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Seventy seven research papers published from 1986 to 2018 were observed. These papers investigated PTEs (Pb, Cd, Cu, As, Fe, Zn, Ni, and total Cr) in leafy (mint, spinach, coriander, and lettuce) and tuberous (potato, carrot, radish, and onion) vegetables irrigated by wastewater. The studies observed in our paper were conducted in 19 countries. The PTEs concentrations were compared among studies and the human health risk was observed. According to the obtained meta-analysis results, PTEs concentrations (mg/kg) in vegetables were found in the following order Zn (34.216)> Cu (22.581)> Ni (14.056)> Pb (10.173)> Cr (8.308)> Fe(8.130)> As(1.881)> Cd (1.763). Hazard index for children was higher than that for adults and for both groups, the calculated HQ was higher than 1, which indicates that there is a health risk for the consumers. This study provides a comprehensive analysis that demonstrates the urgent necessity for treating PTE pollution in agricultural areas worldwide. [ABSTRACT FROM AUTHOR]

The primary purpose of this study was to investigate the efficiency of a Compound Parabolic Concentrator (CPC) equipped with a sun tracking system in the photolysis of carbamazepine as a refractory organic compound. The natural sunlight experiments were accomplished during the period May–July 2017 in Tehran, Iran. The intermediate by-products of the process of solar photodegradation of carbamazepine (CBZ) were characterized using LC–MS. The results showed that increasing the reactor temperature did not significantly change CBZ degradation efficiency. However, the solution pH played a comparatively important role in CBZ solar photo degradation: removal efficiency increased considerably with pH from about 49% at pH 7 to almost 61% at pH 9. According to our findings, using a CPC reactor equipped with a sun tracker system promotes the solar photo-transformation rate of CBZ by 2-3 fold. In addition, LC/MS analysis showed that eight main intermediates were formed in the treated solution after solar photodegradation of CBZ. Therefore, complete mineralization of CBZ was not accomplished.

An N,S-codoped TiO2/Montmorillonite nanocomposite, as a photocatalyst, was synthesized in the sol-gel method and used for the degradation of ciprofloxacin (Cip) in an aqueous solution. N,S-codoped TiO2/Montmorillonte was characterized by powder X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and X-ray fluorescence (XRF) analyzes. A central composite design (CCD) was used to optimize the variables for the removal of Cip by the N,S-codoped TiO2/Montmorillonite. A maximum decomposition of 92% of Cip was achieved in optimum conditions. The band gap value for the nanocomposite was 2.77 eV. Moreover, with the use of nanocomposite in the four consecutive runs, the final removal efficiency was 66%. The results show that the N,S-codoped TiO2/ Montmorillonite under simulated sunlight irradiation can be applied as an effective photocatalyst for the removal of Cip from aqueous solutions.

In the present study, sequencing batch moving-bed biofilm reactor (SBMBBR) was developed as a new treatment system and was used to treat wastewater containing cefixime antibiotic (CFX). The effect of initial concentration of CFX (0–122 mg/L) on common parameters including total nitrogen (TN), nitrite (NO2−), nitrate (NO3−), and chemical oxygen demand (COD) was also evaluated. When a small concentration of CFX (45 mg/L) was added to the SBMBBR, good removal efficiencies were obtained for CFX, COD, and TN. Slight changes in mixed liquor-suspended solids (MLSS) and specific oxygen uptake rates (SOUR) in the reactor containing 92 mg/L of CFX showed that microorganisms had high adaptation in the new SBMBBR system. Biological removal of TN, COD, and CFX was decreased from 70.75, 74.81, and 70.9% to 27.38, 23.2, and 34.8%, respectively, when the initial CFX concentration was increased from 45 to 122 mg/L. Also, value of MLSS was decreased at CFX concentrations of 92 and 122 mg L-1, indicating that bacterial growth was inhibited. CFX degradation products were detected by performing the liquid chromatography-mass spectroscopy (LC-MS/MS) and the results obtained from analysis showed that the CFX was first converted into 5-vinyl-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid and thiazol-2-amine by breaking C-N bond and chain ring. Then, acetic acid and ethyl (methyl) sulphone were formed with further destruction of the chain ring and ring opening. Finally, these by-products can be converted into CO2 and H2O. Accordingly, the results of the present study demonstrated that hybrid process of SBMBBR with minimal reduction in the concentration of MLSS and SOUR can be a good alternative to processes alone in treatment of high concentrations of CFX. [ABSTRACT FROM AUTHOR]

