wastewater treatment plant

Wastewater treatment plants are systems that can contribute to the health of the industry and the environment provided that they function properly. Mathematical and statistical simulators coupled with various models can be used to alleviate the costs of monitoring and managing wastewater treatment systems.

This is a retrospective descriptive- analytical study. Considering the complexity of biological processes along with the advances in data processing methods, algorithms (ANN) and M5 model tree were used in this study in order to make a modelto estimate the effluent COD in the sanitary wastewater treatment plant of one of the country's refineries. ANN and M5 were developed through learning and testing stages based on daily data of five consecutive years (2015-2020). Various statistical indicators such as MSE and R were used to evaluate the models. Ethical considerations were observed in all stages of the study.

In the ANN model with 100 hidden layers, through the training step, the amount of MSE and R respectively decreased and increased, compared to the two modes of 10 and 30 hidden layers. This is why 100 layers were chosen for this model. Also, in the M5 tree model, R-SqOptimal = 0.6147 was calculated by selecting independent data as input, which is significant at the 0.05 level. In other words, with 95% confidence, the developed model is considered sufficiently logical for predicting CODout. The results showed that the ANN model outperformed M5 model tree for predicting effluent COD with a coefficient of determination equal to 0.90 and 0.61, respectively.

Both models have high robustness, reliability and generalizability. Therefore, ANN and M5 model tree data mining techniques can be successfully used for environmental decision-making and estimation of lost data in wastewater treatment plants.

Since 2019, the spread of the coronavirus has caused an epidemic worldwide, and the transmission of the disease through respiratory droplets has been declared as the primary method of transmission in 2020. However, in this study, the indirect transmission of the virus through sewage has been investigated.

Wastewater related to hospital and urban wastewater treatment plants in 5 regions of Ardabil province (northwest of Iran) were investigated. A total of 22 samples were kept in pre-test conditions (temperature -20 degrees Celsius) and were used to identify the viral genome. Specific primer and chain reaction probes targeting ORF1ab and N (nucleoprotein gene) genes were used.

In this research, out of all the samples collected, the result of 3 samples was positive. All three positive samples are related to incoming sewage.

The results of this research showed that sewage epidemiology (WBE) can be considered a cost-effective method for diagnosing and predicting pathogenic agents and an effective method for making decisions to protect citizens' health.

Employees of wastewater treatment plants are exposed to various harmful factors in the work environment that can threaten their health. In this research, the health status of the employees of Mashhad sewage treatment plants has been evaluated to help by implementing intervention programs to improve the health of employees.

In this descriptive-analytical study, (bioaerosols, UV rays, heat stress, and hydrogen disulfide gas) were measured in 5 treatment plants in Mashhad. All study variables, including health status, clinical tests, and job stress, were analyzed analytically in two operational and administrative employee groups. The standard HSE occupational stress questionnaire was used to investigate the state of occupational stress. All data were transferred to the computer and data analysis was done with the help of software SPSS20.

The amount of pollutants except H2S gas was lower than the national occupational exposure limit. The number of smokers, diabetics, knee pain, and hearing loss was higher among operational than administrative employees, and hypertension, increased cholesterol, back pain, and skin disease were also more common in office workers than operational workers, but there were no statistically significant differences. Obesity and overweight (p<0.009) and increased triglycerides (p<0.05) were more common in administrative than operational workers, which had statistically significant differences. The state of job stress in operational employees was statistically significant compared to administrative employees regarding role (p<0.018) and communication (p<0.002).

Appropriate occupational health interventions to reduce pollutants, implement ergonomic programs and improve nutrition and increase physical activity and stress management can play an effective role in improving the health of employees of these units.

Due to the expansion of agricultural activities and the occurrence of successive droughts, the utilization of urban effluents for agricultural purposes is a suitable and economical way. However, the safely and responsibly use of these resources is essential. The purpose of this study is to investigate the possibility of using the effluent of the Borujen municipal wastewater treatment plant for agricultural irrigation.

In this descriptively-analytically study, the physical, chemical and microbial properties of the effluent of Borujen municipal wastewater treatment plant were measured according to the standard methods for the examination of water and wastewater, for 6 months and then was compared with the standard of Institute of Standards and Industrial Research of Iran (IRNDOE) and The Food and Agriculture Organization (FAO).

