جستجوی مقالات مرتبط با کلیدواژه « wastewater treatment » در نشریات گروه « پزشکی »

In recent decades, there has been a growing concern about the presence of antibiotics in water resources. The presence of these micropollutants even in low concentrations has significant effects on the environment and human health, and their entry into the soil and especially receiving waters should be prevented as much as possible. As effluents from wastewater treatment plants (WWTPs) are significant sources of antibiotics in the environment, this study aimed to investigate the efficiency of antibiotics removal in municipal WWTPs.

In this study, Isfahan East WWTP with a combination of stabilization ponds and an aeration lagoon, and Isfahan South WWTP with conventional activated sludge treatment were selected as well as four antibiotics from the beta-lactam group including ampicillin, amoxicillin, cephalexin, and penicillin, and their removal efficiency was investigated in both WWTPs. Samples were collected from the influent and effluent of both WWTPs on 13 occasions and analyzed immediately after being transferred to the laboratory. The concentration of antibiotics was determined by high-performance liquid chromatography (HPLC).

In the Isfahan East WWTP, the average removal efficiency was 86.22 ± 19.84% for ampicillin, 34.35 ± 31.38% for amoxicillin, 78.75 ± 23.81% for cephalexin, and 89.80 ± 19.42% for penicillin. In the Isfahan South WWTP, the average removal efficiencies of amoxicillin, ampicillin, cephalexin, and penicillin were equal to 54.82 ± 33.29%, 66.85 ± 24.88%, 87.65 ± 21.76%, and 82.76 ± 21.85%, respectively.

The study's findings revealed that Isfahan municipal WWTPs were unable to fully eliminate antibiotics. According to statistical analysis, there were significant differences in the concentration of antibiotics in both WWTPs, and no critical correlation was observed between the removal efficiency of antibiotics and other principal wastewater parameters. Consequently, there is a need for stricter control over the discharge of effluent into the river or its use for agricultural irrigation.

The tension and crisis caused by the lack of water is one of the major problems in Iran and the world. The available water resources are under threat with the increase in population and the water per capita is constantly decreasing. The use of wastewater treatment plant effluents for irrigation of green spaces, agriculture and other purposes as an alternative and suitable source is very necessary and must be given more attention. This problem shows the importance of proper operation and maintenance of wastewater treatment plants, especially the activated sludge method as a very efficient process with the production of wastewater with suitable quality for use in irrigation of green spaces and agriculture. Achieving this importance depends on the adequate training of local operators and the existence of necessary incentive and monitoring programs and policies. This article is presented with the aim of introducing one of the most important and practical techniques in the operation of wastewater treatment plants using the activated sludge method. This article is presented with the aim of introducing one of the most important and practical techniques in the operation and maintenance of wastewater treatment plants using the activated sludge method.

The presence of emerging-resistant contaminants in wastewater poses challenges to the efficacy of the biological treatment process. Advanced oxidation processes show great potential for enhancing the quality of wastewater. The aim of this study was to enhance the efficacy of the effluent from the Parand City treatment plant through the optimization of the sonoelectrochemical process.

Pilot used 500 cc sonoelectrochemical reactor with direct current generator, ultrasonic, and graphene electrodes. To determine pH (4–8), direct electric current (50–100 mA), reaction time (60–120 min), and frequency (30–50 kHz), the central composite design was used. We looked at the process pace, energy utilization, waste physical and chemical qualities, and overall impact. The purification parameters were obtained using water and wastewater testing methods.

The P-value and F-value indicate the selected model was significant. The best process conditions to use are a pH of 6.5, an electric current intensity of 82.8 mA, a reaction time of 113 min, and a frequency of 35 kHz. Under these conditions, the removal of COD, TOC, BOD5, nitrogen, and phosphorus was 81%, 69%, 93.2%, 96%, and 94.7%, respectively. The kinetics of the process follow first-order kinetics, and the synergistic effect coefficient was 1.62. The energy efficiency was determined to be 98.07 mg/kWh.

The utilization of the sonoelectrochemical process can be employed as a sophisticated method for treatment. However, it is imperative to conduct a comprehensive analysis of the process's efficacy by utilizing raw wastewater samples.

Tetracycline represents the most prevalent antibiotic group in production and utilization and is extensively employed for the prophylaxis and treatment of infectious diseases in both human and veterinary medicine. The primary objective of this investigation was to assess the efficacy of electro-activated persulfate (EC/PS/HR) for eliminating tetracycline from aqueous solutions.

