Civil & Environmental Engineering

The objective of this research was to analyze the indirect tensile strength of the asphalt concrete mixture with fiber reinforcement that was immersed on the sea water. The method of research was an experimental testing on the mechanical properties of fibers and indirect tensile strength of the mixture with a variation of length were 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 14 mm and the variation of fiber content for each composition was respectively 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 1.2% with the optimum diameter of fiber was 0.3 mm. Each composition of the mixture was tested for each variation of length and fiber content with the optimum asphalt content of 5.9%. The seawater-immersed fibers with the immersion duration of 3 weeks gave high tensile strength and strain. The 0.3 mm diameter fibers with 3 weeks immersion had a maximum stress = 130.45 N / mm 2 , and maximum strain of 14.24% while those in control had a maximum stress = 13.71 N / mm2 and maximum strain of 13.89%. While the indirect tensile strength (ITS) test results on five variations of length and percentage of fibers in the asphalt concrete mixture, the 0.6% fiber content composition provided ITS value of a maximum stress = 26795.84 kPa and maximum strain in the fiber length of 8 mm was 0.01486 and an elastic modulus was 2318478.25 kPa. The composition yield a Poisson ratio = 0.44. The Poisson number is an indicator of the ductility of a mixture.
Keywords: elastic modulus, indirect tensile strength, strain

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations. Abstract This study aims to examine the nonsterilized fermentation conditions for coproduction of pectinases and lipase enzymes using several fruit wastes as an energy source. Thermophilic fungal strain, Penicillium expansum CMI 39671 was used as a fermenting strain. The effect of process conditions including; nitrogen sources, pH, temperature, time and moisture contents, on the production of both enzymes were studied. The highest activities of pectinase and lipase (2817, 1870 U/g dry substrate) enzymes were found with orange peel feedstock, whereas the lowest activities of 1662 U/g and 1266 U/g were found with banana peel and papaya peel feedstocks respectively. Overall, pectinase showed higher enzymatic activities than lipase enzymes, both having similar increasing and decreasing trends, at all studied conditions. The optimum process conditions of peptone as a nitrogen source, pH 7, 40°C, 5 days and 70% moisture contents, were found to show highest enzymatic activities for both enzymes. The orange peel feedstock showed no significant difference in both enzymes' activities at sterilized and nonnotarized process conditions. Pectinase and lipase enzymes showed (13791 U/g) and (8114 U/g) for sterilized and (14091 U/g) and (8324 U/g) for nonnotarized process conditions respectively. In addition, the fungal strains also produce bacteriocin-like compounds that could inhibit microbial growth. These findings will help to design and develop robust, cost-effective and less energy intensive enzyme production processes and consequently an efficient fruit waste to energy system through open fermentation. Abstract This study aims to examine the nonsterilized fermentation conditions for coproduction of pectinases and lipase enzymes using several fruit wastes as an energy source. Thermophilic fungal strain, Penicillium expansum CMI 39671 was used as a fermenting strain. The effect of process conditions including; nitrogen sources, pH, temperature, time and moisture contents, on the production of both enzymes were studied. The highest activities of pectinase and lipase (2817, 1870 U/g dry substrate) enzymes were found with orange peel feedstock, whereas the lowest activities of 1662 U/g and 1266 U/g were found with banana peel and papaya peel feedstocks respectively. Overall, pectinase showed higher enzymatic activities than lipase enzymes, both having similar increasing and decreasing trends, at all studied conditions. The optimum process conditions of peptone as a nitrogen source, pH 7, 40°C, 5 days and 70% moisture contents, were found to show highest enzymatic activities for both enzymes. The orange peel feedstock showed no significant difference in both enzymes' activities at sterilized and nonnotarized process conditions. Pectinase and lipase enzymes showed (13791 U/g) and (8114 U/g) for sterilized and (14091 U/g) and (8324 U/g) for nonnotarized process conditions respectively. In addition, the fungal strains also produce bacteriocin-like compounds that could inhibit microbial growth. These findings will help to design and develop robust, cost-effective and less energy intensive enzyme production processes and consequently an efficient fruit waste to energy system through open fermentation.

