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Healthcare facility wastewater considerably increases the levels of micropollutants in municipal wastewater. Considering this, the presence of contaminants of emerging concern in the environment has been highlighted as a global environmental problem. Electrochemical advanced oxidation (EAO) generate strong oxidants such as HO•, H2O2, and O3–which can remove organic pollutants in water including pharmaceutical. This review presents the latest research findings concerning the mechanisms, influencing factors, and innovative approaches for treating wastewater generated by healthcare institutions. Electrochemical oxidation has proven a promising wastewater treatment technology, especially, for pharmaceutical-contaminated wastewater. EAO is widely regarded as a pioneering technique in the field of wastewater treatment because of its strong performance in the mineralization treatment for pharmaceuticals as well as the detoxification treatment of extremely biologically harmful organics. The use of EAO technology is of utmost importance in augmenting the efficiency of electrochemical systems in the decomposition of organic substances. Furthermore, it lays the groundwork for implementing these systems to treat wastewater derived from medical facilities and hospitals. Nevertheless, it is noteworthy that most experimental studies have focused on single-component wastewater that has been artificially prepared in laboratory settings. Wastewater from healthcare institutions often exhibits a complex and diverse composition, influenced by various factors.

In this study, four coagulants were used to investigate their performances for the treatment of raw landfill leachate. Two inorganic coagulants, namely, ferric sulfate, Fe2(SO4)3and zinc sulfate, ZnSO4were compared to two types of palm date seeds, that is, khlas and sukkari as natural coagulants. Type of coagulant, dosage, pH and rapid mixing speed were designated as input variables, that is, operating conditions. In order to determine and compare the leachate treatment performances of the four coagulants, four responses were selected for this research, namely, chemical oxygen demand (COD), color, ammoniacal nitrogen (NH3–N) or simply ammonia and total suspended solids (TSS). A response surface model (RSM) was developed for each selected response to find the optimum operating conditions for the input variable and for each coagulant that result in maximum removals. 72 experiments under different operating conditions were performed of which 18 runs were conducted for each type of coagulant wherein 100 mL of raw landfill leachate was the sample volume used for each run. The optimum operating conditions were found in the models and experimentally validated. The optimum dosage of ferric sulfate, zinc sulfate and khlas was found to be 6 mL. However, a lower dosage of 4.32 mL was found to be the optimum for sukkari. The optimal pH for ferric sulfate and sukkari was 5, whilst a pH of 9 was obtained for khlas and zinc sulfate. Finally, the optimum rapid mixing speeds for khlas and sukkari were rounded off to 195 and 200 rpm, respectively. Meanwhile, higher optimal rapid mixing speeds of 240 and 250 rpm were rounded out for ferric sulfate and zinc sulfate, correspondingly. Hence, the optimal reductions of COD, color, ammonia and TSS by (ferric sulfate–zinc sulfate) were rounded off to 55%–53%, 89%–73%, 15%–17% and 91%–89%, respectively. On the other hand, the optimum removals obtained by the natural coagulants (khlas–sukkari) were as the following: 12%–15% COD, 53%–56% color, 12%–14% ammonia and 78%–67% TSS. As regards the maximum removals of COD, color, ammonia and TSS by (ferric sulfate–zinc sulfate), they were found and rounded off to 60%–60%, 89%–84%, 18%–21% and 95%–96%, respectively. Contrariwise, the maximum reductions obtained by the natural coagulants (khlas–sukkari) were as the following: 16%–24% COD, 70%–74% color, 17%–17% ammonia and 91%–82% TSS. Thereupon, the natural coagulants showed effective removals, notably in terms of color, ammonia and TSS that could adequately replace the inorganic coagulants. A big margin of improvement in the removal of COD and other pollutants by khlas and sukkari could possibly be achieved in the upcoming studies by extensively investigating the preparation techniques of the natural coagulants.

This study examines the use of date stone powder-based plant natural coagulant in the treatment of iron and steel industrial effluent. Coagulation process was conducted using different dosage from date stone powdered (0.2–10 g/L) and different pH values (5–10) using orbital shaker at 200 rpm. The treatment efficiency was evaluated by examine the removal for chemical oxygen demand (COD), total suspended solids (TSS), ammonia-nitrogen (NH3–N), manganese (Mn), iron (Fe), zinc (Zn), aluminum (Al), and nickel (Ni). The maximal removal for COD, TSS, NH3–N, Mn, Fe, Zn, Al, and Ni were 59.4%, 99%, 92.1%, 87.1%, 97.7%, 94.8%, 65.8%, and 80.3%, respectively. Date stone powder has enormous promise as a plant-based natural coagulant for industrial effluent wastewater treatment and might be used to treat effluent from the iron and steel industries.

