A comprehensive perspective on potentially hazardous elements (PHEs) bound with particulate matters in ambient air of landfill sites: a systematic review and probabilistic risk assessment.

Air pollution from Potentially Hazardous Elements bound with particulate matter (PHEs bound PM) in landfill air is a significant concern for human health. To date, no comprehensive research has focused on the health risks of PHEs bound to PM in landfill air. This systematic review aimed to examine PHEs, including Lead (Pb), Cadmium (Cd), Chromium (Cr), Arsenic (As), Nickel (Ni), and Zinc (Zn) bound with PM in landfill air and assess the health risk for workers and waste management personnel. The systematically search was made in different electronic databases. After the screening, 18 most relevant studied focused on PHEs bound PM in landfill air were selected. The data extraction analysis indicated that mean concentrations of Pb, Cd, Cr, As, Ni, and Zn in landfill air were 0.3037, 0.0941, 0.4093, 0.0221, 0.2768, and 0.7622 µg/m3, respectively. Except for Pb, the concentrations of other PHEs bound to PM exceeded USEPA air quality standards. In addition, Non-carcinogenic risks from Cd, Cr, and Ni exposure exceeded permissible limits (HQ > 1), while As had an HQ value of 0.401. Carcinogenic risks from As, Cd, Ni, and Pb exposure were 1.31 × 10-5, 5.10 × 10-4, 3.51 × 10-5, and 2.03 × 10-6, respectively. Notably, the lifetime carcinogenic risk for workers exposed to Cr in polluted air (6.17 × 10-3) exceeded permissible limits (10-4 to 10-6). In conclusion, given the high carcinogenic and non-carcinogenic risks of some PHEs bound PM in landfills, it is necessary to conduct more research on the health effects of interaction with these PHEs bound PM on communities and the environment in different countries. Also, it is necessary to evaluate the role of different landfill operational activities on atmospheric dispersion of PHEs bound PM) in landfill air.

The spinning disc reactor for photocatalytic degradation: A systematic review.

In recent years, the use of a horizontal spinning disc reactor (SDR) as a photocatalytic reactor for the degradation of various pollutants in aqueous solutions has increased. This study was searched based on the PRISMA method. Two autonomous researchers carried out for the relevant studies using Scopus, Web of Science (WOS), and Science Direct databases. The search terms expanded focusing on the performance of horizontal spinning disc photocatalytic reactor (SDPR). In this review article, the main objective of the effect of operational factors on the efficiency of the degradation of pollutants with changes in the type of light source (range of visible light and UV radiation), disc rotational speed, flow rate, initial concentration of pollutants, pH, type of disc structure and flow regime are considered. Current challenges in SDPR include issues such as limited mass transfer, uneven light distribution, and difficulties in scaling up. To overcome these challenges, improvements can be made by optimizing reactor design for better mass transfer, enhancing light distribution through advanced light sources or reactor configurations, and developing scalable models that maintain efficiency at larger scales. Additionally, the use of innovative materials and coatings could improve the overall performance of SDPR.

A comprehensive study on the spatial and temporal variation of BTEX and asbestos in the northwest of Iran: Human risk assessment.

Substances like asbestos and other air pollutants, such as BTEX (benzene, toluene, ethylbenzene, and xylene), are hazardous compounds due to their adverse effects on human health. This study aims to investigate the levels, seasonal variations, spatial distribution, potential sources, and associated health risks associated with BTEX compounds and asbestos fibers in the ambient air of Tabriz. Air samples were taken at 16 different locations during the 2020-2021 period. Glass containers with charcoal were used for sample collection, and the BTEX content was determined using the GC-FID method. Phase-contrast microscopy (PCM) analysis was conducted with a low-volume peripheral pump for asbestos fiber sampling. The results showed that the average concentration of ∑BTEX was 37.94 and 27.98 µg/m3 in autumn and spring, respectively. The same parameter was 2.26 and 1.68 f/L for asbestos in the autumn and winter, respectively. The contribution of BTEX to ozone formation potential (OFP) in the research area showed that xylene and toluene were the major contributors to ozone production in different seasons. The risk of exposure to benzene compounds was 24 × 10-4 in children and 55.9 × 10-4 in adults, while the risk of exposure to ethylbenzene was 3.78 × 10-4 in children and 3.25 × 10-4 in adults. The estimated lifetime cancer risk was found to be the highest for benzene, followed by ethylbenzene. The estimated cancer risk for benzene and ethylbenzene exceeded the threshold values set by EPA, which signals a significant carcinogenic risk due to exposure to these substances in the ambient air of Tabriz. According to the EPA guidelines, the low carcinogenicity risk levels are between 10-4 and 10-6. According to the findings for the exposure to asbestos fibers, the maximum values of excess cancer risk (ECR) and estimated lifetime cancer risk (ELCR) were observed in the 16-30 age range across all locations, suggesting increased exposure to asbestos fibers compared to other age groups.

