Effect of enzyme secreting bacterial pretreatment on enhancement of aerobic digestion potential of waste activated sludge interceded through EDTA

Kavitha, S.; Kumar, S. Adish; Yogalakshmi, K.N.; Kaliappan, S.; Banu, J. Rajesh

doi:10.1016/j.biortech.2013.10.021

Cited by 144 publications

(51 citation statements)

References 30 publications

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“…The results show that suspended solids and COD reduction is enhanced by deflocculation. The presently obtained SS reduction value of 53% is comparatively higher than 24% which was reported for a biological mode of sludge reduction (Kavitha et al 2013). In addition, the Fenton-mediated sludge reduction happens in relatively short retention time (30 min), when compared to other treatment processes (Vimala et al 2015).…”

Section: Total Cod Reduction and Suspended Solids Reductionmentioning

confidence: 72%

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Effect of deflocculation on the efficiency of sludge reduction by Fenton process

Amudha

Kavitha

Fernandez

et al. 2016

Environ Sci Pollut Res

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Section: Total Cod Reduction and Suspended Solids Reductionmentioning

confidence: 72%

“…Loosely Bound EPS (LB EPS), tightly bound EPS (TB EPS), and DNA were estimated by adopting the methods described by Yu et al (2009). Enzyme activity (protease and amylase) measurements were calculated as per the methodology described by Kavitha et al (2013).…”

Section: Methodsmentioning

confidence: 99%

Effect of deflocculation on the efficiency of sludge reduction by Fenton process

Amudha

Kavitha

Fernandez

et al. 2016

Environ Sci Pollut Res

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“…Multi-enzymatic hydrolysis is a biological technology of primary disintegration of sewage sludge. It accelerates and improves the efficiency of the natural process of hydrolysis [1] occurring in the first stage of sludge digestion, uses a number of naturally produced [2] or additionally dosed forms of [3] enzymes: amylase, protease [4] and lipase [5], which reduce the activation energy of the hydrolysis of selected organic compounds. As a result, the percentage of biodegradable organic matter increases, which provokes the increase in the efficiency of biogas production.…”

Section: Introductionmentioning

confidence: 99%

Application of multi-enzymatic hydrolysis for improving the efficiency of the biogas production in solid waste fermentation process in Ostróda WWTP

Lipiński

Umiejewska

2017

E3S Web Conf.

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Abstract. Biomass fermentation is one of the important sources of renewable energy in EU. Application of multi-enzymatic hydrolysis process enables a significant increase in efficiency of biogas production. The main goal of the paper is to present the results of the pilot scale research performed in WWTP in Ostróda. The fixed combination of three enzymes was continiously introduced: amylase, lipase and protease. Research aimed at verifying the impact of enzyme dose on sludge digestion process and on the amount of biogas produced. Statistical analysis of the research results allows to determine the influence of dosing the enzymes in mesophilic digestion on the biogas production.

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“…Besides the enhanced cell lysis caused by FNA pre-treatment, many studies show that both aerobic and anaerobic biodegradability of WAS is enhanced by removing the EPS from the WAS flocs, through lytic bacterial strains, by bacterially secreted enzymes or by addition of surfactant (Kavitha et al, 2013, Lakshmi et al, 2014. Therefore, FNA may also break down EPS by reacting with the macromolecules and changing their chemical structures.…”

Section: Introductionmentioning

confidence: 99%

“…In fact, EPS can account for up to 33~42% of the volatile solids in sludge (Frølund et al, 1996 and their components and structure have significant impacts on sludge biodegradability , Wang et al, 2007, Park et al, 2008. Many studies show that both aerobic and anaerobic biodegradability of WAS is enhanced effectively by removing the EPS from the WAS flocs, this being achieved through application of lytic bacterial strains, bacterial secreted enzymes or surfactant (Kavitha et al, 2013, Lakshmi et al, 2014. However, a detailed understanding of the role of EPS in FNA-based WAS pretreatment and the mechanisms in the combined pre-treatment with FNA and the oxidants are lacking, and such detail is in need for the application and optimization of the technology.…”

Section: Introductionmentioning

confidence: 99%

FNA-based pre-treatment of primary, secondary and digested sludge

Zhang¹

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Wastewater treatment plants (WWTP) are widely applied in practice to remove nutrients from wastewater and to minimize its impact when discharged to the environment. However, approximately 1/3 of the total organic carbon is converted into waste activated sludge (WAS), the treatment and disposal of which accounts for up to 20~60% of the overall costs of the wastewater treatment due to its poor biodegradability. In order to achieve sludge reduction and maximize the methane production from WAS, pre-treatment is often required. The overall objective of this thesis is to investigate the effects of free nitrous acid (FNA, i.e. HNO2) pre-treatment on the biodegradability of primary, secondary and digested sludges in WWTPs and also to reveal the mechanisms by which FNA works to improve the sludge degradability.The feasibility of a novel pre-treatment strategy using combined FNA and hydrogen peroxide (H2O2) to enhance methane production from WAS was investigated. WAS from a full-scale plant was treated with FNA alone (1.54 mg N/L), H2O2 alone (10~80 mg/g TS), and their combinations followed by biochemical methane potential (BMP) tests. Combined FNA and H2O2 pre-treatment substantially enhanced methane potential of WAS by 59~83%, compared to 13~23% and 56% with H2O2 pretreatment alone and FNA pre-treatment alone respectively. Model-based analysis indicated the increased methane potential was mainly associated with an increase of up to 163% in rapidly biodegradable fraction with combined pre-treatment. In some WWTPs, primary sludge (PS) and WAS are commonly mixed and digested simultaneously in the anaerobic digester. In order to reveal whether and how the PS and WAS should be jointly II treated by FNA in WWTPs, the effects and mechanisms of FNA pre-treatment on methane production from PS was studied. Full-scale derived PS was pre-treated with FNA at concentrations of 0~3.85 mg N/L followed by BMP tests. FNA treated PS was then centrifuged to separate the supernatant from the solid phase and BMP tests were performed on both fractions. The FNA pre-treatments resulted in methane potential reductions of 1~7%. The methane production from both supernatant and solid phases had also decreased. The molecular weight and chemical structure analysis of components of the soluble phase showed very limited release of readily biodegradable substances from PS with the FNA pre-treatment. As the FNA pre-treatment compromised the methane production from PS, this indicates that FNA-based sludge pre-treatment technology should be implemented solely on WAS to maximise the methane production from the two sludge streams.The ever increasing production of the two sludge streams occurring due to increased population will create challenges for handling, treatment and disposal of the sludge at current capacity, making it difficult to achieve the desirable sludge reduction efficiency in anaerobic digestion. Post anaerobic digestion of anaerobically digested sludge (ADS) has been applied to enhance sludge reduction, however, so far this has had on...

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Effect of enzyme secreting bacterial pretreatment on enhancement of aerobic digestion potential of waste activated sludge interceded through EDTA

Cited by 144 publications

References 30 publications

Effect of deflocculation on the efficiency of sludge reduction by Fenton process

Effect of deflocculation on the efficiency of sludge reduction by Fenton process

Application of multi-enzymatic hydrolysis for improving the efficiency of the biogas production in solid waste fermentation process in Ostróda WWTP

FNA-based pre-treatment of primary, secondary and digested sludge

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