Air pollution has increasingly become a serious concern, predominantly because of its impact on health, agriculture and the general well-being of humans, floral and faunal population. A study in 2018 revealed, dust and construction contribute 17% and 38% of PM2.5 concentrations and 25% and 41% of PM10 concentration in Delhi during summer and winters respectively. Indicating a clear demand to reduce exhaust and non-exhaust emissions, from the city-particularly associated with roads dust. Thus, due to increasing development and requirements of clean air, limited availability of human workforce and high labor costs, mechanization of road sweeping is growing worldwide. Thus, to oversee mechanized road sweeping (MRS) operations and identify lacunae which need to be addressed to make operations more efficient, physical audits of these MRS operations were undertaken, for all 04 urban local bodies of Delhi. These audits were designed, to collect data on time spent by MRS machines on various on-shift activities, actual kilometers of sweeping undertaken and measures to improve upon shift sweeping outputs. This was a first of its kind of audit undertaken in India to help make MRS operations more efficient and effective. Catering to 59 MRS machines in total, these audits covered 352 shifts, since mid of 2018 till March 2020 with >90% confidence level. The audits indicate that ULBs in Delhi on an average sweep around 26.17 kms of road length per shift, with East Delhi Municipal Corporation utilizing highest of 75% of shift time on sweeping activity. The gaps in existing monitoring systems, operational inefficiencies as well as good practices of MRS operations have also been highlighted in this paper to make policy makers, city managers, consultants, technocrats, and other related stakeholders realise the importance of such audits and setup monitoring, review and verification mechanisms for continual improvement. This paper also brings forth the results of individual audits along with existing contractual mechanisms and its impact on performance, highlighting a need for having performance-based contracts.

Biomass pyrolysis is a promising renewable sustainable source of fuels and petrochemical substitutes. It may help in compensating the progressive consumption of fossil-fuel reserves. The present article outlines biomass pyrolysis. Various types of biomass used for pyrolysis are encompassed, e.g., wood, agricultural residues, sewage. Categories of pyrolysis are outlined, e.g., flash, fast, and slow. Emphasis is laid on current and future trends in biomass pyrolysis, e.g., microwave pyrolysis, solar pyrolysis, plasma pyrolysis, hydrogen production via biomass pyrolysis, co-pyrolysis of biomass with synthetic polymers and sewage, selective preparation of high-valued chemicals, pyrolysis of exotic biomass (coffee grounds and cotton shells), comparison between algal and terrestrial biomass pyrolysis. Specific future prospects are investigated, e.g., preparation of supercapacitor biochar materials by one-pot one-step pyrolysis of biomass with other ingredients, and fabricating metallic catalysts embedded on biochar for removal of environmental contaminants. The authors predict that combining solar pyrolysis with hydrogen production would be the eco-friendliest and most energetically feasible process in the future. Since hydrogen is an ideal clean fuel, this process may share in limiting climate changes due to CO 2 emissions.
Keywords Sustainable and renewable energy source; Fossil-fuel alternatives; Biomass pyrolysis; Biofuel (bio-oil, biogas, biochar); Charcoal (activated carbon); Hydrogen fuel

Due to the rapid growth of urbanization and popularization the problem of organic solid waste management or garbage becomes extensive critical. As, this is the era of revolution and use of green technology. It is necessary to recycle and utilize product from the waste. Eco enzyme is a product produced with the use of raw material such as fruits peeled and vegetable waste, jiggery or brown sugar and water with the recipe and methods published in media. These study asses effects of Eco enzyme dilutions (5% and 10%) in the domestic waste water treatment. The effluent characteristics of treated domestic waste water sample met the irrigation standards after 5 days.

A Cost-effective and Efficient method for Municipal Wastewater Treatment using an Upflow Anaerobic Sludge Blanket (UASB) reactor followed by Flash Aeration (FA) as the post-treatment, without implementing aerobic biological processes is examined in this paper. The UASB reactor was operated without recycle, at Hydraulic Retention Time (HRT) of 8 h and achieved consistent removal of BOD, COD and TSS of 60–70% for more than 12 months. The effect of Flash Aeration (FA) on UASB effluent post-treatment was studied at different HRT (15, 30 and 60 min) and dissolved oxygen (DO) concentrations (low DO = 1–2 mg/L and high DO = 5–6 mg/L). The optimum conditions for BOD, COD and sulfide removal were 30–60 min HRT and high DO concentration inside the FA tank. The Final Effluent after clarification was characterized by BOD and COD values of 28–35 and 50–58 mg/L, respectively. Sulfides were removed by more than 80%, but the fecal coliform only by ~2 log. The UASB followed by FA is a simple and efficient process for municipal wastewater treatment, except for fecal coliform, enabling water and nutrients recycling to agriculture.

