Influence of plants on microbial activity in a vertical-downflow wetland system treating waste activated sludge with high organic matter concentrations

2012 ◽  
Vol 95 ◽  
pp. S158-S164 ◽  
Author(s):  
Runying Wang ◽  
Virginie Baldy ◽  
Claude Périssol ◽  
Nathalie Korboulewsky
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Microbial Activity ◽  
Waste Activated Sludge ◽  
High Organic Matter ◽  
Wetland System

Determination of Main Components in the Excess Activated Sludge

2012 ◽  
Vol 534 ◽  
pp. 249-252 ◽  
Author(s):  
Rui Jing Su ◽  
Deng Xin Li
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Waste Activated Sludge ◽  
Measurement Results ◽  
Main Components

In the study, we determine the content of the main components, i.e., protein, polysaccharides and lipids in the excess activated sludge. The measurement results were consistent with those obtained before. In conclusion, the research indicated that the waste activated sludge consisted of 73.85% organic matter, 58.1% protein, 10.39 mg/g carbohydrate, less than 1% lipid.

scholarly journals The synergy of combined free nitrous acid and Fenton technology in enhancing anaerobic digestion of real sewage waste activated sludge

2019 ◽  
Author(s):  
Razieh Karimi ◽  
Seyed Mostafa Hallaji
Keyword(s):  
Organic Matter ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Methane Production ◽  
Nitrous Acid ◽  
Waste Activated Sludge ◽  
Free Nitrous Acid ◽  
Digestion Process ◽  
Treatment Technologies ◽  
Pre Treatment

Abstract Background Recently, free nitrous acid (FNA) pre-treatment of sewage waste activated sludge has been introduced as an economically attractive and environmentally friendly technique for enhancing methane production from the anaerobic digestion process. Fenton pre-treatment of sewage sludge, as an advanced oxidation process, has also been introduced as a powerful technique for methane improvement in a couple of studies. This study, for the first time, investigates the synergy of combined FNA and Fenton pre-treatment technologies in enhancing the methane production from the anaerobic digestion process and reducing waste sludge to be disposed of. Actual secondary waste activated sludge in laboratory-scale batch reactors was used to assess the synergistic effect of the pre-treatments. The mechanisms behind the methane enhancement were also put into perspective by measuring different microbial enzymes activity and solubilisation of organic matter. Result This study revealed that the combined pre-treatments release organic matter into the soluble phase significantly more than the bioreactors pre-treated with individual FNA and Fenton. For understanding the influence of pre-treatments on solubilisation of organic matter, soluble protein, soluble polysaccharide and soluble chemical oxygen demand (SCOD) were measured before and after the treatments and it was shown that they respectively increased by 973%, 33% and 353% after the treatments. Protease and cellulose activity, as the key constituents of the microbial community presenting in activated sludge, decreased considerably within the combined pre-treatments (42% and 32% respectively) and methane production enhanced by 43-69%. Furthermore, total solids and volatile solids destruction improved by 26% and 24% at the end of anaerobic digestion, which can reduce transport costs of sludge and improve the quality of sludge for application in farms and forests. Conclusions The results obtained from the experiments corroborate the synergic effect of the combined FNA and Fenton pre-treatment technologies in degrading the organic and microbial constituents in waste activated sludge, which improved methane production accordingly. This is of paramount importance because the total costs of wastewater treatment plants operation and greenhouse gas emission from sludge treatment and disposal processes would reduce considerably, which pave the way for the implementation of these technologies.

scholarly journals Effects of Waste Activated Sludge Extracellular Polymeric Substances on Biosorption

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 218
Author(s):  
Tiow Ping Wong ◽  
Roger W. Babcock ◽  
Theodore Uekawa ◽  
Joachim Schneider ◽  
Bing Hu
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Humic Acids ◽  
Extracellular Polymeric Substances ◽  
Contact Process ◽  
Cation Exchange Resin ◽  
Waste Activated Sludge ◽  
Untreated Wastewater ◽  
Biosorption Process ◽  
Raw Wastewater

