Is dissolved COD a suitable design parameter for ozone oxidation of organic micropollutants in wastewater?

Ekblad, Maja; Falås, Per; El-taliawy, H.; Nilsson, Fredrik; Bester, Kai; Hagman, Marinette; Cimbritz, Michael

doi:10.1016/j.scitotenv.2018.12.085

Cited by 31 publications

(7 citation statements)

References 35 publications

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“…In this study, raw sludge was collected from secondary sedimentation, thus, the SCOD in the supernatant of the raw sludge should be the same as the e uent of secondary sedimentation. It was reported that SCOD in the e uent of secondary sedimentation was generally below 40 mg/L (Ekblad et al, 2019;Shin et al, 2019). Hence, the result is consistent with the reality.…”

Section: Resultssupporting

confidence: 85%

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

Chen

Zhang

et al. 2020

Preprint

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Background: Converting wastewater sludge to lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from wastewater sludge is the low yield (0.10-0.16 g lipid/g dry sludge) due to the low availability of easily uptaken materials (such as soluble monosaccharide and oligosaccharide) in sludge to oleaginous microorganism (Rhodotorula glutini, Trichosporon oleaginosus, Lipomyces starkey). Pretreatments are efficient methods to improve sludge bioavailability. This study is aimed to achieve high lipid production from sludge and high sludge reduction. Results: In this study, it was observed that the soluble chemical oxygen demand (SCOD) had significantly increased after different pretreatment.The SCOD in the supernatant was increased from 32.64 to 180.25 mg/L, 924.16 mg/L, 1029.89mg/L and 3708.31 mg/L after acidic (pH 2 for 2 h), alkaline (pH 12 for 2 h), microwave irradiation (15 min with 5 min interval) and ultrasonication (30 min at 450 W and 20 kHz frequency with 5 s on and 2 s off mode) pretreatment, respectively. Pretreatments have also increased the release in total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as medium for lipid production, and the highest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%. For other pretreatment, the lipid content and sludge reduction were 18.42% and 32.63% in acid pretreatment case, 21.08% and 36.44% in alkaline pretreatment case, and 26.31% and 43.03% in microwave pretreatment case, respectively.Conclusion: It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD) and to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement in lipid yield and sludge reduction. Lipids produced from pretreated sludge was transesterified to biodiesel and the analysis showed that the biodiesel had similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

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Section: Resultssupporting

confidence: 85%

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

Chen

Zhang

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

Section: Resultssupporting

confidence: 85%

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

Chen

Zhang

et al. 2020

Preprint

View full text Add to dashboard Cite

Background: Converting wastewater sludge to lipid is considered as one of the best strategies of sludge management. The current problem of lipid production from wastewater sludge is the low yield (0.10-0.16 g lipid/g dry sludge) due to the low availability of easily uptaken materials (such as soluble monosaccharide and oligosaccharide) in sludge to oleaginous microorganism (Rhodotorula glutinis, Trichosporon oleaginosus, Lipomyces starkeyi). Pretreatments are efficient methods to improve sludge bioavailability. This study is aimed to achieve high lipid production from sludge and high sludge reduction. Results: In this study, it was observed that the soluble chemical oxygen demand (SCOD) had significantly increased after different pretreatment. The SCOD in the supernatant was increased from 32.64 to 180.25 mg/L, 924.16 mg/L, 1029.89mg/L and 3708.31 mg/L after acidic (pH 2 for 2 h), alkaline (pH 12 for 2 h), microwave irradiation (15 min with 5 min interval), and ultrasonication (30 min at 450 W and 20 kHz frequency with 5 s on and 2 s off mode) pretreatment, respectively. Pretreatments have also increased the release of total nitrogen (TN) and total phosphorus (TP) from solids. The sludge after different pretreatments were used as medium for lipid production, and the highest lipid content (36.67% g/g) was obtained in the fermentation with ultrasonication pretreatment sludge, and the sludge reduction was 63.10%. For other pretreatments, the lipid content and sludge reduction were 18.42% and 32.63% in acid pretreatment case, 21.08% and 36.44% in alkaline pretreatment case, and 26.31% and 43.03% in microwave pretreatment case, respectively.Conclusion: It was found that ultrasonication pretreatment was the most efficient way to increase the sludge biodegradability (SCOD) and to release TN and TP from solid phase to liquid phase. Pretreated sludge for lipid production achieved significant improvement in lipid yield and sludge reduction. Lipids produced from pretreated sludge were transesterified to biodiesel and the analysis showed that the biodiesel had a similar composition as commercial biodiesel. The study reveals that pretreatment on sludge is a promising method for enhancing biological sludge management efficiency.

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“…In general, the total effluent organic matter (EfOM) concentrations (in the range of mg/L) are 10 3 to 10 6 times higher than target MP concentrations (in the range of ng -µg/L). Hence, required ozone doses are based on EfOM concentrations, using specific ozone dosages such as g O 3 /g TOC or g O 3 /g COD, and not on MP concentrations (Ekblad et al 2018;Hansen et al 2016a;Lee et al 2013;Nilsson et al 2017). Both TOC and COD are bulk parameters that mainly give information about the quantity of EfOM.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Micropollutant Removal by Ozonation; Interference of Effluent Organic Matter Fractions

Gijn

Sohier

Maasdam

et al. 2021

Ozone: Science & Engineering

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Ozonation for micropollutant removal from wastewater treatment plant effluent is energy and costintensive because of competition between background organic matter and micropollutants. This study aims to elucidate the interference of different organic matter fractions during the ozonation of micropollutants. Wastewater treatment plant effluent was fractionated using membranes and XAD-8 resin. All membrane and resin fractions were spiked with 18 micropollutants (2 µg/L) and ozonated with 0.25, 0.5 and 1 g O 3 /g TOC. Results show that these fractions differ in their interference with the ozonation of micropollutants. Interference was lower in the smallest size fraction (<1 kDa) than in all other fractions for micropollutants with low and medium ozone reactivity. The hydrophobic neutrals and hydrophilics resin factions showed a high interference for ozonation of micropollutants with medium and high ozone reactivity, respectively. The four parameters that were analyzed (specific UV absorbance at 254 nm, fluorescence, chemical oxygen demand and nitrite) could not elucidate the differences in micropollutant removal. Still, we conclude that understanding the type of organic matter present in the matrix, is essential to optimize micropollutant ozonation and other tertiary micropollutant removal treatments.

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Is dissolved COD a suitable design parameter for ozone oxidation of organic micropollutants in wastewater?

Cited by 31 publications

References 35 publications

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

Pretreatments for enhancing sewage sludge reduction and reuse in lipid production

Optimizing Micropollutant Removal by Ozonation; Interference of Effluent Organic Matter Fractions

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