Effect of free nitrous acid pre-treatment on primary sludge at low exposure times

Zahedi, S.; Icaran, Pilar; Yuan, Zhiguo; Pijuan, Maite

doi:10.1016/j.biortech.2016.12.117

Cited by 33 publications

(11 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, during the first 5 days of the digestion process, the volume of biogas produced from the pre-treated rectors was slightly lower than that of the control, and it gradually overtook the volume of the control after 5 days. This is in agreement with previous studies in which a slight delay in biogas yield from pre-treated bioreactors was observed [ 18 , 25 , 26 ]. This is likely due to slight inhibitory effect on anaerobic organisms’ activity, which is produced by low nitrite/FNA concentration and probably also by overloading the pre-treated reactors with soluble organic matter that could produce a delay in the biogas production [ 27 ].…”

Section: Resultssupporting

confidence: 94%

Improvement of anaerobic digestion of sewage mixed sludge using free nitrous acid and Fenton pre-treatment

Hallaji

Torabian

Aminzadeh

et al. 2018

Biotechnol Biofuels

View full text Add to dashboard Cite

BackgroundRecently, it has been indicated that free nitrous acid (FNA) and Fenton pre-treatment of waste activated sludge can enhance methane production in anaerobic digestion of waste activated sludge. In addition, it has been revealed that the substances used in these pre-treatments are both eco-friendly and economically attractive because not only are they produced in anaerobic digestion, but they are also low priced. Since primary sludge and waste activated sludge are mixed prior to anaerobic digestion in the majority of wastewater treatment plants, this study aims to assess the influence of combined FNA and Fenton on the anaerobic digestion of mixed sludge.ResultsAccording to this study’s results, methane generation from anaerobic digestion of mixed sludge was enhanced when using FNA and Fenton pre-treatment, affirming the effectiveness of the individual and combined pre-treatments in anaerobic digestion of mixed sludge. The enhanced methane production was significant in combined pre-treatments (up to 72%), compared with FNA and Fenton pre-treatment alone (25% and 27%, respectively). This corroborates the positive synergistic effect of the combined pre-treatments on methane production. The enhanced methane can be attributed to augmented soluble fractions of organic matter in addition to increased readily biodegradable organic matter, caused by the pre-treatments. Additionally, the amount of chemical oxygen demand (COD) was assessed during anaerobic digestion, and it was revealed that COD decreased considerably when the pre-treatment strategies were combined.ConclusionsThis study reveals that the pre-treatments are potentially applicable to full-scale wastewater treatment plants because a mixture of primary sludge and waste activated sludge was used for the pre-treatments. Additionally, combined FNA and Fenton pre-treatments prove more effective in enhancing methane production and organic removal than these pre-treatments alone. The enhanced methane production is important for two reasons: a higher amount of renewable energy could be generated from the enhanced methane production and the COD of digested sludge reduces in such a way that facilitates application of the sludge to agricultural lands and reduces sludge transport costs.Electronic supplementary materialThe online version of this article (10.1186/s13068-018-1235-4) contains supplementary material, which is available to authorized users.

show abstract

Section: Resultssupporting

confidence: 94%

Improvement of anaerobic digestion of sewage mixed sludge using free nitrous acid and Fenton pre-treatment

Hallaji

Torabian

Aminzadeh

et al. 2018

Biotechnol Biofuels

View full text Add to dashboard Cite

show abstract

“…These conditions have been demonstrated to significantly enhance methane production (Zahedi et al, 2017a(Zahedi et al, , 2017b(Zahedi et al, , 2016). …”

Section: Fna Pre-treatment and Bmp Testsmentioning

confidence: 99%

“…However when a source of nitrite is not available in wastewater treatment plants (WWTPs), this pre-treatment can become expensive due to the costs associated with the purchase of commercial nitrite and hydrochloric acid to achieve high FNA concentrations (Zahedi et al, 2017a). It is a priority for the industry that new sludge pre-treatments do not incur more costs than the benefits associated with the enhancement in methane production.…”

Section: Introductionmentioning

confidence: 99%

Exploring alternatives to reduce economical costs associated with FNA pre-treatment of waste activated sludge

Zahedi¹,

Icaran

Yuan

et al. 2017

Bioresource Technology

Self Cite

View full text Add to dashboard Cite

Please cite this article as: Zahedi, S., Icaran, P., Yuan, Z., Pijuan, M., Exploring alternatives to reduce economical costs associated with FNA pre-treatment of waste activated sludge, Bioresource Technology (2017), doi: http:// dx.doi.org/10. 1016/j.biortech.2017.06.140 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractRecent studies have shown the effectiveness of Free Nitrous Acid (FNA) pre-treatment in enhancing sludge biodegradability and improving its methane production potential. FNA is regarded as an environmental friendly pre-treatment which can be easily applied when a source of nitrite is present in wastewater treatment plants. However, when nitrite is not available and needs to be purchased, this treatment can become less attractive due to the costs associated to nitrite. In order to overcome this possible limitation, two different strategies to optimize the use of nitrite during FNA treatment were investigated: i) Recovering NO2-after the pre-treatment is completed; and ii) Concentrating the sludge before FNA pre-treatment. Results show that recovering NO2-from the pre-treated sludge is not suitable due to the loss of soluble organic matter present in the supernatant after the pre-treatment. However, concentrating the sludge before the pre-treatment seems a good strategy to optimize the use of nitrite.

show abstract

“…Sludge, as the residue waste of wastewater treatment processes, is commonly generated from wastewater treatment plants (WWTPs) . According to the different treatment processes, sludge can be divided into primary sludge, waste activated sludge, biofilm sludge, digested sludge and chemical precipitated sludge . On the other hand, sludge is divided into municipal sludge and industrial sludge according to different sources .…”

Section: Introductionmentioning

confidence: 99%

Strategies of valorization of sludge from wastewater treatment

Sheng

Zhang

2018

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

Sludge is regarded as a potential source to achieve valorization via strategies such as resource recovery, sludge based adsorbents preparation, bioflucculants production, sludge manufacturing construction materials preparation, sludge composting and thermal valorization, which are currently common and effective strategies. Appropriate treatment strategies of sludge are of great importance worldwide for the fast growing population and rapidly increasing waste. This mini review summarized some widely used and effective strategies to achieve sludge valorization based on whether the strategy would utilize or reuse the potential of sludge to obtain valuable product and eliminate secondary pollution. Anaerobic digestion of sludge is perceived as a potentially cost‐effective method to achieve sludge reduction and resource recovery including carbon, nitrogen, phosphorus resource recovery coupled with other technologies. Utilizing sludge as raw material for preparation of valuable products including sludge based adsorbents, bioflocculants and construction materials is another aspect to achieve sludge valorization. Sludge composting and thermal valorization are also introduced in the mini review since the two strategies could also achieve sludge valorization. In addition, the strategies mentioned were discussed and analyzed in the mini review from environmental and economic aspects. © 2017 Society of Chemical Industry

show abstract

Effect of free nitrous acid pre-treatment on primary sludge at low exposure times

Cited by 33 publications

References 24 publications

Improvement of anaerobic digestion of sewage mixed sludge using free nitrous acid and Fenton pre-treatment

Improvement of anaerobic digestion of sewage mixed sludge using free nitrous acid and Fenton pre-treatment

Exploring alternatives to reduce economical costs associated with FNA pre-treatment of waste activated sludge

Strategies of valorization of sludge from wastewater treatment

Contact Info

Product

Resources

About