This study was conducted in a batch mode utilizing an electro-activated persulfate (EC/PS/HR) system. All experiments were carried out under constant temperature conditions. Response surface methodology (RSM) in conjunction with a central composite design (CCD) was employed to optimize the variables associated with the electro-activated persulfate and hydrogen peroxide process, including pH, current density, and the persulfate/hydrogen peroxide molar ratio, with the aim of tetracycline removal. Data analysis in this study was performed using Data Designer 8.0.6 software.

The results of this study revealed the use of a quadratic model to predict the impact of independent variables on the efficiency of tetracycline removal in the process. The exceedingly low (p <0.0001) and the high correlation coefficient (R2) of the obtained model signify a robust correlation between experimental and predicted data. The optimal conditions for achieving maximum efficiency in the degradation of tetracycline through electro-activated persulfate were determined to be a pH of 5.6, a persulfate/hydrogen peroxide molar ratio of 1.1, and a current density of 31 mA. Under these conditions, tetracycline degradation reached approximately 95.2%.

Based on the findings of this investigation, it can be deduced that the advanced oxidation process relying on electro-activated persulfate (EC/PS/HR) is capable of eliminating contaminants in aqueous environments, influenced by various factors such as hydrogen peroxide dosage, catalyst concentration (persulfate), and pH. The study highlights the capability of the electro-activated persulfate (EC/PS/HR) hybrid process to decompose recalcitrant pollutants like tetracycline from aqueous environments. Overall, the electro-activated persulfate process demonstrates promise for the degradation of tetracycline in aqueous solutions.

The consequence of using coagulant materials such as aluminum sulfate and ferric chloride in the coagulation unit of conventional water treatment plants can generate plenty of sludge that contains large amounts of coagulant, which in addition to environmental risks, will also possess disposal costs. Today, intending to preserve the environment and reduce treatment costs, researchers emphasize the recovery and reuse of coagulants from sludge. In this regard, the present study was proposed and implemented to recover and reuse water treatment plant sludge as a low-cost coagulant in wastewater treatment.

This research is an experimental-laboratory study. In order to recover the coagulant from the collected sludge, acid hydrolysis method was used. The physicochemical characteristics of the recovered sludge were also determined using FTIR, FE-SEM, and BET analysis. Moreover, the efficiency of recovered sludge in different doses (50 to 300 mg/L) on wastewater treatability in terms of COD, TSS, VSS, turbidity, phosphorus, and coliform indices was compared with aluminum sulfate, ferric chloride coagulants, also the results of the study were analyzed and presented using Excel software (version, 2016).

According to the results, the prepared sludge had no crystalline structure with amorphous morphology. In addition, recovered coagulant from water treatment sludge has demonstrated high efficiency for wastewater treatment, so 66.6%, 82.49%, 79.66%, 80%, 65 %, 99.18% of COD, turbidity, TSS, VSS, phosphorus, total coliform were removed at the highest dosage of recovered coagulant (300 mg/L), respectively. Furthermore, the recovered coagulant dosage had a significant effect on the performance of the coagulation and flocculation process in wastewater treatment.

The results showed that recovered coagulant from the sludge of the water treatment plant can be considered an acceptable option with appropriate effectiveness in the wastewater treatment processes.

This study aimed to evaluate the performance of biological process treatment (Modified Ludzack Ettinger) of municipal wastewater treatment plant No. 4 in Mashhad- Alteymur.

The performance of treatment plant was evaluated in a 12-month period from March 2020 to February 2021. Based on flow changes, a sampling of raw sewage inlet and outlet effluent was done in combination.  Moreover, studied parameters, including BOD5, COD, TSS, TDS, EC, pH, total coliform, and fecal coliform were measured according to the methods presented in the standard method book for water and wastewater tests. ANOVA test was used to analyze the data and compare them.

Based on the results, the highest removal efficiencies are related to the parameters of T.C, FC, TSS, BOD5, COD, TDS, and EC, respectively, with 100, 100, 98.48, 97.88, 48.96, 25.97, and 25.88 percent, respectively. The significant removal efficiency of measured parameters in the effluent from wastewater treatment plant No. 4 of Mashhad (Altimour) shows the proper performance of MLE process system. The results of the ANOVA test to compare the removal efficiency of parameters in different seasons showed that the performance of treatment plant was not affected by the change of seasons.

The amounts of pollutants were compared with the standard of the Environmental Protection Organization of Iran for discharge to the environment and using the wastewater. According to the studies performed on the tested parameters, the effluent is in line with the standards of the Environmental Protection Organization for irrigation and agriculture, surface water, and absorption wells, but for other uses and proper efficiency of the effluent, all aspects should be considered.

