Investigating green roofs' CO2 sequestration with cold- and drought-tolerant plants (a short- and long-term carbon footprint view)

In recent years, green roofs have become the subject of increasing interest because of their good aesthetic qualities, energy conservation, and ability to reduce thermal island effect and absorb greenhouse gases, especially carbon dioxide (CO₂). Given the typically significant carbon emission of construction activities, adding any extra component to a structure increases the amount of carbon to be released during the execution stage. This also applies to green roofs, which require more materials and more extensive construction activities than traditional roofs. However, plants of green roofs absorb substantial amounts of CO₂ during their lifetime, thus leaving both short- and long-term positive impacts on the building's carbon footprint. This study investigated the short- and long-term effects of green roofs on carbon footprint, as compared to conventional roofs. For this investigation, the CO₂ uptake of eight plant species with suitable drought- and cold-resistant properties was measured by infrared gas analysis (IRGA), and the effect of green roof on the building's carbon footprint was analyzed using the software Design Builder. The results showed that building a green roof instead of a traditional roof increases the carbon emission of the construction process by 4.6 kg/m² of roof area. Investigations showed that, under high light intensities (1500-2000 μmol/m² s), Sedum acre L. has the best performance in compensating the extra carbon emission imposed on the construction process (in 264 days only). Under low light intensities (1000-1500 μmol/m² s), Frankenia laevis showed the best increase in the amount of carbon uptake (2.27 kg/m² year).

Evaluation of traffic noise pollution using geographic information system and descriptive statistical method: a case study in Mashhad, Iran

Environmental consequences and the epidemiologic results of noise pollution have chronic effects leading to widespread complications in the long run. As far as we know, there are a few studies for pollution monitoring and control systems in comparison with other environmental pollutants. One of the largest metropolitan cities located in Iran is Mashhad city as known as one of the biggest religious cities in the world. Different properties of this city including historical, industrial, and religious draw thousands of visitors to Mashhad, yearly. This fact motivates us to contribute to the concept of noise pollution in streets and sidewalks around the Holy Shrine, namely, Imam Reza. In this regard, different measurements using geographic information system (GIS) and descriptive statistical methods were conducted for our case study in Mashhad, Iran. All measurements and records were done during the peak of morning crowd (10-12 AM) and evening crowd (4-6 PM) on both sidewalks of each street around the Holy Shrine. This study showed that the pollution in the evening time span (4-6 PM) has the maximum level of noise. Among all streets in our case study in Mashhad, Iran, Tabarsi street has the most amount of noise pollution with a mean of 78 dB(A) for the mean intensity for each point, and Imam Reza street has the minimum amount of pollution with a mean of 72.75 dB(A). Our findings from the temporal perspective analysis confirm that the noise pollution peaks in the evening, when weather conditions are favorable. From the spatial perspective analysis, the most intensive noise pollution was observed around residential and accommodation land uses, which have the highest number of arterial routes towards the Holy Shrine.

Improvement of wastewater sludge dewatering using ferric chloride, aluminum sulfate, and calcium oxide (experimental investigation and descriptive statistical analysis)

In this research, application of chemical conditioners for the conditioning of sludge and their effects on the improvement of sludge thickening of the wastewater treatment plant in the city of Bojnourd (Iran) is investigated. The concentration of chemical conditioners, pH and coagulation and flocculation time is from among the parameters studied in this research work. The results obtained indicate that sludge volume reduction for the chemical conditioners used, including Ferric Chloride (FeCl₃ ), Aluminum Sulfate (Al₂ (SO₄ )₃ ), and Calcium Oxide (CaO) are 41, 17, and 33 percent, respectively. The optimal concentration for FeCl₃ , Al₂ (SO₄ )_3, and CaO are 550, 1100, and 292 mg/L, respectively, and the optimal values of pH are 9, 7.5, and 10, respectively. The time to filtration (TTF) and reduction in sludge moisture content (SMC) for Ferric Chloride, Aluminum Sulfate, and Calcium Oxide are 45 s and 6.2%, 135 s and 3.3%, 190 s and 2.4% respectively. PRACTITIONER POINTS: Investigating the sludge conditioning by Ferric Chloride, Aluminum Sulfate, and Calcium Oxide. Determining the optimal concentration, pH, and coagulation/flocculation time. Calculating the time to filtration (TTF) and reduction in sludge moisture content (SMC). Predicting the settled sludge volume using descriptive statistical analysis.

