Air is one of the precious natural resources that are essential for animal including the human being. It is also the most important gift of nature without which human cannot survive. Pollution in the urban areas like Cairo, Delhi, Mexico and Dhaka far surpasses the acceptable limits set by the World Health Organization (WHO). Urban air pollution in the South Asian region is approximated to cause more than 300,000 deaths and billions of cases of respiratory disease per year. In Bangladesh, about 200000 people die each year due to the air pollution as the WHO estimates in 2018. The air in Dhaka City, the capital of Bangladesh, has become worsen to a level that the city has been identified as one of the most polluted cities in the world. Taking the problem with utmost importance into consideration as it is related with the public health, air pollution is being treated as one of the priority issues. The level of pollution at roadside environment is deeply connected with the density of motor vehicles plying on the roads. This situation is expected to worsen further in the upcoming days due to the increasing number of motor vehicles resulted from rapid economic growth and industrialization. This paper aims to provide the present statues of the air pollution in Dhaka city and some specific recommendations for making the city as a better living place through reducing its air pollution.

It has been more than 20 years that the Measurement of Pollution in The Troposphere (MOPITT) mission onboard the NASA Terra satellite keeps providing us CO atmospheric concentration measurements around the globe. The current paper observes CO mixing ratio from the MOPITT Version 8 (MOP03J_V008) instrument in order to study the spatiotemporal analysis of CO (spanning from April 2000 to February 2020) in the Troposphere of Iran. Results indicate that the average CO in Iran’s troposphere has been 133.5 ppbv (i.e., 5.5 ppbv lower than the global mean CO). The highest distribution of CO (with an average of 150 ppbv) belongs to the city of Tehran (the capital of Iran) as well as the Caspian Sea coastal area, while the lowest value (with an average of less than 110 ppbv) has been estimated on the Zagros Mountains (southwestern Iran). The highest and lowest CO values have been observed in cold and hot months, respectively. Seasonally speaking, it is also clear that the highest and lowest carbon monoxide values occur in winter and summer, respectively. The vertical profile of MOPITT CO shows the maximum CO concentration at lower levels of the troposphere. It has been expanded up to 150 hPa. The trend is investigated by means of Pearson correlation coefficient statistical method. Overall, long-term monitoring of MOPITT CO in Iran indicates a decreasing trend of tropospheric CO over the 20 years (Y=-0.008X+449.31). Possible reasons for such a decrease can be related to improved transportation fleet, increased fuel quality, plans for traffic control, promotion of heating systems, and promotion of industrial fuels and factories.

Textile manufacturing industry produces a huge amount of pollutants from its textile dyeing units. To combat the problem of water pollution, various processes are being already adopted by textile industries to treat wastewater before its discharge into the nearby environment. However, the inadequate traditional treatments are leading towards the development of different technologies with major concern on material’s high efficacy. One of the newest advancement in this area is nanotechnology. The zero valent iron nanoparticles (nZVI) are gaining extreme importance, due to its potential capabilities of reducing chemical substances, dye colour and other constituents from the waste effluent. In the present article, synthesis of nZVI particles was carried out by borohydride chemical reduction method using ferrous heptahydrate sulphate salt. Its characterization such as surface morphology and structure was analyzed by using X-Ray diffraction (XRD), Scanning Electron Microscope (SEM) and Brunauer- Emmett-Teller method (BET). Further, the stability of nanoparticles was also investigated via chemical and thermal processes at different pH ranges and temperatures. The results revealed that the synthesized nanoparticles were as per the available literature in terms of size, surface morphology, structure & stability. Hence, ready for the batch experimental studies on laboratory scale.

