Avicenna Journal of Environmental Health Engineering
Year:2018 | Volume:5 | Issue:1|Papers Count:8

In Ethiopia, occupation-related respiratory symptoms are extensively increasing with the expansion of cement manufacturing industries. However, little information is available on the extent of emissions and its association with chronic respiratory diseases. This study assessed the emission level of PM2. 5 and its association with chronic respiratory symptoms among workers in Mugher Cement Factory, in 2018. A cross sectional study was employed on a total of 309 cement factory workers. Air check sampler, model 224-54, was used to measure the concentration of PM2. 5. Variables with P value < 0. 2 during bivariate analysis were selected as candidate for multiple logistic regressions. Significance level was set at P value <0. 05. A total of 309 workers participated in the study with an overall response rate of 97%. The mean age of the respondents was 32. 02 years (± 4. 7 SD). Emission levels of all PM2. 5 samples were above the allowed standard. Among the workers, 50. 8% had chronic respiratory symptoms and factors associated were: working in raw material receiving unit (adjusted odds ratio [AOR]= 7. 5, 95% CI, 2. 9, 19. 4), cement milling unit (AOR = 2. 4, 95 % CI, 1. 2, 4. 8), packing unit (AOR= 2. 2, 95% CI= 1. 1, 4. 3), workers’ monthly income level below 3000 ETB (AOR; 5. 8, 95% CI, 1. 9, 17. 6), and workers’ regular medical checkup (AOR = 2. 4, 95 % CI, 1. 0, 5. 2). The concentration level of PM2. 5 and prevalence of chronic respiratory symptoms were high in the study area. Use of personal protective devices and periodic monitoring of installed pollution control devices is highly recommended.

The piped water supply in Lucknow was introduced in 1892 to serve the population of 2 Lacs. However, the population has risen exponentially since then from 2. 1 million in 2001 to 2. 86 million in 2011 according to the census data of the Government of India. In this paper, statistical analysis was done and it was projected that the population of Lucknow will be as high as 4. 2 million in 2025 followed by 6. 42 million in 2040. Since the water demand is proportional to the population, it is projected that present water demand of 550 million liters per day (MLD) would rise to the maximum of 1300 MLD in the year 2040 which is twice more than the present volume. The major concern of Lucknow city is the poor efficiency of wastewater treatment facilities which are deteriorating the quality of underground water and surface sources. The major concern lies in Gomti River. The wastewater generation in 2025 would be as high as 700 MLD while for the year 2040 it would be 1100 MLD. To meet the given figures a well-planned and effective wastewater treatment system has to be designed and implemented which may include centralized and decentralized treatment facilities in accordance with the need of the particular division followed by up-gradation of the present water supply and sewerage system. Care should be taken while discharging the sewage into river Gomti and other natural streams as it should strictly follow the prescribed standards by central state pollution control boards, also there should be the least disturbance of aquatic ecosystem. Furthermore, deterioration of the water quality must be minimized to a large extent.

Concerns about water quality have widely increased in the last three decades; thus, water quality is now as important as its quantity. To study and model the quality of the Gamasiab River, its data, including chemical oxygen demand (COD), biological oxygen demand (BOD), dissolved oxygen (DO), total dissolved solids (TDS), total suspended solids in water, acidity, temperature, turbidity, and cations and anions were measured at four stations. Then, the correlations between these parameters and COD were measured using Pearson’ s correlation coefficient and modeled by multilayer perceptron artificial neural network. In order to minimize the cost of the experiments performed and to provide the input parameters to the artificial neural network based on the correlations between the data and COD, the number of input parameters was reduced and finally, model No. 3, with the Momentum training function and the TanhAxon activation function with the validation correlation coefficient of 0. 97, mean absolute error of 2. 88, and normalized root mean square error of 0. 11 was identified as the most accurate model with the lowest cost. The results of the present study showed that the multilayer perceptron neural network has high ability in modeling the COD of the river, and those data correlated with each other have the greatest effect on the model. Moreover, the number of input parameters can be reduced in order to lower the cost of experiments while the performance of the model is not undermined.

The batch and fixed-bed column adsorption of methylene blue (MB), a widely used toxic dye, onto graphene oxide (GO) was investigated in this study. GO was synthesized using modified Hummers method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Response surface methodology (RSM) was employed to optimize batch and fixed-bed column adsorption of MB. Batch adsorption experiments were carried out by central composite design (CCD) with three input parameters including initial MB concentration (C0: 50-350 mg/L), GO dosage (D: 0. 05-0. 7 g/L), and pH (pH: 3-9). The adsorption capacity of GO for MB removal in the optimum level of factors (C0: 50 mg/L, D: 0. 05 g/L, and pH: 8. 5) was predicted by the model to be 700 mg/g. Adsorption kinetic data were tested using pseudo-first order, pseudo-second order, and intraparticle diffusion models. The kinetic experimental data was well fitted with pseudo-second order kinetic model (R2=1). The adsorption of MB onto GO demonstrated that Langmuir model (R2=0. 999) could better fit the adsorption data than the Freundlich model (R2=0. 914). Thermodynamic parameters including enthalpy (Δ H), Gibbs free energy (Δ G), and entropy (Δ S) were also investigated. Positive value of Δ H and negative value of Δ G indicated the endothermic and spontaneous nature of the adsorption. The positive value of Δ S also showed increased randomness at the solid/liquid interface during the adsorption of MB onto GO. The real wastewater experiment at optimum conditions showed high performance of adsorbent in the presence of other ions. Fixed-bed column experiments were designed using a three-factor, three-level Box-Behnken design (BBD) to investigate the single and combined effects of influent concentration (Cinf: 50-200 mg/L), flow rate (Q: 0. 25-0. 8 mL/min), and bed height (BH: 3-7 cm). MB removal from GO in the optimum levels of factors (Cinf: 51 mg/L, BH: 5. 7 cm, and Q: 0. 25 mL/min) was predicted by the model to be 86% (qe=459. 3 mg/g). Fixed-bed experimental data were also fitted well to the Thomas and BDST models. The results showed that GO can be used as an efficient adsorbent for batch and fixed-bed adsorption of cationic dyes from synthetic and real wastewater.