Efficient removal of oxytetracycline antibiotic from aqueous media using UV/g-C3N4/Fe3O4 photocatalytic process.

Residual pharmaceuticals in the environment are a class of emerging pollutants that endanger human health. Tetracycline's family, including oxytetracycline (OTC), are known as one of the most produced and consumed antibiotics worldwide. The g-C3N4/Fe3O4 nanocomposite with high level of catalytic efficiency features suitable performance in water/wastewater treatment. Therefore, in the present study, this nanocomposite was applied to remove the oxytetracycline from the aqueous environment. In this research study, g-C3N4/Fe3O4 nanocomposite (serving as catalyst) was initially synthesized by a simple hydrothermal method. The effect of key operating parameters such as initial solution pH, dose of catalyst, contact time and initial concentration of OTC in aqueous solutions was investigated under UV irradiation. In addition, COD and TOC tests, the kinetics and the effect of radical scavengers on the applied photocatalytic process were all evaluated. The maximum removal efficiency of OTC (99.8 %) was achieved under the following conditions: neutral solution pH 7; catalyst dose, 0.7 g/L; and an initial OTC concentration of 5 mg/L. The data showed that the kinetics of the reaction followed the first-order model with R2 of 0.9755. The respective COD and TOC efficiency values for the applied photocatalytic process were determined to be 87 and 59 %, respectively. In addition, the lowest removal efficiency of OTC was observed in the presence of tert-butanol radical scavengers, and OH radicals played a main role. The UV/g-C3N4/Fe3O4 photocatalytic process proved to be highly efficient for the removal of OTC antibiotic and could be potentially applied for the removal of other pollutants from aqueous solutions.

Novel nanostructure approach for antibiotic decomposition in a spinning disc photocatalytic reactor.

Conventional wastewater treatment processes are often unable to remove antibiotics with resistant compounds and low biological degradation. The need for advanced and sustainable technologies to remove antibiotics from water sources seems essential. In this regard, the effectiveness of a spinning disc photocatalytic reactor (SDPR) equipped with a visible light-activated Fe3O4@SiO2-NH2@CuO/ZnO core-shell (FSNCZ CS) thin film photocatalyst was investigated for the decomposition of amoxicillin (AMX), a representative antibiotic. Various characterization techniques, such as TEM, FESEM, EDX, AFM, XRD, and UV-Vis-DRS, were employed to study the surface morphology, optoelectronic properties, and nanostructure of the FSNCZ CS. Key operating parameters such as irradiation time, pH, initial AMX concentration, rotational speed, and solution flow rate were fine-tuned for optimization. The results indicated that the highest AMX decomposition (98.7%) was attained under optimal conditions of 60 min of irradiation time, a rotational speed of 350 rpm, a solution flow rate of 0.9 L/min, pH of 5, and an initial AMX concentration of 20 mg/L. Moreover, during the 60 min irradiation time, more than 69.95% of chemical oxygen demand and 61.2% of total organic carbon were removed. After the photocatalytic decomposition of AMX, there is a substantial increase in the average oxidation state and carbon oxidation state in SDPR from 1.33 to 1.94 and 3.2, respectively. Active species tests confirmed that ·OH and ·O2- played a dominant role in AMX decomposition. The developed SDPR, which incorporates a reusable and robust FSNCZ CS photocatalyst, demonstrates promising potential for the decomposition of organic compounds.

Examining the relationship between land use and childhood leukemia and lymphoma in Tehran.

