Bioflocculant production by Haloplanus vescus and its application in acid brilliant scarlet yellow/red removal

2015 ◽  
Vol 73 (4) ◽  
pp. 707-715 ◽  
Author(s):  
Chun-Ying Zhong ◽  
Hong-Gao Chen ◽  
Gang Cao ◽  
Jun Wang ◽  
Jian-Gang Zhou

A novel bioflocculant MBF057 produced by a salt-tolerant Haloplanus vescus HW0579 was investigated in this study. The effects of culture conditions such as initial pH, inoculum size, and chemical oxygen demand (COD) of K-acid wastewater on MBF0579 production were studied. The result showed that 8.09 g/L purified MBF0579 was extracted with the following optimized conditions: 780 mg/L COD of K-acid wastewater as carbon source, inoculum size 12.5%, and initial pH 7.0. The biopolymer contained 78.6% polysaccharides and 21.1% proteins. The highest flocculating rate of 81.86 and 95.07% for the COD and chroma of acid brilliant scarlet gelb rot (yellow/red, GR) dye wastewater were achieved at a dosage of 150 mg/L, pH 2.0 and contact time 100 min. Overall, these findings indicate bioflocculation offers an effective alternative method of decreasing acid brilliant scarlet GR during dye wastewater treatment.

2012 ◽  
Vol 441 ◽  
pp. 555-558
Author(s):  
Feng Tao Chen ◽  
San Chuan Yu ◽  
Xing Qiong Mu ◽  
Shi Shen Zhang

The Ti/SnO2-Sb2O3/PbO2 electrodes were prepared by thermal decomposition method and its application in the electrochemical degradation of a heteropolyaromatic dye, Methylene blue (MB), contained in simulated dye wastewater were investigated under mild conditions. The effects of pH, current density and electrolysis time on de-colorization efficiency were also studied. Chemical oxygen demand (COD) was selected as another parameter to evaluate the efficiency of this degradation method on treatment of MB wastewater. The results revealed that when initial pH was 6.0, current density was 50 mA·cm2, electrolysis time was 60 min, Na2SO4 as electrolyte and its concentration was 3.0 g·dm3, the de-colorization and COD removal efficiency can reach 89.9% and 71.7%, respectively.


2021 ◽  
Vol 37 (1) ◽  
pp. 65-70
Author(s):  
Aram Dokht Khatibi ◽  
Kethineni Chandrika ◽  
Ferdos Kord Mostafapour ◽  
Ali Akbar Sajadi ◽  
Davoud Balarak

Conventional wastewater treatment is not able to effectively remove Aromatic hydrocarbons such as Naphthalene, so it is important to remove the remaining antibiotics from the environment. The aim of this study was to evaluate the efficiency of UV/ZnOphotocatalytic process in removing naphthalene antibiotics from aqueous solutions.This was an experimental-applied study that was performed in a batch system on a laboratory scale. The variables studied in this study include the initial pH of the solution, the dose of ZnO, reaction time and initial concentration of Naphthalene were examined. The amount of naphthalene in the samples was measured using GC.The results showed that by decreasing the pH and decreasing the initial concentration of naphthalene and increasing the contact time, the efficiency of the process was developed. However, an increase in the dose of nanoparticles to 0.8 g/L had enhance the efficiency of the process was enhanced, while increasing its amount to values higher than 0.8 g/L has been associated with a decrease in removal efficiency.The results of this study showed that the use of UV/ZnOphotocatalytic process can be addressed as a well-organized method to remove naphthalene from aqueous solutions.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Devagi Kanakaraju ◽  
Soon Pang Wong

The objective of this study was to assess the efficiency of a novel TiO2/modified sago bark (TiO2/MSB) mixture for the degradation of sago wastewater effluent by employing response surface methodology (RSM) using chemical oxygen demand (COD) removal as the target parameter. The highest COD removal of 64.92% was obtained using TiO2/MSB mixture sample prepared by combining 0.2 g/L TiO2and 1 w/w% MSB. Given that the highest removal was produced using this mixture sample, further optimisation of sago wastewater treatment was conducted by varying the independent variables, namely, dosage and contact time. Under this optimum condition, 0.10 g of 0.2 g/L TiO2/1% MSB had successfully reduced 52.83% COD in 120 min. Surface morphology, functional groups, and elemental analysis supported observations of the ability of TiO2/MSB mixture to remove COD. Additionally, aeration had further improved COD removal by 11%. The regression value (R2>0.99) of the model indicated a high degree of correlation between the evaluated parameters. These results proved the feasibility of TiO2photocatalysis as an appealing alternative protocol for sago wastewater treatment and solid waste from the industry can be utilised for wastewater degradation.


