Ciprofloxacin degradation by catalytic activation of monopersulfate using Mn-Fe oxides: performance and mineralization.

In this work, Mn2O3/Fe2O3 (MFO) was synthesized and used to activate monopersulfate (MPS) for the degradation of ciprofloxacin (CIP). The effect of several parameters was studied on CIP degradation. Under the optimum conditions (pH = 6.3 (natural pH), MFO = 300 mg/L and MPS = 2 mM), around 92% of CIP was decomposed. Nitrite, phosphate and bicarbonate ions had a strong inhibitory effect on the MFO/MPS process while the effect of chloride and nitrate ions was neutral. The catalytic activity of MFO was also studied by other chemical oxidants such as peroxydisulfate, periodate, hydrogen peroxide, percarbonate and peracetic acid. Scavenging tests showed that the role of sulfate radicals is more than hydroxyl radicals. MFO exhibited high catalytic activity in four recycling with insignificant leaching of Mn and Fe. During CIP oxidation, 45.5% carbon mineralization occurred and antibacterial activity of treated CIP solution was reduced. Finally, MFO/MPS was applied on actual wastewater (hospital effluent) and the results showed that MFO/MPS can be considered as a practical method for the treatment of contaminated water with emerging pollutants.

Spatial distribution and risk assessment of agricultural soil pollution by hazardous elements in a transboundary river basin.

The present study aimed to evaluate the sources of pollution and the potential human and ecological risks of hazardous elements (HEs) in 40 hotspot sites of the agricultural soil around the Arvand River, Iran. The mean concentrations of As, Cd, Co, Cr, Ni, Pb, Zn, and Hg were measured to be 7.2, 0.8, 14.0, 67.9, 69.5, 63.0, 296, and 0.66 (mg kg-1), respectively. With the exception of Ni, the mean concentrations of all the elements were found to be higher than those in the background. The spatial distribution of HEs in the study area indicated an increasing trend of contamination from the north to the south. Pb, Zn, and Hg were the most enriched elements, resulting in a high pollution load. Moreover, the agricultural soil of the study area was threatened by a very high ecological risk due to the contribution of Hg, Cd, and Pb. Multivariate statistical analyses determined that the pollution sources are specified by the oil refinery emissions and effluents, irrigation with polluted water, fertilizers, dust storms, and airport emissions. The carcinogenic risk of HEs in both adults and children revealed an acceptable level; however, children faced a great chance of non-carcinogenic risk. The results provide a scientific basis for monitoring HEs and managing health risks via effective methods in the agricultural areas of the Arvand River basin.

Intrinsic kinetics for fixed bed bioreactor in hospital wastewater treatment.

Variation in hospital wastewater (HWW) pollutants and differences with municipal wastewater (MWW), make the use of biokinetic coefficients obtained from activated sludge in the MWW treatment unprofitable for designing, modeling and evaluation of biological processes for HWW treatment. Since this study was conducted to evaluate the performance and biokinetic coefficients of a fixed bed bioreactor (FBBR) using rice husks as fixed media in HWW treatment, a new modified method was also proposed for biokinetic estimation in FBBR processes. For these purposes, five hydraulic retention times along with five sludge retention times were introduced to a pilot setup and the required data were attained. The performance process for chemical oxygen demand (COD) removal was significant (87.8-97.5%) in different conditions. The values of biokinetic coefficients k, Ks, Y and Kd were obtained as 2.42 (day-1), 55.5 (mgCOD/L), 0.2929 (mgBiomass/mgCOD) and 0.0164 (day-1), respectively. The rice husks with high surface area and high affinity for biomass accumulation on its surface are promising media for a green and environmentally friendly FBBR process. The kinetics parameters values are utilizable for modeling of FBBR using rice husks as fixed media in HWW treatment.

Potentially toxic elements contamination in surface sediment and indigenous aquatic macrophytes of the Bahmanshir River, Iran: Appraisal of phytoremediation capability.

To determine the status and sources of contamination and phytoremediation capability of Typha latifolia L. in the Bahmanshir River of Iran, the concentration of eight potentially toxic elements (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in sediment and plant tissues from ten sampling sites were measured. Mean concentrations of Cd, Cr, Cu, Pb, and Zn in the sediment exceeded those of local background. PCA-MLR receptor analysis suggested that the sediment contamination was due to municipal wastewater/vehicular pollution and weathering/industrial/agricultural activities, with contributions of 66% and 34%, respectively. Average enrichment factor (EF) and modified hazard quotient (mHQ) for Pb and Cu were categorized as moderate. Modified pollution index (MPI) and modified ecological risk index (MRI) values suggested moderate to heavy pollution and low ecological risk, respectively. The values of sediment quality guidelines (SQGs), ecological contamination index (ECI), contamination severity index (CSI), and toxic risk index (TRI) were all similar, reflecting low to moderate contamination and toxicity. Typha latifolia L. showed good phytostabilization capability for Cd, Cu, and Pb, and phytoextraction capacity for Zn. Using the metal accumulation index (MAI) and the comprehensive bioconcentration index (CBCI), Typha latifolia L. was shown to have acceptable performance in the accumulation of Cd, Cu, Pb, and Zn and thus, can be considered a good candidate for bioaccumulation of these elements in the study area. Overall, this study suggests that phytoremediation using Typha latifolia L. could be a practical method for uptake and remove of potentially toxic elements from aquatic environments.

Determination of bisphenol a migration from food packaging by dispersive liquid-liquid microextraction.

