Environmental Health Engineering and Management Journal

353-360

Authors: Lelisa Regea Mengistu, Chali Dereje Kitila

Background: Electrocoagulation is becoming a promising eco-friendly wastewater treatment technique. It is a low-cost wastewater treatment method suitably applied for various wastewater effluent characteristics. Nevertheless, there are different kinds of electrocoagulation; comparison among them in terms of nutrient removal is investigated in the present research. This study analyzed nitrate (NO3 -) and phosphate (PO4 3-) removal potential of the sono-alternative and direct-current electrocoagulation process. Methods: Batch reactor and sono-direct current (SDC)/sono-alternative current (SAC) electrocoagulation cell were employed to investigate NO3 - and PO4 3- removal efficiency from domestic effluents. The data gathered from laboratory experiments were analyzed using response surface methodology (RSM). ANOVA was used to examine the interaction effects of diverse parameters in terms of NO3 _ and PO4 3- removal from domestic wastewater effluents. Results: At extreme experimental conditions, the percentage of NO3 - and PO4 3- removal attained with sono-direct current electrocoagulation (SDCE) and sono-alternative current electrocoagulation (SACE) were 96.5%, 96.2% and 96.8%, 96.5, respectively. The SACE was more successful in eliminating NO3 - and PO4 3- than the SDCE process. The appearance of resistant oxide coating on the cathode and the appearance of corrosion on the anode due to oxidation processes in the case of SDCE were identified as principal factors highly affecting NO3 - and PO4 3- removal efficiency. Conclusion: With optimum process efficiency, experimental findings show that the SACE process is more capable of NO3 - and PO4 3- removal than the SDCE process.

373-387

Authors: Mohammad Ali Zazouli, Yalda Hashempour, Alireza Ala

Background: Removing natural organic substances from drinking water sources is necessary to prevent the formation of toxic and carcinogenic disinfection by-products (DBPs). The nano-photocatalytic oxidation process to remove these substances is easier, faster, cheaper, and more efficient than other methods. Methods: This study investigated the efficiency of the TiO2/UV nano-photocatalytic process in removing humic acid (HA) and fulvic acid (FA) from aqueous solutions. Batch tests were performed to investigate the effect of various parameters such as contact time (15, 30, 45, 60, and 75 minutes), initial pH (4, 7, and 9), initial HA and FA concentration (0.5, 1, 2, 5, and 7 mg/L-1), TiO2 dose (5, 10, 15 and 20 mg/L-1), and different UV irradiation (8 W and 16 W) for the removal of HA and FA from aqueous solutions using TiO2/UV at room temperature (20 ± 3 °C). The equilibrium adsorption data and the standard parameters were evaluated. Data were analyzed using SPSS version 25. Results: The efficiency of this process in optimal conditions (pH: 4, anatase TiO2: 10 mg/L-1, irradiation time: 60 min, UV = 16 W) for removing humic and fulvic (initial HA concentration: 2 mg/L-1 and initial FA concentration: 5 mg/L-1) was 89% and 92%, respectively. The analysis of the experimental isotherm data showed that in the adsorption process of HA and FA on TiO2/UV, the Langmuir isotherm and the first-order reaction had the best fit with the experimental data. Conclusion: TiO2/UV nano-photocatalytic process is suitable for the photo-degradation and removal of HA and FA in aqueous solutions.

401-408

Authors: Desmond Eseoghene Ighravwe, Akpevweoghene Solomon Abijah, Daniel Osezua Aikhuele, Sunday Thomas Ajayi, Johnson Adeleke Adeyiga

Background: Several aquaculture industries in underdeveloped nations use fossil fuel-powered generators to produce electricity. This pattern has raised greenhouse gas emissions as well as the price of aquaculture products. Methods: To address this issue, this study contains a bi-objective model that optimizes the parametric settings of waste-to-energy (WTE) plants for aquaculture firms: Levelized cost of energy and power expenses for reverse logistics. The best values for these objectives were created using a genetic algorithm and goal programming. Results: Four planning periods were taken into account during implementation, and actual data were gathered from a Nigerian aquaculture company. The electricity costs from biodiesel ranged from N0.7541 per kW to N0.7628 per kW, respectively. Reverse logistics has energy costs ranging from N6 329 492.10 to N7 121 015.53. The proposed model produced average values for several WTE parametric parameters, including a 1.69 million kg hydrogen gas, a 59.16% hydrogen gas compression efficiency, and an 83.39% electricity conversion efficiency. Furthermore, the system had logistics’ minimum and maximum fractions of 0.18% and 21%, respectively. Conclusion: Our findings demonstrated how WTE parametric parameters impact the aquaculture industry’s electrical power unit.

