Environmental Health Engineering and Management Journal
Volume:9 Issue: 3, Summer 2022

In recent years, the world has faced with the COVID-19 pandemic, followed by a significant increase in the use of antibiotics to control the COVID-19 and other secondary infections. The non-biodegradable characteristics of antibiotics and their residues in the environment leads to increased microbial and drug resistance. Therefore, due to the high importance of antibiotics, two antibiotics, ampicillin and penicillin G, were studied in Isfahan municipal WWTPs.

Sampling was performed for two months during 13 sampling periods and antibiotics were measured using high-performance liquid chromatography with UV detector (HPLC/UV) instrument.

Ampicillin and penicillin G were identified in all samples taken from the both WWTPs. The average concentration of penicillin G in WWTP E and S at the influent, effluent and its removal efficiency were 1050.54±761.43 μg/L, 52.89±49.27 μg/L, 89.80±19.42%, 2055.12±1788.08 μg/L, 143.01±162.59 μg/L and 82.76±21.85%, respectively. Also, the average concentration of ampicillin in WWTP E and S in the influent (796.44 ± 809.6 and 447.1±322.39 μg/L), effluent (48.94 ± 24.25 and 90.31±75.91 μg/L), and its removal efficiency (86.22 ± 19.84% and 66.85±24.88%) were determined.

In two studied WWTPs, the concentration of antibiotics was higher during the COVID-19 pandemic in comparison with previous studies. The statistical analysis showed that there was no significant relationship between the concentration of antibiotics in WWTPs (P<0.05). Also, the statistical results indicated that the correlation is not significant between removal efficiency of antibiotics and removal efficiency of wastewater main parameters.

To control pollution, wastewater treatment from textile plays an important role in treating wastewater to meet quality standards before it is discharged into the environment. Without properly treated wastewater from the textile industry, it contains organic and inorganic pollutants that cause environmental problems such as water pollution, loss of marine life, and soil and air pollution. The aim of this study was to design and simulate a textile sewage treatment plant.

This study was conducted by simulating the process and operation of a wastewater treatment plant using STOAT software. In addition, STOAT’s graphical and static data analysis models are efficient in removing multi-component pollutants from the textile industry.

Some pollutant parameters prior to the design model are SS (260 mg/L), DS (3600 mg/L), ammonia (65 mg/L), BOD (430 mg/L), nitrate (35 mg/L), and DO (12 mg/L). The wastewater of the simulation result of the sewage treatment plant model contained SS (3.3 mg/L), ammonia (25 mg/L), BOD (4 mg/L), nitrate (61.3 mg/L), and the removal percentage of TSS, BOD, and Ammonia was 99.75, 99.1, 61.33mg/L, respectively. Through the treatment process, Ammonia was oxidized and nitrification was processed rather than denitrification.

Using the stoat modeling software, wastewater treatment plant design is very effective in removing contaminants from textile wastewater by selecting specific parameters.

The need to understand the causes of CO2 emissions has prompted the formulation of strategies to prevent global warming. Therefore, the purpose of the study was to determine the input variable that is the most influential in contributing to CO2 emissions and at the same time to forecast the effect of a shock in macroeconomic variables on CO2 emissions for 6 leading African countries over the period of 1970 to 2019.

In this study, the statistical methods of impulse response function and variance decomposition techniques of analysis were used.

A one-standard-deviation rise in economic growth leads to an increase in CO2 emissions. A shifts in the square of economic growth increased CO2 emissions, the shock was smaller than that of economic growth. This confirms the theory of EKC in Africa. A shocks to FDI had a positive influence on CO2 emissions. A one standard deviation shock in financial development had an instantaneous positive impact on CO2 emissions. FDI had a greater effect than other factors in explaining CO2 emissions over the short and medium term. In the long run, economic growth contributes the most to CO2 emissions among the explanatory variables.

The findings of the study can be used as a reference for international organizations and environmental policymakers in forecasting climate change and assisting in policy decision-making. Africa must boost economic growth through industrial, agricultural, and energy usage patterns and integrate innovation, research, and technology advances into their developmental agenda to fulfil sustainable development goals while lowering CO2 emissions and their consequences.

Spatial noise level mapping using a geographical information system (GIS) is essential for the visual colour representation of noise analysis, which is a necessity for strategic planning and mitigating measures.

Extech noise meter (model 407750) was used for sound measurement and a GIS (inverse distance weighted) was used in 54 study locations for the spatial interpolation. The study was classified into five categories based on Nigeria’s WHO standard and National Environmental Standards and Regulations Enforcement Agency (NESREA).

For the LDAY (D), LEvening (E), LNight (N), and LDEN, all the locations exceeded the WHO standard while 94.4%, 90.7%, 83.3%, and 83.3% of the locations exceeded the NESREA standard. The LDay (D) ranged from the minimum value of 67.6 dB (A) at the Ijaw residential area to the maximum value of 93.0 dB (A) at Kwangila site (1) intersection. The LNight ranged from the minimum value of 63.3 dB (A) at Dogorawa residential area to the maximum value of 92.1 dB (A) at Kwangila site (1). The LDEN ranged from the minimum value of 73.1 dB (A) at Hanwa residential areas to the maximum value of 97.2 dB (A) at Kwangila site (1). The noise quality rating ranged from satisfactory to unallowed noise quality grading. The selected intersections and residential areas with light commercial activities had the highest and lowest noise levels, respectively.