In the current work, a rapid and simple dispersive liquid-liquid microextraction method (DLLME) was used to determine Bisphenol A (BPA). High performance liquid chromatography with the photodiode-array detector (HPLC-DAD) coupled DLLME method was employed to analyze BPA in food samples packaged including cans, paper boxes, and glass jars. The calibration curve was obtained to be in the linear range 0.009-25 ngg-1 with a correlation coefficient of R2 = 0.9981. The mean relative standard deviations (RSDs) was of 5.2% (n = 3). The limit of detection (LOD) and the limit of quantification (LOQ) of the method were obtained to be 0.001 ngg-1 and 0.08 ng.g-1, respectively. In sum, this method presents:•A rapid, simple and efficient modified DLLME method was used to measure BPA in packaged foods.•The advantages of this method were low detection limit, fast preparation, and high BPA recovery.•The DLLME-HPLC method consists of low detection limit and high recoveries to determine BPA in samples.•The results indicated that DLLME -HPLC-DAD was an applied method to measure BPA in food samples.

Multi-route human health risk assessment from trihalomethanes in drinking and non-drinking water in Abadan, Iran.

Natural organic matter reacted with chlorine used for disinfection, and finally, trihalomethanes (THMs) are formatted. The main purpose of this study was to determine four THM concentrations and human health cancer risk and non-cancer risk assessment from exposure through oral ingestion, dermal contact, and inhalation for males and females in Abadan. Two sampling sites were selected, and five samples before and after treatment by two different water treatment systems (RO and ion exchange) were collected every week. Results showed that total THM concentrations before and after treatment by RO were 98.1 and 8.88 µg/L, and ion exchange ranged between 101.9 and 14.96 µg/L, respectively, that before treatment was upper than the maximum of 80 mg/L recommended by USEPA. Inhalation was the primary route of exposure by around 80-90% of cancer risk. Total cancer risk was higher than the USEPA acceptable limit of 10-6 via three exposure routes. Oral route has the higher hazard index values than dermal ways.

Oxidative removal of benzotriazole using peroxymonosulfate/ozone/ultrasound: Synergy, optimization, degradation intermediates and utilizing for real wastewater.

This study investigated the degradation efficiency of BTA using combination of ultrasound (US), peroxymonosulfate (PMS), and ozone. The effects of different operational parameters were investigated to optimize the process performance. The results showed that the highest removal efficiency was reached at neutral pH, ozone = 6.8 mg/L, PMS = 1.5 mM and US power = 200 W. Under these conditions, 40 mg/L of BTA was completely degraded within 60 min leading to the almost 85% of chemical oxygen demand removal, 75% of total organic carbon removal and 73.3% of organic nitrogen removal. Based on the scavenging tests, it was found that hydroxyl radical was the main oxidizing agent in the oxidation of BTA by PMS/ozone/US process. The inhibitive effect of anions on BTA removal was under this order NO2- > HCO3- > Cl- > NO3- > SO42-. Degradation intermediates of BTA were identified and oxidation pathway was proposed. Finally, real samples of saline water, petrochemical wastewater and secondary effluent matrices were investigated for the performance of PMS/ozone/US process and it was found that 54%, 72.3% and 94.6% BTA removal efficiency were reached, respectively. PMS/ozone/US process was compared to US/peroxone (ozone + H2O2) and the results showed importance of US irradiation in both systems. Accordingly, PMS/ozone/US process could be considered as an efficient and promising process for BTA degradation in various wastewaters.

Selecting the best stabilization/solidification method for the treatment of oil-contaminated soils using simple and applied best-worst multi-criteria decision-making method.

Oil-contaminated soils resulted from drilling activities can cause significant damages to the environment, especially for living organisms. Treatment and management of these soils are the necessity for environmental protection. The present study investigates the field study of seven oil-contaminated soils treated by different stabilization/solidification (S/S) methods, and the selection of the best treated site and treatment method. In this study, first, the ratios of consumed binders to the contaminated soils (w/w) and the treatment times for each unit of treated soils were evaluated. The ratios of consumed binders to the contaminated soils were between 6 and 10% and the treatment times for each unit of treated soils were between 4.1 and 18.5 min/m3. Physicochemical characteristics of treated soils were also determined. Although S/S methods didn't change the water content of treated soils, they increased the porosity of soils. Unexpectedly, the cement-based S/S methods didn't increase the pH of the treated soils. The highest and the lowest leaching of petroleum hydrocarbons was belonging to S/S using diatomaceous earth (DE) and the combination of Portland cement, sodium silicate and DE (CS-DE), respectively. The best acid neutralization capacity was obtained for soils treated using the combination of Portland cement and sodium silicate (CS). Based on the best-worst multi-criteria decision-making method (BWM-MCDM), the soils treated using CS-DE was select as the best. The BWM-MCDM can be used as an effective tool for the selection of the best alternative in all areas of environmental decontamination.

Developing a method for measurement of dehydrogenase activity in biological wastewater treatment processes applied for toxic compounds degradation.

Biological wastewater treatment processes are among the environmentally friendly techniques for degradation of organic compounds. They are also preferred to the physical and chemical processes which are due to the ability of biological processes to treat wide range of organic compounds with lower operational costs. However, biological processes are usually affected by variation in the inlet wastewater quality and quantity. In order to investigate the performance of the wastewater treatment plant, various parameters in case of effluent quality such as COD, BOD, TSS, TDS etc. are required to be measured. Microorganisms in bioreactors use various enzymes to degrade the organic contaminants. Higher toxic organic load on the biological process may lead to the deterioration of the process performance which is due to the reduction in microbial activity of the biomass. Dehydrogenase enzyme produced in biological processes could be used as an indicator for the biological wastewater treatment. Present study introduces a simple and modified method for evaluation of biological wastewater treatment process measuring dehydrogenase activity. In the present study, the effective parameters such as incubation time and types of solvent were investigated and the best procedure is developed for measuring the dehydrogenase activity in biological wastewater treatment process.