The mean concentrations of Biological Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), and Total dissolved solids (TDS) parameters in the effluent were 10.00 ± 1.17, 39.19 ± 4.10, and 513.0 ± 8.7 mg/L respectively. The average of chemical parameters including Cl-, SO42-, PO43-, NO3-, NO2-, Na, Mg, Sodium adsorption ratio (SAR), HCO3-, CO32-, Ca, and alkalinity was within the standard range of IRNDOE and FAO. The average of turbidity in the effluent was 54.27 ± 16.47 NTU. This effluent, in terms of SAR and EC was in the great and acceptable water group respectively. The average concentration of heavy metals was less than the permissible level for these metals. The mean concentration of total coliform, fecal coliform were higher than the standard set for these parameters. Also, no parasite eggs were detected in the effluent.

The results showed that the average chemical parameters of effluent of Borujen wastewater treatment plant were within the standards of effluent use in agriculture. However, the concentration of biological parameters of the effluent was higher than the standard level; and in case of more microbiological purification, it can be used for irrigation of edible agricultural products.

Today, plastics have a special place among the various issues that are considered as sources of pollution. Most of these plastics are in the dimensions of Micro and Nano. One of the most important sources of Microplastics transfer is wastewater treatment plants, where a large amount of these particles, which are not removed in the treatment process, enter the receiving environment. The purpose of this study is to first determine the optimal method of identifying and extracting particles from wastewater for counting and then to investigate the amount of removal and also to determine the amount of particles leaving the treatment plant.Sampling of inlet and outlet of wastewater treatment plant located in Mazandaran province was done seasonally in three seasons of spring, summer and autumn to determine in which season of the year, the amount of microplastics in wastewater increases or decreases. Also, the extraction and identification method is based on acid washing operation and based on creating a density difference, which has resulted in a favorable result with optimization and innovation.Using this method, the amount of Microparticles and microfibers along with the size and shape of the particle was determined and it was determined to what extent the normal treatment process is able to separate Microplastics from wastewater. The treatment plant can remove an average of 95% of the particles, which means that the remaining 5% of the particles are removed with the effluent and enter the aqueous environment.Finally, it was found that the determined laboratory method can identify and extract Microplastics in very small sizes to a very desirable extent. Also, determining the appropriate parameters of liquid volume, salt consumption and the use of dual capacity iron increased the efficiency compared to other methods and led to the identification of smaller particles than previous research.

Build wastewater treatment plants alone will not resolve environmental concerns. But, for achieve optimal environmental standards, the performance of the treatment plants must be constantly monitored and evaluated. The purpose of this study was to feasibility of reuse of output effluent wastewater treatment plant of Ardakan.

This was a descriptive cross-sectional study. During a 6-month period from April 2019 to September 2019, 48 input and output samples were collected. The parameters studied included COD, BOD5, TSS, total coliform and fecal coliform. Which were measured according to the methods outlined in the Standard Method Book for Water and Wastewater Testing. Finally, the results were analyzed by statistical tests.

The results showed that, the mean COD, BOD5, TSS, Fecal coliform and Total coliform at the output were 14.36, 4.56, 2.6 mg/L, 41 MPN/100 mL and 11.2 MPN/100 mL, respectively. Also removal efficiency for COD, BOD5 and TSS, total coliform and fecal coliform were 96.27, 96.81, 98.84, 99.99 and 99.99 Percentage, respectively.

The results showed that wastewater treatment plant Ardakan resulted in a significant reduction of organic matter and microbial contamination and was in good condition. And complies with standards in the reuse of wastewater for agricultural use, discharge into surface water and discharge to sorbent wells. Document Type: Research article

Emission of bioaerosols from wastewater treatment plants is a potential hazard to human health. In this study aimed at investigating the effects of surface and deep aeration techniques on density and type of airborne bacteria and fungi in two municipal wastewater treatment plants. This descriptive cross-sectional study was done in two wastewater treatment plants in Tehran equipped with surface and deep aerations. Microbial samples were taken from air beside aeration tank, grit chamber, secondary sedimentation basin and two control points (upwind and downwind) every 6 days during summer and autumn 2017. Samples were analyzed for density of bioaerosols and types of bacteria and fungus applying standard methods. Wastewater treatment plant with surface aeration tank had the greatest effect on emission of bioaerosols than the plant with deep aeration. Mean values for density of bacterial bioaerosols and fungal emission were 6845 and 15784 CFU/m2/h in summer and 535 and 899 CFU/m2/h in autumn, respectively. Different gram-positive and gram-negative bacteria were identified in both wastewater treatment plants investigated. According to current study, emission of bioaerosol in wastewater treatment plants with surface aeration is more than that of those with deep aeration and has greater potential hazard.

