A mechanistic model for assessing biodegradability of complex wastewaters

Mao, Huazhong; Smith, Daniel

doi:10.1016/0043-1354(94)00342-5

Cited by 6 publications

(2 citation statements)

References 18 publications

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“…The respirations, BOD 5 /COD values and COD, TOC removal ratios analysis can provide a possibility of biodegradation but cannot tell which one biodegrade faster or slower. Previous studies indicated that the BOD with time of low concentration organic compound under activated sludge treatment, approached to single-molecule reaction mechanism, and accorded with first-order reaction kinetics model [20].…”

Section: The Biodegradation Kinetics Of Different Oil Based Fatliquorsmentioning

confidence: 90%

The Biodegradabilities of Different Oil‐Based Fatliquors

Chunchun

Fan

Chen

et al. 2010

J Americ Oil Chem Soc

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The biodegradabilities of different oil-based fatliquors derived from rape oil, fish oil, castor oil or mineral oil variants were investigated by evaluating the respiration curves, BOD 5 /COD values, COD (chemical oxygen demand) and TOC (total organic carbon) removal ratios. Simultaneously, degradation kinetics of the fatliquors were also studied. The results indicated that the BOD 5 /COD values and the COD and TOC removal ratios of all the natural oil based products are higher than 0.45 and 85%, respectively, implying that all of them are biodegradable. The mineral oil based fatliquors have lower than 0.2 and 10% values, showing unbiodegradable characteristics and were used as the control. The biodegradability order is castor oil [ fish oil [ rape oil [ mineral oil product. Further study indicated that the differences in biodegradability result from the varying fatty acid composition (such as ricinoleic acid and polyunsaturated fatty acids). The higher the active group content, the more beneficial for modification reactions and result in a higher biodegradation rate. The degradation kinetics studies revealed that the degradation rate constants (k) of castor oil, fish oil and rape oil products are 0.87, 0.84 and 0.81 d -1 for the sulfated fatliquor, and 0.95, 0.93, 0.85 d -1 for the oxidized-sulfited fatliquors, respectively; indicating that the overall degradation rate followed the same trend as the biodegradability order where castor oil [ fish oil [ rape oil, whether the fatliquors underwent modification as sulfated or oxidized-sulfited.

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Section: The Biodegradation Kinetics Of Different Oil Based Fatliquorsmentioning

confidence: 90%

The Biodegradabilities of Different Oil‐Based Fatliquors

Chunchun

Fan

Chen

et al. 2010

J Americ Oil Chem Soc

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“…During activated sludge process, wastewater could be considered as a single substrate and the process as a monomolecular reaction (Mao and Smith 1995). Then, the disappearing rate of biochemical-oxygen-consuming substances in the wastewater can be derived as:…”

Section: Effects Of Diluting On Biodegradability Of Vet Wastewatermentioning

confidence: 99%

Biodegradability of tannin-containing wastewater from leather industry

Yao

Sun

et al. 2006

Biodegradation

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Tannins occur commonly in the wastewaters from forestry, plant medicine, paper and leather industries. The treatment of this kind of wastewaters, including settling and biodegradation, is usually difficult because tannins are highly soluble in water and would inhibit the growth of microorganisms in activated sludge. The objective of this study is to investigate biodegradability of tannin-containing wastewaters, so as to characterize the pollution properties of such wastewaters and provide a reference for their biological treatment in wastewater treatment plants. The research was typified by using the wastewater collected from vegetable tanning process in leather industry. A model was developed to describe the activated sludge process, and the biodegradation kinetics of vegetable tanning wastewater (VET wastewater) was studied. It was found that the biodegradability of tannin-containing wastewater varies heavily with the content of tannins in wastewater. The biodegradation of VET wastewater with tannin content around 4,900 mg/l occurred inefficiently due to the inhibition of tannins to the activated sludge process, and only 34.7% of biodegradation extent was reached in 14 days of incubation. The optimal biodegradability of VET wastewater was observed when its tannin content was diluted to 490 mg/l, where the COD and tannin removals reached 51.3% and 45.1% respectively in 6 days. Hence, it is suggested that a proper control of tannin content is necessary to achieve an effective biodegradation of tannin-containing wastewaters in wastewater treatment plants.

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Estimation of biological kinetic parameters from an analysis of the BOD curve of waste waters–effects of a chemical preoxidation

Beltrán¹,

García‐Araya²,

Álvarez³

1997

Acta Biotechnologica

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Urban waste waters were treated with pure ozone or combinations of ozone. hydrogen peroxide and/or UV radiation to study the course of resulting BOD (biological oxygen demand)-time profiles and to propose a kinetic model. BOD-time profiles of chemically treated waste waters show an initial lag period that first order kinetic models cannot describe. A second order kinetic model is then proposed that satisfactorily fits experimental BOD-time profiles. except when hydrogen peroxide has been used. In these cases, BOD-time profiles present the highest lag periods observed. By applying this model, three parameters are determined: the biokinetic constant (k) which is an index of the biological removal rate; the potential amount of biodegradable matter (BOW), and the measure of the size of inocula and microbial activities of microorganisms (a). The model was checked with experimental results of BOD-time protiles corresponding to both untreated and chemically ozonated urban waste waters. Ozonated waste waters showed the highest values of k and B O R , which implies an improvement of waste water biodegradability after ozonation. However, values of d corresponding to ozonated waste waters presented lower values than those of untreated waste waters This was due to the lag period observed in the BOD-time profile. which was a consequence of a lack of microorganism acclimation to ozonated waste waters. The effect of the ozone dose, pH and carbonates during ozonation on COD (chemical oxygen demand) and the above indicated parameters was also studied. There was an optimum ozone dose which was 138 mg/l for this specific system. This led to the highest biodegradable fraction (q) and the highest biokinetic constant (39% increase in pand 4.7-fold increase in the value of k, respectively, compared to untreated waste waters.). Another significant fact was that a higher COD reduction w s observed in the absence of carbonate during ozonation at basic pH values. In addition, the percentage of variation in the biodegradable fraction (Ap) of ozonated waste water increased compared to the untreated waste water at acid pH. The results suggest that ozonolysis, the direct molecular ozone way of reaction, due to its selective character, increases the biodegradability of waste water more than other chemically advanced oxidation processes based on hydroxyl radical reactions.

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A mechanistic model for assessing biodegradability of complex wastewaters

Cited by 6 publications

References 18 publications

The Biodegradabilities of Different Oil‐Based Fatliquors

The Biodegradabilities of Different Oil‐Based Fatliquors

Biodegradability of tannin-containing wastewater from leather industry

Estimation of biological kinetic parameters from an analysis of the BOD curve of waste waters–effects of a chemical preoxidation

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