Types Of Kilns Research Articles

Sustainable conversion of agricultural waste into solid fuel (Charcoal) via gasification and pyrolysis treatment

Managing agricultural waste by burning it in the fields is a straightforward method, but leads to significant pollution. One promising alternative is to convert agricultural waste into solid fuel, such as charcoal, to support renewable energy from biomass. The quality of barbecue charcoal depends upon selecting suitable materials and employing heating methods to ensure efficient transformation. This research aims to study the charcoal conversion process from agricultural waste using two types of kilns: 1) direct heating (gasification kiln: GK) and 2) indirect heating (pyrolysis kiln: PK) designed to recirculate syngas from wood as fuel for the pyrolysis process. The study tested three types of agricultural waste materials, including coconut shells (CS), cassava rhizome (CR), and acacia wood (AW), to examine the differences in charcoal produced by the two heating methods. The tests revealed that the maximum temperatures inside the kilns were 792.45 ± 127.18 °C, 907.67 ± 37.3 °C, and 980.07 ± 110.56 °C for the GK, and 921.88 ± 57.84 °C, 801.93 ± 10.16 °C, and 937.82 ± 95.85 °C for the PK. The charcoal from the PK exhibited higher calorific values than the GK, with 7474.68 ± 36.62, 6429.04 ± 72.22, and 7268.33 ± 52.86 calories per gram. The charcoal yield was also higher in the PK, at 31.29 ± 4.39, 34.33 ± 3.39, and 17.58 ± 2.09 percent for coconut shells charcoal (CSC), cassava rhizome charcoal (CRC), and acacia wood charcoal (AWC), respectively. However, the PK required more fuel and longer ignition times. The resulting charcoal from the slow pyrolysis process in the PK is suitable as barbecue fuel due to its size, which is similar to the original material. In contrast, the charcoal from the GK, which tends to shrink or break into smaller pieces, is more suitable for grinding into briquettes. This study provides a guideline for producing high-quality barbecue charcoal, offering commercial benefits including the gasification and pyrolysis processes that improve combustion efficiency and reduce pollution by producing high-quality gas for fuel, unlike traditional kilns that emit a large amount of CO during the conversion of wood to charcoal and enabling the selection of appropriate raw materials for different heating methods to maximise the utility of the products. This approach adds value to agricultural raw materials and helps effectively manage agricultural waste (zero waste) for further utilisation and development.

Comparative Analysis of Gas Emissions from Ecokiln and Artisanal Brick Kiln during the Artisanal Firing of Bricks

This article focuses on the research of gas emissions in two types of brick kilns located in the Maule Region, Chile. One of them is an artisanal brick kiln known as a “chonchón” (AKC), while the other is a semi-artisanal brick kiln with an improved design. The latter is referred to as the Ecokiln. This study focuses on the assessment of the emission profiles of key pollutants such as particulate matter (PM), CO, CO2, SO2, and NOx. The emission measurements of gasses, temperature, and flow were conducted during the operation of the kilns. These measurements were carried out following the protocol established by Chilean standards. The Ecokiln’s design facilitates optimal fluid dynamics. In direct comparison to the AKC, it exhibits reduced fuel consumption, shorter operation periods, an increased brick processing capacity, decreased burnt brick losses, and notably lower emissions, with a concentration of SO2 that is 83% less than that of the AKC, NOx emissions, 58% lower than the AKC, and a remarkable 74.3% reduction in PM10 emissions. Moreover, the Ecokiln reduces pollutant emissions, improving the well-being of brickmakers and their communities. These results offer insights into the environmental impact of local brick production and support sustainable manufacturing practices.