Wastewater treatment plants represent one of the most important approachs for water conservation. On the other hand, wastewaters can act as a source of antibiotics in aquatic environments. The aim of this study was to evaluate the performance of the Yasooj municipal wastewater treatment plant for removal of Escherichia coli, Pseudomonas aeruginosa and Listeria monocytogenes and also the antibiotic resistance pattern of these bacteria. In this cross sectional study, samples of inlet, outlet aerated lagoon, outlet settlement lagoon and outlet effluent were collected from the wastewater treatment plant in order to count, isolate, and identify E. coli, P. aeruginosa and L. monocytogenes. Antibiotic resistance pattern was investigated using disk diffusion method for 6 different antibiotics according to CLSI reference method. E. coli, P. aeruginosa and L. monocytogenes were isolated and identified in all levels of purification of wastewater treatment plants. The effectiveness of sewage treatment processes to remove E. coli, P. aeruginosa and L. monocytogenes was 54.17-99.33 in the outlet effluent. The bacterial isolates showed high rate of resistance against cefixime and trimethoprim-sulfamethoxazole and low resistance to imipenem. Multidrug resistance pattern (double and triple) was observed in bacterial isolates. This study showed that antibiotic-resistant bacteria in the outlet effluent are discharged into the environment. Further research needs to be undertaken to improve sewage treatment technologies, thereby producing a better quality treated sewage effluent.

Antibiotics are a group of emerging contaminants in the aquatic environment. Antibiotic residues threaten the human health and ecosystem in the low concentrations found in the environment. Hence, the present work has been conducted to investigate the occurrence and removal efficiency of most prescribed antibiotics including amoxicillin, penicillin, cefixime, cephalexin, ciprofloxacin, erythromycin and azithromycin detected in two urban wastewater treatment plants (WWTPs) in Tehran. The present work is an applied research based on USEPA method no. 1694, to investigate pharmaceuticals residues in water by HPLC/MS/MS in year 2016. The differences between target antibiotics residues were investigated statistically. After the calculation of the removal efficiencies, the normality of the data was assessed. Then, parametric and non-parametric tests were used to compare the removal efficiencies in both WWTPs. There was not a significant difference between the influent and effluent concentrations of cefixime and azithromycin (in Ekbatan WWTP) and cefixime (in southern Tehran WWTP). There is a significant difference between the removal efficiencies of cephalexin (p=0.005) and erythromycin (p=0.002) in two WWTPs. The Highest median removal efficiencies were observed for cephalexin 94.41 and 99.47 in Ekbatan WWTP and southern Tehran WWTP, respectively. In addition to the type of treatment processes, it is physicochemical properties of the selected compound has a significant influence on removal efficiencies.

Odors are one of the problems of water and wastewater treatment, especially in the vicinity of residential areas. Hydrogen sulfide and ammonia, mineral compounds in waste water treatment plants are odorous. These gases have unfavoraitable effects on humans and the environment.
This Cross-sectional study was conducted in the Faculty of Health, Qazvin University of Medical Sciences. After field visits around the plant, the number of 12 sampling stations was determined. Sampling stations are selected in four geographical directions with regard to permanent trade winds that are zero, two and four kilo meters from the plant to Residential settlements. Sampling was performed in the morning and evening during the four seasons and 192 samples were provided.
Results showed that the concentration of ammonia and hydrogen sulfide gas was more in warm seasons significantly and more odor caused (P=0.011, P=0.004) and the maximum emission is in the summertime. According to the results, the highest concentration of these gases was in the evening during the day.
According to the results, the concentration of hydrogen sulfide and ammonia gases in all the seasons except winter is within the threshold. Concentration of hydrogen sulfide in the summer and ammonia concentrations in all the seasons were higher than US. EPA standards and World Health Organization guidelines.

