oxygen demand
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Separations ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 19
José Gustavo Ronderos-Lara ◽  
Hugo Saldarriaga-Noreña ◽  
Mario Alfonso Murillo-Tovar ◽  
Laura Alvarez ◽  
Josefina Vergara-Sánchez ◽  

This study evaluated the distribution and potential estrogenic risk of the presence of bisphenol A (BPA), 4-nonylphenol (4NP), naproxen (NPX), ibuprofen (IBU), 17-β-estradiol (E2) and 17-α-ethinylestradiol (EE2) in water and sediments of the Apatlaco river micro-basin (Morelos, Mexico). The concentration of the determined compounds ranged between <LOD to 86.40 ng·L−1 and <LOD to 3.97 ng g−1 in water and sediments, respectively. The Log Kd distribution obtained (from 1.05 to 1.91 L Kg−1) indicates that the compounds tend to be adsorbed in sediments, which is probably due to the hydrophobic interactions confirmed by the significant correlations determined mainly between the concentrations and parameters of total organic carbon (TOC), total suspended solids (TSS), biological oxygen demand (BOD5) and chemical oxygen demand (COD). Of five sites analyzed, four presented estrogenic risk due to the analyzed endocrine-disrupting compounds (EEQE2 > 1 ng·L−1).

2022 ◽  
Vol 8 (1) ◽  
pp. 61-70
F. Allakhverdiyeva

The article examines the tendency of changes in the hydrochemical regime of the water of the Main Shirvan collector over a long period of time and the suitability of the collector water for irrigation. Continuous laboratory analyzes performed between 2004 and 2019 were compared to 1986. According to experimental data, it was determined that the hydrochemical regime of the collector water is gradually improving, and the salt content is decreasing. The degree of mineralization of the collector water decreased by 2.3 times, the total hardness by 2.2 times, the number of chloride ions by 10.5 times, the number of calcium ions by 1.3 times, the number of magnesium ions by 2.8 times, the total number of cations sodium and potassium decreased by 3.9 times. For 2004–2019 biochemical oxygen consumption in collector water increased 7.9 times, chemical oxygen demand increased 7.5 times, and the number of suspended particles increased 9 times. The amount of iron ions in water decreased by 2 times, while the amount of aluminum and zinc did not change. The suitability of collector water for irrigation was determined according to 7 internationally accepted assessment criteria. Collector water is considered suitable for irrigation in accordance with 6 assessment criteria — the degree of salinity, irrigation coefficient, sodium sorption coefficient, potential salinity, water alkalinity index and percentage of sodium, as well as 1 criterion not suitable for irrigation — the percentage of magnesium. Collector water can be used to irrigate crops.

2022 ◽  
Vol 9 ◽  
Shuai Zhang ◽  
Huixue Ren ◽  
Kaifang Fu ◽  
Wenqing Cheng ◽  
Daoji Wu ◽  

The printing and dyeing wastewater produced by different dyes, as well as different printing and dyeing processes, have different components. These wastewater have high toxicity, high organic concentration, and deep chromaticity. Ozone catalytic oxidation is a very promising technical method for wastewater treatment. In this paper, Mn/Mg/Ce ternary catalyst was prepared, and the ozone catalytic oxidation treatment of actual and simulated printing and dyeing wastewater was performed to study the performance of four different carrier catalysts, namely, molecular sieve (MS), silica gel (SG), attapulgite (ATP), and nano alumina (Al2O3), by simulated dynamic test. The effects of reaction time, pH, and catalyst dosage on methyl orange degradation were studied. The results showed that under the optimum treatment conditions (120 min, pH 11, and 12.5 g/L catalyst dosage), the degradation rate of methyl orange reached 96% and the removal rate of the chemical oxygen demand of printing and dyeing wastewater reached 48.7%. This study shows that the treatment effect of ozone catalytic oxidation on printing and dyeing wastewater is remarkably improved after catalyst addition. This study provides a new choice of ozone catalyst for the degradation of printing and dyeing wastewaters in the future.

