scholarly journals Microbial communities in biological denitrification system using methanol as carbon source for treatment of reverse osmosis concentrate from coking wastewater

2017 ◽  
Vol 8 (3) ◽  
pp. 360-371 ◽  
Author(s):  
Enchao Li ◽  
Xuewen Jin ◽  
Shuguang Lu

Abstract A biological denitrifying process using methanol as a carbon source was employed for the treatment of reverse osmosis concentrate (ROC) from coking wastewater in a sequencing batch reactor (SBR). The results showed that the average removal efficiencies of chemical oxygen demand (COD), total organic carbon, total nitrogen and nitrate were 81.4%, 83.7%, 90.6% and 92.9%, respectively. Different microbial communities were identified on the MiSeq platform, showing that the most abundant bacterial phyla were Proteobacteria and Bacteroidetes, the sum of which, in this study, accounted for almost over 92%. The key genera responsible for denitrification were Hyphomicrobium, Thauera and Methyloversatilis. Quantitative real-time polymerase chain reaction was used to quantify the absolute abundances of microbial genera by using 16S rRNAs and denitrifying genes, such as narG, nirS and nirK, during both start-up and stable operations in the SBR. nirS was much more abundant than nirK, thus became the main functional gene to execute nitrite reduction. The high removal efficiency of COD and nitrate suggests that a biological denitrifying process using SBR is an effective technique for treating ROC from coking wastewater.

2017 ◽  
Vol 76 (12) ◽  
pp. 3289-3298 ◽  
Author(s):  
Enchao Li ◽  
Shuguang Lu

Abstract A biological denitrifying process was employed for the treatment of nanofiltration (NF) concentrate with high conductivity, which was generated from coking wastewater in a sequencing batch reactor (SBR). The results showed that the average removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and nitrate were 47.6%, 61.1% and 94.6%, respectively. Different microbial communities were identified by sequencing the V1-V3 region of the 16S rRNA gene using the MiSeq platform, showing that the most abundant bacterial phylum in the SBR system was Proteobacteria, with the subclasses β-Proteobacteria and α-Proteobacteria being dominant. The key microorganisms responsible for denitrification belonged to the genera Thauera, Hyphomicrobium, Methyloversatilis, Hydrogenophaga, Ignavibacterium, Rubrivivax and Parvibaculum. Quantitative real-time polymerase chain reaction was used to assess the absolute abundance of microbial genera, using 16S rRNAs and denitrifying genes such as narG, nirS, nirK, nosZ, in both SBR start-up and stable operation. The abundances of narG, nirK and nosZ were lower during stable operation than those during the start-up period. The abundance of nirS at a level of 104–105copies/ng in DNA was much higher than that of nirK, thus being the dominant functional gene in nitrite reduction.


2012 ◽  
Vol 65 (7) ◽  
pp. 1238-1243 ◽  
Author(s):  
Guochao Li ◽  
Jie Chen ◽  
Tao Yang ◽  
Jianqi Sun ◽  
Shenglu Yu

In this research the agricultural by-product corncob was investigated as a carbon source as well as a biofilm carrier to remove organic matter, expressed as chemical oxygen demand (COD) and nitrate nitrogen (nitrate-N), from wastewater in a batch laboratory reactor. The performance of a reactor with corncob as the carbon source and the biofilm carrier was compared with a control batch reactor with suspended plastic carriers and glucose as the sole carbon source. With 60 vol% of corncob carriers inside the reactor, a soluble COD/N ratio of 4.2 g COD g N−1 was enough for total denitrification, nearly half of the control reactor (9.5 g COD g N−1), at 23 h reaction time. The specific denitrification rate decreased with increasing soluble COD consumption for both reactors. Nitrate and COD removal efficiencies decreased with shorter retention times, with accentuated effects in the reactor. This study suggested corncob as a feasible carbon source and that reaction time was a limiting factor with corncob used as the carbon source for denitrification.


2016 ◽  
Vol 73 (10) ◽  
pp. 2324-2331 ◽  
Author(s):  
Changyong Wu ◽  
Yuexi Zhou ◽  
Jiamei Song

A sequencing batch reactor was used to investigate the effect of carbon sources on the metabolism of activated sludge. Acetate and phenol, with the chemical oxygen demand (COD) of 330–350 mg L−1, was used as the carbon source in Periods I and II, respectively. Acetate decreased in the initial 120 min with the intracellular storage materials (XSTO), extracellular polymeric substances (EPS), and the soluble microbial products (SMP) accumulating to 131.0 mg L−1, 347.5 mg L−1, and 35.5 mg L−1, respectively. Then, XSTO and EPS decreased to 124.5 mg L−1 and 340.0 mg L−1, respectively, in the following 120 min. When acetate was replaced by phenol, it could not be used at the beginning due to its toxicity. The XSTO decreased from 142 mg L−1 to 54.6 mg L−1 during the aeration period. The EPS had a significant increase, with the highest value of 618.1 mg L−1, which then decreased to 245.6 mg L−1 at 240 min. The phenol was gradually degraded with the acclimation and it can be fully degraded 18 d later. Meanwhile, the usage ratio of the internal carbon source decreased. The effluent SMP in Period II was 1.7 times that in Period I.