In order to prevent water pollution, protect public health, and reuse of the treated wastewater; controlling on quality of the wastewater treatment plant effluent has been considered a necessary.
To compare the quality of wastewater treatment plant effluent in Lia industrial zone with Iranian environmental protection standards.
This cross-sectional study was performed in one of the industrial zones in Qazvin (Lia). Samples were collected from wastewater treatment plant from May to September 2015 and analyzed in the laboratory. Chemical oxygen demand (COD) parameters were determined twice per week when the pH values were daily measured by pH meter. Sampling was carried out weekly to determine other important operational parameters including biochemical oxygen demand (BOD), total suspended solids (TSS), total coliform (TC) and fecal coliform (FC). Sampling and experiments were done according to the latest standard methods. The data were analyzed with SPSS 16 software (T-Test a single group).
Findings: The average of BOD, COD, TSS, FC, TC in effluent were achieved to 73.3±13.2, 156.2±42, and 76.43±50.8 mg/L 1.1×103,1.1×103 MPN/100 ml respectively. The total average of removal efficiencies for BOD, COD and TSS were calculated 92.41%, 92.75%, and 87.46%, respectively.
The results obtained that the wastewater treatment plant systems can be used as an efficient system for reduction of common pollutants by providing the Iranian standards for irrigating when the most important such as BOD, COD, TSS and PH are considered. The quality of the treated wastewater was found to be within the permissible Iranian standards for irrigating. However, it is important to keep in mind that reduce microbial contamination within standards is needed to be considered.

Recently contact with bioaerosols has been presented as an important problem which endangers human being’s health. The aim of this investigation is to compare potential of separation of fungal aerosols in the air around Tehran’s Milad hospital, blood transfusion organization and waste water treatment plant of Tehran’s Shahrake Ghods. this cross-sectional investigation was done in Milad hospital, blood transfusion organization and Tehran’s Shahrake Ghods waste water treatment plant within for 4 months. The sampling was done passively for 1 hour and once in 6 days. The culture medium was Sabouraud dextrose agar. comparing selected sampling stations the most fungal density was for 100 meters after the last unit of waste water treatment plant (67 CFU) and the least density was for Milad hospital (30 CFU). Dominant genera of fungal in waste water treatment plant and blood transfusion organization was related to Cladosporium (in order of 49% and 84%) and in air around Milad hospital was related to Alternaria (47%). according to the results processing and operating sections in waste water treatment plant can be effective in fungal density and separation of bioaerosols. Therefore it seems to be vital that the responsible organizations should do necessary actions to develop guidelines and standards related to bioaerosols. Also appropriate administration of environmental health in waste water treatment plant can be an important factor in reduction of aerosol separation.

Background and Wastewaters are the most important sources of antibiotics entrance into the aqueous environments. Conventional wastewater treatments cannot eliminate these micropollutants and antibiotic resistant bacteria. The aim of this study was to determine the antibiotic resistance pattern in bacteria isolated from untreated sewage and effluent of municipal wastewater treatment plant in Tabriz. In this cross sectional study, in addition to counting the number of different types of bacteria in raw sewage and municipal wastewater effluent, various bacteria including Enterobacteriaceae and Staphylococcus, Bacillus and Pseudomonas were identified using specific mediums, API E20 kits and biochemical tests. Susceptibility test of bacteria to antibiotics was determined by Kirby-Bauer's disc diffusion. The results showed lower than one log removal efficiency for coliforms bacteria by the wastewater treatment plants. The difference in the number of colonies apart from staphylococci was not significant in wastewater influent and effluent. Aeromonas and staphylococci were the most frequent bacteria in wastewater influent and effluent, respectively. Enterobacteriaceae were generally more sensitive than other bacteria. Resistance to antibiotics was found to be higher in the penicillin member of antibiotics. Resistant to four antibiotics including cephalexin, ampicillin, methicillin and amoxicillin were between 60 to 100%. The resistance of all species increased in the effluent of wastewater treatment plant. Growth and survival of antibiotic resistant bacteria increases in wastewater treatment plants and conventional treatment processes do not demonstrate enough efficiency for removal of these strains.