The Gulf Cooperation Countries (GCC) consistently rank among the top 10% of per capita waste producers in the world. Collectively around 120 million tons of waste is produced annually in GCC; 55% construction and demolition (C&D) waste, 20% municipal solid waste (MSW), 18% industrial waste, and 7% hazardous waste. Like other GCC nations, the Kingdom of Saudi Arabia (KSA) generates massive amounts of MSW, C&D waste, and industrial waste. This study aims to examine 81 construction companies in the Eastern Province of KSA to determine which factors critically affect the sustainable management of C&D waste in the country. Only 39.5% of the companies studied had a pollution control plan for their projects. It was also found that only 13.6% of C&D waste is recycled and reused every year, whereas the remaining 86.4% C&D waste eventually goes to the landfills. Most of the C&D waste in the country is a promising source of potential recyclable construction materials such as gravel from debris, metals, and sand. This would not only fulfill the requirements of gravel and metal production of the KSA but also solve the waste disposal issues along with generating huge economic benefits. However, to accomplish the goal of sustainable construction waste management, it is critical to underline the various factors that might impact the construction waste management practices in the country. Keywords Construction and demolition (C&D) waste · Municipal solid waste (MSW) · Waste recycling · Landfill sites · Sustainable construction material

This study discusses the production of briquettes as an alternative household fuel. Briquettes were produced from sawdust collected from one of the saw-mills in Akure, Ondo State. Water and cow dung were used both as binders in the production. Five briquettes were produced at 100%, 120%, 140%, 160% and 180% weight of water to sawdust while the other five were produced at water to cow dung ratios of 80:20, 60:40, 40:60, 20:80 and 0:100 percentages added to 1.5kg of sawdust. Combustion related properties of the briquettes viz: moisture content, dry density, percentage volatile matter, percentage fixed carbon and heating values were determined. Also, the cost analysis of producing 1000 briquettes was carried out. The results show that briquettes made from sawdust using solely water as binder has good combustion capacity than those produced from sawdust using the mixture of water and cow dung as binders. The cost analysis carried out shows the economic viability of using briquettes as a good substitute of the current ever increasing conventional cooking fuels available. Therefore, the use of wood residues for briquette production will reduce deforestation and environmental degradation by minimizing waste in the sawmill industry

The octane enhancement of light straight run naphtha is one of the significant solid acid catalyzed processes in the modern oil refineries due to limitations of benzene, aromatics, and olefin content in gasoline. This paper aims to examine the role of various catalysts that are being utilized for the isomerization of light naphtha with an ambition to give an insight into the reaction mechanism at the active catalyst sites, and the effect of various contaminants on catalyst activity. In addition, different technologies used for isomerization process are evaluated and compared by different process parameters.

The current inadequate drinking water services and sanitation problems have incited the need for a better management strategy by the country's water and sanitation organizations. In this study, a logical review of the water supply and sanitation origin and management structures was done to suggest a plausible management option in Nigeria. The paper also revealed that the overall management practices of these organizations at the three tiers of governments (federal, states and local) is very poor and uncoordinated which have resulted in low level of water and sanitation coverage. Thus, in order to ameliorate these problems, the study recommends sector wide reforms with the aim of radical improvement in the management processes of these organizations. Other
proposed improvement strategies include: private sector participation, effective and reasonable tariff regime for effective cost recovery, increment in political support and leadership commitment, introduction of benchmarking amongst the utilities to encourage healthy competition, strengthening of the legislative and institutional framework- that will enhance the autonomy of these organizations, improvement in the issues of accountability, transparency and stakeholders involvement in the activities of these organizations. It is hoped that the adoption and implementation of these strategies will lead to attainment of improved and sustainable water supply and sanitation coverage that will meet current and future demands.

This paper aims at establishing changes in land use and land cover in Igbokoda municipality using Geographic Information System and remote sensing techniques. Three satellite images for three different epochs 1986, 1999 and 2013 were used to produce a land use/land cover map classification for Igbokoda. In determining the extent of land use/land cover changes in the township from 1986 through 1999 to 2013, Landsat images of the town were downloaded from the United State Geological Survey online archive. The images were analyzed using change detection technique (NDVI differencing) along with SRTM 90m DEM of the study area to generate the extent of the changes that have occurred. Ground trotting was carried out to ascertain the accuracy of data and the major changes in the land use/land cover. Results show that vegetation has decreased from 75.04% in 1986 to 46.81% in 2013 which was due to increase in population and rapid urbanization. In 1996 the Built-up area covers 19.6321 km2 of the study area but has increased rapidly to 39.1505 km2 in the year 1999 with an average annual increment of 2.025Km2/year. By the year 2013, the built-up area has increased to 64.1520Km2. Also in the same vein, the bare surface area which was 13.28029km2 in 1986 was increased to 39.6053 and 50.240Km2 in 1999 and 2013 respectively. On the contrary, the vegetated area of Igbokoda reduced from 196.3046Km2 in 1999 to 122.4680Km2 in 2013. This study has demonstrated that remotely sensed data and GIS based approach is timely and cost effective than the conventional method of analysis, classification of land use pattern effective for planning and management. It further shows that If the rapid change in land use is not properly manage, the situation poses a serious threat to Igbokoda town by increasing surface runoff and susceptibility to flooding.