2019 ◽  
Vol 1 (2) ◽  
pp. 1
Author(s):  
Lindawati Lindawati

Sebuah Sequencing Batch Reactor (SBR) digunakan untuk mengevaluasi peranan Biochemical Oxygen Demand (BOD) biosensor dalam proses optimasi proses pengolahan nutrien karbon, nitrogen dan fosfat. Hasil penelitian menunjukkan bahwa BOD biosensor dapat dipergunakan untuk penentuan karbon organik, sehingga reduksi siklus SBR dapat dilakukan dan efisiensi proses meningkat. Pola konsumsi karbon organik ditemukan dengan adanya ‘tanda diam’ pada fase anoksik/ anaerobik, di mana dari tanda ini, fase aerobik dapat segera dimulai. Reduksi durasi siklus SBR dari 8 jam menjadi 4 jam meningkatkan efiesiensi pengolahan C, N dan P yang meningkat pula (hampir dua kali lebih tinggi).


2013 ◽  
Vol 726-731 ◽  
pp. 2521-2525
Author(s):  
Zhi Yong Zhang ◽  
De Li Wu

Coking wastewater is a kind of recalcitrant wastewater including complicate compositions. Advanced treatment of coking wastewater by Fenton-Like reaction using pyrite as catalyst was investigated in this paper. The results show that the chemical oxygen demand (COD) of coking wastewater decreased significantly by method of coagulation combined with two-stage oxidation reaction. COD of wastewater can decrease from 250mg/l to 45mg/l after treatment, when 2g/L pyrite was used in each stage oxidation and the dosage of hydrogen peroxide (H2O2) is 0.2ml/l for first stage treatment, 0.1ml/l for second stage treatment respectively. The pyrite is effective to promote Fenton-Like reaction with low cost due to high utilization efficiency of H2O2, moreover, catalyst could be easily recovered and reused. The Fenton-Like reaction might be used as a potential alternative to advanced treatment of recalcitrant wastewater.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3557
Author(s):  
Athina Mandalenaki ◽  
Nicolas Kalogerakis ◽  
Eleftheria Antoniou

Typically, oil pollution cleanup procedures following first response actions include dispersion. Crude oil is biodegradable, and its bioavailability can be increased when dispersed into very fine droplets by means of chemical surfactants. Although their use is widely spread in many applications, the latter may prove toxic, depending on the extent of use. The use of biological means, such as bioremediation and biosurfactants, has emerged over the past years as a very promising ‘green’ alternative technology. Biosurfactants (BSs) are amphiphilic molecules produced by microorganisms during biodegradation, thus increasing the bioavailability of the organic pollutants. It is their biodegradability and low toxicity that render BSs as a very promising alternative to the synthetic ones. Alcanivorax borkumensis SK2 strain ability to produce BSs, without any impurities from the substrate, was investigated. The biosurfactant production was scaled up by means of a sequencing batch reactor (SBR) and a heavy oil residue substrate as the carbon source. The product is free from substrate impurities, and its efficiency is tested on oil bioremediation in the marine environment. The product’s dispersion efficiency was determined by the baffled flask test. The production method proposed can have a significant impact to the market, given the ever-increasing demand for ecologically friendly, reliable, commercially viable and economically competitive environmental cleanup techniques.


2021 ◽  
Vol 11 (2) ◽  
pp. 510
Author(s):  
Elza R. Mikheeva ◽  
Inna V. Katraeva ◽  
Andrey A. Kovalev ◽  
Dmitriy A. Kovalev ◽  
Alla N. Nozhevnikova ◽  
...  

This article presents the results of the start-up of continuous production of biohydrogen from cheese whey (CW) in an anaerobic filter (AF) and anaerobic fluidized bed (AFB) with a polyurethane carrier. Heat and acid pretreatments were used for the inactivation of hydrogen-scavengers in the inoculum (mesophilic and thermophilic anaerobic sludge). Acid pretreatment was effective for thermophilic anaerobic sludge to suppress methanogenic activity, and heat treatment was effective for mesophilic anaerobic sludge. Maximum specific yields of hydrogen, namely 178 mL/g chemical oxygen demand (COD) and 149 mL/g COD for AFB and AF, respectively, were obtained at the hydraulic retention time (HRT) of 4.5 days and organic load rate (OLR) of 6.61 kg COD/(m3 day). At the same time, the maximum hydrogen production rates of 1.28 and 1.9 NL/(L day) for AF and AFB, respectively, were obtained at the HRT of 2.02 days and OLR of 14.88 kg COD/(m3 day). At the phylum level, the dominant taxa were Firmicutes (65% in AF and 60% in AFB), and at the genus level, Lactobacillus (40% in AF and 43% in AFB) and Bifidobacterium (24% in AF and 30% in AFB).


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