We conducted a hospital-based case-control study to explore the association between proximity to various land use types and childhood leukemia and lymphoma. This research involved 428 cases of childhood leukemia and lymphoma (2016-2021), along with a control group of 428 children aged 1-15 in Tehran. We analyzed the risk of childhood cancer associated with land use by employing logistic regression adjusted for confounding factors such as parental smoking and family history. The odds ratio (OR) for children with leukemia and lymphoma residing within 100 m of the nearest highway was 1.87 (95% CI = 1.00-3.49) and 1.71 (95% CI = 1.00-2.93), respectively, in comparison to those living at a distance of 1000 m or more from a highway. The OR for leukemia with exposure to petrol stations within 100 m was 2.15 (95% CI = 1.00-4.63), and for lymphoma it was 1.09 (95% CI = 0.47-2.50). A significant association was observed near power lines (OR = 3.05; 95% CI = 0.97-9.55) within < 100 m for leukemia. However, no significant association was observed between power lines and the incidence of childhood lymphoma. There was no association between bus stations, major road class 2, and the incidence of childhood leukemia and lymphoma. In conclusion, our results suggest a possible association between the incidence of childhood leukemia and proximity to different urban land uses (i.e., highways and petrol stations). This study is the first step in understanding how urban land use affects childhood leukemia and lymphoma in Tehran. However, comprehensive studies considering individual-level data and specific pollutants are essential for a more nuanced understanding of these associations.

A systematic review on garbage enzymes and their applications in environmental processes.

Understanding the new insight on conversion of organic waste into value-added products can improve the environmental activities driven by microorganisms and return the nutrients to environment and earth. Here, we comprehensively review the available knowledge on application of garbage enzyme (GE) for different environmental activities including waste activated sludge, composting process, landfill leachate treatment, soil remediation and wastewater treatment with special focus on their efficiency. To identify peer-reviewed studies published in English-language journals, a comprehensive search was performed across multiple electronic databases including Scopus, Web of Science, Pubmed, and Embase. The search was conducted systematically using relevant keywords. The eligible studies were analyzed to extract data and information pertaining to components of GE, fermentation process operational parameters, type of hydrolytic enzymes and improved environmental performance. The findings derived from this current review demonstrated that GE produced from the fruit and vegetable peels, molasses or brown sugar (carbon source), and water within fermentation process contain different hydrolytic enzymes in order to facilitate the organic waste degradation. Therefore, GE can be considered as a promising and efficient pathway in order to improve the environmental activities depended on microorganism including, composting, wastewater and leachate treatment and bioremediation process.

Evaluating the mortality and health rate caused by the PM2.5 pollutant in the air of several important Iranian cities and evaluating the effect of variables with a linear time series model.

All over the world, the level of special air pollutants that have the potential to cause diseases is increasing. Although the relationship between exposure to air pollutants and mortality has been proven, the health risk assessment and prediction of these pollutants have a therapeutic role in protecting public health, and need more research. The purpose of this research is to evaluate the ill-health caused by PM2.5 pollution using AirQ + software and to evaluate the different effects on PM2.5 with time series linear modeling by R software version 4.1.3 in the cities of Arak, Esfahan, Ahvaz, Tabriz, Shiraz, Karaj and Mashhad during 2019-2020. The pollutant hours, meteorology, population and mortality information were calculated by the Environmental Protection Organization, Meteorological Organization, Statistics Organization and Statistics and Information Technology Center of the Ministry of Health, Treatment and Medical Education for 24 h of PM2.5 pollution with Excel software. In addition, having 24 h of PM2.5 pollutants and meteorology is used to the effect of variables on PM2.5 concentration. The results showed that the highest and lowest number of deaths due to natural deaths, ischemic heart disease (IHD), lung cancer (LC), chronic obstructive pulmonary disease (COPD), acute lower respiratory infection (ALRI) and stroke in The effect of disease with PM2.5 pollutant in Ahvaz and Arak cities was 7.39-12.32%, 14.6-17.29%, 16.48-8.39%, 10.43-18.91%, 12.21-22.79% and 14.6-18.54 % respectively. Another result of this research was the high mortality of the disease compared to the mortality of the nose. The analysis of the results showed that by reducing the pollutants in the cities of Karaj and Shiraz, there is a significant reduction in mortality and linear modeling provides a suitable method for air management planning.

Biological feasibility of discharge a local WTTP sludge to sewer network and centralized WWTP; a case study: Tehran, Iran.