2022 ◽  
Vol 11 (6) ◽  
pp. 667-675
Amina-Afaf MOUFFAK

Furfural is one of the petroleum products posing a potential danger to the environment and human health. However, the decontamination of these pollutants released into the environment is primarily governed by biodegra-dation processes. This study is based on biodegradation kinetics at increasing concentrations of furfural by natural mixed culture in order to assess the potential of this process in the elimination of furfural from petrochemical effluents from the ARZEW refinery. This biodegradation was measured through physicochemical parameters such as pH, electrical conductivity, con-centration of hydrocarbons, the chemical oxygen demand (COD), biochemi-cal oxygen demand (BOD5) and the concentration of furfural. The results obtained show at a concentration of 250ppm of injected furfural: a decrease in pH 4.9 and an increase in other parameters (conductivity 3450 μS.cm-1, HC 102 mg / l; furfural 210 ppm, COD 327mg / l, BOD5 98mgO2 / l. The study findings indicated that the injection of these effluents with concentrations greater than 180 ppm leads to values of pH, EC, HC, Furfural, COD, BOD5 which do not comply with direct discharge standards and disrupt biological treatment. The high levels of furfural not only cause a pollution problem but can also disrupt the functioning of bacteria at the biological treatment level. Therefore, dilution with the filtration wash water before switching to biologi-cal treatment is recommended in order to reduce the concentrations below 180 ppm.

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 205
Tahereh Rookesh ◽  
Mohammad Reza Samaei ◽  
Saeed Yousefinejad ◽  
Hassan Hashemi ◽  
Zahra Derakhshan ◽  

Electrocoagulation is a widely used method for treating leachate since it is cost effective and eco-friendly. In the present study, the electrocoagulation process was employed to remove chemical oxygen demand (COD), NH4+, total dissolved solids (TDS), total suspended solids (TSS), turbidity, and color from landfill leachate. At first, lime was used as a pretreatment, then the Fe/Gr and Ti/PbO2/steel electrodes were used, and the optimum electrode was selected. Afterwards, the effects of some variables, including pH, current density, temperature, the inter-electrode distance, and the type of electrolyte were investigated. Results showed that COD, NH4+, TSS, TDS, electrical conductivity (EC), turbidity, color, and pH of effluent pretreatment chemical reached 22,371, 385, 884, 21,820 (mg/L), 13.8 (ms/cm3), 1355 (NTU), 8500 (TCU) and 10, respectively (the removal efficiency was 0, 20.37, 32.4, 61.99, 59.18, and 56.6 percent). With the Fe/Gr electrode, the optimal condition was observed as follows: pH of 7.5, current density of 64 mA/cm2, inter-electrode distance was equal to 1.5 cm, temperature at 20 °C, and retention time 2–4 h. Overall, the electrocoagulation with the Fe/Gr electrode was a suitable technology for landfill leachate treatment due to its effectiveness for the removal of both COD and NH4+, with advantageous performance indicators.

2022 ◽  
Vol 32 (1) ◽  
Saroj Kumar Chapagain ◽  
Geetha Mohan ◽  
Andi Besse Rimba ◽  
Carolyn Payus ◽  
I. Made Sudarma ◽  

AbstractAn adequate water supply is essential for the continued and sustainable growth of the Balinese economy. In addition to mounting water demand, Bali’s water supply has been constrained by high levels of water pollution. Despite being paid great attention, Bali’s earlier efforts to control water pollution yet to prove effective, mainly owing to their reliance on traditional methods and regulations that focus on water pollution being linked to discrete sets of economic activity (e.g., processing industries, livestock farming, and hotels). However, an economy of a region/country comprises a set of sectoral activities, which are interconnected through supply chains; thus, water pollution could be well explained by examining the entire sectoral economic activities and their environmental performance. Therefore, determining the structural relationships between water pollution and economic activity serves as an important basis for more effective forms of pollution control for the Balinese economy. In this study, accordingly, we employed an environmentally extended input–output model to establish the links between water pollution and the production processes of the entire economy. Using biochemical oxygen demand (BOD) as a proxy for water quality in our analysis, we estimated that 246.9 kt of BOD were produced from Bali’s economic activity in 2007. Further, we identified the chief BOD-emitting sectors and found that intermediate demand and household demand were the major causes of BOD discharge in the economy. We also accounted for the indirect role of each sector in total BOD emissions. Moreover, we categorized the sectors into four groups based on their direct and indirect BOD emission characteristics and offered appropriate policy measures for each group. Managing demand (i.e., lowering household consumption and exports) and shifting input suppliers (i.e., from polluters to non-polluters) are effective measures to control pollution for Categories I and II, respectively; clean production and abatement is advised for Category III; and a hybrid approach (i.e., demand management and abatement technology) is recommended for Category IV.

