This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The presence of arsenic in water bodies poses a significant risk to both human health and the env... more The presence of arsenic in water bodies poses a significant risk to both human health and the environment. Arsenic (As) contamination in water sources is a global environmental concern caused by both natural processes and human activities. Due to its toxic and persistent nature, arsenic has detrimental e ects on ecosystems and human wellbeing. This study aimed to elucidate the mechanisms behind arsenic accumulation in water bodies. In aquatic environments, arsenic concentrations in drinking water have been reported as high as , µg/L (Nicaragua), while groundwater levels exceeded , µg/L (Thailand), and wastewater contained up to , µg/L (landfill leachate in Brazil). Furthermore, bioaccumulation of arsenic (µg/g) in fish species ranges from. (catfish in the Paraná River Delta, Brazil) to (Pteromylaeus bovinus, Northern Adriatic Sea). Recent research has predominantly focused on removing arsenic from aqueous solutions through adsorption methods. Notably, nanoparticle adsorbents and graphene-based adsorbents demonstrate a high capacity for arsenic removal from water bodies.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, ... more Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, are a family of fluorinated organic compounds of anthropogenic origin. PFAS can endanger the environment and human health because of their wide application in industries, long-term persistence, unique properties, and bioaccumulation potential. This study sought to explain the accumulation of different PFAS in water bodies. In aquatic environments, PFAS concentrations range extensively from <0.03 (groundwater; Melbourne, Australia) to 51,000 ng/L (Groundwater, Sweden). Additionally, bioaccumulation of PFAS in fish and water biota has been stated to range from 0.2 (Burbot, Lake Vättern, Sweden) to 13,900 ng/g (Bluegill samples, U.S.). Recently, studies have focused on PFAS removal from aqueous solutions; one promising technique is advanced oxidation processes (AOPs), including microwaves, ultrasound, ozonation, photocatalysis, UV, electrochemical oxidation, the Fenton process, and hydrogen peroxide-based and sulfate radical-based systems. The removal efficiency of PFAS ranges from 3% (for MW) to 100% for UV/sulfate radical as a hybrid reactor. Therefore, a hybrid reactor can be used to efficiently degrade and remove PFAS. Developing novel, efficient, cost-effective, and sustainable AOPs for PFAS degradation in water treatment systems is a critical area of research.
The presence of dyes in aquatic environments can have harmful effects on aquatic life, including ... more The presence of dyes in aquatic environments can have harmful effects on aquatic life, including inhibiting photosynthesis, decreasing dissolved oxygen levels, and altering the behavior and reproductive patterns of aquatic organisms. In the initial phase of this review study, our aim was to examine the categories and properties of dyes as well as the impact of their toxicity on aquatic environments. Azo, phthalocyanine, and xanthene are among the most frequently utilized dyes, almost 70–80% of used dyes, in industrial processes and have been identified as some of the most commonly occurring dyes in water bodies. Apart from that, the toxicity effects of dyes on aquatic ecosystems were discussed. Toxicity testing relies heavily on two key measures: the LC50 (half-lethal concentration) and EC50 (half-maximal effective concentration). In a recent study, microalgae exposed to Congo Red displayed a minimum EC50 of 4.8 mg/L, while fish exposed to Disperse Yellow 7 exhibited a minimum LC50 of 0.01 mg/L. Anaerobic membrane bioreactors (AnMBRs) are a promising method for removing dyes from water bodies. In the second stage of the study, the effectiveness of different AnMBRs in removing dyes was evaluated. Hybrid AnMBRs and AnMBRs with innovative designs have shown the capacity to eliminate dyes completely, reaching up to 100%. Proteobacteria, Firmicutes, and Bacteroidetes were found to be the dominant bacterial phyla in AnMBRs applied for dye treatment. However, fouling has been identified as a significant drawback of AnMBRs, and innovative designs and techniques are required to address this issue in the future.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The potential of microalgal photobioreactors in removing total ammonia nitrogen (TAN), chemical o... more The potential of microalgal photobioreactors in removing total ammonia nitrogen (TAN), chemical oxygen demand (COD), caffeine (CAF), and N,N-diethyl-m-toluamide (DEET) from synthetic wastewater was studied. Chlorella vulgaris achieved maximum removal of 62.2% TAN, 52.8% COD, 62.7% CAF, and 51.8% DEET. By mixing C. vulgaris with activated sludge, the photobioreactor showed better performance, removing 82.3% TAN, 67.7% COD, 85.7% CAF, and 73.3% DEET. Proteobacteria, Bacteroidetes, and Chloroflexi were identified as the dominant phyla in the activated sludge. The processes were then optimized by the artificial neural network (ANN). High R2 values (>0.99) and low mean squared errors demonstrated that ANN could optimize the reactors’ performance. The toxicity testing showed that high concentrations of contaminants (>10 mg/L) and long contact time (>48 h) reduced the chlorophyll and protein contents in microalgae. Overall, a green technology for wastewater treatment using microalgae and bacteria consortium has demonstrated its high potentials in sustainable management of water resources.