2011 ◽  
Vol 71-78 ◽  
pp. 2294-2297
Author(s):  
Yan Li Mao ◽  
Yun Yu ◽  
Shi Tian Luo ◽  
Xiao Lin Lv

The optimal conditions of production of biopolymer by the culture of Bacillus sp.were examined, using molasses wastewater to replace glucose as carbon source and energy source in the culture medium. Results showed that the COD concentration in molasses wastewater favorable for the growth of the Bacillus sp.was 4500 mg•L-1, and inoculum size of 6%(v/v), 28◦C, initial pH 7.0 and shaking speed of 160 r•min-1, under the optimal culture conditions, the highest flocculating activity achieved for Kaolin suspension was 97.5% and 4.0 g biomass /L broth was obtained. The Bacillus sp. biomass was effective in flocculating some soluble reactive dyes in aqueous solution, reactive Light-Yellow K-4G and reactive Turquoise Blue KN-G with a decolorization efficiency of 98.5 and 92.5%, respectively, using 20 mL of the flocculant in 500 mL of 100 mg•L-1 dye solution.


Author(s):  
Jiawei Tang ◽  
Yu Liu ◽  
Peidong Su ◽  
Jingwei Quan ◽  
Yufeng Hu ◽  
...  

Abstract This study investigated the removal of chemical oxygen demand (COD), NH4-N, and perfluorinated compounds (PFCs) in the effluent from a wastewater treatment plant (WWTP) using ZnO coated activated carbon (ZnO/AC). Results suggested that the optimal dosage of the ZnO/AC was 0.8 g/L within 240 min of contact time, at which the maximum removal efficiency of COD was approximately 86.8%, while the removal efficiencies of PFOA and PFOS reached 86.5% and 82.1%. In comparison, the removal efficiencies of NH4-N, PFBA, and PFBS were lower, at approximately 47.9%, 44.0%, and 55.4%, respectively. In addition, COD was preferentially adsorbed before PFCs and NH4-N, when the contact time ranged from 0 to 180 min, and the order of PFCs removal showed a positive correlation with C-F chain length. The kinetic study revealed that the removal of COD, NH4-N, and PFCs could be better depicted and predicted by the Lagergren quasi-second order dynamic model with high correlation coefficients, which involved liquid membrane diffusion, intraparticle diffusion, and photocatalytic reactions. The saturated ZnO/AC was finally regenerated using ultrasound for 3 h and retained excellent performance, which proved it could be considered as an effective and alternative technology.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sahar Keskes ◽  
Wafa Jallouli ◽  
Imen Ben Atitallah ◽  
Fatma Driss ◽  
Emna Sahli ◽  
...  

AbstractThis study investigates the optimization of the culture conditions for enhancing Photorhabdus temperata biopesticide production using wastewater (WS4) as a raw material. Box-Behnken design (BBD) was used to evaluate the effects of carbon to nitrogen ratio (C/N), sodium chloride concentration and inoculum size on P. temperata biomass production and insecticidal activity. For an enhanced biopesticide production, the optimum operating conditions were as follows: inoculum size = 4%; C/N ratio = 12.5 and [NaCl] = 4 g/L for two responses. 1.95 and 2.75 fold improvements in oral toxicity and biomass production were respectively obtained in the cost-effective medium developed in this study (WS4 I) using the three variables at their optimal values. Under the optimized conditions, WS4 I-grown cells exhibited higher membrane integrity according to flow cytometry analysis since dead cells presented only 9.2% compared to 29.2% in WS4. From batch fermentations carried out in WS4 I and WS4, P. temperata kinetic parameters in terms of biomass production and substrate consumption rates were modeled. The obtained results showed that the maximum specific growth rate in WS4 I was of 0.43 h−1 while that obtained in WS4 was of 0.14 h−1. In addition, the efficiency of P. temperata to metabolize organic carbon was enhanced by optimizing the culture conditions. It reached 72.66% instead of 46.18% in the control fermentation after 10 h of incubation. Under the optimized conditions, P. temperata cells showed the highest specific consumption rate resulting in a toxin synthesis improvement.