Sludge/TiO2 composite was synthesized from drinking water treatment sludge, as a waste material and TiO2 , by a sol- gel method. Various sludge adsorbent / TiO2 ratios (1:1, 1:2 and 2:1 w/w) were prepared, and characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), X-ray Fluorescence (XRF), and BET. The prepared composites were applied successfully for photodegradation of methylene blue (MB) dye from a solution. The photocatalytic degradation of MB dye was investigated using UV irradiation, or UV/H2O2. Initial dye concentration, solution pH, composite dosage, and UV irradiation time were applied to study the optimum conditions for MB degradation. The results revealed the highest MB dye degradation with composite (2:1). It was found that the maximum MB degradation efficiency was at pH=7, 4 h irradiation time, 0.125 g composite dose, and 50 ppm initial dye concentration. MB removal efficiency was 95.7% using UV irradiation, and 99.8% of that using UV/ H2O2. The rate of MB dye degradation followed the first order kinetics. Results from this study offer the best conditions for recycling drinking water treatment sludge, and use it for wastewater treatment.

The impact of Industrialization has always been related to the better economic and social transformation. However, it should be well planned for environmental sustainability. Landfilling is the most used municipal solid waste (MSW) disposal method in Malaysia. Raw and treated leachate collected from Jerangau-Jabor Landfill Site (JJLS), Kuantan, Pahang were analysed for the content of silver, cadmium, chromium, copper, iron, lead, zinc using Flame Atomic Absorption Spectrometry (FAAS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The metal analyses result were compared with standard limits from the Environmental Quality (Control of Pollution from Solid Waste Transfer Station and Landfill) Regulations 2009, Malaysian Environmental Quality Act 1974 (Act 127) set by the Department of Environment, Ministry of Natural Resources and Environment, Malaysia and used to calculate the sub-leachate pollution index of heavy metals (sub-LPIhm) to evaluate the pollution potential of the heavy metals. The sub-LPIhm is one of the sub-index needed to calculate the Leachate Pollution Index (LPI) together with the sub-LPI organic (sub-LPIorg) and sub-LPI inorganic (sub-LPIinorg). LPI is the level of leachate pollution potential of a landfill site. All the heavy metals in the raw leachate were significantly higher than the treated leachate. Some were found to be above the permissible standard limit stipulated in the regulation. However, the sub-LPIhm showed that the level of heavy metal pollution potential of the leachate is low. It is recommended that the treated leachate should undergo continuous treatment to ensure the discharge leachate complied with the standard limit.

Hydrocarbon storage tanks, the major source of volatile organic compounds (VOCs) emission, have unfavorable effects on atmospheric chemistry and human health. The present study aims at calculating the amount of VOCs’ loss with an emphasis on benzene, toluene, ethylbenzene, and xylene (BTEX). It has been performed by means of TANKs 4.0.9d and WATER9 Software Programs, as well as field measurement for validation. It, then, provides control strategies to reduce the amounts of VOCs in the shipping port area. Emission sources include 32 internal and external floating roof storage tanks, 7 pump houses, and one wastewater treatment pool. Field sampling has been done, using SKC sampling pump and activated carbon adsorption tube according to NIOSH 1501 standard. The obtained samples have been analyzed with FID and GC-MS. Results show that the total emission of VOCs has been equal to 933.25 tons/year, the majority of which (881.74 tons/year ) comes from storage tanks, followed by pump houses and wastewater treatment pool (47.88 and 3.63 tons/year, respectively). BTEX emission includes 1.49 tons/year of benzene, 3.2 tons/year of toluene, 0.57 tons/year of ethylbenzene, and 1.53 tons/year of xylenes. In order to reduce the emission of VOCs from the storage tanks, the paper proposes to change the design of tanks’ roof and sealing. As a result, the total emission of VOCs could be reduced by 18.27%, equivalent to 158.16 tons/year. The total cost of the oil vapors loss is estimated at 253’000 $/year, part of which (i.e., up to 43’000 $/year) could be saved by applying the proposed control strategies.