Creating the so-called graphite-coated pottery of the Late Bronze and Early Iron Ages

Over the centuries, various minerals were used in pottery production; for some societies, graphite played a unique role. Certain areas lack local sources of this mineral but simultaneously reveal a great occurrence of ‘graphite-coated’ pottery. Still, it is commonly believed that the surface of these vessels was coated with graphite. The aim of the article is to examine whether the surface visually characterised as ‘graphited’ (suggesting the use of graphite) could be achieved without the application of the mineral and what the technological process of manufacturing might have looked like. Macroscopical and archaeometry recognition features of ‘graphite-coated’ pottery and mineral graphite were indicated. A series of experiments were performed to achieve a lustrous, silver surface without applying mineral graphite. The firing process was conducted in two types of kilns reconstructed according to archaeological sources from the territory of Poland dated to the Late Bronze and Early Iron Ages. The reproduced pottery shows surfaces very similar to their prehistorical counterparts. The significant occurrence of this type of pottery indicates its production could also be conducted in areas lacking mineral graphite.

Investigating the Impact of Shifting the Brick Kiln Industry from Conventional to Zigzag Technology for a Sustainable Environment

The brick kiln industry is one of the largest and most highly unregulated industrial sectors in developing countries. Most of the kilns use low-quality coal as primary fuel along with small quantities of bagasse, rice husk, and wooden chips. As a result of inefficient methods of combustion in conventional brick kilns, such as fixed chimney Bull’s trench kilns (FCBTKs), harmful pollutants are emitted in high quantities, which ultimately deteriorate the environment and are widely in operation in Pakistan. The most prominent harmful pollutants include carbon dioxide (CO2), carbon monoxide (CO), sulphur dioxide (SO2), black carbon (BC), and particulate matter less than 2.5 microns (PM2.5). Over the years, new technologies have been adopted by developed countries for the reduction of environmental burdens. One of these technologies is induced draught zigzag kilns (IDZKs), or zigzag kilns (ZZKs), technology, which effectively improves the combustion across the path of bricks stacked in a zigzag pattern. For the mass adoption of this technology, environmental assessment and comparison of both technologies is a crucial step. Both types of kiln sites are investigated for the analysis of their emissions and their environmental impact in this work. Carbon mass balance equations are used for the calculation of emission factors. Collected inventory data is then used for the life cycle assessment of both types of kilns using open LCA (version 1.10.3) and the Eco-invent database. According to the study, ZZK technology outperforms FCBTK in all aspects. The analysis of the specific energy consumption (SEC) of fired bricks for each kiln type reveals that ZZKs require 30% less energy than the conventional FCBTK. This implies that ZZKs demand lesser fuel than FCBTKs. The zigzag technology adoption scenario, in particular, can lead to approximately 30% lower CO2 emissions, which can be further reduced by up to 80% when taking into account black carbon (BC) emissions. Additionally, the adoption of zigzag technology can result in a 35% decrease in PM2.5 emissions. The study shows that adopting ZZK technology significantly reduces impact categories, such as particulate matter formation (PMF), photochemical oxidant formation (POF), and terrestrial acidification (TA) by 63%, 93%, and 95%, respectively.

Evaluation of Four Types of Kilns Used to Produce Charcoal from Several Tree Species in Mexico

Charcoal production is an activity that dates back over the years. The objective of the study was to determine the temperature and heating ramp in industrial carbonization processes using different kiln types and to quantify its impact on yield and quality of charcoal from different firewood species. The selection of sites, kiln types, and species investigated was based on those with highest production in Mexico. Brazilian beehive kilns using Arbutus xalapensis, Quercus durifolia, and Quercus sideroxyla species were analyzed; modified Brazilian beehive kilns with Pithecellobium dulce and Tamarindus indica; Argentine half-orange kilns with Quercus magnoliifolia and Q. sideroxyla, industrial metal kilns with Brosimum alicastrum, Vitex gaumeri, Manilkara zapota, and Pouteria unilocularis. The process time, temperature, heating ramp, production yield, and quality of charcoal produced were determined. Data were analyzed in a completely random statistical design. The industrial type kilns showed the highest production yield (>35%), and the Brazilian beehive kilns obtained the longest carbonization time (>240 h). On the other hand, the modified Brazilian beehive kilns obtained the best energetic characteristics (>75% fixed carbon and <16% volatile material). A carbonization process with a slow heating ramp (<1 °C min−1) and temperatures of 500–600 °C can generate a charcoal with export quality.