International Journal of Scientific Research in Knowledge, 2013
Sequencing batch reactor (SBR) process uses for treatment of different types of wastewaters such ... more Sequencing batch reactor (SBR) process uses for treatment of different types of wastewaters such as municipal wastewater, landfill leachate, dairy wastewater, slaughterhouse wastewater etc. Operation parameters of SBR technique are cycle time, aeration rate, volume of reactor, hydraulic retention time (HRT) and other parameters. In this work, operational parameters and removal efficiencies of pollutants for SBR method were studied. In addition, boundaries for operational parameters in SBR process were explained as well.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Recently, national and international effluent standards have become more stringent, posing a sign... more Recently, national and international effluent standards have become more stringent, posing a significant challenge in the water treatment industry. Accordingly, treatment techniques with minimal energy consumption and maximal performance are urgently required for wastewater and water treatments. This topic was investigated from both technical and environmental perspectives to improve water and wastewater treatment techniques and enhance the quality of water bodies. This Special Issue (SI) has attracted investigations by researchers worldwide, including those from Australia,
The consumption of pharmaceuticals and personal care products (PPCPs) has been widely increasing,... more The consumption of pharmaceuticals and personal care products (PPCPs) has been widely increasing, yet up to 90–95% of PPCPs consumed by human are excreted unmetabolized. Moreover, the most of PPCPs cannot be fully removed by wastewater treatment plants (WWTPs), which release PPCPs to natural water bodies, affecting aquatic ecosystems and potentially humans. This study sought to review the occurrence of PPCPs in natural water bodies globally, and assess the effects of important factors on the fluxes of pollutants into receiving waterways. The highest ibuprofen concentration (3738 ng/L) in tap water was reported in Nigeria, and the highest naproxen concentration (37,700 ng/L) was reported in groundwater wells in Penn State, USA. Moreover, the PPCPs have affected aquatic organisms such as fish. For instance, up to 24.4 × 103 ng/g of atenolol was detected in P. lineatus. Amongst different technologies to eliminate PPCPs, algae-based systems are environmentally friendly and effective because of the photosynthetic ability of algae to absorb CO2 and their flexibility to grow in different wastewater. Up to 99% of triclosan and less than 10% of trimethoprim were removed by Nannochloris sp., green algae. Moreover, variable concentrations of PPCPs might adversely affect the growth and production of algae. The exposure of algae to high concentrations of PPCPs can reduce the content of chlorophyll and protein due to producing reactive oxygen species (ROS), and affecting expression of some genes in chlorophyll (rbcL, psbA, psaB and psbc).
Journal of Environmental Chemical Engineering, 2021
Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biologi... more Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biological method for nitrogen treatment from aqueous solutions. However, slow growth rate, negative effects of high concentration of nitrite, ammonia and other pollutants (such as metals) on anammox activity are the main drawbacks of using anammox. Thus, in this study, anammox was attached on chitosan to improve anam- mox performance. Two reactors comprising chitosan and anammox bacteria (first reactor, chitosan/anam- mox) and solely anammox (second reactor, control) were run for 73 d. The nitrogen loading rate (NLR) var- ied from 2 to 14 gN/(L d), while the nitrogen concentration varied from 80 to 700 mg/L. The chitosan/ anammox reactor showed a better performance than the sole anammox (control), with respective maxi- mum abatement values of ammonia (NH4+), nitrite (NO2-), and total nitrogen (TN) of 90.8%, 83.5%, and 81.7% on days 20–25 under a NLR of 8–10 kgTN/(m3 d). Response surface methodology (RSM) was em- ployed to optimize the performance of both reactors, and a reasonable R2 value showed that the RSM well optimized the performance of the reactors. After Xnding the optimum performance conditions for both re- actors, Fe and Cu (0.5–7.0 mg/L) were added to the inYuent to monitor the effects of metals on the perfor- mance of both reactors. The performance of both reactors decreased to 0% following the addition of 7.0 (first reactor) and 6.5 (second reactor) mg/L Cu and Fe, respectively. This indicated that chitosan not only enhanced nitrogen removal by anammox but also improved the resistance of anammox to metals.