Iran is one of the largest producers of CO2 in the world. Therefore, in order to lessen its greenhouse gas production, thus complying with the Intended Nationally Determined Contributions (INDCs), it should cut its CO2 emissions by about 4% by 2030, compared to 2010. Hence this paper aims at finding an early solution to this problem. Because the country's electricity sector is responsible for the highest annual CO2 emissions, the paper focuses on two technologies that can effectively reduce CO2 emissions from the electricity sector, namely renewable energy and Combined Heat And Power Plants (CHP) with CO2 capture and storage (CCS). Further it assesses adoption of these technologies and their impact on Iran's annual CO2 emission by 2030, considering two main scenarios: the optimistic scenario (OS) which assumes that the policies of the Sixth Development Plan (SDP) will be fully realized as well as the fair scenario (FS) which believes that SDP policies will be followed to some extent by the end of the program. To this end, twenty six micro-factors, affecting CO2 emissions, have been identified and classified into five different groups. The detected micro factors are then introduced to a Gradient Boosting Decision Tree (GBDT) Algorithm to identify the most important specific microscopic factors in Iran. The final detected micro-factors have finally been included in a Gaussian regression model to predict CO2 emissions in Iran by 2030. The findings suggest that if Iran intends to comply with the INDCs, CHP-CCS technology is a solution that has an early return, compared to renewable technologies.

Inoculation of endophytic bacteria has been accepted as a promising technique to assist phytostabilization of heavy metal-contaminated soils. This study investigated the effects of inoculating a bacterial strain closely related to Pseudomonas pyschrophila on the plant growth, and phytostabilization of fast-growing trees Acacia mangium and Eucalyptus camaldulensis, growing on artificial spiked soil with Pb up to 1500 mg/kg. After 60 days, the results showed that the strain closely related to P. pyschrophila slightly increased Pb bioavailability and Pb uptake by A. mangium, compared to non-inoculated controls. It slightly reduced Pb bioavailability in soil, but it did not affect the Pb uptake by E. camaldulensis, compared to non-inoculated controls. Interestingly, it was able to significantly increase Pb content in shoots by 3.07-fold in A. mangium and 2.95-fold in E. camaldulensis, compared to non-inoculated controls. Although the inoculation of the strain closely related to P. pyschrophila slightly increased the translocation factor (TF) of Pb in both tree species, their TF values were less than 1. This indicates that plants associated with the strain closely related to P. pyschrophila are suitable for phytostabilization of A. mangium, which may be used for cleaning up Pb contaminated sites. This strain displayed different influences on plant species and was found not suitable for phytostabilization of E. camaldulensis.

Currently, the reduction of reactive dyes present in the textile effluent is a big challenge due to the threat to the environment. Existing physical and chemical methods contains many drawbacks. In the present scenario microbial reduction pays much attention and current focus of research. Therefore, the present study isolated dye decolorizing bacterium Exiguiobacterium aurantiacum (TSL7) from activated sludge and identified by molecular techniques and 16S rDNA sequences. Decolorization was not established in Bushnell hass broth composition in accordance with absence of carbon and nitrogen source. The three environmental factors pH, starch and beef extract were selected from Plackett-Burman design experiments. The central composite design was employed to optimize the maximum removal of remazol golden yellow (91.83%) with pH, 6.89, starch, 0.49% (w/v) and beef extract 0.67% (w/v) respectively, These key factors playing a major role in the bacterial dye removal and the interactions were evaluated statistically. The optimal value of significant factors supports to maximize the dye removal competency of isolated bacterium. Thus results exhibited that local salt tolerant bacterium Exiguiobacterium aurantiacum (TSL7) could be a potential candidate for an in situ-bioremediation of inorganic salts abundant textile effluents in the textile industry.

A newly developed Smart Pouch with enclosed biomaterial (Aloe vera and coconut husk powder) has been experimented for elimination of heavy metals i.e. (Pb2+, Cu2+, Ni2+ and Zn2+) from wastewater. The effect of concentration, pH, temperature, contact duration etc. was investigated using batch experiments which resulted that the Pouch may be accepted for convenient, efficient and low-cost accumulation of several heavy metals simultaneously from waste water. The maximum Pb removal was 99.99%, 93.21% for Cu, and for Ni, it was 91.97% whereas for Zn, 86.41% was obtained and also, the uptake capacity of pouch was quite sensitive towards initial metal concentration in the studied range of 10-200mg/L present in wastewater. The findings were further interpreted by quantum chemical study as theoretical support, various adsorption isotherms, FTIR, SEM, XRD, and physiochemical properties of metal ions to justify the synergized performance of new Pouch. A good correlation was found between experimental methods and theoretical findings.