Efficient maintenance of silencers, planting trees with dense foliage, and strategic planning would be necessary panacea in curbing excessive noise.

As concentrations of heavy metals in hair can reflect both metals exposure and intake concentrations, hair sample analysis is widely applied in forensic sciences, evaluation of environmental or occupational exposure and other studies. The aim of this study was to evaluate the concentrations of As, Cd, Pb, Cr, Cu, Co, Mn, Zn, Fe and Ni in the scalp hair of an urban population from Kermanshah in western Iran.

In the present research, 30 points of the city were selected for human scalp hair sampling. Samples were taken from healthy inhabitants (aged 6 to 46 years) in Kermanshah city. Multivariate analysis method was applied to distinguish the anthropogenic and natural sources of heavy metals. Levels of elements in the scalp hair were measured by ICP-MS.

The mean concentrations of Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb and As were 33.53±9.05, 27.98±7.77, 203.18±22.31, 1.94±0.85, 18.44±3.40, 107.11±22.56, 119.21±10.52, 0.97±0.36, 60.27±13.84, and 0.34±0.51 μg/g in the urban area, respectively. The highest concentration of all elements was found in the age group of 31-40 and 41-50 years except Fe, the maximum concentration of which was found in the age group of 6-20 years. Significant differences were found between smokers and non-smokers.

Comparison of the heavy metals concentrations in the scalp hair of this area showed that the concentrations of the elements were clearly higher than those reported in other studies. However, the high concentrations of the elements in hair indicated that the inhabitants in the urban areas of Kermanshah might be at risk of exposure to high levels of toxic elements.

The emergence and spread of SARS-CoV-2 has increased environmental disinfectant usage to reduce the transmission of this virus. Ethanol 70-90% and 5% sodium hypochlorite have the highest consumption for disinfection of various environmental surfaces during the COVID-19 pandemic. Dental unit waterlines (DUWLs) are more susceptible to microbial contamination due to their particular structure. This study aimed to investigate the effect of increasing the use of disinfectants during the COVID-19 pandemic on the bacterial contamination of DUWLs.

During November (before the COVID-19 pandemic) and December (during the COVID-19 pandemic), a questionnaire was used to assess the frequency of disinfection of unit surfaces and other environmental surfaces and the type of disinfectants used. The water samples were collected from different parts of DUWLs. The gram staining method followed by the biochemical method was used to identify the desired bacteria.

The results showed that the frequency of disinfection of dental units increased 8 times in December compared to November. There is a significant inverse relationship between the frequency of disinfection of dental units surfaces and the bacterial contamination of dental unit waterlines.

The microbial load in different parts of the DUWLs was less than 200 CFU/mL. The American Dental Association (ADA) recommended and indicated the allowable microbial concentration and the appropriate quality and water used in these units.

Adsorption is a process in which some of the components in the fluid phase, are selectively transferred to the surface of the porous solid particles in the filled bed, which is called the adsorbent. The aim of this study was to examine the adsorption effectiveness of CO2 by activated carbon functionalized with Methyl diethanolamine (MDEA), as well as the effects of adsorption temperature, the total pressure of adsorption, and mass of adsorbent.

Activated carbon was first produced using the desired biomasses and suitable activated carbon was chosen. The activated carbon was then functionalized with MDEA amination method. The crystal structure of adsorbents was studied using XRD methods. In addition, the porosity, specific surface area and structure of prepared activated carbon were measured using BET techniques. Finally, the morphology and strength of the functional groups were measured using FESEM and FTIR analyses.

The findings of the FESEM and BET analyses for functionalized activated carbon revealed that the specific surface area of the adsorbent increased  hroughout the chemical and physical modification process, resulting in a BET amount of 725/84 m2/g. The results showed that the selectivity of the functionalized activated carbon is greater than that of the non-functionalized adsorbent.

The adsorption capacity of functionalized activated carbon was 3.98 mmol CO2 g-1 sorbent, compared to 2.587 mmol CO2 g-1 sorbent in the non-functionalized carbon, indicating a 35% improvement in the efficiency of the functionalized sample. According to the findings of the desorption experiments, functionalized carbon shows a 25% decrease in CO2 adsorption efficiency after 20 desorption steps.

Recalcitrant organics remediation from water resources continues to be a significant environmental problem and there is a continued effort to demonstrate practicable and economical treatment options for pollution removal.

In this study, the efficiency of the permeable reactive barrier (PRB) in a column reactor using zero-valent iron (ZVI) particles and sand mixture in the removal of methyl tert-butyl ether (MTBE) from aquatic phases was investigated. The system performance was MTBE removal while initial pH,reaction time, pollutant content, catalyst load, hydraulic loading rate (HLR), and the reaction rate constant were independent variables.