Various chemical coagulants have previously been used for wastewater treatment with substantial efficacy in eliminating heavy metals and other criteria. However, their economic effectiveness and the remnant of harmful chemical precipitates that pose hazards to human health and the environment. As a result, utilizing plant-based natural coagulants is seen as an alternative non-toxic, biodegradable, and ecologically beneficial strategy. This study aims to investigate the performance of pinecone seed powder as a natural coagulant in iron and steel factory wastewater treatment, as well as to optimize the operating parameters to determine the feasibility of employing pinecone seed powder in wastewater treatment. Using 0.6 g/200 mL pinecone as a controlling factor, pH, and settling time, the response surface methodology, a statistical experimental design was utilized to increase the chemical oxygen demand (COD), ammoniacal nitrogen (NH3–N), and heavy metals removal efficiency. COD, NH3–N, Fe, Mn, Ai, Cu, and Ni removal efficiencies at pH 8 were 76%, 44%, 88%, 93%, 87%, 50%, and 92%, respectively. Except for Fe (0.0170), Mn (0.0021), and Cu (0.001), the quadratic models for the parameters specified were determined to be significant with a low probability.

Solar energy has recently become a viable option for desalinating seawater, primarily in arid regions. However, increasing the productivity of solar still by integrating experimental base and modelling methods is still subject to prediction errors; therefore, the main objective of this research is to postulate and test boosting algorithms for predicting the efficiency and productivity of the system. Five boosting regressors were deployed and evaluated: categorical boosting, adaptive boosting, extreme gradient boosting, gradient boosting machine, and gradient boosting machine (LightGBM). The proposed regressors are implemented based on the system’s actual recorded dataset (consisting of 720 observations). The dataset consists of input variables, which are the wind speed (V), cloud cover, humidity, ambient temperature (T), solar radiation (SR), (Tio), (Tw), (Tv), and (Tt). Also, the output variable is represented by the productivity of the system. The dataset was separated into training (70%) and testing (30%) sets. In order to decrease regressors errors, hyperparameter optimization was employed. GradientBoosting approach provided the best prediction, with 95% R2accuracy and 39.57 root mean square error (RMSE) error. The LightGBM technique achieved 94% R2accuracy and 40.07 RMSE error in the testing dataset. The results reveal that GradientBoosting outperforms the cascaded forward neural network in predicting system productivity (CFNN).

The use of olive seed powder as a plant-based natural coagulant in treating iron and steel factory wastewater was studied. The concentrations of chemical oxygen demand (COD), total suspended solids (TSS), ammonia-nitrogen (NH3–N), manganese (Mn), iron (Fe), zinc (Zn), aluminum (Al), and nickel (Ni) in effluent wastewater were investigated. Coagulation experiments on the effects of iron and steel factory wastewater, pH, and olive seed powder dosage on coagulation efficacy were conducted using an orbital shaker and a flocculation device. The maximum removal percentages of COD, TSS, NH3–N, Mn, Fe, Zn, Al, and Ni by olive seeds powder were 86.3%, 99%, 72.4%, 80.9%, 91.5%, 92.6%, 73.7%, and 84.3% for effluent at natural pH 8 using a 5 g/L dosage, respectively. The Fourier-transform infrared spectroscopy study showed the presence of several functional groups involved in the coagulation process. It is possible to argue that olive seed powder has enormous potential as a plant-based natural coagulant for wastewater treatment and that it might be used to treat wastewater from iron and steel factories.

