The integrated electrocoagulation-assisted adsorption (ECA) system with a solar photovoltaic power supply has gained more attention as an effective approach for reduction chemical oxygen demand (COD) ...from pharmaceutical wastewater (PhWW). In this research, the ECA system was used for the treatment of PhWW. Several operating parameters were investigated, including electrode number, configuration, distance, operating time, current density, adsorption time, and temperature. A current density of 6.656 mA/cm
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, six electrodes, a 20-min time, a 4 cm distance, an MP-P configuration, and a 45 °C temperature produced the maximum COD reductions, where the operating cost of conventional energy was 0.273 $/m
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. The EC, adsorption, and combination of EC and adsorption processes achieved efficient COD reductions of 85.4, 69.1, and 95.5%, respectively. The pseudo-second-order kinetic model and the Freundlich isotherm fit the data of the endothermic adsorption process. Therefore, it was found that the combination processes were superior to the use of these processes in isolation to remove COD.
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The combination of the chemical coagulation-assisted electrocoagulation (CC-EC) process with a solar photovoltaic energy source has attracted increasing attention for the efficient removal of ...chemical oxygen demand (COD) from pharmaceutical wastewater. In this paper, the CC-EC process has been utilized as an alternative to conventional chemical processes for the treatment of pharmaceutical wastewater. The effects of the various operating parameters, such as coagulant dosage, coagulant type, number of electrodes, the distance between electrodes, electrode configuration, operating time, and current density, on COD removal efficiency were investigated. The results indicated that the optimum conditions were achieved at 500 mg/L of alum dosage, 3.105 mA/cm2 of current density, six electrodes with a distance of 4 cm between electrodes, and the MP-S electrode configuration, where the operating cost of conventional energy was 0.283 $/m3. Indeed, by using the CC process alone, the COD removal efficiency was 26% and 61.5% at the optimal dosages of 750 mg/L of NaOH and 500 mg/L of alum, respectively. In the CC-EC treatment, the removal efficiencies of COD were 88.7, 92.9, 94.4, and 89.4% using six electrodes, 2 cm of distance between electrodes, MP-S electrode configuration, and 20 min with 1.553 mA/cm2 of current density, respectively. The removal efficiencies of COD achieved through CC, EC, and CC-EC processes were 61.5, 85.4, and 94.4%, respectively.
Sanitary landfilling is the predominant process for solid urban waste disposal, but it generates leachate that poses environmental, economic, and social concerns. Landfill leachate (LL) contains ...complex and refractory pollutants and toxic compounds that can vary depending on landfill maturity, age, and biochemical reactions, making its treatment challenging. Due to its unique characteristics and occurrence in remote locations, LL requires separate treatment from wastewater. Various conventional treatment processes involving biological, chemical, and physical processes have been used for LL treatment, but a single treatment process is insufficient to meet environmental standards. This review demonstrates that combined treatment processes are more effective and efficient for LL treatment compared to single processes. Among the various combinations, chemical–chemical and chemical–biological treatments are the most commonly used. Specifically, the integration of Fenton with adsorption and a membrane bioreactor (MBR) with nanofiltration (NF) processes shows promising results. The combined processes of MBR with NF, Fenton with adsorption, and PF with biological treatment show maximum removal efficiencies for COD, reaching 99 ± 1%, 99%, 98%, and 97%, respectively. Additionally, the combined Fenton with adsorption process and EC with SPF process enhance biodegradability as indicated by increased BOD5/COD ratios, from 0.084 to 0.82 and 0.35 to 0.75, respectively. The findings emphasize the importance of developing and implementing enhanced combined treatment processes for LL, with the aim of achieving efficient and comprehensive pollutant mineralization. Such processes have the potential to address the environmental concerns associated with LL and contribute to sustainable waste management practices.