Development of the delta-normal stress combining CE-QUAL-W2 as a novel method for spatio-temporal monitoring of water quality in Karkheh Dam Reservoir

Continuous monitoring of water quality in dam reservoirs is a typically difficult and costly operation. In this study, the results of computer modeling with the CE-QUAL-W2 model were combined with data mining techniques to develop a new method called "delta-normal stress" for identifying the critical temporal and spatial monitoring ranges. For this purpose, long-term variations of three quality parameters including nitrite-nitrate level, dissolved oxygen (DO) level, and water temperature near the outlet of the dam, which is the point of interest for reservoir exploitation, were analyzed. Based on this analysis, the time intervals and depth ranges with the highest frequency of significant variations in terms of each parameter were identified. The results showed that given the difference between the delta-normal stress trend of temperature and that of other parameters in Karkheh Dam Reservoir, temperature can be monitored at much lower sampling resolutions and using cheaper methods and equipment without sacrificing accuracy. Based on the frequency of occurrence of delta-normal stress of more than 20% above the total average, the key sampling times and locations for nitrite-nitrate and DO levels were determined to be the periods of January-February, February-March, and March-April, and depths of 60, 55, 50, and 5 m, respectively.

Designing a smart risk analysis method for gas chlorination units of water treatment plants with combination of Failure Mode Effects Analysis, Shannon Entropy, and Petri Net Modeling

Today, all modern industrial units acknowledge the necessity of efficient and effective safety, health, and environment (HSE) systems. To become practical, these systems must be localized and customized to serve the exact needs of the industry. Nevertheless, most HSE plans are developed upon a set of common presumptions. In the water industry, gas chlorination units require strong HSE plans to mitigate the possibility of chlorine explosion and leak. This study aimed to provide an efficient HSE system for gas chlorination process within water treatment plants. This goal was achieved through a case study performed on a water treatment plant in Razavi-Khorasan province, Iran. In the first stage of this study, the researchers made combined use brainstorming sessions and modified Delphi technique to identify the risk factors of gas chlorination units and classify them into six groups in terms of association with chlorination unit building, gas cylinder storage, technical details of gas cylinders, gas cylinder transport, chlorinator connections, and chlorination unit management. In the second stage, the extracted factors were analyzed by Failure Mode Effects Analysis (FMEA) and Shannon Entropy approaches using two different panels of experts, and the results were compared for validation. Finally, the analysis results were structured by Petri Net modeling. The results showed that, according to FMEA, the risk factors with risk priority number (RPN) of over 46 are of highest importance for the studied unit. Once observed, these factors necessitate shutting down the operation until a risk mitigation solution is reached. Among the analyzed factors, (i) the presence of compounds such as NH₃, O₂, gas and liquid hydrocarbons and oil in gas chlorine cylinders and (ii) non-vertical and non-mechanized handling of full and empty cylinders during loading and unloading, with RPNs of respectively 160 and 120, were found to be significantly more important than others. In the SE analysis, in addition to the above factors, poor implementation of airflow control mechanism inside the chlorination chamber (W = 0.359), storage of chlorine cylinders near electrical and mechanical installations such as elevators or power panels (W = 0.327), poor pipe placement for connecting the injector to the water inlet and the possibility of air suction (W = 0.433), and failure to provide scientific and practical training to the chlorination staff (W = 0.342) were found to be of highest importance.

Thermal, Tensile, Electrical, Dynamic Mechanical Thermal and Rheological Properties of Polyvinylidene Fluoride and Fluoroelastomer Composites Filled with Carbon Black

The present work was focused on studying the effects of different CB loadings on the rheological, thermal, tensile, dynamic mechanical and electrical properties of polyvinylidenefluoride (PVDF) and FKM composites. To these ends, the CB grade and method chosen for compound preparation were CB (N330) and melt mixing, respectively. The composites were melt blended with CB at 190 °C in an internal mixer, after which the properties of filled and unfilled composites were compared. The presence of CB improved the mechanical properties, such as the Young's modulus and tensile strength, and increased thermal stability given the high thermal stability of CB and the interaction between the CB particles and the polymer matrices. The dynamic mechanical thermal analysis (DMTA) showed the glass transition temperatures of the composites. The analysis also revealed that the area under the loss tangent (tan δ) peak decreased and that the tan δ temperature of the rubber phase increased with CB loading. The increase in the electrical conductivity of the composites under different CB loadings was also examined, and the percolation threshold of conductive thermoplastic vulcanizate composite based on conductive CB was observed. The effect of CB and its content on rheological behavior of the PVDF/FKM blends was studied and the experimental data was correlated by a physical model named General Equation Model (GEM). A relation between rheology and conductivity of the blends with filler percolation was found.