Emission characteristics and inventory of volatile organic compounds from the Chinese cement industry based on field measurements

Volatile organic compounds (VOCs) are major precursors of ozone (O3) and secondary organic aerosols (SOA), which degrade air quality and pose a serious risk to human health and ecological systems. Previous studies on the emission characteristics of VOCs have predominantly focused on petrochemical and solvent-using sources, while localized studies on the cement industry are scarce in China. Field measurements for four cement plants were carried out in this study to investigate the emission levels, source profiles, and secondary pollutant generation potential of 98 VOCs species emitted from rotary and shaft kilns in China. Furthermore, a species-differentiated VOCs emission inventory was compiled for the Chinese cement industry in 2019. The results demonstrated that the mass concentration of VOCs emitted from shaft kiln was more than 20-fold higher than that emitted from rotary kilns, and the alkanes was the dominant species (56%) in shaft kilns, while oxygenated VOCs (OVOCs) and halocarbons were the main species in rotary kilns. Moreover, alkenes & alkyne were the dominant contributors to ozone formation potential (OFP) in shaft kilns, whereas alkenes & alkyne and OVOCs were comparable and prominent contributors in rotary kilns. In contrast, secondary organic aerosol potential (SOAP) for the two types of kilns was dominated by aromatics. In 2019, approximately 18.18 kt VOCs were emitted from cement production and were found to be largely concentrated in the southeast and central provinces of China. Considering the influence on environmental conditions, high OFP-contributing species in cement kilns are suggested to be a priority in the pollution mitigation of O3. This study provides a new, comprehensive, and reasonable cognition of the current VOCs emissions from both rotary and shaft kilns in China, which will aid in a better understanding of VOCs emission characteristics and guide future policy-making.

Barriers and drivers for adoption of energy efficient and environment friendly brick kiln technologies in Punjab, Pakistan

Brick manufacturing sector is a major contributor to air pollution and greenhouse gas emissions in South Asian countries. This study investigates barriers and drivers relevant to the adoption of cleaner zig-zag kiln (ZZK) technology in Punjab, Pakistan by surveying 63 kiln owners. These survey respondents owned three different types of brick kiln i.e., ZZK, Fixed chimney bull’s trench kiln (FCBTK), and clamp type kiln (CTK). Roger’s model of innovation diffusion was adopted to access the determinants pertaining to relative advantage, compatibility, complexity, trialability and observability. Survey questionnaire included questions related to 35 factors (20 drivers and 15 barriers) and responses were recorded on Likert scale. These barrier and drivers covered variety of factors associated with regulatory, financial, technological, social, and environmental issues that may influence the perception and decision of kiln owners for the adoption of cleaner ZZK technology. Our results show that most important drivers pertain to economic benefits such as emissions fine reduction, decrease in fuel costs and year-round operations. Other high impact drivers relate to compatibility and similarity between ZZK and FCBTK construction and operations. Top-ranked barriers highlight the challenges associated with financial burden of retrofitting cost, higher salaries demanded by skilled workers, and maintenance issues for blower assembly. Mean scores for the determinants pertaining to the attributes of Roger’s model were computed. Our results show that both relative advantage and compatibility received highest mean scores. On the other hand, trialability and observability received lowest scores. Government, policy makers and other relevant stakeholders should focus on awareness campaigns, capacity building and training of labor, and developing financial instruments to provide loans to kiln owners for covering retrofit costs.

한반도 남부지역 삼국시대 토기생산의 비교

It was understood that pottery production developed into a hierarchical organization with the expansion of mass production and distribution. In this study, we will try to compare and review the changes in the pottery production organization in Honam and Yeongnam regions, which have been integrated into different political groups.
 During the Three Kingdoms Period, a database of kilns was established to establish four types of kilns. The type and consumption of production pottery were inferred for each type to confirm production and distribution. Type A and B pottery kilns produced utilitarian pottery with villages as their main consumption sites, but there are differences in size and location. Type C mainly produces burial pottery and can define the main consumption site as an ancient tomb. Type D is a production area where large-scale kiln, it was located outside the center of each political body at the time to meet the demand for pottery.
 In the early days of the Three Kingdoms period, type A and B coexist, and type C and D emerge as political groups in each region grow. In particular, there is a clear difference between C type in Yeongnam and B type in Honam. In the Yeongnam, a tradition of burial rituals called the mass burial of pottery was formed, affecting production. In the Honam, it could be seen that a large change in the pottery production organization was closely related to the appearance of the central village. Depending on the region, the nature of the main consumer site and the type of demand show a distinct difference. It is confirmed that different types coexist and the difference in proportion varies depending on the time, not the single-line development of mass production in a small scale.