The results showed that the process efficiency decreased by increasing pH, HLR, and pollutant concentration. In this case, the optimal conditions were obtained at pH = 7, HLR = 0.23 m3/m2·d, and C0 = 1 mg/L, which achieved a remarkable removal efficiency up to 90.32%. The high nitrate concentrations and hardness as intervening factors reduced process efficiency to less than 44.61 and 51.4%, respectively. The lack of interfering factors had a considerable effect on the reaction rate of MTBE reduction, which is approximately 2.65 and 4.11 times higher than that in the presence of calcium hardness and nitrate, respectively.

The PRB technology can be suggested as a reliable and robust system to remediate groundwater containing hydrocarbons based on filling media and hydraulic conditions.

Bioconversion of lignocelluloses to biofuel from cheap non-edible materials such as local leftover Injera waste for renewable energy is very important and minimizes environmental pollution. Local leftover Injera is an abundant, inexpensive, reusable waste to the environment, containing a sufficient amount of carbohydrate material, which is the best source of fermentable sugars.

In this study, local leftover Injera was treated followed by drying, acidic hydrolysis, and alcoholic fermentation. Besides, the optimization of the fermentation process was done using a central composite box Behnken design. The process included physical and chemical pre-treatment of biomass, which was then followed by acid hydrolysis as a potential step. The scarification and fermentation methods were analyzed to acquire the maximum yield of ethanol. The local leftover Injera waste was pretreated with sulfuric acid and sodium hydroxide solutions. The effect of temperature, substrate concentration, as well pH on bioethanol production was optimized and studied. The optimization process was performed under special condition (temperature=25-40°C, pH=3-5, and substrate concentration=50-200 mg/L).

The maximum product of ethanol was achieved at a temperature of 32.718°C, substrate concentration of 125 g/L, and a pH of 4 with a maximum ethanol yield of 42.598%.

According to the results, the optimum fermentation conditions for bioethanol production from local leftover Injera waste are the points where the maximum product of ethanol was achieved at a temperature of 32.718°C, substrate concentration of 125 g/L, and a pH of 4.

Industrial pollution of metals is a serious environmental concern. The presence of Sarcheshmeh copper (Cu) mine and the possibility of soil pollution, were the primary motivations for evaluating heavy metals in this area.

A total of 171 soil and 10 sediment samples were collected randomly from the study area for Cu, aluminum (Al), molybdenum (Mo), lead (Pb), and cadmium (Cd) determination. The USEPA method was used to acid digest soil samples, and metals present in the samples were detected using atomic absorption spectroscopy.

By measuring metal concentrations and calculating the geo-accumulation index (Igeo), enrichment factor (EF), and contamination factor (CF), the level of soil pollution by metals was assessed. It was found that soil and sediment samples were contaminated with Cu and the pollution decreased from the mine to Rafsanjan city, indicating that the pollution was anthropogenic. The soil has not been poisoned by Al or non-natural states because it was alkaline. Sediment samples were less than moderately polluted by Mo and Pb, but Cd and Cu were more problematic.

Increasing the distance from the Cu mine resulted in a decrease in toxic metal concentration. The study concludes that by monitoring and filtering wastewater from the Cu mine, pollution caused by trace elements in the soil can be greatly reduced.

Helicobacter pylori is classified as a carcinogen, and it is also the most common cause of chronic bacterial infection and peptic ulcers. Approximately 45% of people are infected with the bacterium.

In this study, the H. pylori genes, CagA and VacA, were investigated in drinking water, using 100 samples (50 samples from the municipal water supply and 50 samples from the effluent of household water treatment devices). DNA was extracted from colonies with a positive heterotrophic plate count (HPC) for use in molecular testing and microbial identification. The polymerase chain reaction (PCR) was used to identify H. pylori.

The study showed that 24% of urban water samples (12% above the World Health Organization [WHO] standards for safe drinking water) and 18% of home water treatment-device samples (4% above the WHO standards) were HPC-positive. The H. pylori genes, CagA and VacA, were identified in 2% of the samples from household water treatment devices and 8% of the municipal water supply samples.

The study findings show that H. pylori may be transmitted in drinking water. However, there is currently no strong evidence that the bacteria can survive after the disinfection process in the water supply system. Therefore, the health risks of this bacterium in drinking water are still unknown.

This study examined the removal of ciprofloxacin (CIP), which is a very widely used antibiotic, from an aqueous medium by applying AgI/Ag2O photocatalyst under visible light radiation.

AgI/Ag2O was synthesized conveniently by applying a two-stage precipitation method. The synthesized compound was characterized by X-ray powder diffraction (XRD), FE- field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray (EDX), and UV-Vis spectrophotometry. Different parameters including initial pH of the solution, initial CIP concentration, reaction kinetics, and catalyst reusability were investigated.

Concurrent use of AgI and Ag2O caused improved photocatalytic properties in the presence of UV light. The pH and initial concentration of CIP affected the process efficiency; 95% efficiency was achieved within 100 min at pH 9. Furthermore, the process efficiency was still maintained over 90% after four consecutive cycles.

The photocatalytic degradation process using AgI/Ag2O nanocomposite under visible light radiation is a suitable method for removing CIP from aqueous media due to its high efficiency and stability.