Biodegradation of phenol by cold-tolerant bacteria isolated from alpine soils of Binaloud Mountains in Iran

Degradation of phenol is considered to be a challenge because of harsh environments in cold regions and ground waters. Molecular characterization of phenol degrading bacteria was investigated to gain an insight into the biodegradation in cold areas. The psychrotolerant and psychrophiles bacteria were isolated from alpine soils in the northeast of Iran. These strains belonged to Pseudomonas sp., Stenotrophomonas spp. and Shinella spp. based on analysis of the 16S rRNA gene. These strains were capable of the complete phenol degradation at a concentration of 200 mg L^-1 at 20 °C. Moreover, the strains could degrade phenol at a concentration of 400 and 600 mg L^-1 at a higher time. Effects of environmental factors were studied using one factor at a time (OFAT) approach for Pseudomonas sp.ATR208. When the bacterium was grown in a liquid medium with 600 mg L^-1 of concentration supplemented with optimum carbon and nitrogen sources, more than 99% of phenol removal was obtained at 20 °C and 24 h. Therefore, the present study indicated the potential of the local cold tolerant bacteria in the phenol bioremediation.

Controlling air pollution in a city: A perspective from SOAR-PESTLE analysis

Strengths, opportunities, aspirations, and results (SOAR) analysis is a strategic planning framework that helps organizations focus on their current strengths and opportunities to create a vision of future aspirations and the results they will bring. PESTLE is an analytical framework for understanding external influences on a business. This research paper describes a field study and interviews of city hall managers from the city of Mashhad, Iran, conducted to investigate the application of SOAR and PESTLE frameworks for managing Mashhad's air pollution. Strategies are prioritized by the technique for order of preference by similarity to ideal solution (TOPSIS), Shannon entropy (SE), and analytic network process (ANP) multicriteria decision-making (MCDM) methods, considering economic conditions, managers' opinions, consensus, city council approvals, and national documents. The results of this research study show that creating centralized databases, supporting local governments, and developing smart city infrastructure, with weights of 0.194, 0.182, and 0.161, respectively, are the highest ranked strategies for managing air pollution in Mashhad. It can also be concluded that citizen involvement is key to achieving success in the employment of any management strategy. Integr Environ Assess Manag 2018;14:480-488. © 2018 SETAC.

Life cycle assessment of concrete production with a focus on air pollutants and the desired risk parameters using genetic algorithm

BACKGROUND

Through a new systematic perspective, the HSE-integrated management system attempts to examine the relationships between safety, health and environment. The purpose of this system is to provide a coordinated, comprehensive and precautionary assessment of the issues and incidents within concrete plants.

METHODS

In addition to a life cycle assessment (LCA) of concrete through air pollutant emissions in this study, the extraction and monitoring of pollutant from three concrete plants in the city of Mashhad are carried out via fieldwork. In the present study, a number of factors such as the extent and time of exposure to each pollutant are estimated using the meta-heuristic genetic algorithm approach (GA) in order to create the desirable risk rate (risk rate ≤ 3).

RESULTS

The results of life cycle assessment indicate the production of 348 kg Carbon Dioxide (CO₂) per cubic meter of concrete processing. However, in addition to its environmental effects, CO₂ in concentrations of more than 5000 ppm may cause asphyxiation as well as epidemiologic effects on the staff.

CONCLUSION

The results of the study show that in order to reduce the risks of developing chronic diseases such as lung cancer, the staff in cement processing sector must be exposed to a period of at most 3.5 h for each 8-h work interval.

Silane crosslinking of electrospun poly (lactic acid)/nanocrystalline cellulose bionanocomposite

Biodegradable nanofibrous mats fabricated by electrospinning are commonly used in tissue engineering, however, lack of essential mechanical properties of such nanofibers is a challenging issue. In this work, vinyltrimethoxysilane (VTMS) was grafted onto poly (lactic acid) (PLA) and the silane grafted PLA was subsequently applied in electrospinning process. Electrospun nanofibrous mats based on PLA/nanocrystalline cellulose (NCC) and PLA-g-silane/NCC nanocomposites were fabricated and immersed in hot water (70°C) for crosslinking of silane grafted PLA. It was found that introducing NCC to the samples cause to reduction in fiber diameter and the other hand the silane crosslinking of PLA increase the mean fiber diameter. DSC thermograms also revealed that silane grafting caused a reduction in mobility of polymer segments, and consequently reduction of crystallinity. On the contrary, the NCC in the PLA-g-silane samples effectively influenced the crystal nucleation, while in the PLA nanofibers the nucleation was lower. The impact of NCC on tensile strength enhancement of samples was notable. The results suggested that the chemical crosslinking remarkably improves the mechanical properties of PLA nanofibers. Furthermore, biocompatibility of such modified nanofibers was also evaluated through cytotoxicity results, therefore the modified PLA nanocomposite can be considered as a practical candidate for hard tissue engineering applications.