Over the recent years, ever-increasing population growth and higher wastewater production has been a challenge for decentralized wastewater treatment plants (WWTPs). In addition, sludge treatment due to high cost for equipment and place make authorities to find a sustainable approach in both of economical and technical perspectives. One of the proposed solutions is transferring the sludge produced from decentralized WWTP to centralized WWTP. However, the appropriate proportional ratio of raw sludge to raw sewage is a challenge, otherwise, it make anaerobic conditions and sewage rotting along the sewer network based on permissible limit of dihydrogen sulfide (H2S) gas (5 ppm). In the present study, seven reactors with different ratios of sludge to raw sewage (0, 15, 20, 25, 50, 75, 100) were used to stimulate the feasibility of transferring Shahrake Gharb WWTP sludge along the wastewater transfer pipe to the centralized sewage treatment south Tehran WWTP plant in Tehran, Iran. The septic situation and H2S emission of different reactors within 7 h (Time to reach the compound in the south treatment plant) was analyzed by gas meter. The results indicated that the optimum ratio of sludge to raw sewage was 15% without H2S production during 7 h. In addition, due to the high volume of sludge produced by the Shahrake Gharb WWTP, the optimal ratio of lime to total solids (TS) in sludge (gr/gr) (0.6) increased the sludge loading rate from 15 to 30% without any H2S emission during the stimulation study period. Therefore, the lime stabilization and transfer of sludge from a decentralized WWTP to a centralized WWTP is a feasible way to manage the sludge and enhance the treatment capacity in local WWTP.

Reduction of the environmental and health consequences of cigarette butt recycling by removal of toxic and carcinogenic compounds from its leachate.

Cigarette butt is a hazardous waste, and its management faces many challenges. The generation of leachate containing many pollutants including heavy metals is one of the limitations of recycling cigarette butts. The aim of this study was to reduce organic compounds and heavy metals in leachate resulting from cigarette butt recycling in an electrocoagulation reactor. For this purpose, two samples, including freshly smoked cigarette butts and littered cigarette butts, were processed and the treatment of leachate resulting from them was studied in an electrocoagulation reactor. The efficiency of leachate treatment was investigated in the treatment time of 10-40 min and current intensity of 20-100 mA. The results showed that the minimum reduction of chemical oxygen demand and turbidity was 25.3% and 33.4%, respectively. Increasing the current intensity and treatment time increased the efficiency of removing turbidity and chemical oxygen demand up to 47.1% and 41.2%, respectively, in optimum conditions. The reduction of nickel, chromium, cadmium, and lead in the lowest current density and minimum treatment time was more than 90%, which increased to more than 99% with the increase of the current density and treatment time. The use of electrocoagulation is a suitable solution to reduce heavy metals in leachate resulting from cigarette butt recycling, while the proper reduction of organic compounds in this type of leachate requires further treatment processes.

Estimating the health impacts of exposure to Air pollutants and the evaluation of changes in their concentration using a linear model in Iran.

In big and industrial cities of developing countries, illness and mortality from long-term exposure to air pollutants have become a serious issue. This research was carried out in 2019-2020 to estimate the health impacts of PM10, NO2 and O3 pollutants by using AirQ+ and R statistical programming software in Arak, Isfahan, Tabriz, Shiraz, Karaj, and Mashhad. Mortality statistics, number of people in required age groups, and amount of pollutants were gathered respectively from different agencies like Statistics and Information Technology of the Ministry of Health, Statistical Center, and Department of Environment and by using Excel, the average 24-hour and 1-hour concentration and maximum 8-hour concentration for PM10, NO2 and O3 pollutants were gathered. We used linear mixed impacts model to account for the longitudinal observations and heterogeneity of the cities. The results of the study showed high number of deaths due to chronic bronchitis in adults, premature death of infants, and respiratory diseases in Mashhad. This research highlights the importance of estimation of health impacts from exposure to air pollutants on residents of the studied cities.

Photocatalytic degradation of ciprofloxacin using a novel carbohydrate-based nanocomposite from aqueous solutions.