Two coagulants (Al2(SO4)3and FeSO4) were investigated for their performance in treating raw and anaerobic effluents from a palm oil mill. The treatment efficiencies for both palm oil mill effluents (POMEs) were assessed based on chemical oxygen demand (COD) removal. Different dosages of Al2(SO4)3and FeSO4were investigated in terms of COD removal in raw and anaerobic effluents under different pH levels. The results show that FeSO4performed better than Al2(SO4)3in removing COD from both effluents. The maximum COD removal efficiency (94%) was achieved when both effluents were treated with 0.4 g of FeSO4at pH 3, while the maximum COD removal achieved by Al2(SO4)3was 70% using 0.4 g at pH 7. Using these optimal operational conditions, the removal of 11 parameters, namely COD, color, total suspended solids (TSS), electrical conductivity, biochemical oxygen demand (BOD), pH, NH3–N, Cu+2, Fe+2, Zn+2, and Pb were measured and assessed. The results were analyzed statistically using factor analysis (FA) and cluster analysis (CA) to identify the main factors responsible for the differences in the parameters and to display the similarity and dissimilarity between the selected parameters among the different POME sources. The FA method produced four factors responsible for more than 99% of the differences in data. The first factor covered COD, color, TSS, and BOD and was responsible for explaining 36% of the differences, whereas the second factor was responsible for explaining 34% of the differences, including NH3–N, Cu+2, Fe+2, and Zn+2. The percentage variance explained by the third and fourth factors was 16% and 14%, respectively. The CA method produced three different groups (clusters). It was found that raw and anaerobic POMEs treated with Al+3and raw POMEs treated with Fe+2were close to each other, representing the second cluster, while the raw treatment represented the first cluster. The last cluster represents the anaerobic effluent before and after coagulation using Fe2SO4. The results reveal that Fe2SO4is an efficient method for removing organic and heavy metal content from POME. The study provides essential data and knowledge that can be used to evaluate and manage POME treatment.

Microplastic is an emerging pollutant causing trouble worldwide due to its extensive distribution and potential hazards to the ecological system. Some fundamental questions about micro-plastics, such as their presence, source, and possible hazards, remain unanswered. These issues develop because of a lack of systematic and comprehensive microplastic analysis. As a result, we thoroughly evaluated current knowledge on microplastics, including detection, characterization, occurrence, source, and potential harm. Microplastics are found in seawater, soil, wetlands, and air matrices worldwide based on findings. Visual classification, which can be enhanced by combining it with additional tools, is one of the most used methods for identifying microplastics. As soon as is practicable, microplastics analytical methods ought to be standardized. New techniques for analyzing nano-plastics are urgently needed in the meantime. Numerous studies have shown that microplastics’ impacts on people and soil are significantly influenced by their size, shape, and surface physicochemical characteristics. Finally, this study suggests areas for future research based on the knowledge gaps in the area of microplastics.

This study aims to investigate the performance plant-based natural coagulant from rosehip seed powder in the treatment of iron and steel factory wastewater. The concentrations of COD, total suspended solids (TSS), ammonia-nitrogen (NH3–N), manganese (Mn), iron (Fe), zinc (Zn), aluminum (Al), and nickel (Ni) in effluent wastewater were examined. Coagulation investigations were carried out using an orbital shaker and a flocculation apparatus to investigate the effects of iron and steel factory effluent, pH, and rosehip seeds powder dosage on coagulation efficacy. The rose-hip powder removes a large amount of COD, TSS, NH3–N, Mn, Fe, Zn, Al, and Ni from effluent at pH 8 with percentages of 86.1%, 99%, 79%, 86%, 91.7%, 90.6%, 73.7%, and 100%, respectively, at 1 g/L. The effects of pH ranges ranging from (5–10) reveal that the wastewater sample’s natural pH (8) demonstrates the maximum practicable removal effectiveness. FTIR analysis revealed the presence of numerous functional groups involved in the coagulation process. One may argue that rosehip seed powder holds great potential as a natural plant-based coagulant for water treatment and could be used to treat effluent from iron and steel factories.

Utilization of pinecone powder as a plant-based natural coagulant for the treatment of iron and steel factory effluent was examined. The concentrations of chemical oxygen demand (COD), total suspended solids (TSS), ammonia-nitrogen (NH3–N), manganese (Mn), iron (Fe), zinc (Zn), aluminum (Al), and nickel (Ni) in effluent wastewater were investigated. Results showed that the maximal removal of COD, TSS, NH3–N, Mn, Fe, Zn, Al, and Ni using pinecone powder were 83.3%, 99%, 83.9%, 86.8%, 93.7%, 89.7%, 73.7%, and 86.7%, respectively for effluent at natural pH 8 using a dosage of 3 g/L. The Fourier-transform infrared spectroscopy result showed the existence of various functional groups involved in the coagulation process. Overall, this study shows that pinecone powder has enormous promise as a natural coagulant for water treatment and it could be utilized to treat effluent from iron and steel plants.