Wastewater treatment of paper recycling and cardboard industries with the aim of water recycling and reducing environmental impact is one of the daily needs of industries. Therefore, the aim of the present study was to optimize the conditions of coagulation and flocculation process in wastewater treatment of paper recycling industries using the response surface method.

In this laboratory study, response surface method and central composite design were used to design the experiments and to determine the effects of the studied variables (pH, concentrations of alum, Poly aluminum chloride (PAC), and cationic polymer) on the total suspended solid (TSS) and chemical oxygen demand (COD) removal efficiency. Data analysis was done using ANOVA statistical test with a significant level of 0.05.

The results showed that in the combination of PAC with cationic polymer (optimal conditions; pH=7.5, PAC concentration=450 mg/L, cationic polymer concentration=1.5 mg/L), the TSS and COD removal efficiency were 97.34% and 75.76%, respectively. In combination of alum with cationic polymer (optimal conditions; pH=8.5, alum concentration=550 mg/L, cationic polymer concentration=2 mg/L), removal efficiencies were 98.96% and 77.83%, respectively. The simultaneous effects of two independent variables, pH and concentration, had a significant effect (p<0.05) in removing TSS and COD variables.

The results showed that the combination of PAC with cationic polymer had a better efficiency. Also, the COD and TSS in the final effluent were higher and lower than the standard values, respectively. Therefore, chemical coagulation process is proposed as pretreatment.

With the industrialization of aquatic ecosystems, the concentration of ammonia in surface water and groundwater have been much higher than standards, and large amounts of industrial, municipal and agricultural effluents containing ammonia are released into water sources, producing unhealthy and harmful products. The aim of this study was to synthesis the biological nanocomposite hydrogels based on kappa-carrageenan/Fe3O4 nanoparticles to absorb three samples of agricultural effluent containing ammonia.

Hydrogels are the most suitable bio-sorbents that exist naturally and synthetically. In this study, carrageenan and acrylic acid hydrogels in the form of radical polymerization were prepared in the room by methylene bis-acrylamide as the crosslinking agent and ammonia persulfate as the initiator. Then, a magnetic hydrogel was prepared using divalent and trivalent iron by co-precipitation method.

By adsorbing the ammonia in the two prepared effluent samples, the optimal values ​​for contact time, pH, temperature and adsorbent were 40 minutes, 5, 15 ° C and 40 mg, respectively. The ammonia equilibrium adsorption process by nanomagnetic hydrogels was studied by the Langmuir, Freundlich and Temkin adsorption isotherms, which show that the maximum adsorption belongs to the Langmuir isotherm. Comparison of experimental data with adsorption models showed that these data follow a quasi-quadratic adsorption model. The optimum temperature for the removal of ammonia from both effluents is 15 ° C and the removal capacity in both effluents increases with rising pH from 2 to 10.

According to the results of this study, it can be estimated that the adsorbent studied in this study, which is a nanomagnetic hydrogel of iron oxide, had a significant reduction in the amount of ammonia in the effluents. It can be said that the nanomagnetic hydrogel of iron oxide is an effective adsorbent for the rapid removal of ammonium ions from an aqueous solution.

Advanced Sequencing batch reactors (SBR) are one of the most suitable modified activated sludge systems. Due to low cost, optimal efficiency, and easy operation, they are recognized as an effective biological treatment system. The purpose of this study was to determine the performance of the SBR biological process in the removal of organic matter and nutrients from Yazd city wastewater.

This descriptive study examines the trend of organic matter and nutrients changes in the biological process of advanced SBR. In this study, the samples were taken from the input and output of the SBR process four times a month for 9 months in 2019. A total of 72 samples were taken. Then COD (chemical oxygen demand) and BOD5 (biochemical oxygen demand) and nutrients (phosphate ( ), total phosphorus, ammonium ( ), nitrate ( ), and nitrite  were measured. Finally, the results were analyzed by one-sample t-test at a significance level of 0.05.

The concentration of COD and BOD5 in the effluent was 42 and 14 mg/L, respectively. The concentration of total phosphorus, phosphate, ammonium, nitrate, and nitrite in the effluent was also shown to be 2.9, 2.4, 6.3, 9.01, and 0.92 mg/L, respectively.

The results showed that the active sludge system in the Yazd wastewater treatment plant has a good and acceptable situation. This has caused a significant reduction in organic matter and nutrients. These results are in accordance with the standards of the Iranian Environment Organization in the reuse of wastewater.