Pharmaceutical substances in the ecosystem pose a notable hazard to human and aquatic organism well-being. The occurrence of ciprofloxacin (CIP) within water sources or the food chain can perturb plant biochemical processes and induce drug resistance in both humans and animals. Therefore, effective removal is imperative prior to environmental discharge. This study introduces a Novel Carbohydrate-Based Nanocomposite (Fe3O4/MOF/AmCs-Alg) as a proficient photocatalytic agent for degrading CIP in aqueous solutions. The fabricated nanocomposite underwent characterization using FTIR, XRD, FESEM, DRS, and VSM techniques. The analyses conducted verified the successful synthesis of the Fe3O4/MOF/AmCs-Alg nanocomposite. Utilizing the optimized parameters (pH = 5, nanocomposite dose = 0.4 g/L, CIP concentration = 10 mg/L, light intensity = 75 mW/cm2, and a duration of 45min), the Fe3O4/MOF/AmCs-Alg/Vis nanocomposite demonstrated an impressive CIP degradation efficiency of 95.85%. Under optimal experiment conditions, CIP removal efficiency in tap water and treated wastewater samples was 91.27% and 76.78%, respectively. Furthermore, the total organic carbon (TOC) analysis indicated a mineralization rate of 51.21% for CIP. Trapping studies demonstrated that the superoxide radical (O2°-) had a notable contribution to the breakdown of CIP. In summary, the Fe3O4/MOF/AmCs-Alg/Vis system offers numerous benefits, encompassing effective degradation capabilities, effortless catalyst retrieval, and remarkable nanocomposite reusability.

UiO66-NH2-TiO2/NiF photoanode for photocatalytic fuel cell by towards simultaneous treatment of antibiotic wastewater and electricity generation.

Environmental destruction, water crisis, and clean energy are among the very important challenges worldwide based on sustainable development goals. Photocatalytic fuel cell, a potential candidate for converting chemical energy into electrical energy through a pollution-free method, holds promise in addressing these challenges. In this regard, we investigated the response of a photoanode covered with UiO66-NH2-TiO2/NiF on a porous nickel foam as an attractive electrochemical response to remove antibiotics from aqueous solution and simultaneously produce electricity using a one-step hydrothermal synthesis. Nickel foam with its fine structure provides a suitable space for the interaction of light, catalyst, and efficient mass transfer of reactive molecules. It appears that it can be used as a competitive electrode in fuel cells. In order to investigate the properties of the photocatalyst, structural analyses including XRD, FESEM, FTIR, and UV-vis DRS were utilized. Additionally, polarization and electrochemical tests such as chronoamperometry and EIS were measured to further examine the electrochemical features of the PFC photoanode system. The obtained results under optimal conditions (SMZ concentration = 20 ppm, pH = 6, irradiation time = 120 min) were as follows: removal efficiency of 91.7%, Pmax = 16.98 µW/cm2, Jsc = 96.75 µA/cm2, Voc = 644 mV. The light-induced current flow in UiO66-NH2-TiO2/NiF exhibited prominent and reproducible photocurrent responses, indicating efficient and stable charge separation in TiO2/NiF composite materials, which is a promising strategy for pollutant removal and simultaneous electricity generation.

Microplastics removal technologies from aqueous environments: a systematic review.

Purpose: Pollution of the environment with all kinds of plastics has become a growing problem. The problem of microplastics is mainly due to the absorption of stable organic pollutants and metals into them, and as a result, their environmental toxicity increases. The main purpose of this study is to investigate the appropriate and efficient methods of removing microplastics from aqueous environments through a systematic review. Methods: Present study designed according to PRISMA guidelines. Two independent researchers followed all process from search to final analysis, for the relevant studies using international databases of PubMed, Scopus and ISI/WOS (Web of Science), without time limit. The search strategy developed based on the main axis of "microplastics", "aqueous environments" and "removal". This research was carried out from 2017 until the March of 2022. All relevant observational, analytical studies, review articles, and a meta-analysis were included. Results: Through a comprehensive systematic search we found 2974 papers, after running the proses of refining, 80 eligible papers included to the study. According to the results of the review, the methods of removing microplastics from aquatic environments were divided to physical (12), chemical (18), physicochemical (27), biological (12) and integrated (11) methods. In different removal methods, the most dominant group of studied microplastics belonged to the four groups of polyethylene (PE), polystyrene (PS), polypropylene (PP) and polyethylene tetra phthalate (PET). Average removal efficiency of microplastics in different processes in each method was as: physical method (73.76%), chemical method (74.38%), physicochemical method (80.44%), biological method (75.23%) and integrated method (88.63%). The highest removal efficiency occurred in the processes based on the integrated method and the lowest efficiency occurred in the physical method. In total, 80% of the studies were conducted on a laboratory scale, 18.75% on a full scale and 1.25% on a pilot scale. Conclusion: According to the findings; different processes based on physical, chemical, physicochemical, biological and integrated methods are able to remove microplastics with high efficiency from aqueous environments and in order to reduce their hazardous effects on health and environment, these processes can be easily used.