Thermal remediation technologies are fast and effective tools for the remediation of contaminated soils and sediments. Nevertheless, the high energy consumption and the effect of high temperature on the soil properties may hinder the wide applications of thermal remediation methods. This review highlights the recent studies focused on thermal remediation. Eight types of thermal remediation processes are discussed, including incineration, thermal desorption, stream enhanced extraction, electrical resistance heating, microwave heating, smoldering, vitrification, and pyrolysis. In addition, the combination of thermal remediation with other remediation technologies is presented. Finally, thermal remediation sustainability is evaluated in terms of energy efficiency and their impact on soil properties. The developments of the past decade show that thermal-based technologies are quite effective in terms of contaminant removal but that these technologies are associated with high energy use and costs and can has an adverse impact on soil properties. Nonetheless, it is anticipated that continued research on thermally based technologies can increase their sustainability and expand their applications. Low temperature thermal desorption is a promising remediation technology in terms of land use and energy cost as it has no adverse effect on soil function after treatment and low temperature is required. Overall, selecting the sustainable remediation technology depends on the contaminant properties, soil properties and predicted risk level.

In this research, the performances of modified tannin and aluminium sulfate (alum) for stabilized leachate treatment were investigated and compared using coagulant dosage, pH, and rapid mixing speed as the input variables. Four different responses were used to compare the treatment performances; the responses are, chemical oxygen demand (COD), color, ammoniacal nitrogen (NH3–N) and total suspended solids (TSS). The results of the analysis for 36 experiments showed that the optimum operating conditions for 1% modified tannin and 10% alum are a coagulant dosage of 6 mL, a pH of 9 and a rapid mixing speed of 100 rpm. The optimum removal efficiencies of COD, color, NH3–N and TSS using 1% modified tannin were 42.86%, 54.38%, 39.39% and 60.33% respectively, and using 10% alum were 60.71%, 63.09%, 42.42% and 60.33%, respectively. The findings revealed that the effectiveness of modified tannin for the treatment of landfill leachate was significant using a ten-time lower dosage concentration than alum. This study will help better understanding the behaviour of organic and inorganic coagulants for wastewater treatments using the same polynomial model.

Nanoscale zero-valent iron (nZVI) has been extensively investigated for the remediation of soil, wastewater, and groundwater contaminated with heavy metals. This paper presents a collective review of nZVI synthesis, nZVI interaction mechanisms with heavy metals, factors affecting nZVI reactivity, recent applications of nZVI for heavy metals removal, and the environmental concerns of nZVI application for soil microorganisms and plants. Modified nZVI, spatially biochar supported nZVI (BC@nZVI) and sulfidation nanoscale zero-valent iron (S-nZVI) showed high heavy metals removal efficiency and more stable performance compared to nZVI alone. The removal of heavy metals by nZVI is as a synergistic process where adsorption, oxidation/reduction and precipitation occur simultaneously or in series. pH and organic matter are the main factors that significantly affect nZVI reactivity. Toxic effects of nZVI are observed for the soil microorganisms as the direct contact may cause a decrease in cell viability and membrane damage. A low concentration of nZVI promotes the growth of plant whereas high concentration decreases root length. It is observed that, further research is needed to enhance nZVI recovery techniques, evaluate the effectiveness of novel modified nZVI and their effects on the environment, and the full-scale application of nZVI.

Landfill remains as the most common municipal waste disposal method in the world. However, the production of leachate associate with landfill persists as a major drawback, which bring harmful effect to the environment. Persulfate oxidation is recently used for stabilized leachate treatment. Persulfate alone is still limited for leachate oxidation and an activation method is required to improve its performance. Accordingly, this study aims to investigate and compare the performance of persulfate subjected to thermal activation in treating stabilized leachate. Different experimental operational factors were considered and evaluated such as, S2O82–/chemical oxygen demand (COD) ratio, temperature, and reaction time. Experiments were designed and optimized by using response surface methodology, and results were analysed by using analysis of variance. The removal efficiencies for COD and colour using inactivation persulfate were reported only at 14% and 29%, respectively. However, the efficiencies were improved to 93.39% and 94.00% for COD and colour after thermal activation of persulfate under an optimum condition of 10 S2O82–/COD ratio, 80°C and 120 min. The maximum efficiency was achieved at the treatment cost of RM0.66 per litre of leachate.