Phenol is considered as one of the major environmental concerns due to its characteristics including chronic toxicity, biological stability, and increasing the toxicological intermediates after biological degradation. Therefore, the aim of this study was to evaluate the photo-degradation of phenol using the titanium dioxide (TiO2) photo-catalyst on ordered mesoporous carbon (CMK-3) support under UV irradiation. In this study, the effects of some parameters including pH value (4, 5, 6, 7, 8, 9, 10), TiO2/CMK-3 concentration (0. 05, 0. 1, 0. 15, 0. 3, 0. 5 g/L), irradiation time (30, 60, 90, 120, 150 min), and phenol concentration (50, 100, 150 and 200 mg/L) were assessed. The properties of the CMK-3 and TiO2/CMK-3 were compared using the transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and N2 adsorption-desorption isotherm. The results revealed that the process studied was remarkably affected by the parameters, and the optimum values of the parameters were as follows: pH=6, TiO2/CMK-3 concentration =0. 15 g/L, phenol concentration = 100 mg/L, and irradiation time=150 min. The phenol degradation efficiency and total organic carbon (TOC) removal efficiency for phenol were 96% and 74%, respectively. Moreover, the stability greater than 7 times for the studied photo-catalyst was indicative of its high potential to be used in photo-degradation processes for the elimination of pollutants.

Particulate Matter (PM10, PM2. 5, and PM1) entry into hospital buildings is important for human exposure and is associated with health effects. The present study investigated the entry of particles into Imam Khomeini general hospital building under different ventilation systems and scenarios using a multi-zone airflow and contaminant transport model. Concentrations of PM10, PM2. 5, PM1, and meteorological variables (atmospheric pressure, air temperature, and relative humidity) were measured and recorded in 6 medical treatment floors and outdoor atmosphere of hospital, from June 2014 to June 2015, 7 days at each season as simulation input variables. Simulated ventilation rates were assessed using the model and then validated using both measured data and simulations. In this study, CONTAM was used as a multi-zone indoor air quality and ventilation analysis software to determine airflows and contaminant concentrations. The simulation results for PM2. 5 concentration as an important contaminant in hospital floors from basement to the top and based on airflow design were 21. 3, 16. 5, 22, 25. 4, 27. 6, and 24. 2 μ g/m3 respectively which showed 8. 1% average deviation with actual measurements in selected locations. The assessment of air ventilation effect on PM2. 5 concentration proved more accumulation in winter. The study results showed that accurate particle deposition and penetration are effective in predicting the time-varying particle concentrations in all floors of hospital building. The comparison between measurements and CONTAM prediction suggests that a multi-zone particle transport model can provide insight into particle entry into the hospital building under various weather and building operating scenarios.

The discharge of wastewater containing reactive dyes into water sources leads to health hazards. Colors can adversely affect the natural environment due largely to some qualities like carcinogenicity, being mutagenic, toxicity, and coloration of water. Environmental degradation can be attributed to the destruction of living organisms and the increased biological oxygen demand (BOD). The aim of this study was to evaluate the removal of Reactive Blue 19 dye using the Fenton process from aqueous solution. This research was an experimental study, in which the effectiveness of Fenton in color removal was investigated. The factors influencing this process were: pH, color concentration, the ratio of Fenton reagent (H2O2/Fe2+), and contact time. Finally, after determining the optimum concentration of color, pH, the ratio of Fenton reagent, and contact time, the residual adsorption rates in the samples were measured using direct photometry by spectrophotometer in a wavelength of 594 nm. The results showed that the highest removal efficiency was obtained under the conditions of pH =3, the color concentration of 2 mg/L, the ratio of Fenton reagent = 1: 5, and the contact time equal to 10 minutes. The Fenton process is able to remove the Reactive Blue 19 under different concentrations. This process achieved the best removal efficiency in acidic pH.

Carbon modified pumice (CP) was successfully synthesized for the rapid removal of fluoride ions from the solvent phase. The batch experiments were conducted to investigate the effect of several operational parameters including carbon content, solution pH, initial fluoride concentration, contact time, adsorbent dose, and temperature on the CP efficiency in fluoride adsorption. The surface morphology, as well as the structural and functional groups of the synthesized CP were evaluated using the scanning electron microscopy (SEM), Brunauer, Emmett and Teller (BET) method, X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR), respectively. The adsorption isotherm and kinetic data were found to be in good agreement with the Langmuir and pseudo-second-order models, respectively. Finally, the negative value of Δ G° revealed the spontaneous nature of the fluoride adsorption onto the CP adsorbent.