2010 ◽  
Vol 171-172 ◽  
pp. 45-48 ◽  
Author(s):  
Yan Li Mao ◽  
Xiao Cun Xiao ◽  
Yan Jing Liu ◽  
Er Li Zhao ◽  
Lv Bin Zhai

The optimal conditions of production of biopolymer by the culture of Pseudomonas fluorescens were examined, using brewery wastewater to replace glucose as carbon source and energy source in the culture medium. Results showed that the COD concentration in brewery wastewater favorable for the production of the biopolymer was 6000 mg•L-1, and an optimal culture condition of inoculum size of 5%(v/v), 28°C, initial pH 7.0 and shaking speed of 150 r•min-1, under the optimal culture conditions, the highest flocculating activity achieved for Kaolin suspension was 97.5% and 3.67 g biopolymer /L broth was obtained. The biopolymer was effective in flocculating some soluble reactive dyes in aqueous solution, reactive Light-Yellow K-4G and reactive Turquoise Blue KN-G with a decolorization efficiency of 95.8 and 96.2%, respectively,using 25 mL of the flocculant in 500 mL of 100 mg•L-1 dye solution.The decolorization efficiency was dependent on the flocculant dosage and solution pH.


Author(s):  
Hee-Jun Kim ◽  
Chan-Hee Won ◽  
Hyun-Woo Kim

This study investigates how the non-thermal plasma (NTP) process leads to advanced oxidation of sewage using response surface methodology. For environmentally viable and efficient operation of the NTP process, temperature and contact time were selected as two important independent variables. Their impacts on the performance were tested following an experimental design to figure out optimal operating conditions. Based on obtained treatment efficiency, statistically optimized conditions were derived by using an approach adapting the central composite design. Results show that coupling 40 °C of temperature and 4 h of contact time demonstrate optimal performance for total chemical oxygen demand (TCOD, 59%) and total suspended solids (85%), respectively. This implies that NTP may present efficient particulate destruction leading to organic solids dissolution. Statistical analysis reveals that the contact time shows more significant dependency than the temperature on the advanced oxidation of TCOD, possibly due to dissolved organic material. For total nitrogen removal, on the contrary, the optimal efficiency was strongly related to the higher temperature (~68 °C). This work provides an inroad to considering how NTP can optimally contribute to better oxidation of multiple pollutants.


2018 ◽  
Vol 34 ◽  
pp. 02039
Author(s):  
S. N. Sabri ◽  
C. Z. A. Abidin ◽  
Fahmi ◽  
S.H. Kow ◽  
N. A. Razali

The degradations characteristic of azo dye Reactive Green 19 (RG19) was investigated using advanced oxidation process (AOPs). It was evaluated based on colour and chemical oxygen demand (COD) removal. The effect of operational parameters such as initial dye concentration, initial dosage of hydrogen peroxide (H2O2), contact time, and pH was also being studied. The samples were treated by ozonation (O3) and peroxone O3/H2O2 process. Advanced oxidation processes (AOPs) involve two stages of oxidation; firstly is the formation of strong oxidant and secondly the reaction of organic contaminants in water. In addition, the term advanced oxidation is referring to the processes in which oxidation of organic contaminants occurs primarily through reactions with hydroxyl radicals. There are several analyses that use to determine the efficiency of the treatment process, which are UV-Vis absorption spectra, COD, Fourier Transform Infrared (FT-IR), and pH. The results demonstrated that the ozone oxidation was efficient in decolourization and good in mineralization, based on the reduction of colour and COD. Additionally, results indicate that H2O2 is able to perform better than ozonation in order to decolourize the dye wastewater with 0.5 mL H2O2/L dye dosage of H2O2 at different initial concentration, initial pH, with contact time.


2012 ◽  
Vol 627 ◽  
pp. 399-403
Author(s):  
Xiao Dan Fan ◽  
Xiang Kai Zhang

Heavy metal leaching limits activated carbon from sewage sludge (referred as ACS) to be used for wastewater treatment. Cr and Cd leaching from ACS exceed the permitted values. The leaching content of Cr and Cd decrease much with depositing ACS with chitosan (CS),below the permitted values. This is mainly due to the bind of Cr and Cd with the much group –NH2 of CS. The effects of initial dye concentration, pH and contact time had been studied. The dye adsorbed can act as a supple complexion agent with increasing initial dye concentration, increase the affinity for Cr and Cd. For Cd, the amount leaching of CS/ACS or ACS remains content with pH.The amount leaching of Cr decreases when the pH from 1 to 5 and then increases above the pH of 6.0. The contact time has no important influence on the leaching contents of Cr or Cd.


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