Enhanced photocatalytic degradation of amoxicillin using a spinning disc photocatalytic reactor (SDPR) with a novel Fe3O4@void@CuO/ZnO yolk-shell thin film nanostructure.

Antibiotics are resistant compounds with low biological degradation that generally cannot be removed by conventional wastewater treatment processes. The use of yolk-shell nanostructures in spinning disc photocatalytic reactor (SDPR) enhances the removal efficiency due to their high surface-to-volume ratio and increased interaction between catalyst particles and reactants. The purpose of this study is to investigate the SDPR equipped to Fe3O4@void@CuO/ZnO yolk-shell thin film nanostructure (FCZ YS) in the presence of visible light illumination in the photocatalytic degradation of amoxicillin (AMX) from aqueous solutions. Stober, co-precipitation, and self-transformation methods were used for the synthesis of FCZ YS thin film nanostructure and the physical and chemical characteristics of the catalyst were analyzed by XRD, VSM,, EDX, FESEM, TEM, AFM, BET, contact angle (CA), and DRS. Then, the effect of different parameters including pH (3-11), initial concentration of AMX (10-50 mg/L), flow rate (10-25 mL/s) and rotational speed (100-400 rpm) at different times in the photocatalytic degradation of AMX were studied. The obtained results indicated that the highest degradation efficiency of 97.6% and constant reaction rate of AMX were obtained under LED visible light illumination and optimal conditions of pH = 5, initial AMX concentration of 30 mg/L, solution flow rate of 15 mL/s, rotational speed of 300 rpm and illumination time of 80 min. The durability and reusability of the nanostructure were tested, that after 5 runs had a suitable degradation rate. Considering the appropriate efficiency of amoxicillin degradation by FCZ YS nanostructure, the use of Fe3O4@void@CuO/ZnO thin film in SDPR is suggested in water and wastewater treatment processes.

A comparative study on polyaluminum chloride (PACl) and Moringa oleifera (MO) chemically enhanced primary treatment (CEPT) in enhanced biogas production: anaerobic digestion performance and the Gompertz model.

A comparative study was performed to estimate biogas production from sludge produced by organic and inorganic chemically enhanced primary treatments (CEPTs). To this end, the effects of two coagulants, polyaluminum chloride (PACl) and Moringa oleifera (MO), on CEPT and biogas production in anaerobic digestion were surveyed within an incubation period of 24 days. The optimal dosage and pH of PACl and MO were optimized in terms of sCOD, TSS and VS parameters in the CEPT process. Next, the digestion performance of anaerobic digestion reactors fed with sludge obtained from PACl and MO coagulants at a batch mesophilic reactor (37 ± 1 °C) was surveyed from the biogas production, volatile solid reduction (VSR) and Gompertz model. At the optimal conditions (pH = 7 and dosage = 5 mg L-1), the removal efficiency of COD, TSS and VS in CEPT assisted with PACL was 63, 81 and 56%, respectively. Moreover, CEPT assisted with MO led to the removal efficiency of COD, TSS and VS until 55, 68 and 25%, respectively. The highest methane yield (0.598 L gVS removed-1) was obtained in an anaerobic digestion reactor with sludge from the MO coagulant. The anaerobic digestion of CEPT sludge instead of primary sludge resulted in higher sCOD removal efficiency, and 43-50% of sCOD was observed compared with the removal of 32% for the primary sludge. Furthermore, the high coefficient of determination (R2) demonstrated the trustworthy predictive precision of the modified Gompertz model with actual data. The combination of CEPT and anaerobic digestion, especially using natural coagulants, provides a cost-effective and practical way to increase BMP from primary sludge.

Hydraulic feasibility of discharging sludge from a local WWTP to a centralized WWTP through sewage network lines.