AN OVERVIEW OF HEALTH AND ENVIRONMENTAL THREATS FROM THE BRICK KILN INDUSTRY AROUND THE CAPITAL OF BANGLADESH

Bangladesh is one of the top brick manufacturing countries in the globe. With rapid urbanization and industrialization, the brick manufacturing industry is elevating to its peak level day by day and contributing to the country’s GDP significantly. This research aims to investigate the current environmental and health threat coming from brick kilns around the capital of Bangladesh. The selected areas are Savar, Tongi, Amin Bazar and Ashulia. The methodology followed in this study was field surveying in the selected areas and information acquisitions from the secondary data. Results from this study revealed that brick kilns are highly responsible for environmental pollution that subsequently deteriorates the air quality, causes land degradation, threatens biodiversity and poses a potential impact on human health. Results also revealed that there are mainly four types of brick kilns found in selected areas e.g. Chimney Kiln (CK), Zigzag kiln (ZK), Hoffman Kiln (HK) and Hybrid Hoffman Kiln (HHK). Of these, the Fixed Chimney Kiln is found to be very obsolete at present days and creates environmental pollution at different levels. Besides these, strict implementation of the Brick Manufacturing and Brick Kilns Establishment (Control) Act, 2013 in the studied locations is still far away. This paper urges the attention of the policymakers as well as the researchers to prioritize the solution to this promising but ever-increasing pollution-causing industry of Bangladesh in sustainable ways.

Rethinking Heat Energy in the Conversion of Clay to Ceramic: A Key to Successful Ceramic Practice

Ceramics as the art and science of baked clay has provided man with several wares with which man solves his daily problems. Heat or thermal energy plays a vital role in the baking, firing or conversion of clay in ceramic production as no green ware, no matter how beautiful, is useful without being subjected to heat treatment which converts clay to its permanent, rocklike, dense, vitreous, impermeable, beautiful and useful ceramic. Over the years, potters as creative people have been producing beautiful wares only to lose a lot of them during firing as a result of lack of adequate knowledge of the action of heat energy in the conversion process. The aim of this paper therefore is to bring to the fore, the action of heat energy in the conversion of clay to ceramic. The objectives will include; to take a look at what a kiln is, to consider the types of kilns, the sources of energy for firing kilns and the approaches towards achieving a successful firing. Data are collected from both primary and secondary sources which will give a better understanding of heat energy and its role in the conversion process.

Emission characteristics and reactivity of volatile organic compounds from typical high-energy-consuming industries in North China

To effectively reduce the compound pollution of fine particulate matter (PM2.5) and ozone (O3), volatile organic compound (VOC) emission sources are being extensively studied. Studies on VOC emission characteristics have mainly focused on solvent-using and technological sources, while research on the combustion processes of high-energy-consuming industries remains limited. Here, we investigate the emission characteristics of 102 VOC species emitted from eight sources (sintering, pelletizing, steel smelting, a coke oven chimney, the topside of a coke oven, thermal power, and two types of cement kilns) used in four types of high-energy-consuming industries. Our results show significant differences among these sources. The average VOC mass concentrations varied from 0.14 to 7.08 mg/m3. Alkanes had the highest percentage contribution to VOCs from sintering (45.9%) and thermal power (44.6%), while aromatics had the highest percentage contribution from steel smelting (47.8%) and the topside of the coke oven (52.9%). Alkenes were abundant in the coke oven chimney (49.1%), and oxygenated VOCs accounted for 65.3% of the total VOCs from pelletizing. We also observed notable differences between the two types of cement kilns. In general, ethane, ethene, benzene, propane, acetaldehyde, and chloromethane were the dominant VOC species in all sources. The differences between the sources were due to factors such as the applied raw materials, calcination temperature, and end-of-pipe treatment. By reviewing studies from the past 20 years, we found that differences in the number of VOC species and the implementation of ultra-low emissions affect VOC emission characteristics. The coke oven chimney and cement kiln chimney-1 had the highest ozone formation potential and secondary organic aerosol potential, respectively. The VOC emissions from coking, iron and steel, thermal power, and cement industries were 1162.1, 289.9, 311.0, and 470.2 Gg, respectively. Our results highlight the need for more effective control measures to minimize VOC emissions from high-energy-consuming industries.

