Nitrite and free nitrous acid sludge pre-treatments to enhance methane production in continuous anaerobic digestion: Comparing process performance and associated costs

2019 ◽  
Vol 95 ◽  
pp. 526-534 ◽  
Author(s):  
Maycoll Romero-Güiza ◽  
Soraya Zahedi ◽  
Victor Monsalvo ◽  
Pilar Icaran ◽  
Maite Pijuan
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Nitrous Acid ◽  
Process Performance ◽  
Free Nitrous Acid ◽  
Acid Sludge

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.

Combining partial nitritation and heterotrophic denitritation for the treatment of landfill leachate previous to an anammox reactor

2010 ◽  
Vol 61 (8) ◽  
pp. 1949-1955 ◽  
Author(s):  
R. Ganigué ◽  
J. Gabarró ◽  
H. López ◽  
M. Ruscalleda ◽  
M. D. Balaguer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Total Nitrogen ◽  
Landfill Leachate ◽  
Nitrous Acid ◽  
Process Performance ◽  
Free Nitrous Acid ◽  
Partial Nitritation ◽  
Feed Strategy ◽  
The Stability ◽  
Conventional Systems

Landfill leachate can present extremely elevated concentrations of ammonium (up to 6,000 mg N-NH4+ L−1) and a low biodegradable organic matter fraction. As an alternative to conventional systems, this wastewater can be treated on a more sustainable way by a fully autotrophic partial nitritation–anammox system. The operation of the first step of this system, the partial nitritation, is critical since the elevated concentrations of ammonium and nitrite in the reactor can severely inhibit ammonium oxidizing bacteria (AOB) activity. In this way, the inclusion of anoxic phases during the feeding events to promote the denitrification via nitrite can be a good option for upgrading the process performance and increasing the stability of the system. This paper deals with the evaluation of an anoxic–aerobic step-feed strategy for the operation of a partial nitritation SBR. Results of this study have revealed a decrease on the total nitrogen inside the reactor of more than 200 mg N L−1 without prejudice on the partial nitritation process. Furthermore, this study has also allowed detecting an AOB activity reduction at the end of aerobic phases due to bicarbonate limitation and/or free nitrous acid inhibition.

Free Nitrous Acid (FNA)-Based Pretreatment Enhances Methane Production from Waste Activated Sludge

2013 ◽  
Vol 47 (20) ◽  
pp. 11897-11904 ◽  
Author(s):  
Qilin Wang ◽  
Liu Ye ◽  
Guangming Jiang ◽  
Paul D. Jensen ◽  
Damien J. Batstone ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Methane Production ◽  
Nitrous Acid ◽  
Waste Activated Sludge ◽  
Free Nitrous Acid

scholarly journals Synergy of combined free nitrous acid and Fenton technology in enhancing anaerobic digestion of actual sewage waste activated sludge

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Razieh Karimi ◽  
Seyed Mostafa Hallaji ◽  
Salar Siami ◽  
Ali Torabian ◽  
Behnoush Aminzadeh ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Nitrous Acid ◽  
Waste Activated Sludge ◽  
Free Nitrous Acid ◽  
Sewage Waste

Enhanced methane production from algal digestion using free nitrous acid pre-treatment

2016 ◽  
Vol 88 ◽  
pp. 383-390 ◽  
Author(s):  
Xue Bai ◽  
Paul A. Lant ◽  
Paul D. Jensen ◽  
Sergi Astals ◽  
Steven Pratt
Keyword(s):  
Methane Production ◽  
Nitrous Acid ◽  
Free Nitrous Acid ◽  
Pre Treatment
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