This study aimed to investigate the effectiveness of combining electrocoagulation with adsorption on natural zeolite (ECA) for the treatment of industrial dairy wastewater. The response surface ...methodology (RSM) was employed to analyze the process. Several operating parameters were investigated, including the initial pH (5–9), electrolysis time (15–45 min), current density (12–48 A/m2), and the zeolite dosage (0.083–0.15 g/ml). The experimental design consisted of 30 runs, which were determined using the Central Composite Design (CCD). The key parameters measured were the removal efficiencies of chemical oxygen demand (COD), turbidity, and energy consumption. The obtained data were analyzed using Minitab 21.2 software, and regression models were constructed. The models demonstrated a strong coefficient of determination (R2), indicating a strong correlation between the experimental and predicted values. The optimal conditions for achieving 92 % COD removal and 97 % turbidity removal were found to be pH 7, a current density of 38 A/m2, an electrolysis time of 20 min, and a zeolite dosage of 0.183 g/ml. To evaluate the impact of natural zeolite on the treatment process, the results obtained from this experimental design were compared with those from a second design involving electrocoagulation (EC) alone (based on 20 runs). The comparison revealed that the addition of natural zeolite did not enhance the treatment efficiency in terms of COD and turbidity removal in dairy wastewater.
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One of the major environmental problems caused by the agro-food industry is the treatment of olive mill wastewater (OMW). OMW is a byproduct of olive oil production and is characterized by high ...concentrations of various organic compounds, including organic acids, pectin, and polyphenols, as well as inorganic compounds like sulfate, chlorides, and phosphoric salts of potassium and sodium, and trace amounts of other elements. These compounds make OMW complex and toxic to plants, inhibiting bacterial activity. Therefore, these compounds must be removed from wastewater before it is discharged into the environment. Many conventional treatment processes for OMW have been used, relying on physical, biological, and chemical methods. However, they have limitations and low efficiency in removing pollutants, as they only transfer pollutants from one stage to another. The ultimate goal of any treatment process is to achieve complete mineralization of pollutants, which can be achieved through the integration of appropriate processes. Over the years, many researchers have evaluated various combined treatment methods to enhance treatment efficiency and comply with environmental regulations regarding wastewater discharge. This review focuses on combined treatment methods for treated OMW. We analyzed preliminary results in the literature and discussed many parameters used to improve the process. Additionally, this review summarizes the combined processes according to their respective types, along with their benefits, drawbacks, and future prospects. It also summarizes the environmental impacts of treating OMW. In general, the results extracted from the literature review show that combined treatment processes have proven effective in treating OMW and should remain a focal point for the development of enhanced processes that can remove more pollutants in a single process.
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•The review summarizes the performance of more than 54 combined processes in removing various pollutants from olive mill wastewater (OMW).•Combined processes are more convincing and efficient than single processes for OMW treatment.•The study found that combined chemical-chemical and chemical-biological treatment processes are OMW's most common and widely used combination treatments.•Fenton and coagulation/flocculation (C/F) methods are the best treatments to be integrated as combined methods.
The rapid urbanization, economic growth, and improved living standards in developing countries are causing a significant increase in the amount of solid waste generated. To ensure a healthy ...environment for city residents and effectively manage waste resources, it is crucial to employ scientific methods as decision-making tools. However, the lack of competent institutions, financial and technical capabilities, and irresponsible social behavior hinder the implementation of an integrated and sustainable solid waste management (SWM) system. To address these challenges, researchers have proposed an optimized solution using mathematical modeling and GIS. This solution aims to enhance collection efficiency, optimize transportation, and maximize resource recovery and waste processing. By using linear mathematical modeling and the Arc-GIS Network Analyst tool, the study achieved a 13% route optimization in Phase 7 Hayatabad, indicating the potential for a more sustainable and cost-effective municipal solid waste (MSW) collection system in urban Peshawar. The study also explored different scenarios, such as increasing waste collection efficiency and implementing waste-to-energy technologies, which resulted in improved economic viability and reduced payback periods. Overall, the research highlights the need for adaptive strategies and policy reforms to establish sustainable and efficient waste management systems in rapidly growing cities, fostering a cleaner and more environmentally responsible urban future.