Over the recent years, due to the increase in the population covered by local wastewater treatment plants (WWTP), upgrading the existing treatment plants needs special attention more than ever. One of the suggested solutions removal the existing sludge treatment units in local WWTP and transfer the sludge to a centralized WWTP. The present study was developed to investigate the hydraulic feasibility of sludge transfer from Shahrak-e-GharbWWTP as a local treatment plant to South Tehran sewage treatment plant in Tehran. To this end, at first, a map containing descriptive information and hydraulic characteristics related to the sewage transmission network between local and centralized WWTP was collected from the sewage company. This information was used to calculate the maximum capacity, current flow and draw the hydraulic profile of the sewage transmission line. Then, the transmission line profile was drawn using Manning's hydraulic model and SewerCAD v10.01 software. According to the obtained results, areas 1 and 3 with sewage line diameters of 1000 and 1400 mm did not have any special problem in terms of entering the sludge. Hydraulic analyzes showed that some lines in areas 2, 4, 5, and 6 suffered setbacks and crises after the increase of sludge, which require auxiliary lines. The results indicated that more than 85% of the sewage network lines have the ability to transfer the excess sludge of the local treatment plant, however, in 36 lines, mostly located in zones 2 and 6, with a diameter of 1200 and 2000 mm, there is a crisis of sewage filling and backflow. Therefore, in order to reduce hydraulic stresses in these lines, it was suggested to build an auxiliary line (bypass ring at the beginning and end of these lines).

Is SARS-CoV-2 a concern in the largest wastewater treatment plant in middle east?

The surveillance of wastewater treatment plant (WWTP) as the end point of SARS-CoV-2 shed from infected people arise a speculation on transmission of this virus of concern from WWTP in epidemic period. To this end, the present study was developed to comprehensively investigate the presence of SARS-CoV-2 in raw wastewater, effluent and air inhaled by workers and employee in the largest WWTP in Tehran for one-year study period. The monthly raw wastewater, effluent and air samples of WWTP were taken and the SARS-CoV-2 RNA were detected using QIAamp Viral RNA Mini Kit and real-time RT-PCR assay. According to results, the speculation on the presence of SARS-CoV-2 was proved in WWTP by detection this virus in raw wastewater. However, no SARS-CoV-2 was found in both effluent and air of WWTP; this presents the low or no infection for workers and employee in WWTP. Furthermore, further research are needed for detection the SARS-CoV-2 in solid and biomass produced from WWTP processes due to flaks formation, followed by sedimentation in order to better understand the wastewater-based epidemiology and preventive measurement for other epidemics probably encountered in the future.

Three-layer business model canvas (TLBMC) as a recycling support tool to achieve sustainable development goals in waste management systems.

Traditional strategies for waste management in developing countries face high-cost problems, severe pollution, limited viable data, lack of global coverage, inefficiency, and slowness. The rapid expansion of the Internet have made new opportunities in waste management, especially waste collection. Online waste management in developing countries can create a revolution and help the government and society to achieve the goals of sustainable development. In this study, a modified three-layer business model canvas (TLBMC) was used to describe the duties of each actors involved in waste management and interactions between different elements in order to show the existing capacities in view point of economic, social, and environmental dimensions. In this online marketplace, the flow of information, the flow of materials and the flow of money in any company or entity or person active in the field of waste, are effectively connected to each other. Supply and demand information is provided in the created platform, and various waste actors are connected to look for options to trade. After agreement between the customer and the buyer, the information is delivered from the website or platform created by the supplier to the applicant. This network can have its usual structural features and create appropriate mechanisms for the continuation of its business operation and the realization of sustainable development of waste management, especially the recycling industry.

Clean environment index: A new approach for litter assessment.

Littered waste is one of the ubiquitous problems in urban environments. In this study, urban environmental pollution was evaluated for the first time using a new developed index. The findings indicated that cigarette butts with an average 58% are the largest share in the composition of littered waste. In addition, the numbers of littered wastes throughout the study area had a spatial variation. According to clean environment index (CEI), the entire study area was found to be in a moderate status. However, 40% of the study areas were classified in a dirty and extremely dirty status. Comparison of the studied urban land-uses showed that residential land use with CEI equal to 3.38 is interpreted in the clean status, while commercial land use with CEI equal to 15.05 can be classified in the dirty status. The application of CEI has a good capability to assess littered waste; this index can be employed to evaluate the pollution of urban sidewalks and other environments such as beaches.