Iron salts dosage for sulfide control in sewers induces chemical phosphorus removal during wastewater treatment

Gutiérrez, Oriol; Park, Donghee; Sharma, Keshab; Yuan, Zhiguo

doi:10.1016/j.watres.2010.03.023

Cited by 132 publications

(101 citation statements)

References 14 publications

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“…Additionally, due to the possible occurrence of anoxic zones, being formed by clumps of worms, the microbial reduction of Fe 3+ to Fe 2+ might have had occurred. However, this is not very likely as this would result in ferrous precipitation with soluble phosphate [82,83]. These precipitates would be included in the total iron concentration, which would therefore not change.…”

Section: Total and Dissolved Cationsmentioning

confidence: 99%

Physical and biochemical changes in sludge uponTubifex tubifexpredation

Valk

Khadem

Foreman

et al. 2016

Environmental Technology

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Worm predation (WP) on activated sludge leads to increased sludge degradation rates, irrespective of the type of worm used or reactor conditions employed. However, the cause of the increased sludge degradation rates remains unknown. This paper presents a comparative analysis of the physical and biochemical aspects of predated sludge, providing insight into the hydrolytic mechanisms underlying WP. To this end, the sessile worm Tubifex tubifex was used as a model oligochaete and was batch cultivated in an 18-L airlift reactor. Predation on activated sludge showed an average reduction rate of 12 ± 3.8%/d versus 2 ± 1.3%/d for endogenous respirated sludge. Sludge predation resulted in an increased release of inorganic nitrogen, phosphate and soluble chemical oxygen demand (sCOD). The sCOD consisted mainly of polysaccharides; however, fluorescence excitation emission matrix spectroscopy analysis also revealed the presence of Tryptophan-protein-like substances. Results suggest that the released polysaccharides contain a protein-like element. Additionally, soluble iron increased slightly in concentration after WP. The extent of hydrolysis seemed to reach an average plateau of about 40% volatile solids (VS) reduction after 4 days, which is substantially higher than the 29% VS reduction for endogenous decay of activated sludge after 30 days. Furthermore, T. tubifex predominantly consumed the protein fraction of the extracellular polymeric substances. Results suggest that that the worms specifically target a fraction of the sludge that is predominantly biodegradable under aerobic conditions, albeit at significantly higher degradation rates when compared to the endogenous decay of waste activated sludge. ARTICLE HISTORY

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Section: Total and Dissolved Cationsmentioning

confidence: 99%

Physical and biochemical changes in sludge uponTubifex tubifexpredation

Valk

Khadem

Foreman

et al. 2016

Environmental Technology

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“…Those include the addition to the sewer-liquid-phase of nitrate (Jiang et al, 2009;Mohanakrishnan et al, 2009a,b;Zhang et al, 2008), nitrite (Jiang et al, 2011a(Jiang et al, , 2010Mohanakrishnan et al, 2008), free nitrous acid (Jiang et al, 2011b), iron salts (Firer et al, 2008;Gutierrez et al, 2010a), oxygen (Boon, 1995;Gutierrez et al, 2008), magnesium hydroxide (Gutierrez et al, 2009) or sodium hydroxide (Gutierrez et al, 2014). Although primarily designed to control sulfide, these chemical-dosing practices may also induce inhibitory effects on methanogens in sewers.…”

Section: Introductionmentioning

confidence: 99%

Implications of Downstream Nitrate Dosage in anaerobic sewers to control sulfide and methane emissions

et al. 2015

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“…Therefore, only a vessel for the storage of the salt solution and a pump are required. However, this technique presents several drawbacks, such as accumulation of FeS in the digester, increased amount of iron in the treated sludge, possible re-oxidation of FeS if aerobic conditions are reached, and high cost due to the price of the reactant and the existence of parallel reactions (Devai and Delaune, 2002;Gutierrez et al, 2010;Speece, 2008). The application of other physicochemical methods in industrial sludge digesters is limited due to the scale (for instance, iron-sponges are only suitable for small/medium productions) or the high chemical consumption and the consequent operating cost (as in the case of scrubbing) (Abatzoglou and Boivin, 2009).…”

Section: Introductionmentioning

confidence: 99%