فهرست مطالب ahmadreza yazdanbakhsh

Anaerobic co-digestion (AcoD) of various wastes is a suitable method for the removal of contaminants and biogas production. The first aim of this study was to determine the optimal ratio of landfill leachate (LL) and sewage sludge (SS) for AcoD, and the second one was to evaluate the effect of
pre-ozonation of the mixture on AcoD.

The LL and SS samples were taken from landfill sites and municipal wastewater treatment plants (MWTPs), respectively. In the first step, five reactors were used and named R1 (100% SS), R2(100% LL), R3 (15% LL/85% SS), R4 (25% LL/75% SS), and R5 (45% LL/55% SS). Mesophilic anaerobic digestion (AD) was performed on the reactors and the optimal ratio was determined. In the second stage, the optimal mixtures were subjected to an ozonation process before AcoD.

The results of the first stage showed that the highest efficiency removal of the total solids (TS), volatile solids (VS), and chemical oxygen demand (COD), and the highest biogas production belonged to R3 digester, containing 15% LL and 85% SS. In the second stage, the results showed that the removal efficiency of COD and VS in the ozonated sample at the dosage of 7.6 gO3/h were 29.8% and 36.6% higher than the non-ozonated sample, respectively. Furthermore, in the ozonated sample, the biogas yield and the content of methane in the gas mixture were 27% and 9% higher respectively, compared to the non-ozonated sample.

According to the results, the appropriate ratio of LL to SS and pre-ozonation of LL/SS mixture have a great impact on the performance of AcoD.

The newfound  pollutant perchlorate, with global distribution, long-term stability in the environment, and solubility in water, is the most crucial health threat of the present era by causing changes in the level of thyroid hormones. Perchlorate enters the body by drinking water or contaminated food with perchlorate. The United States Environmental Protection Agency has provided a guideline of 15 μg/L in drinking water. This study aims to determine the relationship between the concentration of perchlorate in drinking water and the frequency of hypothyroidism in newborns.

238 samples were collected from the water supply network of the study area. The samples were analyzed according to the standard water and wastewater tests and ion chromatography methods.

The results showed that the quality characteristics of drinking water in the water supply systems of the studied area are within the normal range and in accordance with the standard. Drinking water is classified as hard water in Damavand city. Perchlorate concentration of drinking water was detected to be 0.002 - 0.009 mg/liter.

The concentration of perchlorate in the drinking water of the study area is according to the guidelines of the U.S. Environmental Protection Agency and does not threaten consumers’ health.

The removal of formaldehyde as a toxic substance from aqueous solutions is of particular importance. In this research, a sequencing batch rotating-bed bioreactor (SBRB) was used on a laboratory scale for biodegradation of formaldehyde from synthetic wastewater. The reactor was made of plexiglas with a cylindrical shape. Kaldnes media were placed in a rotating cylindrical basket in the reactor. The effects of formaldehyde concentration (500–1500 mg/L), hydraulic retention time (HRT) (8, 15, 24 hours), and injection of hydrogen peroxide (0.1-0.5 mM) on the performance of the reactor were investigated. The results showed that in the SBRB, at an HRT of 24 hours and an inlet formaldehyde concentration of 1000 mg/L, the removal efficiencies of formaldehyde and chemical oxygen demand (COD) were 99.2% and 92%, respectively, while without rotating the bed, the removal efficiency of formaldehyde and COD was found to be 95% and 83%, respectively. By adding hydrogen peroxide at a concentration of 0.3 mM and operation of the SBRB with an HRT of 8 hours and an inlet formaldehyde concentration of 1000 mg/L, an improvement in the removal efficiency of formaldehyde and COD (4% and 22%, respectively) was observed. Accordingly, SBRB stimulation with hydrogen peroxide could be considered as a high-performance process for the removal of formaldehyde and corresponding COD at a short HRT.

Olive mill wastewater (OMW) is characterized by its high organic content and refractory compounds. The aim of this study was to evaluate and compare the efficiency of UV/O3 and UV/ acetylacetone (UV/AcAc) processes for treatment of pretreated OMW by coagulation/microfiltration (C&M) process.

In this study, a laboratory-scale UV plug flow reactor with ancillary equipment was fabricated. The experimental factors including initial pH (5-9), O3 dosages (1.5-4.5 g/h), and AcAc concentrations (0.01-0.03 M) were measured. For both processes, a reaction time of 120 min was considered. The effect of these variables on removal of wastewater contaminants including BOD, COD, TSS, turbidity, phenol, oil, and grease were investigated.

Results showed that raw OMW has a high load of pollutants and very low biodegradability (BOD5/COD = 0.12). In UV/O3 process, the optimal conditions were obtained at pH 8 and ozone injection at 4 g/h. The combined C&M-UV/O3 process removed 78.75% COD, 46.66% BOD5, 90.88% total phenol, 91.78% TSS, 99.14% oil and grease, and 98.38% turbidity, with promotion of BOD5/ COD from 0.12 to 0.33. In UV/AcAc process, the optimal conditions were achieved at pH 5 and AcAc concentration of 0.03 M. The combined C&M-UV/AcAc process removed 58.75% COD, 67.58% BOD5, 38.03% total phenol, 83.50% TSS, 93.65% oil and grease, and 95.00% turbidity, with promotion of BOD5/ COD from 0.12 to 0.22.

The results showed that the UV/O3 process is completely superior to the UV/AcAc process for removal of OMW contaminants, as well as promoting the biodegradability of OMW.

We aimed to conduct a meta-analysis on the concentration of potentially harmful elements (PHEs) in carrots and potatoes irrigated by wastewater and estimate non-carcinogenic health risks among adult and children consumers.