Trichloroacetic acid (TCAA) is considered as one of the major of water chlorination by-products. The present work demonstrates decomposition, mineralisation and dechlorination of TCAA by photocatalytic reduction using F doped TiO2. In this regard, the effects of various operational factors including F-TiO2 dose, the initial concentration of TCAA, photo-reaction time and solution pH were examined on the process efficiency. Based on the results, H C O 3 − , P O 4 − 3 , S O 4 − 2 , C l − and C O 3 − 2 , as the common anions in water, had no considerable impact on the TCAA degradation efficiency. Decomposition and mineralisation rate of TCAA by MeOH/UV/F-TiO2process under the optimum conditions (catalyst dosage of 0.34 g L−1, the contact time of 76 min, TCAA content of 1 mg L−1 and pH of 7.9) were found to be 97.1% and 68%, respectively. The decomposition intermediates of TCAAdetected by LC/MS and LC-MS/MStechniques were non-chlorinated compounds, mainly formic and acetic acids. It can be concluded thatMeOH/UV/F-TiO2processcan use as low energy and efficiently treatment method for the degradation of TCAA contaminated water and wastewater. [ABSTRACT FROM AUTHOR]

The main objectives of this study were PHEs concentration meta-analysis (Fe, Zn, Cr, Ni, Cu, Pb, and Cd) in eggplant irrigated by wastewater and the following estimation of non-carcinogenic (n-CR) risk for the consumers based on countries. According to the results, the rank order of PHEs concentration in eggplant was Fe (88.3 mg/kg -dry weight) > Zn (10.1 mg/kg -dry weight) > Pb (3.0 mg/kg -dry weight) > Ni (2.7 mg/kg -dry weight) > Cu (1.1 mg/kg -dry weight) > Cd (0.9 mg/kg -dry weight) > Cr (0.05 mg/kg -dry weight). Moreover, n-CR risk showed that all investigated countries (China, India, Pakistan, Turkey, and Jordan) except for United Arab Emirates (UAE) had a considerable n-CR in both age groups (adults and children). [ABSTRACT FROM AUTHOR]

The 48-, 72- and 96-h acute toxicity and 14-d chronic toxicity of the sludge of treatment plant No. 1, 3 and 5 were examined based on the survival percentage and fertility changes ofDaphnia magnaandEisenia fetida.The highest percentage ofD. magnadeath in the acute toxicity test appeared in treatment plant No. 1 sludge sample. The 48-h and 72-h LC50of treatment plant No. 1 sludge onD. magnawere calculated to be 86.81 and 44.307% volume of the sludge, respectively. The release of untreated sludge into the environment could adversely affect the life of organisms. [ABSTRACT FROM AUTHOR]

Solar disinfection can significantly improve the microbiological quality of drinking water. Water samples of 0, 50, and 100 nephelometric turbidity units spiked with fecal coliforms (107 CFU/mL) were exposed to natural sunshine in 1 L quartz glass tubes fitted with three different design compound parabolic concentrators (CPC1), CPC2, and CPC3, with concentration factor of the solar radiation of 1. On clear days, the complete inactivation times (more than 7-log unit reduction in bacterial population) in the systems with CPC1, CPC2, and CPC3were 90, 20, and 15 min, respectively. The maximum obtained temperatures in the water samples were 57.9°C for CPC1, 77.7°C for CPC2, and 80°C for CPC3. The use of CPC2–3significantly improved the efficiency of the old CPCStechnique, since these systems shortened the exposure times to solar radiation and also minimized the negative effects of turbidity and also regrowth was zero in the disinfected samples. Overall, this technology has been proved to be a good method enhancement to inactivate micro-organisms under real conditions and represents a good alternative technique to drinking water treatment in developing countries. [ABSTRACT FROM PUBLISHER]