Landfill leachate is characterised by high chemical and biological oxygen demand and generally co... more Landfill leachate is characterised by high chemical and biological oxygen demand and generally consists of undesirable substances such as organic and inorganic contaminants. Landfill leachate may differ depending on the content and age of landfill contents, the degradation procedure, climate and hydrological conditions. We aimed to explain the characteristics of landfill leachate and define the practicality of using different techniques for treating landfill leachate. Different treatments comprising biological methods (e.g. bioreactors, bioremediation and phytoremediation) and physicochemical approaches (e.g. advanced oxidation processes, adsorption, coagulation/ flocculation and membrane filtration) were investigated in this study. Membrane bioreactors and integrated biological techniques, including integrated anaerobic ammonium oxidation and nitrification/denitrification processes, have demonstrated high performance in ammonia and nitrogen elimination, with a removal effectiveness of more than 90%. Moreover, improved elimination efficiency for suspended solids and turbidity has been achieved by coagulation/ flocculation techniques. In addition, improved elimination of metals can be attained by combining different treatment techniques, with a removal effectiveness of 40-100%. Furthermore, combined treatment techniques for treating landfill leachate, owing to its high chemical oxygen demand and concentrations of ammonia and low biodegradability, have been reported with good performance. However, further study is necessary to enhance treatment methods to achieve maximum removal efficiency.
International Journal of Environmental Research and Public Health, 2021
Antibiotics are frequently applied to treat bacterial infections in humans and animals. However, ... more Antibiotics are frequently applied to treat bacterial infections in humans and animals. However, most consumed antibiotics are excreted into wastewater as metabolites or in their original form. Therefore, removal of antibiotics from aquatic environments is of high research interest. In this study, we investigated the removal of sulfamethoxazole (SMX) and ofloxacin (OFX) with Chae-toceros muelleri, a marine diatom. The optimization process was conducted using response surface methodology (RSM) with two independent parameters, i.e., the initial concentration of antibiotics and contact time. The optimum removal of SMX and OFX were 39.8% (0.19 mg L −1) and 42.5% (0.21 mg L −1) at the initial concentration (0.5 mg L −1) and contact time (6.3 days). Apart from that, the toxicity effect of antibiotics on the diatom was monitored in different SMX and OFX concentrations (0 to 50 mg L −1). The protein (mg L −1) and carotenoid (µg L −1) content increased when the antibiotic concentration increased up to 20 mg L −1 , while cell viability was not significantly affected up to 20 mg L −1 of antibiotic concentration. Protein content, carotenoid, and cell viability decreased during high antibiotic concentrations (more than 20 to 30 mg L −1). This study revealed that the use of Chae-toceros muelleri is an appealing solution to remove certain antibiotics from wastewater.
Using microalgae to remove pharmaceuticals and personal care products (PPCPs) mi-cropollutants (M... more Using microalgae to remove pharmaceuticals and personal care products (PPCPs) mi-cropollutants (MPs) has attracted considerable interest. However, high concentrations of persistent PPCPs can reduce the performance of microalgae in remediating PPCPs. Three persistent PPCPs, namely, carbamazepine (CBZ), sulfamethazine (SMT) and tramadol (TRA), were treated with a combination of Chaetoceros muelleri and biochar in a photobioreactor during this study. Two reactors were run. The first reactor comprised Chaetoceros muelleri, as the control, and the second reactor comprised Chaetoceros muelleri and biochar. The second reactor showed a better performance in removing PPCPs. Through the response surface methodology, 68.9% (0.330 mg L −1) of CBZ, 64.8% (0.311 mg L −1) of SMT and 69.3% (0.332 mg L −1) of TRA were removed at the initial concentrations of MPs (0.48 mg L −1) and contact time of 8.1 days. An artificial neural network was used in optimis-ing elimination efficiency for each MP. The rational mean squared errors and high R 2 values showed that the removal of PPCPs was optimised. Moreover, the effects of PPCPs concentration (0-100 mg L −1) on Chaetoceros muelleri were studied. Low PPCP concentrations (<40 mg L −1) increased the amounts of chlorophyll and proteins in the microalgae. However, cell viability, chlorophyll and protein contents dramatically decreased with increasing PPCPs concentrations (>40 mg L −1).