Space Syntax Analysis of the Floor Plans of the Vernacular Buildings in Western Henan Province, China

This study is based on the investigation and analysis of three kinds of the vernacular building in China’s western Henan Province: pit kilns, independent cave-dwelling, and masonry buildings. Their layout characteristics are documented through surveying and photography, classifying and analyzing the floor plans of these buildings. Space syntax theory is employed to analyze the connection value, control value, depth value, and integration value, and relationship are considered between different pit kilns and the other building types. The analysis reveals that the three types of pit kilns do not have an obvious differences in connectivity and depth values, while both the control and the integration of the three types of pit kiln significantly differ. In contrast, Single row houses, Erheyuan, Sanheyuan, Siheyuan, and Modular courtyards have significant differences in connectivity, control, integration, and mean-depth, same for the three types of vernacular buildings. From this work, it can be seen that the pit kiln became the prototype of the western Henan building: all buildings were built with courtyards as the core to organize the entire spatial system. Courtyards therefore form the center of spatial layout and functional organization for all building types.

Environmental consequences of firing technologies evolution in ceramics

Technical ceramics are one of the numerous materials, including metals, glass, and plastics that can be utilized to preserve and protect the environment and also contribute to regenerate damaged ecosystems. This article examines the historical development of pottery, focusing mainly on the organization of the technological process of firing ceramic products as well as its environmental consequences. To obtain durable ceramic products, it was necessary to improve the design of the kiln and increase the firing temperature, which led to the appearance of specialized kilns. For a long time, firewood and coal were the fuels used for firing. Then, as humankind's mastery of the natural environment progressed, fuels in the form of liquid and gas were used in pottery kilns. Today, the advent of electric heating elements has made it possible to simplify the firing even further; the thermoregulation equipment of modern kilns allows potters to maintain a stable temperature throughout the firing process, leading to the increased quality of the final product. The results of this study will provide a complete picture of the various types of ceramic kilns found throughout history, considering relevant environmental issues. It will help to trace how the quality of ceramic products has been influenced by the design of the kilns and the increase in firing temperature while maintaining the damage to the environment to a minimum. This will be of interest both to professional and amateur potters, who may find it useful during the firing process.

Carbonization techniques and wood species influence quality attributes of charcoals produced from industrial sawmill residues in Eastern Cameroon

Cameroon harvests a considerable volume of round wood each year, only a small part of which is used for manufactured products. In recent decades, various charcoal-making initiatives have emerged around industrial timber-processing units, particularly in the eastern region, in order to develop a market for residual biomass. However, the undifferentiated use of these residues obtained from different species often results in products with varying energy potential that are not always appreciated by consumers. Moreover, the physical and chemical characteristics of the charcoal produced are unknown, as are the factors that influence its quality. The aim of this study was to assess the variability of the physical and chemical properties of charcoal produced from industrial sawmill residues in the eastern region of Cameroon using different carbonisation techniques. Three wood species, Ayous, Frake and Movingui, and three types of kilns (traditional, improved traditional and Casamance system) were used. For each species, three bundles of five pieces of wood each were prepared, with an initial moisture content ranging from 28% to 36%. The physical and chemical properties determined were moisture content, apparent density, volatile matter content, fixed carbon content, ash content and Higher Heating Value (HHV). Our results showed that the charcoal properties varied depending on the wood species and types of kilns used. Movingui, with the highest density (0.73 g/cm3), produced charcoal with the lowest moisture content (4.03%) and the highest apparent density (0.42 g/cm3). The lowest volatile matter content (20.32%), the lowest ash content (1.27%) and the highest fixed carbon content (74.95%) were also obtained with this species. All these values were obtained with Movingui charcoal produced with the Casamance system. However, the highest HHV (32.51 MJ/kg) was obtained with charcoal from Ayous, also produced with the Casamance system. On comparing the three charcoaling systems used, the Casamance model yielded the best physical and chemical charcoal properties. All the charcoals studied complied with FAO standards for cooking fuel. The highest HHV obtained with charcoal from Ayous hardwood shows its ability to release large amounts of thermal energy during combustion.
 