The health risk of PHEs concentration, including Pb, Cd, total Cr, Ni, Zn, Cu, and Fe, in the edible parts of carrot and potato irrigated by wastewater was investigated by a meta-analysis using a random-effects model (REM). Accordingly, the related articles were screened from international databases such as Scopus, Medline, and Embase.

The meta-analysis of 32 papers (38 studies) revealed that the rank order of the most accumulated PHEs in potato was Fe (86.54 mg/kg wet weight) > Zn (30.9 mg/kg wet weight) > Cu (13.7 mg/kg wet weight) > Ni (8.42 mg/kg wet weight) > Pb (5.56 mg/kg wet weight) > Cr (3.45 mg/kg wet weight) > Cd (0.58 mg/kg wet weight). This ranking for carrot was Fe (43.36 mg/kg wet weight) > Zn (36.29 mg/kg wet weight) > Ni (13.49 mg/kg wet weight) > Cu (9.79 mg/kg wet weight) > Pb (1.84 mg/kg wet weight) > Cr (1.05 mg/kg wet weight) > Cd (0.28 mg/kg wet weight). Total hazard quotient (THQ) of PHEs was higher than 1 for potato and carrot; its rank order for potato and carrot was Cu > Pb > Cd > Ni > Fe > Zn > Cr and Cd > Pb > Cu > Ni > Fe > Zn > Cr, respectively. The Cd, Pb, and Cu had also a considerable role for consumer health risk.

According to the results, continuous monitor and control of wastewater treatment plants are necessary.

 The recovery of rare-earth elements (REEs) like toxic lanthanides from contaminated waters is vital because of their irreversible effects on humans and the environment.

 In the present research, a chitosan-imprinted nano zero-valent iron (CS@nZVI) nanocomposite was fabricated and utilized to the successful separation of Lanthanum as a model lanthanides.

 The morphological and structural properties of the composites were studied through BET, FTIR, SEM, TEM, and XRD techniques. The adsorption process was modeled and optimized by methodology of response surface (RSM). Then, its four important models were validated by data fitting. Afterward, they were affirmed using ANOVA test.

 According to the outputs of the models, the reduced model was obtained as an appropriate model. Based on RSM plots, the adsorption rate at preliminary pH is low and gets better with increasing the pH value. At lower pH, there is a high concentration of H+ ion with smaller ionic radii and higher adsorption possibility, which makes it difficult to adsorb lanthanum ions by creating a competition between the excess of protons in the solution and cationic metal ions. This competitive adsorption and saturation of adsorptive sites on the surface of CS@nZVI sorbent with hydrogen ions together with repulsion forces are responsible for the La (III) less sorption. The optimum CS@nZVI removal efficiency of La (III) was 88% under the following conditions: pH = 8, 1.2 g/L CS@nZVI dosage, 5 mg/L initial La (III) concentration, and 180 min shaking time. Based on uptake kinetic models, the pseudo-second-order model is optimum in describing the rate equation of the adsorption process.

 Successfully regeneration of CS@nZVI along with its good performance for Lanthanum separation provide a promising and feasible method in order to contaminated streams purification.

The goals of this study were to assess the microbiological quality and coastal water quality index (CWQI) in the Persian Gulf alongshore of Bandar Abbas city. Water samples were collected from five different coastal sites in spring and summer seasons. To assess the microbiological quality: Total Coliforms, Fecal Coliforms, Fecal Streptococci and Clostridium perfringens were measured. Also, eight physicochemical parameters (DO, BOD, TSS, Turbidity, Temperature, pH, Nitrate, Phosphate) were examined for calculating the CWQI. The mean for microbiological indicators was respectively, 3667, 1055, 50, 211 MPN/100ml. for physicochemical parameters, the average of water temperature was 32 °C, electrical conductivity was 57mmho/cm, the turbidity was 70.7 NTU, pH 8.1, and also the average concentration of phosphate, nitrate, nitrite, and ammonium was 180, 18.2, 4.9, 12.16μmol/L, and the mean of concentration BOD, COD and DO were 4.89, 11 and 6.8mg/L, respectively. In addition, the water quality index for all months and at selected stations was 65. The results showed that in the most samples the levels of microbiological indicators were exceeded the national standard and guideline values. Also, the computed CWQI showed that quality of water was weak. All the extracted results are closely related to the inlets connected to the sea. These inlets except the Ghadir station will affect the rest of the stations. In general, in low tide, the Bactria index was more than high tide

Alcohol distillery wastewater is a highly polluted wastewater which its treatment poses a special problem. In this work, the efficiency of ozonation process exploited in a spiral high pressure super mixing reactor was studied for COD removal and decolorization of alcohol distilleries wastewater. The results was also compared with a conventional reactor.

The present laboratory-scale research was done on real effluent from anaerobic wastewater treatment unit of alcohol wastewater. Experiments were conducted in a pressurized spiral super mixing reactor equipped with static mixers and also in a control conventional reactor with the same volume. The process performance criteria, such as COD, BOD and color, were determined according to standards methods for water and wastewater examination.

The pressurized spiral super mixing reactor showed high efficiency in removing pollutants and reducing ozone consumption as compared to conventional reactor. Typically, during 30 min, and pH =5.3, the COD removal efficiency in the pressurized spiral super mixing reactor was 4.8 times higher than that of conventional reactor. According to the results, the efficacy of ozonation process increased by changing the pH from acidic to alkaline. Generally, the respective highest removal efficiency of COD and color was obtained at pH=11 and pH=5.3 in both reactors at their maximum retention time. Also the biodegradability of wastewater (BOD/COD) was enhanced in both reactors following ozonation process.

The pressurized spiral super mixing reactor performance in reducing ozone consumption highlights the potential applicability of this reactor for wastewater treatment of alcohol industry. The reactor can be used as pre-treatment or post treatment processes for the appropriate treatment of industrial wastewater.