This review delves into the significant potential of Advanced Oxidation Processes (AOPs) for tackling the intricate issues found in treating petroleum wastewater. It particularly focuses on the utilization of processes like Fenton reactions, Ozonation-based AOPs, and photocatalytic techniques, highlighting their role in producing powerful reactive oxygen species capable of breaking down organic contaminants. The review also discusses recent advancements in merging Electro-Fenton and photocatalysis to enhance pollutant removal efficiency. Furthermore, it investigates how these methods are being applied specifically to petrochemical wastewater management, including innovative approaches like Fenton, Photo- Fenton, Electro-Fenton, Photo-catalytic oxidation, persulfate activation based AOPs. Operational cost including treatment time, energy requirements, pH adjustment, complexity of reactor setup, removal efficiencies and treated effluent quality, and by-products are some of the challenges critically examined. The article aims to highlight these issues and identify emerging challenges, proposing a shift towards more sustainable and effective wastewater treatment strategies in the future.

In this study, selected physicochemical and heavy metal concentrations were identified and analyzed in leachate samples. The leachate samples were collected at four different stages namely; raw equalization pond (EqP), dissolved air floatation combined with coagulation (DAF1/coagulation), sequencing batch reactor (SBR), and dissolved air floatation combined with coagulation (DAF2/coagulation). For each stage, 19 parameters were tested covering 12 physiochemical parameters including pH, dissolved oxygen (DO), biochemical oxygen demand (BOD5), chemical oxygen demand (COD), color, ammonical nitrogen (NH3–N), total suspended solids (TSS), total dissolved solids (TDS), electrical conductivity (EC), total concentrations of sodium (Na), magnesium (Mg), and calcium (Ca) as well as the total concentrations of seven heavy metals involving iron (Fe), copper (Cu), cadmium (Cd), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn). Identifying the characteristics of the four leachate samples from each stage was aided with three different statistical methods consisting of descriptive, factor, and cluster analyses. The results of factor analysis showed that 95.34% of the total variation in the selected parameters was explained by two factors and identified as the responsible factors. Cluster analysis exhibited that the four ponds entirely have different properties (EqP, DAF1, SBR, and DAF2). This study helps to evaluate and comprehend the behavior of the designated parameters and better understand their relationships with one another for more efficient, practical, and productive landfill leachate treatment and management.

High levels of heavy metals in industrial wastewater pose a significant environmental concern due to their toxicity to living organisms and ecosystems. Traditional techniques that use chemical coagulants to eliminate heavy metals from industrial wastewater have proven effective. However, the use of chemical coagulants produces sludge that is highly toxic and requires careful management. On the other hand, natural coagulants offer a cost-effective and sustainable alternative that is safer to handle, locally available, and potentially useful for resource recovery. These benefits make natural coagulants a promising substitute for chemical coagulants. This study aimed to investigate the performance of combining Date stone powder (DSP) and aluminum chloride (AlCl3), to remove heavy metals from industrial wastewater efficiently. Through an optimization process of DSP/AlCl3dosage and pH, the study sought to determine the optimal conditions for heavy metal removal. The main findings indicate that a DSP/AlCl3dosage of 7:1 (g/g) was the most effective coagulant dosage, resulting in high removal efficiencies for COD (88.56%), color (89.56%), TSS (99.00%), NH3-N (92.50%), Mn (94.10%), Fe (95.47%), Zn (93.57%), Al (88.42%), and Ni (93.3%) at pH 8. Interestingly, the results of pH optimization showed that no pH modification was necessary, as it already achieved high removal efficiencies for COD (84.57%), color (88.94%), TSS (99.00%), NH3-N (92.25%), Mn (92.66%), Fe (90.57%), Zn (95.59%), Al (99.00%), and Ni (93.33%). This study demonstrates that the hybrid DSP/AlCl3coagulation method can be an effective and sustainable solution for removing heavy metals from industrial wastewater. However, further research is necessary to assess its scalability and potential limitations.