Bruno de Oliveira Freitas ◽  
Luan de Souza Leite ◽  
Maria Teresa Hoffmann ◽  
Antonio Wagner Lamon ◽  
Luiz Antonio Daniel

Abstract Biological reactors with immobilized biomass on free carriers have provided new perspectives for wastewater treatment, once they reduce the system size and increase the treatment capacity. In this study, the performance of three Moving Bed Biofilm Reactors (MBBR) using different carriers (with and without protected surface area) were evaluated for domestic wastewater treatment in continuous flow. Each MBBRs (i.e., R1, R2, and R3) was filled at a ratio of 50% with high-density polyethylene carriers with different characteristics: both R1-K1 and R2-Corrugated tube with protected surface and R3-HDPE flakes without protected surface. Chemical oxygen demand (COD) removal of 80 ± 5.0, 80 ± 3.5, and 78 ± 2.4% was achieved by R1, R2, and R3, respectively. The oxygen uptake by biofilm attached on the carriers was 0.0079 ± 0.0013, 0.0033 ± 0.0015, and 0.0031 ± 0.0026 μg DO·mm−2 for the K1, corrugated tube, and HDPE flakes, respectively. No significant differences were observed between the performance of the three MBBRs in terms of physico-chemical parameters (alkalinity, pH, and dissolved inorganic carbon) and COD removal. Results showed that the carrier type and its characteristics (total area and with/without protected area) did not affect the organic matter removal. Thus, the carrier without a protected surface in MBBR could be a promising low-cost option for domestic wastewater treatment.

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 76
Emmanuel Kweinor Tetteh ◽  
Sudesh Rathilal

This study presents the bio-photocatalytic upgrading of biogas utilising carbon dioxide (CO2) as a potential option for beginning fossil fuel depletion and the associated environmental risks in the pursuit of sustainable development. Herein, magnetite photocatalyst (Fe-TiO2) was employed with an integrated anaerobic-photomagnetic system for the decontamination of municipality wastewater for biogas production. The Fe-TiO2 photocatalyst used, manufactured via a co-precipitation technique, had a specific surface area of 62.73 m2/g, micropore volume of 0.017 cm3/g and pore size of 1.337 nm. The results showed that using the ultraviolet-visible (UV-Vis) photomagnetic system as a post-treatment to the anaerobic digestion (AD) process was very effective with over 85% reduction in colour, chemical oxygen demand (COD) and turbidity. With an organic loading rate (OLR) of 0.394 kg COD/L·d and hydraulic retention time (HTR) of 21 days, a 92% degradation of the organic content (1.64 kgCOD/L) was attained. This maximised the bioenergy production to 5.52 kWh/m3 with over 10% excess energy to offset the energy demand of the UV-Vis lamp. Assuming 33% of the bioenergy produced was used as electricity to power the UV-Vis lamp, the CO2 emission reduction was 1.74 kg CO2 e/m3, with good potential for environmental conservation.

2022 ◽  
Vol 12 (2) ◽  
pp. 699
Danyelle Medeiros de Araújo ◽  
Elisama V. Dos Santos ◽  
Carlos A. Martínez-Huitle ◽  
Achille De Battisti

Hydroxychloroquine (HCQ) has been extensively consumed due to the Coronavirus (COVID-19) pandemic. Therefore, it is increasingly found in different water matrices. For this reason, the concentration of HCQ in water should be monitored and the treatment of contaminated water matrices with HCQ is a key issue to overcome immediately. Thus, in this study, the development of technologies and smart water solutions to reach the Sustainable Development Goal 6 (SDG6) is the main objective. To do that, the integration of electrochemical technologies for their environmental application on HCQ detection, quantification and degradation was performed. Firstly, an electrochemical cork-graphite sensor was prepared to identify/quantify HCQ in river water matrices by differential pulse voltammetric (DPV) method. Subsequently, an HCQ-polluted river water sample was electrochemically treated with BDD electrode by applying 15, 30 and 45 mA cm−2. The HCQ decay and organic matter removal was monitored by DPV with composite sensor and chemical oxygen demand (COD) measurements, respectively. Results clearly confirmed that, on the one hand, the cork-graphite sensor exhibited good current response to quantify of HCQ in the river water matrix, with limit of detection and quantification of 1.46 mg L−1 (≈3.36 µM) and 4.42 mg L−1 (≈10.19 µM), respectively. On the other hand, the electrochemical oxidation (EO) efficiently removed HCQ from real river water sample using BDD electrodes. Complete HCQ removal was achieved at all applied current densities; whereas in terms of COD, significant removals (68%, 71% and 84% at 15, 30 and 45 mA cm−2, respectively) were achieved. Based on the achieved results, the offline integration of electrochemical SDG6 technologies in order to monitor and remove HCQ is an efficient and effective strategy.

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