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Assessment of Energy Recovery Potential of Faecal Sludge
Mehejabin Chowdhury Ankan,
Md. Murad Hasan,
Md. Jobaer Howlader
Issue:
Volume 5, Issue 2, June 2020
Pages:
21-26
Received:
16 December 2019
Accepted:
26 December 2019
Published:
28 May 2020
Abstract: Faecal sludge generating from fixed-place defecation system has been an increasing concern in Bangladesh. In the city, this challenge is acute due to high population density, rapid and unplanned growth, and inadequate service provisions. Energy can be recovered from faecal sludge (FS) by converting the waste into usable heat, electricity, or fuel through pyrolization. Through Pyrolyzation biochar, biofuel, biogas can be obtained. Biochar can be produced by heating FS at high temperature. The burned portion of the sludge is the biochar, condensed steam is the biofuel and the uncondensed part is the biogas. This study shows that FS has volatile matter ranged between 39 to 50%, which qualify the FS as fuel. The ash residue of FS is between 34 to 45%. The rest of this is moisture. From Thermo Gravimetric Analysis (TGA) it was observed that major thermal events (mass loss rate) were found approximately between 150°C and 400°C which was considered as the ideal temperature range for pyrolysis process. Significant amount of biochar but negligible amount of biogas and biofuel were obtained from the samples by the pyrolysis process. 93.3% biochar, 2.8% biofuel and 3.8% biogas (at 200°C); 91.4% biochar, 3.5% biofuel and 5.1% biogas (at 300°C); 84.6% biochar, 9.3% biofuel and 6.1% biogas (at 400°C) were obtained. The result of pyrolysis analysis shows significant potential for energy recovery from FS.
Abstract: Faecal sludge generating from fixed-place defecation system has been an increasing concern in Bangladesh. In the city, this challenge is acute due to high population density, rapid and unplanned growth, and inadequate service provisions. Energy can be recovered from faecal sludge (FS) by converting the waste into usable heat, electricity, or fuel t...
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Geotechnical Properties of Gopalganj Sub-soil in Bangladesh
Sabbir-Ul-Islam,
Md. Ebrahim Shaik
Issue:
Volume 5, Issue 2, June 2020
Pages:
27-32
Received:
15 January 2020
Accepted:
29 January 2020
Published:
29 May 2020
Abstract: Gopalganj town is situated on southern region of Bangladesh which is near to the coastal region. The sub-soil in this region is formed by the alluvial deposits from different rivers. For economical and effective selection and design of foundation, it is very important for geotechnical engineers to go for detailed investigations of geotechnical properties of sub-soil. Some soil samples were collected from Gopalganj town area and tested in the Geotechnical laboratory of Khulna University of Engineering and Technology (KUET), Khulna to determine the geotechnical properties of soil and other data were collected from soil investigation reports prepared by CRTS (Civil), KUET, Khulna. The sub-soil is composed of fine grained soils of soft to medium stiff consistency up to 30 ft depth from the existing ground surface and the soil predominantly consists of course grained soils of medium to very dense compactness below 30 ft depth. For the Gopalganj sub-soil the values of unit weight, specific gravity, natural moisture content, liquid limit, plastic limit, unconfined compressive strength, cohesion, angle of internal friction, compression index and natural void ratio varies from 13.23 kN/m3 to 14.21 kN/m3, 2.68 to 2.73, 32% to 65%, 33% to 60%, 26% to 48%, 5kPa to 90kPa, 0.93kPa to 8.20kPa, 27° to 38°, 0.16 to 1.0 and 0.83 to 2.30 respectively. For the construction of low rise building, shallow foundation may be used with or without replacing the soil layer below the foundation with sand having proper compaction. For medium to high rise buildings, pile or piled raft foundations may be used that penetrate through the soils of very soft to stiff consistency to deeper strata of dense compactness located at 30 to 40ft depth from the ground surface. The results obtained in this study will be useful for those owners who are interested to construct building without soil investigation.
Abstract: Gopalganj town is situated on southern region of Bangladesh which is near to the coastal region. The sub-soil in this region is formed by the alluvial deposits from different rivers. For economical and effective selection and design of foundation, it is very important for geotechnical engineers to go for detailed investigations of geotechnical prop...