Nowadays, fresh drinking water has become increasingly scarce, especially in arid and semi-arid areas. Usually, the water found in these areas is seawater or brackish water and contains harmful contaminants, which directly affect human health, and therefore cannot be used for drinking purposes. Since arid and semi-arid areas are blessed with abundant solar radiation, small solar still units can be used to desalinate seawater and produce cheap drinking water. In this study, the capacity of an inclined copper-stepped solar still to produce fresh drinking water from seawater using solar energy was experimentally tested. This study aims to evaluate the distilled water quality produced by the solar desalination system. The system effectively eliminated all physicochemical parameters such as total suspended solids (TSS), pH, total dissolved solids (TDS), turbidity, salinity, conductivity, and atomic elements (Ca2+, Cl−, Mg2+, Na+, SO42−, and K+). Biological analyses were also conducted in this study including the analysis of ammoniacal nitrogen (NH3–N), biological oxygen demand (BOD), and chemical oxygen demand (COD). Each parameter was found to have values that are within the safe limits set by the Malaysian NDWQS and WHO.

Paracetamol has been remarked as one of the most heavily used and prescribed drugs nowadays. The presence of paracetamol in the sewage effluent with the average concentration of 0.01 mg/L has been reported in this paper. This study investigated the removal of paracetamol from synthetic pharmaceutical wastewater using titanium dioxide (TiO2) photocatalysis treatment method under natural solar irradiation. Compound parabolic collecting reactor was used as a treatment medium. The effect of each variable (pH, concentration of TiO2and initial concentration of paracetamol) on the photocatalytic degradation efficiency of paracetamol was investigated by using the single-variable-at-a-time method. Central composite design based on the response surface methodology was used to optimize TiO2and paracetamol concentrations. Experimental results and analysis of variance analysis showed that the model was significant with the high coefficient of determination (R2) of 0.9883. The optimum conditions of 1.0 g/L of TiO2concentration and 0.06 g/L of paracetamol initial concentration were predicted for the maximum removal efficiency of 88%. Finally, the performance of UV lamp and natural sunlight in the photocatalytic degradation of paracetamol was compared and discussed in detail. The in situ experimental results in this study have proven the reliability of the solar operation on the photocatalysis treatment process.

AbstractIn this work, factorial design analysis based on central composite design of experiments was employed to study the effect of process parameters for biosorption of Reactive Red-84 dye onto bioethanol fermentation spent waste biomass of Saccharomyces cerevisiae. Factorial experiments with five factors: mixing rate rpm, incubation period h, process temperature °C, initial dye concentration mg/L and biosorbent dosage wt% (w/v) at three levels were conducted. A highly statistically significant quadratic model at 95% confidence level (p < 0.0001, R20.9120 and 0.8519) was developed to charcterize the influence of the different considered variables on biosorption efficiency. Response surface methodology was employed to optimize the process, recording maximum biosorption % of ≈62% (51.67 mg/g) at 90 rpm, 13 h, 15°C, 100 mg/L and 0.6%, respectively. Approximately 95% of adsorbed dye was desorbed by elution with NaOH solution of pH 9 and the regenerated biosorbent was employed for four successive cycles. TiO2nanoparticles 6–15 nm were prepared and used for photo-catalytic degradation of desorbed dye solution. The proposed integrating biosorption and photo-catalytic degradation process results in no secondary pollution in the form of any concentrated wastes, which is an important environmental aspect.

In this work, factorial design analysis based on central composite design of experiments was employed to study the effect of process parameters for biosorption of Reactive Red-84 dye onto bioethanol fermentation spent waste biomass of Saccharomyces cerevisiae. Factorial experiments with five factors: mixing rate rpm, incubation period h, process temperature °C, initial dye concentration mg/L and biosorbent dosage wt% (w/v) at three levels were conducted. A highly statistically significant quadratic model at 95% confidence level (p < 0.0001, R20.9120 and Radj20.8519) was developed to charcterize the influence of the different considered variables on biosorption efficiency. Response surface methodology was employed to optimize the process, recording maximum biosorption % of ≈62% (51.67 mg/g) at 90 rpm, 13 h, 15°C, 100 mg/L and 0.6%, respectively. Approximately 95% of adsorbed dye was desorbed by elution with NaOH solution of pH 9 and the regenerated biosorbent was employed for four successive cycles. TiO2nanoparticles 6–15 nm were prepared and used for photo-catalytic degradation of desorbed dye solution. The proposed integrating biosorption and photo-catalytic degradation process results in no secondary pollution in the form of any concentrated wastes, which is an important environmental aspect.