Occurrence of pharmaceutical micropollutants in aquatic environments has been one amongst serious... more Occurrence of pharmaceutical micropollutants in aquatic environments has been one amongst serious environmental problems. During this study, two reactors, including a sequencing batch reactor (SBR) + powdered composite adsorbent (CA) (first reactor, SBR + CA) and a sequencing batch reactor (second reactor, SBR), were designed to treat synthetic wastewater. Powdered CA was added with a dosage of 4.8 g L−1 to the first reactor. Tap water was contaminated with chemical oxygen demand (COD), ammonia and three pharmaceuticals, namely, atenolol (ATN), ciprofloxacin (CIP) and diazepam (DIA) to produce synthetic wastewater. The SBR + CA illustrated a better performance during synthetic municipal wastewater treatment. Up to 138.6 mg L−1 (92.4%) of COD and up to 114.2 mg L−1 (95.2%) of ammonia were removed by the first reactor. Moreover, optimisation of pharmaceuticals removal was conducted through response surface methodology (RSM) and artificial neural network (ANN). Based on the RSM, the best elimination of ATN (90.2%, 2.26 mg L−1), CIP (94.0%, 2.35 mg L−1) and DIA (95.5%, 2.39 mg L−1) was detected at the optimum initial concentration of MPs (2.51 mg L−1) and the contact time (15.8 h). In addition, ANN represented a high R2 value (>0.99) and a rational mean squared error (<1.0) during the optimisation of micropollutants removal by both reactors. Moreover, adsorption isotherm study showed that the Freundlich isotherm could justify the abatement of micropollutants by using CA better than the Langmuir isotherm.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The presence of arsenic in water bodies poses a significant risk to both human health and the env... more The presence of arsenic in water bodies poses a significant risk to both human health and the environment. Arsenic (As) contamination in water sources is a global environmental concern caused by both natural processes and human activities. Due to its toxic and persistent nature, arsenic has detrimental e ects on ecosystems and human wellbeing. This study aimed to elucidate the mechanisms behind arsenic accumulation in water bodies. In aquatic environments, arsenic concentrations in drinking water have been reported as high as , µg/L (Nicaragua), while groundwater levels exceeded , µg/L (Thailand), and wastewater contained up to , µg/L (landfill leachate in Brazil). Furthermore, bioaccumulation of arsenic (µg/g) in fish species ranges from. (catfish in the Paraná River Delta, Brazil) to (Pteromylaeus bovinus, Northern Adriatic Sea). Recent research has predominantly focused on removing arsenic from aqueous solutions through adsorption methods. Notably, nanoparticle adsorbents and graphene-based adsorbents demonstrate a high capacity for arsenic removal from water bodies.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, ... more Per- and polyfluoroalkyl substances (PFAS), one of the main categories of emerging contaminants, are a family of fluorinated organic compounds of anthropogenic origin. PFAS can endanger the environment and human health because of their wide application in industries, long-term persistence, unique properties, and bioaccumulation potential. This study sought to explain the accumulation of different PFAS in water bodies. In aquatic environments, PFAS concentrations range extensively from <0.03 (groundwater; Melbourne, Australia) to 51,000 ng/L (Groundwater, Sweden). Additionally, bioaccumulation of PFAS in fish and water biota has been stated to range from 0.2 (Burbot, Lake Vättern, Sweden) to 13,900 ng/g (Bluegill samples, U.S.). Recently, studies have focused on PFAS removal from aqueous solutions; one promising technique is advanced oxidation processes (AOPs), including microwaves, ultrasound, ozonation, photocatalysis, UV, electrochemical oxidation, the Fenton process, and hydrogen peroxide-based and sulfate radical-based systems. The removal efficiency of PFAS ranges from 3% (for MW) to 100% for UV/sulfate radical as a hybrid reactor. Therefore, a hybrid reactor can be used to efficiently degrade and remove PFAS. Developing novel, efficient, cost-effective, and sustainable AOPs for PFAS degradation in water treatment systems is a critical area of research.
