A Review on Utilization of Organic Matters in Activated Sludge

2013 ◽  
Vol 773 ◽  
pp. 353-361
Author(s):  
Guang Jie Duan ◽  
Rui Jing Su ◽  
Deng Xin Li
Keyword(s):  
Wastewater Treatment ◽  
Physicochemical Properties ◽  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Land Reclamation ◽  
Chemical Compositions ◽  
Organic Matters ◽  
Treatment Practices ◽  
Treatment And Disposal ◽  
And Function

Activated sludge process has been applied worldwide in municipal and industrial wastewater treatment practices. Excess sewage sludge, produced in sedimentation after wastewater bio-treatment, is an inevitable by-product of wastewater treatment processes. In any case sludge treatment and disposal should always be considered as an integral part of treatment of wastewater. Currently, the most widely available options in the world are the agriculture utilization, the waste disposal sites, the land reclamation and restoration, the incineration and other novel uses. Extracellular polymeric substances (EPS), as high-molecular weight compounds are secreted by activated sludge microorganisms, which can significantly influence the physicochemical properties and function of activated sludge flocs. Because of the crucial roles of EPS, many researchers have been made to explore their chemical compositions and physicochemical properties. Polysaccharides, humic substances and proteins are usually found to be the major components of EPS. The present paper sought to review past and future trends in sludge handling, focusing mainly at the organic matters.

Tanneries: A Short Survey of the Methods Applied for Wastewater Treatment

1986 ◽  
Vol 18 (9) ◽  
pp. 69-76 ◽  
Author(s):  
D. Tsotsos
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Production Process ◽  
Quantitative Data ◽  
Biological Systems ◽  
Treatment Plant ◽  
Short Description ◽  
Qualitative And Quantitative ◽  
Effluent Discharge ◽  
Treatment And Disposal

A short description of the tannery production process is given, mentioning the main points related to an effluent discharge. Qualitative and quantitative data are presented and several methods used for wastewater treatment are also reviewed. It is stated that biological systems (activated sludge) cannot be operated in the same way as for municipal effluents, since tne main pollutants (Cr - salts, sulfides) negatively affect the action of microorganisms. Therefore, a pretreatment step is required prior to the effluent discharge into a municipal treatment plant. Another problem is the treatment and disposal of the precipitated sludge. Several already applied methods trying to eliminate the problem are discussed. All represented data are taken from research studies published in international 1iterature.

Diversity and metabolic potentials of As(III)-oxidizing bacteria in activated sludge

2021 ◽  
Author(s):  
Rui Xu ◽  
Duanyi Huang ◽  
Xiaoxu Sun ◽  
Miaomiao Zhang ◽  
Dongbo Wang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Carbon Fixation ◽  
Stable Isotope Probing ◽  
Synthetic Wastewater ◽  
Contaminated Water ◽  
Natural Environments ◽  
Genes Encoding ◽  
Treatment Facilities

Biological arsenite (As(III)) oxidation is an important process in the removal of toxic arsenic (As) from contaminated water. However, the diversity and metabolic potentials of As(III)-oxidizing bacteria (AOBs) responsible for As(III) oxidation in wastewater treatment facilities are not well documented. In this study, two groups of bioreactors inoculated with activated sludge were operated under anoxic or oxic conditions to treat As-containing synthetic wastewater. Batch tests of inoculated sludges from the bioreactors further indicated that microorganisms could use nitrate or oxygen as electron acceptors to stimulate biological As(III) oxidation, suggesting the potentials of this process in wastewater treatment facilities. In addition, DNA-based stable isotope probing (DNA-SIP) was performed to identify the putative AOBs in the activated sludge. Bacteria associated with Thiobacillus were identified as nitrate-dependent AOBs, while bacteria associated with Hydrogenophaga were identified as aerobic AOBs in activated sludge. Metagenomic binning reconstructed a number of high-quality metagenome-assembled genomes (MAGs) associated with the putative AOBs. Functional genes encoding for As resistance, As(III) oxidation, denitrification, and carbon fixation were identified in these MAGs, suggesting their potentials for chemoautotrophic As(III) oxidation. In addition, the presence of genes encoding secondary metabolite biosynthesis and extracellular polymeric substance metabolism in these MAGs may facilitate the proliferation of these AOBs in activated sludge and enhance their capacity for As(III) oxidation. Importance AOBs play an important role in the removal of toxic arsenic from wastewater. Most of the AOBs have been isolated from natural environments. However, knowledge regarding the structure and functional roles of As(III)-oxidizing communities in wastewater treatment facilities are not well documented. The combination of DNA-SIP and metagenomic binning provides an opportunity to elucidate the diversity of in situ AOBs community inhabited the activated sludges. In this study, the putative AOBs responsible for As(III) oxidation in wastewater treatment facilities were identified, and their metabolic potentials including As(III) oxidation, denitrification, carbon fixation, secondary metabolites biosynthesis, and extracellular polymeric substances metabolisms were investigated. This observation provides an understanding of anoxic and/or oxic AOBs during the A(III) oxidation process in wastewater treatment facilities, which may contribute to the removal of As from contaminated water.

The Effect of Ferric Ion and Copper Ion on Extracellular Polymeric Substances

2012 ◽  
Vol 260-261 ◽  
pp. 1035-1040 ◽  
Author(s):  
Li Yun Ge ◽  
Huan Huan Deng ◽  
De Xiang Gao ◽  
Hong Wu Wang
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Metal Ion ◽  
Extracellular Polymeric Substances ◽  
Copper Ion ◽  
Total Content ◽  
Biological Wastewater Treatment ◽  
Ferric Ion ◽  
Main Components

Extracellular polymeric substances (EPS), which are vital cellular polymeric substances, play an important role in biological wastewater treatment. In this paper, four SBRs (blank, added 20mg/L Fe3+, added 40mg/L Cu2+, added both 20mg/L Fe3+ and 40mg/L Cu2+, respectively) were used to investigate the effect of Fe3+ and Cu2+ on EPS produced by microorganism from activated sludge. Carbohydrate and protein were main components of EPS. The total content of EPS, the content of protein and carbohydrate, and the content of DNA in EPS were detected. The results show metal ion had an effect on the formation of EPS and the total content of the EPS. The effect of ferric ion on protein was more obvious than copper ion. Furthermore, the addition of metal ion had little effect on DNA in EPS.

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