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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. [ABSTRACT FROM AUTHOR]

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 )3 and zinc sulfate, ZnSO4 were 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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% R2 accuracy and 39.57 root mean square error (RMSE) error. The LightGBM technique achieved 94% R2 accuracy 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). [ABSTRACT FROM AUTHOR]

Microplastic is an emerging pollutant causing trouble worldwide due to its extensive distribution and potential hazards to the ecological system. Some fundamental questions about microplastics, 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. [ABSTRACT FROM AUTHOR]

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 rosehip 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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, S2 O8 2–/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 S2 O8 2–/COD ratio, 80°C and 120 min. The maximum efficiency was achieved at the treatment cost of RM0.66 per litre of leachate. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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+, SO4 2−, 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. [ABSTRACT FROM AUTHOR]

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 ofSaccharomyces 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 and0.8519) 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. [ABSTRACT FROM PUBLISHER]

The current study investigated the effects of S 2 O 8 2− and S 2 O 8 2− /H 2 O 2 oxidation processes on the biodegradable characteristics of an anaerobic stabilized leachate. Total COD removal efficiency was found to be 46% after S 2 O 8 2− oxidation (using 4.2 g S 2 O 8 2− /1 g COD 0 , at pH 7, for 60 min reaction time and at 350 rpm shaking speed), and improved to 81% following S 2 O 8 2− /H 2 O 2 oxidation process (using 5.88 g S 2 O 8 2− dosage, 8.63 g H 2 O 2 dosage, at pH 11 and for 120 min reaction time at 350 rpm). Biodegradability in terms of BOD 5 /COD ratio of the leachate enhanced from 0.09 to 0.1 and to 0.17 following S 2 O 8 2− and S 2 O 8 2− /H 2 O 2 oxidation processes, respectively. The fractions of COD were determined before and after each oxidation processes (S 2 O 8 2− and S 2 O 8 2− /H 2 O 2 ). The fraction of biodegradable COD (bi) increased from 36% in raw leachate to 57% and 68% after applying S 2 O 8 2− and S 2 O 8 2− /H 2 O 2 oxidation, respectively. As for soluble COD ( s ) , its removal efficiency was 39% and 78% following S 2 O 8 2− and S 2 O 8 2− /H 2 O 2 oxidation, respectively. The maximum removal for particulate COD was 94% and was obtained after 120 min of S 2 O 8 2− /H 2 O 2 oxidation. As a conclusion, S 2 O 8 2− /H 2 O 2 oxidation could be an efficient method for improving the biodegradability of anaerobic stabilized leachate. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to investigate the performance of employing persulfate reagent in the advanced oxidation of ozone to treat stabilized landfill leachate in an ozone reactor. A central composite design (CCD) with response surface methodology (RSM) was applied to evaluate the relationships between operating variables, such as ozone and persulfate dosages, pH, and reaction time, to identify the optimum operating conditions. Quadratic models for the following four responses proved to be significant with very low probabilities (<0.0001): COD, color, NH3–N, and ozone consumption (OC). The obtained optimum conditions included a reaction time of 210min, 30g/m3 ozone, 1g/1g ratio, and pH 10. The experimental results were corresponded well with predicted models (COD, color, and NH3–N removal rates of 72%, 96%, and 76%, respectively, and 0.60 (kg O3/kg COD OC). The results obtained in the stabilized leachate treatment were compared with those from other treatment processes, such as ozone only and persulfate only, to evaluate its effectiveness. The combined method (i.e., ) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. Furthermore, the new method is more efficient than ozone/Fenton in advanced oxidation process in the treatment of the same studied leachate. [Copyright &y& Elsevier]

Abstract: Ozonation, combined with the Fenton process (O3/H2O2/Fe2+), was used to treat matured landfill leachate. The effectiveness of the Fenton molar ratio, Fenton concentration, pH variance, and reaction time were evaluated under optimum operational conditions. The optimum removal values of chemical oxygen demand (COD), color, and NH3–N were found to be 65%, 98%, and 12%, respectively, for 90min of ozonation using a Fenton molar ratio of 1 at a Fenton concentration of 0.05molL−1 (1700mg/L) H2O2 and 0.05molL−1 (2800mg/L) Fe2+ at pH 7. The maximum removal of NH3–N was 19% at 150min. The ozone consumption for COD removal was 0.63kg O3/kg COD. To evaluate the effectiveness, the results obtained in the treatment of stabilized leachate were compared with those obtained from other treatment processes, such as ozone alone, Fenton reaction alone, as well as combined Fenton and ozone. The combined method (i.e., O3/H2O2/Fe2+) achieved higher removal efficiencies for COD, color, and NH3–N compared with other studied applications. [Copyright &y& Elsevier]