 Keywords: Charcoal, carbonization technologies, eastern Cameroon, physicochemical properties, industrial sawmills wastes.

Study of Characteristics of Bricks Produced in Kathmandu, Nepal

The quality of brick is determined by its physical, mechanical and microstructure characteristics. The main objective of this study was to assess the characteristics of different types of bricks produced under various clay composition, different types of kiln used, and various firing temperature, and cooling process, which are considered as the major factors affecting the brick quality. A mixed-method approach was used to carry out this study. Both primary and secondary data were collected form field observations, discussions, lab experiments, and literature review. Literature review was done to identify the relationship between affecting factors and brick characteristics. The status of bricks produced was assessed through lab tests. The results from both methods were compared and discussed thoroughly. The purposive sampling method was adopted to collect brick samples from six different brick factories situated in Kathmandu and lab tests were carried out in the Engineering Material Lab at Institute of Engineering (IOE) Pulchowk Campus, Lalitpur, Nepal. Deformation, bulk density, water absorption capacity, and compressive strengths of sampled bricks were observed and then compared with standard code values as well as with previous findings. The study showed that none of the brick samples was found within the standard benchmarks, and the bulk density was low, however, the water absorption capacity and compressive strength values of all the sampled bricks were found to be within the allowable limit, even though they were close to the lower bound. The study also discussed technical, social and environment policy related issues that are important for producing and making the best use of quality bricks. The study results may be applied to other places where similar situation exists.

Impact of brick kilns industry on environment and human health in Pakistan

The increase in population has led to the rise in the construction and manufacturing of bricks. Bricks are manufactured in brick kilns that emit very harmful gases which in turn affect the human health, environment and economy. In Pakistan, the diseases related to skin, and respiratory system have created a lot of problems for the humans and animals. According to experts and professionals, one of the main causes of the environment and health related problems is brick kiln. It is very important to identify the brick kilns and emissions that are extremely harmful for the environment and human health. Therefore, the objective of this research paper is threefold. Firstly, to identify and rank the emissions from brick kilns based on their harmful impact on human health and environment. Secondly, to rank the three types of brick kilns i.e. Traditional Brick Kilns (TBK) with coal as a fuel, Traditional Brick Kilns (TBK) with rubber as a fuel and Contemporary Brick Kilns (CBK) (technologically advanced brick kilns) based on their impact on human health and environment. Thirdly, to identify the relation of three alternative brick kilns with health and environmental problems, respectively. DEMATEL and Fuzzy-TOPSIS have used for achieving the objectives. The results show that CO2, CO and SO2 have the most harmful effects on the environment. Similarly, carcinogenic dioxin, SO2 and PM have the adverse effects on the human health. TBK in which rubber is used as a fuel is the most harmful and CBK is the safest types of brick kilns, respectively. In the light of the results, it is recommended to the government of Pakistan to formulate and implement the rules and regulations for minimizing the negative impacts of brick kilns on human health and environment. Moreover, new technologies should be used in order to reduce the harmful impacts.

