins separately. Absorption in this region is extremely rapid due to this network of lymphatics. The practical application of this knowledge is found in the Fowler position, whereby, upon elevating the head of the bed after operation for abdominal infection, the infected material is permitted to gravitate toward the pelvic peritoneum.