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Use of Ceramic Waste as Fine Aggregate in Bituminous Mix in Flexible Pavement Design
Md. Murad Hasan,
Mehejabin Chowdhury Ankan,
Md. Ebrahim Shaik,
Md. Rasel Ali
Issue:
Volume 5, Issue 2, June 2020
Pages:
33-37
Received:
2 December 2019
Accepted:
16 December 2019
Published:
3 June 2020
Abstract: In bituminous road construction aggregate is the principal material. Aggregates constitute about 90% or even more of the total construction materials. While selecting aggregate for road construction, search has to be intensified for easily accessible, low-cost natural aggregates and investigate the suitability of indigenous aggregates. Every effort must be taken to select the most economical aggregate which should also perform satisfactorily the design criteria for the road construction conditions. A laboratory investigation was carried out to investigate the design performance of bituminous pavement using different fine aggregates. While constructing bituminous pavement a mix of coarse aggregate, fine aggregate, mineral filler, and bitumen are used. The demand for natural fine aggregate can be reduced by recycling waste tiles chips. Waste tiles, chips aggregate refer to aggregate that has been previously used in the concrete structure as a floor finish. This study easy carried out to investigate the possibility of using waste tiles, chips as a fine aggregate. Therefore, two types of fine aggregate were used to study and compare the behavior of bituminous mixes using waste tiles with that of coarse sand. The Marshall Mix design procedure specified by AASHTO standard was followed in the determination of stability, flow, density, voids in the mixes and the optimum bitumen content. The test specimens were compacted with 50 blows from the consideration of medium traffic. The test results indicated that dense graded bituminous mixes with two types of different fine aggregates satisfy the Marshall Design criteria. From the economic consideration, mixes with waste tiles, chips are comparatively more suitable when available at the construction site. Dense bituminous mix using waste tiles, chips as fine aggregate for medium traffic, is a feasible option from the standpoint of stability, stiffness, deformations and void characteristics.
Abstract: In bituminous road construction aggregate is the principal material. Aggregates constitute about 90% or even more of the total construction materials. While selecting aggregate for road construction, search has to be intensified for easily accessible, low-cost natural aggregates and investigate the suitability of indigenous aggregates. Every effort...
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The Vulnerability of Nairobi to the Effects of Climate Change Between 1984 and 2016
Sunday Julius Abuje,
Bernard Moirongo Otoki,
Bernard Mugwima Njuguna,
Gerryshom Munala
Issue:
Volume 5, Issue 2, June 2020
Pages:
38-45
Received:
5 May 2020
Accepted:
12 June 2020
Published:
20 June 2020
Abstract: Urban areas are exposed to compounded effects of climate change emanating from the confluence of a globally changing climate and the unique characteristics of urban climate. The unique urban climate is brought about by land cover patterns and the interaction between urban surfaces and weather elements. Among the recorded effects of this include the Urban Heat Island, increased surface runoff and altered wind flow patterns. Nairobi city has continued to experience these effects and it is projected that they may worsen under the changing climate. This study sought to establish the physical characteristics that make Nairobi City vulnerable to the climate change effects of flooding, to recommend adaptation measures. Nairobi City County watershed was the research situs. A descriptive research design was used to model runoff over two distinct periods of 1984 and 2016 using the Curve Number Method. The results pointed to a 162% increase in urban sprawl and a 45% increase in average rainfall for the corresponding period. The surface sealing from urban sprawl and the increasing surface runoff expose the city to a higher flooding risk. At the same time, the ecological services of green systems within urban areas are diminishing due to fragmentation of the green networks. It is recommended that urban development adopt a paradigm shift towards the use of green infrastructures like greenways, small urban green spaces and green roofs alongside water sensitive urban design approaches to adapt urban areas to the effects of climate change.
Abstract: Urban areas are exposed to compounded effects of climate change emanating from the confluence of a globally changing climate and the unique characteristics of urban climate. The unique urban climate is brought about by land cover patterns and the interaction between urban surfaces and weather elements. Among the recorded effects of this include the...
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