The presence of dyes in aquatic environments can have harmful effects on aquatic life, including ... more The presence of dyes in aquatic environments can have harmful effects on aquatic life, including inhibiting photosynthesis, decreasing dissolved oxygen levels, and altering the behavior and reproductive patterns of aquatic organisms. In the initial phase of this review study, our aim was to examine the categories and properties of dyes as well as the impact of their toxicity on aquatic environments. Azo, phthalocyanine, and xanthene are among the most frequently utilized dyes, almost 70–80% of used dyes, in industrial processes and have been identified as some of the most commonly occurring dyes in water bodies. Apart from that, the toxicity effects of dyes on aquatic ecosystems were discussed. Toxicity testing relies heavily on two key measures: the LC50 (half-lethal concentration) and EC50 (half-maximal effective concentration). In a recent study, microalgae exposed to Congo Red displayed a minimum EC50 of 4.8 mg/L, while fish exposed to Disperse Yellow 7 exhibited a minimum LC50 of 0.01 mg/L. Anaerobic membrane bioreactors (AnMBRs) are a promising method for removing dyes from water bodies. In the second stage of the study, the effectiveness of different AnMBRs in removing dyes was evaluated. Hybrid AnMBRs and AnMBRs with innovative designs have shown the capacity to eliminate dyes completely, reaching up to 100%. Proteobacteria, Firmicutes, and Bacteroidetes were found to be the dominant bacterial phyla in AnMBRs applied for dye treatment. However, fouling has been identified as a significant drawback of AnMBRs, and innovative designs and techniques are required to address this issue in the future.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
The potential of microalgal photobioreactors in removing total ammonia nitrogen (TAN), chemical o... more The potential of microalgal photobioreactors in removing total ammonia nitrogen (TAN), chemical oxygen demand (COD), caffeine (CAF), and N,N-diethyl-m-toluamide (DEET) from synthetic wastewater was studied. Chlorella vulgaris achieved maximum removal of 62.2% TAN, 52.8% COD, 62.7% CAF, and 51.8% DEET. By mixing C. vulgaris with activated sludge, the photobioreactor showed better performance, removing 82.3% TAN, 67.7% COD, 85.7% CAF, and 73.3% DEET. Proteobacteria, Bacteroidetes, and Chloroflexi were identified as the dominant phyla in the activated sludge. The processes were then optimized by the artificial neural network (ANN). High R2 values (>0.99) and low mean squared errors demonstrated that ANN could optimize the reactors’ performance. The toxicity testing showed that high concentrations of contaminants (>10 mg/L) and long contact time (>48 h) reduced the chlorophyll and protein contents in microalgae. Overall, a green technology for wastewater treatment using microalgae and bacteria consortium has demonstrated its high potentials in sustainable management of water resources.
International Journal of Scientific Research in Knowledge, 2013
Sequencing batch reactor (SBR) process uses for treatment of different types of wastewaters such ... more Sequencing batch reactor (SBR) process uses for treatment of different types of wastewaters such as municipal wastewater, landfill leachate, dairy wastewater, slaughterhouse wastewater etc. Operation parameters of SBR technique are cycle time, aeration rate, volume of reactor, hydraulic retention time (HRT) and other parameters. In this work, operational parameters and removal efficiencies of pollutants for SBR method were studied. In addition, boundaries for operational parameters in SBR process were explained as well.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Recently, national and international effluent standards have become more stringent, posing a sign... more Recently, national and international effluent standards have become more stringent, posing a significant challenge in the water treatment industry. Accordingly, treatment techniques with minimal energy consumption and maximal performance are urgently required for wastewater and water treatments. This topic was investigated from both technical and environmental perspectives to improve water and wastewater treatment techniques and enhance the quality of water bodies. This Special Issue (SI) has attracted investigations by researchers worldwide, including those from Australia,
The consumption of pharmaceuticals and personal care products (PPCPs) has been widely increasing,... more The consumption of pharmaceuticals and personal care products (PPCPs) has been widely increasing, yet up to 90–95% of PPCPs consumed by human are excreted unmetabolized. Moreover, the most of PPCPs cannot be fully removed by wastewater treatment plants (WWTPs), which release PPCPs to natural water bodies, affecting aquatic ecosystems and potentially humans. This study sought to review the occurrence of PPCPs in natural water bodies globally, and assess the effects of important factors on the fluxes of pollutants into receiving waterways. The highest ibuprofen concentration (3738 ng/L) in tap water was reported in Nigeria, and the highest naproxen concentration (37,700 ng/L) was reported in groundwater wells in Penn State, USA. Moreover, the PPCPs have affected aquatic organisms such as fish. For instance, up to 24.4 × 103 ng/g of atenolol was detected in P. lineatus. Amongst different technologies to eliminate PPCPs, algae-based systems are environmentally friendly and effective because of the photosynthetic ability of algae to absorb CO2 and their flexibility to grow in different wastewater. Up to 99% of triclosan and less than 10% of trimethoprim were removed by Nannochloris sp., green algae. Moreover, variable concentrations of PPCPs might adversely affect the growth and production of algae. The exposure of algae to high concentrations of PPCPs can reduce the content of chlorophyll and protein due to producing reactive oxygen species (ROS), and affecting expression of some genes in chlorophyll (rbcL, psbA, psaB and psbc).