Tipologija rimskih ciglana s područja Bosne i Hercegovine / Typology of Roman figlinae from the territory of Bosnia and Herzegovina

Following the establishment of Roman rule, the eastern Adriatic coast and its hinterland quickly began to accept and employ new methods of construction and production of building materials. Import of stamped bricks from large north italian workshops was first reduced by military units which started the brick production of their own, in figlinae based around military camps. Soon afterwards, first private brick workshops began to emerge starting the development of local brickmaking industry. Their work in interior of province of Dalmatia can be traced primarily through remains of brick kilns (fornaces) and secondarily through finds of stamped bricks which also serve as an indicator of spatial distribution and intensity of brick production. Previous archaeological investigation on the territory of Bosnia and Herzegovina have led to identifying the remains of 10 Roman brick kilns. Detailed and comparative analysis of their architecture from the aspect of typology hasn’t been the subject of former scholarly discourse. Following the typology suggested by N. Cuomo di Caprio, it is possible to identify several types of brick kilns all belonging to a group of quadrilateral – plan kilns with vertical firing mechanism thus having close analogies in numerous examples of kilns from other Roman provinces.

Microbiological quality of traditional and improved kiln smoked catfish (Clarias gariepinus; Pisces; Clariidae) in Lake Chilwa Basin.

Microbiological quality of smoked catfish (Clarias gariepinus) locally known as Mlamba was assessed in this study where traditional and improved smoking kilns were used to smoke fish. Catfish is common fish caught in abundance in the Lake Chilwa basin, and the fish is usually smoked to reduce postharvest losses and increase shelf life. Samples were collected in sterile polythene bags, well labeled, and collected in cooler boxes transported ready for laboratory analysis. One gram representative sample was obtained aseptically from the muscle of the fresh and smoked catfish (Mlamba) samples. The samples were grounded, and fourfold serial dilutions (10−1–10−4) of the homogenized samples were made using sterile distilled water. Fish samples were analyzed for total plate count (TPC), Escherichia coli counts, and pathogenic organisms (Salmonella) following the methods prescribed by AOAC (Official methods of analysis, Association of Official Analytical Chemistry, Arlington, VA, 2000). Each analysis was carried out in triplicates. There were significant differences (p = 0.05), with respect to total viable bacterial counts between traditional kiln smoked and improved kiln smoked catfish (5.6 × 106 cfu/g, 1.9 × 106 cfu/g, respectively). Traditional kiln smoked catfish harbored significantly higher total viable counts as well as a higher population of E. coli compared to improved kiln smoked catfish. However, for both types of smoking kilns there were detected levels of pathogenic bacteria Salmonella with traditional kiln smoked catfish containing 2.1 × 104 cfu/g which were significantly higher than amount found in improved kiln smoked catfish (1.5 × 104 cfu/g; p = 0.05). Salmonella is a microbe of public health importance and has implications on the handling and source of the fish.

Speciated online PM<sub>1</sub> from South Asian combustion sources – Part 1: Fuel-based emission factors and size distributions

