scholarly journals Removal of COD, BOD and Color from Municipal Solid Waste Leachate using Silica and Iron nano particles - A Comparative Study

2017 ◽  
Vol 19 (1) ◽  
pp. 122-130 ◽  

<p>Application of nano particle in the treatment of municipal solid waste leachate is of recent interest. In this paper, the effectiveness of silica nano particles synthesized from blast furnace slag and iron nano particle synthesized from chemicals was studied for the removal of organic pollutants and color. The synthesized nano particles were characterized using SEM, TEM, EDX and FTIR analysis. Batch experiments were conducted to remove the BOD, COD and color from Aged landfill leachate (ALL) and leachate from the composting yard (CYL).Influencing parameters like pH, contact time, nano particle dosage and Hydrogen peroxide concentration were studied. The maximum removal was achieved at the pH of 6 for both the nano particle, contact time 90 minutes for silica nano particle and 120 minutes for iron nano particle, silica nano particle dose as 0.4g/50 ml, iron nano particle dose as 0.3g/50ml and hydrogen peroxide concentration was found to be 3M and 4M for silica and iron nano particles respectively. The removal efficiency in CYL and ALL using silica nano particle was obtained as 87.15%, 72.72%, 83.15% and 82.5%, 62.5%, 77.34% for color, BOD and COD respectively. Similarly for iron nano particle, the removal efficiency was found to be 60.3%, 65%, 67.43% and 57.06%, 57.27%, 67% for the removal of color, BOD and COD in CYL and ALL, respectively.</p>

Author(s):  
Negar Jafari ◽  
Afshin Ebrahimi ◽  
Karim Ebrahimpour ◽  
Ali Abdolahnejad

Introduction: Microcystin-leucine arginine (MC-LR) is a toxin with harmful effects on the liver, kidney, heart, and gastrointestinal tract. So, effective removal of MC-LR from water resources is of great importance. The aim of this study was to remove microcystin-LR (MC-LR) from aqueous solution by Titanium Dioxide (TiO2). Materials and Methods: In the present study, TiO2, as a semiconductor, was used for photodegradation of MC-LR under ultraviolet light (UV). The Response Surface Methodology was applied to investigate the effects of operating variables such as pH (A), contact time (B), and catalyst dose (B) on the removal of MC-LR. The MC-LR concentration was measured by high-performance liquid chromatography (HPLC). Results: The results showed that single variables such as A, B, and C had significant effects on MC-LR removal (pvalue < 0.05). In other words, increase of the contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but the effect of pH was negative. The analysis of variance showed that BC, A2, and C2 variables had a significant effect on the MC-LR removal (pvalue < 0.05). Finally, the maximum removal efficiency of MC-LR was 95.1%, which occurred at pH = 5, contact time = 30 minutes, and catalyst dose = 1 g/l. Conclusion: According to the findings, TiO2, as a photocatalyst, had an appropriate effect on degradation of the MC-LR.


2018 ◽  
Vol 141 (4) ◽  
Author(s):  
Tao Wang ◽  
Zhenxing Huang ◽  
Hongyan Ren ◽  
Hengfeng Miao ◽  
Minxing Zhao ◽  
...  

This study aimed to investigate the effectiveness of the full-scale internal circulation (IC) reactor in biodegrading of municipal solid waste (MSW) fresh leachate under mesophilic conditions, where the anaerobic process stability, biogas yield, and sludge granulation were intensively investigated. The effects of operational parameters on the influent organic loading rate (OLR), chemical oxygen demand (COD) removal efficiency, alkalinity (ALK), pH, volatile fatty acids (VFAs) accumulation, and effluent recirculation were also studied. The results showed that the reactor operated stably and effectively. The COD removal efficiency and biogas yield could be maintained at (92.8 ± 2.0)% and (0.47 ± 0.05) m3/kg CODremoval, respectively, with the influent OLR (24.5 ± 0.9) kg COD/(m3 d) and hydraulic retention time (HRT) 2.7d during the stable operation phase. Meanwhile, this study demonstrated that 1.5–3.0 m/h would be the optimal Vup for the reactor, corresponding to the effluent recirculation of 32.5–78.0 m3/h. Moreover, it was found that the content of extracellular polymeric substances (EPS) in the anaerobic sludge increased from 50.3 to 140.7 mg/g volatile suspended solids (VSS), and the sludge had good granular performance during the reactor operation.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Malik Muhammad Hassan ◽  
Noor Haleem ◽  
Muhammad Anwar Baig ◽  
Yousuf Jamal

Abstract Grasses have been used widely to remediate contaminants present in domestic wastewater, but leachate generated from municipal solid waste that usually contain some concentrations of heavy metals has never been reported to be treated with grasses, especially Rhodes grass. A series of experiments was performed to investigate the contaminant uptake from municipal solid waste leachate by Chloris gayana (Rhodes grass) grown in combination with two commonly available grass varieties namely Vetiveria zizanioides (Vetiver grass) and Pennisetum purpureum (Elephant grass). Leachate used for the experiments had high values for chemical oxygen demand (5 g/L), pH (8.5), electrical conductivity (9.0 mS/cm), nitrates (182.1 mg/L), phosphates 6.4 mg/L along with heavy metals i.e. copper, zinc and manganese. Different dilutions of leachate ranging from 0 to 100% were applied in batches and their result showed that collectively all the grasses reduced overall contaminant concentrations. These were reported for chemical oxygen demand, electrical conductivity, nitrates, and phosphates reduced up to 67, 94, 94, and 73%, respectively. Metals uptake by grasses also showed a significant decrease in applied dose i.e. zinc (97%), copper (89%), and manganese (89%). Plant analysis showed that all grasses showed preference to heavy metals uptake e.g. Rhodes grass favoured up taking zinc, Elephant grass for copper and Vetiver grass preferred manganese. Overall growth performance of Rhodes grass was better in dilute leachate, whereas in more concentrated leachate, Rhodes grass did not perform better and production of biomass decreased. In Vetiver grass, root and shoot lengths decreased with increasing leachate strength, but the biomass did not change significantly.


2015 ◽  
Vol 14 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Biplob Kumar Pramanik ◽  
Sagor Kumar Pramanik ◽  
Fatihah Suja

Effects of biological activated carbon (BAC), biological aerated filter (BAF), alum coagulation and Moringa oleifera coagulation were investigated to remove iron and arsenic contaminants from drinking water. At an initial dose of 5 mg/L, the removal efficiency for arsenic and iron was 63% and 58% respectively using alum, and 47% and 41% respectively using Moringa oleifera. The removal of both contaminants increased with the increase in coagulant dose and decrease in pH. Biological processes were more effective in removing these contaminants than coagulation. Compared to BAF, BAC gave greater removal of both arsenic and iron, removing 85% and 74%, respectively. Longer contact time for both processes could reduce the greater concentration of arsenic and iron contaminants. The addition of coagulation (at 5 mg/L dosage) and a biological process (with 15 or 60 min contact time) could significantly increase removal efficiency, and the maximum removal was observed for the combination of alum and BAC treatment (60 min contact time), with 100% and 98.56% for arsenic and iron respectively. The reduction efficiency of arsenic and iron reduced with the increase in the concentration of dissolved organics in the feedwater due to the adsorption competition between organic molecules and heavy metals.


1999 ◽  
Vol 20 (2) ◽  
pp. 211-217 ◽  
Author(s):  
L. Borzacconi ◽  
I. López ◽  
M. Ohanian ◽  
M. Viñas

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