Journal of Environmental Chemical Engineering, 2021
Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biologi... more Anaerobic ammonia oxidation (anammox) is an environmentally friendly, cost-effective, and biological method for nitrogen treatment from aqueous solutions. However, slow growth rate, negative effects of high concentration of nitrite, ammonia and other pollutants (such as metals) on anammox activity are the main drawbacks of using anammox. Thus, in this study, anammox was attached on chitosan to improve anam- mox performance. Two reactors comprising chitosan and anammox bacteria (first reactor, chitosan/anam- mox) and solely anammox (second reactor, control) were run for 73 d. The nitrogen loading rate (NLR) var- ied from 2 to 14 gN/(L d), while the nitrogen concentration varied from 80 to 700 mg/L. The chitosan/ anammox reactor showed a better performance than the sole anammox (control), with respective maxi- mum abatement values of ammonia (NH4+), nitrite (NO2-), and total nitrogen (TN) of 90.8%, 83.5%, and 81.7% on days 20–25 under a NLR of 8–10 kgTN/(m3 d). Response surface methodology (RSM) was em- ployed to optimize the performance of both reactors, and a reasonable R2 value showed that the RSM well optimized the performance of the reactors. After Xnding the optimum performance conditions for both re- actors, Fe and Cu (0.5–7.0 mg/L) were added to the inYuent to monitor the effects of metals on the perfor- mance of both reactors. The performance of both reactors decreased to 0% following the addition of 7.0 (first reactor) and 6.5 (second reactor) mg/L Cu and Fe, respectively. This indicated that chitosan not only enhanced nitrogen removal by anammox but also improved the resistance of anammox to metals.
Landfill leachate is characterised by high chemical and biological oxygen demand and generally co... more Landfill leachate is characterised by high chemical and biological oxygen demand and generally consists of undesirable substances such as organic and inorganic contaminants. Landfill leachate may differ depending on the content and age of landfill contents, the degradation procedure, climate and hydrological conditions. We aimed to explain the characteristics of landfill leachate and define the practicality of using different techniques for treating landfill leachate. Different treatments comprising biological methods (e.g. bioreactors, bioremediation and phytoremediation) and physicochemical approaches (e.g. advanced oxidation processes, adsorption, coagulation/ flocculation and membrane filtration) were investigated in this study. Membrane bioreactors and integrated biological techniques, including integrated anaerobic ammonium oxidation and nitrification/denitrification processes, have demonstrated high performance in ammonia and nitrogen elimination, with a removal effectiveness of more than 90%. Moreover, improved elimination efficiency for suspended solids and turbidity has been achieved by coagulation/ flocculation techniques. In addition, improved elimination of metals can be attained by combining different treatment techniques, with a removal effectiveness of 40-100%. Furthermore, combined treatment techniques for treating landfill leachate, owing to its high chemical oxygen demand and concentrations of ammonia and low biodegradability, have been reported with good performance. However, further study is necessary to enhance treatment methods to achieve maximum removal efficiency.