Background and purpose: Chloroform is a disinfection byproducts (DBPs) that results from reactions between residual chlorine and organic compounds as precursors. The presence of these DBPs in chlorinated drinking water can pose a severe public health threat including potential carcinogenicity. In this study chloroform concentrations as an indicator of DBPs of chlorinated water was evaluated in Tehran's drinking water system. Material and Methods: This study was a cross-sectional study in which the samples were taken from water treatment outlet and from certain points of the water distribution network in different seasons during 2009. The samples were analyzed for presence of chloroform compounds using standard methods. The temperature, pH, and residual chlorine concentration were measured as the most important factors associated with chloroform concentrations. Results: Total average concentrations of chloroform in the water treatment plant outlet and in the distribution network were 11.2 and 36.5 micrograms per liter, respectively. These amounts in distribution network concentrations were almost 3.3 times more than the amount of water treatment outlet concentrations. Conclusion: Evaluation of chloroform concentrations in the water treatment plant outlet and distribution network involving temperature, pH, and chlorine residual indicated a direct correlation between them, which was significant in distribution network system and non-significant in the water treatment plant. [ABSTRACT FROM AUTHOR]

Abstract: The catalytic advanced oxidation process (CAOP) of O3/MgO/H2O2 was integrated with a sequencing batch reactor (SBR) system to completely treat concentrated formaldehyde wastewater, demonstrating that this combination is an effective method for treating such wastewaters. The influence of several operational variables – including pH, MgO powder dosage, and the concentrations of H2O2 and O3 – was investigated for the O3/MgO/H2O2 degradation of a 7000mg/L formaldehyde wastewater. The optimum conditions were found to be a pH of 8, 5g/L dose of MgO powder, 0.09mole/L concentration of H2O2, and 0.153g/Lmin dose of O3. The formaldehyde and COD concentrations were reduced 79% and 65.6%, respectively, in the CAOP for 120min of reaction time under the optimum condition stated above. The remaining concentrations of formaldehyde and COD were 1500mg/L and 3200mg/L, respectively, in the effluent. The degradation of formaldehyde in CAOP was determined to be a first-order reaction with a constant of 0.015/min, and radical oxidation was the predominant degradation mechanism. This effluent was post-treated in SBR system for a total cycle time of 24h. The SBR completely removed the formaldehyde and removed 98% of the COD, reducing the COD concentration to lower than 60mg/L. Therefore, the integrated O3/MgO/H2O2 and SBR process is demonstrated as a promising technology for the complete treatment of wastewater with high concentrations of toxic and inhibitory compounds such as formaldehyde. [Copyright &y& Elsevier]

• One-pot synthesis of narrow band gap Ag-doped S-MgO nanosphere as a durable catalyst. • Excellent enhancing the photochemical properties of S-MgO due to Ag doping. • Efficient activation of as-made catalyst with a low dose of UVA photons. • Singlet oxygen non-radical degradation of diclofenac in the UVA/Ag-S-MgO process. Ag-doped S-MgO powder was synthesized by doping of S-MgO with Ag and its photocatalytic activity was investigated under UVA-LED light irradiation for diclofenac (DCF) degradation. The S-MgO doped with 1 mol% of Ag showed the highest photocatalytic activity under UVA irradiation. The Ag-doped S-MgO was nanosphere with a band gap of 2.20 eV and the surface defects. Introducing Ag in the lattice of S-MgO accelerated the charge transfer and thus its photocatalytic activity. Complete degradation of 50 mg/L DCF was achieved via non-radical singlet oxygen mechanism within 15 min in the UVA/LED photocatalytic process with Ag-doped S-MgO in natural pH. In addition, 86% of DCF was mineralized within 60 min in the process. Reusability of the catalyst was successfully carried out for five consecutive runs. Accordingly, the Ag-doped S-MgO nanosphere is an efficient and durable catalyst effectively activated using a relatively low dose of UVA radiation for the degradation and mineralization of emerging water contaminants. [ABSTRACT FROM AUTHOR]

The lack of necessary air pollution control measures in the construction of hospital wastewater treatment plants results in the release of harmful bioaerosols in and around the hospital. A sampling of airborne bacteria and fungi was performed using the gravitational method in 9 sites including an upwind site, intra-plant and outside a hospital wastewater treatment plants with activated sludge technology in Tehran (1, 5 and 3 points, respectively) from March to June. Bioaerosol on nutrient agar media were identified quantitatively and qualitatively. Intra-plant airborne particulate matter concentrations were measured by an optical particle sizer in intervals of 6 s for 60 min. The environmental parameters were also recorded in the sampling period. Experimental data was collected and analyzed by Excel software and SPSS statistical software version 23, respectively. This work is useful to help manage bioaerosols exposure risk such as WWTP., (© 2019 The Authors.)