Objective: To assess the contamination level of total and faecal coliforms in water wells and distribution networks, and their association with human health in Gaza Governorate, Gaza Strip. Methods: Data were obtained from the Palestinian Ministry of Health on contamination of total and faecal coliforms in water wells and distribution networks, and on the incidence of water-related diseases in Gaza Governorate. An interview questionnaire was conducted with 150 residents of Gaza. Results: The contamination level of total and faecal coliforms exceeded that of the World Health Organization (WHO) limit for water wells and networks. However, the contamination percentages in networks were higher than that in wells. Giardiasis was strongly correlated with faecal coliform contamination in water networks (r = 0.7) compared with diarrhoeal diseases and hepatitis A (r = 0.3 and 0.1, respectively). Diarrhoeal diseases were the highest self-reported diseases among interviewees in Gaza city. Such diseases were more prevalent among people using municipal water than people using desalinated water and water filtered at home for drinking (OR = 1.6). Intermittent water supply and sewage flooding seemed to contribute largely to self-reported diseases. People in Gaza Strip have good knowledge on drinking water contamination, and this is reflected in good practice. Conclusions: Water quality has deteriorated in Gaza Strip. This may contribute to the prevalence of water-related diseases. Self-reported diseases among interviewees in Gaza City were associated with source of drinking water, intermittent water supply, sewage flooding and age of water, and wastewater networks. [ABSTRACT FROM AUTHOR]

This study investigated glucose production through the hydrolysis process of centipede grass (Eremochloa ophiuroides) using dilute hydrochloric acid. The centipede grass was characterized for moisture content, volatile matter, and fixed carbon before using it in the hydrolysis process for glucose production. Two statistical designs were used to optimize the hydrolysis process variables. The model validation was studied through the first-order two-level factorial design and independent variable optimization through response surface methodology's second-order face-centered central composite design (FCCD). Twenty experiments obtained from FCCD were analyzed, and graphs are plotted for the main effect and significant interactions. The results showed that maximum (optimum) absorbance of glucose (0.36 equivalent to 17.24 mg glucose/10 g centipede grass) was achieved after 108 min of hydrolysis time at temperature 50.5 °C with the hydrochloric acid concentration of 8.94%. The analysis of variance results revealed that incubation time, reaction temperature, and hydrochloric acid concentration significantly affect glucose absorbance. The regression model showed that there are two options to achieve maximum absorbance of glucose. Glucose extraction from grass will be the future source of energy. The benefit of turning grass biomass into a value-added product is not only economical beneficial but also help in waste management and pollution remediation. [Display omitted] • Hydrolysis process was applied on Centipede grass to produce glucose. • The statistical design was used to optimize the hydrolysis process. • The second-order model was predicted for the highest glucose yield. • At optimum conditions, the glucose yield was 1.72 mg/g of dried centipede grass. [ABSTRACT FROM AUTHOR]

In this paper, the application of combined S 2 O 8 2 − /Zn2+ oxidation was investigated for landfill leachate treatment. Several dosage ratios (g/g) from Sodium persulfate (Na 2 S 2 O 8 M = 238 g/mol) and Zinc chloride (ZnCl 4 207.1920 g/mole) were added to the leachate sample in one oxidation reactor. Results showed that the maximum removal efficiencies for COD (88%) and colour (98%) were obtained using 2 g/12 g S 2 O 8 2 − /Zn+2 dosage, pH (11), and 120 min reaction time, while the maximum removal for NH 3 –N (60%) was obtained at 180 min of oxidation. In addition, the biodegradability (BOD 5 /COD) ratio was improved from 0.07 to 0.19. Moreover, the performance of the new oxidation processes (S 2 O 8 2 − /Zn2+) compared to other related treatment processes such as S 2 O 8 2 − oxidation alone, ZnCl 4 coagulation, S 2 O 8 2 − oxidation followed by ZnCl 4 coagulation and ZnCl 4 coagulation followed by S 2 O 8 2 − . The results of S 2 O 8 2 − /Zn2+ oxidation achieved higher removal for COD, colour and ammonia compared to other related processes. The results revealed that S 2 O 8 2 − /Zn2+ oxidation system can be recommended as an efficient process for organic and ammonia removal from leachate. • Removal of COD (88%) and colour (98%) obtained at 2 g/12 g S 2 O 8 2 − /Zn+2, pH 11, and 120 min. • The maximum removal for NH 3 –N (60%) obtained at 180 min of oxidation. • Biodegradability (BOD 5 /COD) ratio was improved from 0.07 to 0.19. [ABSTRACT FROM AUTHOR]