Abstract. Combustion of biomass, garbage, and fossil fuels in South Asia has led to poor air quality in the region and has uncertain climate forcing impacts. Online measurements of submicron aerosol (PM1) emissions were conducted as part of the Nepal Ambient Monitoring and Source Testing Experiment (NAMaSTE) to investigate and report emission factors (EFs) and vacuum aerodynamic diameter (dva) size distributions from prevalent but poorly characterized combustion sources. The online aerosol instrumentation included a “mini” aerosol mass spectrometer (mAMS) and a dual-spot eight-channel aethalometer (AE33). The mAMS measured non-refractory PM1 mass, composition, and size. The AE33-measured black carbon (BC) mass and estimated light absorption at 370 nm due to organic aerosol or brown carbon. Complementary gas-phase measurements of carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4) were collected using a Picarro Inc. cavity ring-down spectrometer (CRDS) to calculate fuel-based EFs using the carbon mass balance approach. The investigated emission sources include open garbage burning, diesel-powered irrigation pumps, idling motorcycles, traditional cookstoves fueled with dung and wood, agricultural residue fires, and coal-fired brick-making kilns, all of which were tested in the field. Open-garbage-burning emissions, which included mixed refuse and segregated plastics, were found to have some of the largest PM1 EFs (3.77–19.8 g kg−1) and the highest variability of the investigated emission sources. Non-refractory organic aerosol (OA) size distributions measured by the mAMS from garbage-burning emissions were observed to have lognormal mode dva values ranging from 145 to 380 nm. Particle-phase hydrogen chloride (HCl) was observed from open garbage burning and was attributed to the burning of chlorinated plastics. Emissions from two diesel-powered irrigation pumps with different operational ages were tested during NAMaSTE. Organic aerosol and BC were the primary components of the emissions and the OA size distributions were centered at ∼80 nm dva. The older pump was observed to have significantly larger EFOA than the newer pump (5.18 g kg−1 compared to 0.45 g kg−1) and similar EFBC. Emissions from two distinct types of coal-fired brick-making kilns were investigated. The less advanced, intermittently fired clamp kiln was observed to have relatively large EFs of inorganic aerosol, including sulfate (0.48 g kg−1) and ammonium (0.17 g kg−1), compared to the other investigated emission sources. The clamp kiln was also observed to have the largest absorption Ångström exponent (AAE = 4) and organic carbon (OC) to BC ratio (OC : BC = 52). The continuously fired zigzag kiln was observed to have the largest fraction of sulfate emissions with an EFSO4 of 0.96 g kg−1. Non-refractory aerosol size distributions for the brick kilns were centered at ∼400 nm dva. The biomass burning samples were all observed to have significant fractions of OA and non-refractory chloride; based on the size distribution results, the chloride was mostly externally mixed from the OA. The dung-fueled traditional cookstoves were observed to emit ammonium, suggesting that the chloride emissions were partially neutralized. In addition to reporting EFs and size distributions, aerosol optical properties and mass ratios of OC to BC were investigated to make comparisons with other NAMaSTE results (i.e., online photoacoustic extinctiometer (PAX) and off-line filter based) and the existing literature. This work provides critical field measurements of aerosol emissions from important yet under-characterized combustion sources common to South Asia and the developing world.

Particulate black carbon and gaseous emission from brick kilns in Greater Dhaka region, Bangladesh

Eighteen brick kilns of three brick-making technologies (Fixed Chimney Kiln (FCK), Zigzag, and Hoffmann) were selected to measure the concentrations of particulate matter (PM2.5) with Aerocet 531S (USA) sampler, black carbon (BC) with Magee Scientific, OT-21 Soot scan Transmissometer (USA), and gaseous pollutants (CO2, CO, SO2, NOx, and volatile organic carbon (VOC)) with Aeroqual 500 gas sampler (New Zealand) to understand the emission scenario from brick sector in Greater Dhaka region, Bangladesh. Emission factor (EF) of each pollutant was computed from their respective concentration for three brick kiln technologies. Ambient PM2.5 and PM10 were measured in brick kiln premises and 1 km far from the respective kilns to see the effect on the surrounding areas. The PM2.5 concentration was found on an average of 141 ± 86, 128 ± 72, and 110 ± 53 mg/m3 in FCK, Zigzag, and Hoffmann kilns, respectively. The average BC concentration was found 16.6 ± 7.1 (FCK), 11.8 ± 4.2 (Zigzag), and 8.9 ± 4.4 (Hoffmann) mg/m3. FCK has a greater emission of CO, whereas Zigzag has a higher CO2 emission. A comparatively higher value of CO2 and lower value of CO indicates effective combustion of coal, and this is found to be more efficient for Zigzag and Hoffmann compared to traditional FCK. SO2 and VOC emissions were depending not only on the kiln types but also on the fuel qualities. From EF calculation, approximately 4526 t of PM2.5, 340 t of BC, 209,776 t of CO2, 8700 t of CO, 19,441 t of SO2, and 835,450 t of VOC per year found to emit from 1000 brick kilns. The conversion of traditional FCK to improved one, i.e., Zigzag and/or Hoffman is not a straight forward solution, as CO2 emission was higher in Zigzag whereas BC and PM2.5 emissions were higher in FCK. Therefore, considering EF of various pollutants from these three types of kilns, conversion of FCK to Zigzag or Hoffmann could be a better choice.