The Gaza Strip suffers from complicated problems of water resources. Groundwater (GW) aquifer is the main source of water for drinking, industry, and agriculture purposes in this area. However, the quality of GW is unsuitable for drinking and other purposes. Wastewater is an environmental, social, and economic resource that needs to be managed appropriately. The treated effluent quality does not satisfy the guidelines for discharge and reuse options because of the overload of wastewater treatment plants. This study evaluated the public response toward water resource management and reuse. A study population with 300 hundred questionnaire interviews was prepared and collected. Only 7.3% of the interviewed people used municipal water for drinking, and the others used desalinated water and home filter units. Approximately 96% believed that water in the Gaza Strip is unsuitable for drinking. Meanwhile, 85% agreed for an additional increase in municipal water bill in exchange for good quality of water that is suitable for drinking and other purposes. The study also reported that 63% of the interviewed people disagreed to reuse the current treated wastewater for agriculture and 82.3% disagreed to consume agriculture products irrigated by the treated wastewater.

Some unfortunate accidents of large amount of oil hydrocarbons have been reported in Mediterranean Sea which has caused severe environmental damage to the area. To safeguard the Libyan coastline and marine ecologysince thousands of human activity such as fishing largely depends on the healthycoastal environment.Twenty crude oil-degrading bacterial isolates were obtained from oil-contaminated sites at Al Hariga Oil Terminal and Nafoora Oilfield. Based on a high growth rate in crude oil and hydrocarbon degradation efficiency, two isolates were selected from the twenty isolates for further analysis. The nucleotide sequence of 16S rRNA gene showed that these isolates are likely Pseudomonas aeruginosa andKocuriapastrius. One of the isolates is a potential Gram-negative Pseudomonas bacterium based on petroleum hydrocarbon degradation efficiency and potent emulsifying activity; thus, this isolate is identified as P. aeruginosa NAF1; the other isolate K. pastrius SAR3 is identified as a Gram-positive bacterium. Corn steep liquor (CSL) and solid waste date (SWD) were used for an in situ molasses technique to enhance bacterial growth and biodegradation efficiency. P. aeruginosa NAF1 exhibited 70% and 76% crude oil degradation in 0.2% (w/v) CSL and SWD in 28 d, respectively. Likewise, K. pastrius SAR3 yielded 68% and 70% crude oil degradation in 0.2% (w/v) CSL and SWD in 28 d, respectively.

Landfill leachate generation is one of the main problems from sanitary landfill. Chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), and color are among the most problematic parameters in stabilized leachate. In this regard, dedicated treatment facilities are required before leachate can be discharged into the environment. The performance of the combined ozonation (O3) and zirconium tetrachloride (ZrCl4) to treat two types of stabilized leachate was investigated during this study. Leachate samples were collected from an anaerobic stabilized leachate (Alor Pongsu Landfill Site, APLS) and semi-aerobic stabilized leachate (Pulau Burung Landfill Site, PBLS). Zirconium tetrachloride dosage was determined as 1 g/1 g (COD/ZrCl4 ratio) and then added to the leachate samples with 60 min ozonation at natural leachate pH (8). COD, color, and NH3-N were removed from the APLS sample at 33%, 70%, and 53% rates, respectively, whereas 48%, 75%, and 69%, respectively, from the PBLS samples. Ozone consumption was also calculated with the highest value (3.81 Kg O3/ Kg COD) reported in PBLS, whereas the lowest value (2.32 Kg O3/ Kg COD) was reported in APLS. Biodegradability of (BOD5/COD) was investigated and improved from 0.07 to 0.08 for the APLS samples and 0.05 to 0.11 for the PBLS samples after leachate oxidation. Results showed that the performance of O3/ZrCl4 oxidation is more efficient in treating semi-aerobic stabilized leachate than anaerobic stabilized leachate Moreover, the combined method proved to be more efficient in remediating leachate compared with ozone and zirconium treatment alone.

Among numerous techniques, electro-oxidation occupies a noticeable place in landfill leachate treatment. In recent years, electro-oxidation processes have been shown to be effective alternative for the removal of refractory organic compounds from stabilized landfill leachate. This paper aims to provide an overview about the effectiveness and mechanism of electro-oxidation processes employed for stabilized landfill leachate treatment. A review of the recent literature published on the electro-oxidation processes (i.e. electrochemical, electro-Fenton, photoelectro-Fenton, photoelectrochemical, and electrochemical peroxidation) performance and efficiency in stabilized leachate treatment are summarized and presented in this study. This study concluded that, although the high treatment cost caused by the energy consumption may limit electro-oxidation techniques, electro-oxidation processes are still a promising and effectual technology for the reduction of pollutants in stabilized landfill leachate.