419-428

Authors: Parisa Nasrollahi, Seyyed Abbas Mirzaee, Zeinab Gholami, Mohsen Mansouri, Zahra Noorimotlagh

Background: The widespread presence of organic dyes in the various industries’ effluent such as paper, textile, and clothing has led to significant environmental pollution. Titanium oxide (TiO2) nanoparticles immobilized on zeolite (ZSM-5) were investigated under UV light for activation of peroxymonosulfate (PMS) for photocatalytic degradation of Orange II (OII) dye in aqueous solutions. Methods: In this study, the photocatalyst used was prepared by immobilizing different amounts of TiO2 nanoparticles on ZSM-5. Characterization analyses including X-ray diffractometer (XRD), Fourier transform infrared (FTIR), BET, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were performed on the synthesized samples. Then, the effect of various parameters, such as TiO2 nanoparticles loading onto the ZSM-5, pH, contact time, dye concentration, and TiO2/ ZSM-5 dosage, is investigated for the removal of OII as a model molecule under the UV irradiation with 15 W power. Results: The highest removal percentage of OII dye (97.44%) was obtained in the optimal operating conditions of pH = 3, the initial dye concentration = 5 ppm, amount of TiO2/ZSM-5 = 10 mg/L, amount of PMS = 50 mg/L, and reaction time = 120 minutes. The Langmuir–Hinshelwood kinetics model fitted with the experimental data. Conclusion: The obtained results of this research showed that PMS can be used as a suitable oxidant activated with ZSM-5/TiO2 nanocomposite in OII degradation in different water environments, by optimizing the effective operating factors.

441-449

Authors: Hassan Hashemi, Nasim Salehi, Saeed Rajabi, Kaan Isinkaralar

Background: Leachate, a highly contaminated liquid, is produced by separating wastes and introducing moisture into the waste layers. Biological toxicity evaluation is a method that may be used to analyze the toxicity of leachate to organisms and plants. Sorghum bicolor was employed in this study to evaluate the acute toxicity of raw leachate and landfill leachate. Methods: Leachate was collected from different locations within the refuse that was collected and mixed in a sampling container. The physiochemical characteristics of the leachate were analyzed in both raw leachate and landfill leachate. Germination rate, root weight, and root length were measured 24, 48, and 72 hours after planting for leachate dilutions of 25%, 50%, 75%, and 100%, respectively. Results: Raw leachate had greater concentrations of metals (Fe, Zn, Cu, Mn, Cr, Cd, and Pb), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS), nitrate, ammonia, and phosphate, as well as a more acidic pH (< 6), as compared to landfill leachate. The results showed that landfill leachate had a lower potential for toxicity than raw leachate, with seed-germination rates of 0.1 and 0 in the presence of 75% landfill leachate after 48 and 72 hours, respectively, as opposed to 0.3 and 0.1 in the presence of raw leachate. Conclusion: The findings show that raw leachate can include higher concentrations of metals and organic compounds, which can be one of the causes of Sorghum seed phytotoxicity. Waste leachate management is one of the most important pillars of environmental protection, and it should be taken into consideration by the right authorities.

459-467

Authors: Francis Acheampong Osei, Esther Asantewaa Effah

Background: Many countries undertake development activities that utilize resources from the environment. In the Democratic Republic of the Congo (DRC), the Congolese Environmental Agency is supervised by the Ministry of Environment and Sustainable Development to undertake an environmental assessment of all projects that pose risks to the environment. The present study conducted a critical review of the country’s existing environmental assessment legislation, identifying strengths and weaknesses in the Environmental and Social Impact Assessment (ESIA) system. Methods: A literature survey was done in the Google Scholar, Taylor & Francis, and Elsevier databases, which were also guided by the PRISMA. All full-text articles included in the study were written or translated (using online translation software) into the English language, and also, reported on environmental impact assessment as well as legislation. A textual examination of the included literature was done. A set of adapted analytical criteria was used to critically review the ESIA system in the DRC. The results were discussed, and recommendations were given. Results: It was found that the decree was not effective and efficient for the ESIA study. Some of the key limitations of the ESIA decree included the lack of scoping in the entire ESIA process, alternatives that were limited in scope, fees and charges that were not explicitly stated in the legislation, and the lack of public participation at some stages. Conclusion: The ESIA system in the DRC is ineffective and needs revision to improve its effectiveness.