Abstract Global demand of palm oil and palm oil derivatives lead to generate a huge quantity of palm oil mill effluent (POME). A post treatment is an essential step to a polish biologically treated POME before final discharge. In this study, the performance of employing hydrogen peroxide to enhance electro coagulation process in polishing POME was investigated. Operational variables including current density, contact time, initial pH, and H 2 O 2 dosage were applied and optimized using Response Surface Methodology (RSM). An optimized condition of 40.21 mA/cm2 of current density, 45.67 min of contact time, initial pH of 4.4 and 0.5 g/L of H 2 O 2 was able to achieve removal of 71.3%, 96.8%, and 100% for Chemical Oxygen Demand (COD), colour, and Total Suspended Solid (TSS), respectively. The parameters of polished POME were found below discharge limits of 1000 mg/L and 400 mg/L for COD and TSS, respectively. The biodegradability of POME increased from 0.037 to 0.14 by electro-coagulation-peroxidation (ECP) process. Compared with electrocoagulation alone, employing ECP in polishing POME can reduce current density by 28.2% and reaction time by 30%. Graphical abstract Image Highlights • Electro-coagulation-peroxidation (ECP) was examined as a post treatment for Palm Oil Mill Effluent (POME). • The optimum treatment efficiency of 71.3%, 96.8%, and 100% for COD, colour, and TSS were obtained, respectively. • The optimum factors were current density 40.21 mA/cm2, contact time 45.67 minutes, initial pH of 4.4 and 0.5 g/L of H 2 O 2. • Employing ECP in polishing POME instead of EC alone can reduce current density by 28.2% and 30% of reaction time. [ABSTRACT FROM AUTHOR]

Abstract: Leachate pollution is one of the main problems in landfilling. Researchers have yet to find an effective solution to this problem. The technology that can be used may differ based on the type of leachate produced. Coliform bacteria were recently reported as one of the most problematic pollutants in semi-aerobic (stabilized) leachate. In the present study, the performance of the Electro-Fenton process in removing coliform from leachate was investigated. The study focused on two types of leachate: Palau Borung landfill leachate with low Coliform content (200MPN/100m/L) and Ampang Jajar landfill leachate with high coliform content (>24×104 MPN/100m/L). Optimal conditions for the Electro-Fenton treatment process were applied on both types of leachate. Then, the coliform was examined before and after treatment using the Most Probable Number (MPN) technique. Accordingly, 100% removal of coliform was obtained at low initial coliform content, whereas 99.9% removal was obtained at high initial coliform content. The study revealed that Electro-Fenton is an efficient process in removing high concentrations of pathogenic microorganisms from stabilized leachate. [Copyright &y& Elsevier]

Hybrid coagulants have recently received attention in water and wastewater treatment technologies mainly due to their cost-efficiency and exceptional performance. As such, this study highlights the recent advanced applications of hybrid coagulants in wastewater treatment. The materials used for hybrid coagulants, such as those hybridised in chemical bond, structurally-hybridised, and functionally-hybridised under certain combination techniques (e.g., organic/inorganic, organic/organic, inorganic/inorganic, organic/natural polymer, inorganic/natural polymer, organic/biopolymer, & inorganic/biopolymer), were evaluated and compared based on their applications on different type of wastewaters, experimental conditions, and treatment efficiency. The performance of inorganic/inorganic hybrid coagulation demonstrated high removal of turbidity (98.5%), chemical oxygen demand (COD) (73.3%), heavy metals (99.2%), and colour (98%) - seemingly better than organic removal efficiency. The optimum operational conditions for inorganic/organic coagulants at varied pH levels (6–12) lowered the cost for chemicals used for pH adjustment in treating industrial wastewater. Referring to the review outcomes, hybrid coagulation applications are indeed efficient for treatment of highly concentrated industrial wastewater, such as oily wastewater. • The efficiency of using hybrid coagulants in wastewater treatment. • The performance of inorganic/inorganic hybrid coagulates shows high efficiency. • Hybrid coagulants are more efficient, environmentally friendly, cost-efficiency. • Cost-efficient hybrid materials are promising for industrial purposes. [ABSTRACT FROM AUTHOR]