International Journal of Environmental Research and Public Health, 2021
Antibiotics are frequently applied to treat bacterial infections in humans and animals. However, ... more Antibiotics are frequently applied to treat bacterial infections in humans and animals. However, most consumed antibiotics are excreted into wastewater as metabolites or in their original form. Therefore, removal of antibiotics from aquatic environments is of high research interest. In this study, we investigated the removal of sulfamethoxazole (SMX) and ofloxacin (OFX) with Chae-toceros muelleri, a marine diatom. The optimization process was conducted using response surface methodology (RSM) with two independent parameters, i.e., the initial concentration of antibiotics and contact time. The optimum removal of SMX and OFX were 39.8% (0.19 mg L −1) and 42.5% (0.21 mg L −1) at the initial concentration (0.5 mg L −1) and contact time (6.3 days). Apart from that, the toxicity effect of antibiotics on the diatom was monitored in different SMX and OFX concentrations (0 to 50 mg L −1). The protein (mg L −1) and carotenoid (µg L −1) content increased when the antibiotic concentration increased up to 20 mg L −1 , while cell viability was not significantly affected up to 20 mg L −1 of antibiotic concentration. Protein content, carotenoid, and cell viability decreased during high antibiotic concentrations (more than 20 to 30 mg L −1). This study revealed that the use of Chae-toceros muelleri is an appealing solution to remove certain antibiotics from wastewater.
Using microalgae to remove pharmaceuticals and personal care products (PPCPs) mi-cropollutants (M... more Using microalgae to remove pharmaceuticals and personal care products (PPCPs) mi-cropollutants (MPs) has attracted considerable interest. However, high concentrations of persistent PPCPs can reduce the performance of microalgae in remediating PPCPs. Three persistent PPCPs, namely, carbamazepine (CBZ), sulfamethazine (SMT) and tramadol (TRA), were treated with a combination of Chaetoceros muelleri and biochar in a photobioreactor during this study. Two reactors were run. The first reactor comprised Chaetoceros muelleri, as the control, and the second reactor comprised Chaetoceros muelleri and biochar. The second reactor showed a better performance in removing PPCPs. Through the response surface methodology, 68.9% (0.330 mg L −1) of CBZ, 64.8% (0.311 mg L −1) of SMT and 69.3% (0.332 mg L −1) of TRA were removed at the initial concentrations of MPs (0.48 mg L −1) and contact time of 8.1 days. An artificial neural network was used in optimis-ing elimination efficiency for each MP. The rational mean squared errors and high R 2 values showed that the removal of PPCPs was optimised. Moreover, the effects of PPCPs concentration (0-100 mg L −1) on Chaetoceros muelleri were studied. Low PPCP concentrations (<40 mg L −1) increased the amounts of chlorophyll and proteins in the microalgae. However, cell viability, chlorophyll and protein contents dramatically decreased with increasing PPCPs concentrations (>40 mg L −1).
Occurrence of pharmaceutical micropollutants in aquatic environments has been one amongst serious... more Occurrence of pharmaceutical micropollutants in aquatic environments has been one amongst serious environmental problems. During this study, two reactors, including a sequencing batch reactor (SBR) + powdered composite adsorbent (CA) (first reactor, SBR + CA) and a sequencing batch reactor (second reactor, SBR), were designed to treat synthetic wastewater. Powdered CA was added with a dosage of 4.8 g L−1 to the first reactor. Tap water was contaminated with chemical oxygen demand (COD), ammonia and three pharmaceuticals, namely, atenolol (ATN), ciprofloxacin (CIP) and diazepam (DIA) to produce synthetic wastewater. The SBR + CA illustrated a better performance during synthetic municipal wastewater treatment. Up to 138.6 mg L−1 (92.4%) of COD and up to 114.2 mg L−1 (95.2%) of ammonia were removed by the first reactor. Moreover, optimisation of pharmaceuticals removal was conducted through response surface methodology (RSM) and artificial neural network (ANN). Based on the RSM, the best elimination of ATN (90.2%, 2.26 mg L−1), CIP (94.0%, 2.35 mg L−1) and DIA (95.5%, 2.39 mg L−1) was detected at the optimum initial concentration of MPs (2.51 mg L−1) and the contact time (15.8 h). In addition, ANN represented a high R2 value (>0.99) and a rational mean squared error (<1.0) during the optimisation of micropollutants removal by both reactors. Moreover, adsorption isotherm study showed that the Freundlich isotherm could justify the abatement of micropollutants by using CA better than the Langmuir isotherm.
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