Extracellular polymeric substances (EPS) reportedly make up approximately half of the organic matter in activated sludge (AS), and therefore strongly influence AS properties. This study evaluated the component fractions of EPS normalized to volatile suspended solids (VSS) in waste activated sludge (WAS) from a trickling-filter-solids contact process (TF/SC) and its ability to biosorb organic matter from raw wastewater with 30 min of contact time. Biosorption is the process in which organic matter (carbohydrates, proteins, humic acids, DNA, uronic acids, and lipids) in a sorbate, such as raw wastewater, sorbs onto a sorbent such as WAS. A statistically significant correlation was found between both the total concentration of EPS and the proteins component of the EPS and the biosorption removal of soluble chemical oxygen demand (sCOD) and truly soluble COD (ffCOD). Thus, the biosorption of soluble forms of COD can accurately be predicted by quantifying just the amount of proteins in WAS-associated EPS. No significant correlations were found for the biosorption of colloidal COD (cCOD). WAS biosorbed 45–75 mg L−1 of COD in 30 min. WAS absorbed or stored the proteins fraction of the soluble microbial products (SMP) during the biosorption process. Higher concentrations of humic acids were found in the biosorption process effluent than in the untreated wastewater, which warrants further study. Longer cation exchange resin (CER) extraction times yielded more total EPS from the sludge: 90 ± 9, 158 ± 3, and 316 ± 44 mg g−1 VSS, for 45-min, 4-h, and 24-h extraction times, respectively. Thus, EPS extracted represented only 9%, 15.8%, and 31.6% of the VSS, respectively, raising questions about whether the accurate characterization of EPS can be performed using the typical extraction time of 45 min due to different extraction rates for different components. It was found that the humic acids fraction was extracted much more slowly than the other fractions.

scholarly journals Genome-Centric Metagenomic Insights into the Impact of Alkaline/Acid and Thermal Sludge Pretreatment on the Microbiome in Digestion Sludge

2020 ◽  
Vol 86 (23) ◽  
Author(s):  
Zhiwei Liang ◽  
Jiangjian Shi ◽  
Chen Wang ◽  
Junhui Li ◽  
Dawei Liang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Activated Sludge ◽  
Metabolic Networks ◽  
Waste Activated Sludge ◽  
Metabolic Potential ◽  
Sludge Digestion ◽  
Sludge Pretreatment ◽  
A Genome ◽  
Unique Source ◽  
The Impact

ABSTRACT Pretreatment of waste-activated sludge (WAS) is an effective way to destabilize sludge floc structure and release organic matter for improving sludge digestion efficiency. Nonetheless, information on the impact of WAS pretreatment on digestion sludge microbiomes, as well as mechanistic insights into how sludge pretreatment improves digestion performance, remains elusive. In this study, a genome-centric metagenomic approach was employed to investigate the digestion sludge microbiome in four sludge digesters with different types of feeding sludge: WAS pretreated with 0.25 mol/liter alkaline/acid (APAD), WAS pretreated with 0.8 mol/liter alkaline/acid (HS-APAD), thermally pretreated WAS (thermal-AD), and fresh WAS (control-AD). We retrieved 254 metagenome-assembled genomes (MAGs) to identify the key functional populations involved in the methanogenic digestion process. These MAGs span 28 phyla, including 69 yet-to-be-cultivated lineages, and 30 novel lineages were characterized with metabolic potential associated with hydrolysis and fermentation. Interestingly, functional populations involving carbohydrate digestion were enriched in APAD and HS-APAD, while lineages related to protein and lipid fermentation were enriched in thermal-AD, corroborating the idea that different substrates are released from alkaline/acid and thermal pretreatments. Among the major functional populations (i.e., fermenters, syntrophic acetogens, and methanogens), significant correlations between genome sizes and abundance of the fermenters were observed, particularly in APAD and HS-APAD, which had improved digestion performance. IMPORTANCE Wastewater treatment generates large amounts of waste-activated sludge (WAS), which consists mainly of recalcitrant microbial cells and particulate organic matter. Though WAS pretreatment is an effective way to release sludge organic matter for subsequent digestion, detailed information on the impact of the sludge pretreatment on the digestion sludge microbiome remains scarce. Our study provides unprecedented genome-centric metagenomic insights into how WAS pretreatments change the digestion sludge microbiomes, as well as their metabolic networks. Moreover, digestion sludge microbiomes could be a unique source for exploring microbial dark matter. These results may inform future optimization of methanogenic sludge digestion and resource recovery.

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