Characterizing solids retention, head loss development and micropollutant removal in the case of direct powdered activated carbon dosage upstream of deep bed filtration

Krahnstöver, Thérèse; Zenker, Armin; Baggenstos, Martin; Kobler, Bernd; Leikam, K.; Koch, Gerhard; Wintgens, Thomas

doi:10.1039/c9ew00658c

Cited by 9 publications

(4 citation statements)

References 39 publications

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“…The exact amount of PAC being released from WWTPs is to date still unknown as is the environmental fate and both topics should be the subject of future research. Up to now, leakages are considered to be small [38]. However, in standard operation also small amounts of PAC that are continuously released may settle in waters with low disturbance and will accumulate over time in sediments.…”

Section: Discussionmentioning

confidence: 99%

Micropollutant-loaded powdered activated carbon released from waste water treatment plants: a risk for sediment-dwelling organisms?

2021

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Background In order to protect aquatic environments and to reduce the presence of micropollutants in the global water cycle, wastewater treatment plants (WWTPs) often implement an additional treatment step. One of the most effective measures is the use of powdered activated carbon (PAC) as an adsorbent for micropollutants. This method provides sufficient elimination rates for several micropollutants and has been successfully employed in many WWTPs. Despite this success, there might be a drawback as the retention of the PAC in the WWTP can be challenging and losses of micropollutant-loaded PAC into the aquatic environment may occur. Upon emission, micropollutant-loaded PAC is expected to settle to the benthic zone of receiving waters, where sediment-dwelling organisms may ingest these particles. Therefore, the present study investigated possible adverse effects of micropollutant-loaded PAC from a WWTP as compared to unloaded (native) and diclofenac-loaded PAC on the sediment-dwelling annelid Lumbriculus variegatus. Results Native PAC induced the strongest effects on growth (measured as biomass) and reproduction of the annelids. The corresponding medium effective concentrations (EC50) were 1.7 g/kg and 1.8 g/kg, respectively. Diclofenac-loaded PAC showed lower effects with an EC50 of 2.5 g/kg for growth and EC50 of 3.0 g/kg for reproduction. Although tested at the same concentrations, the micropollutant-loaded PAC from the WWTP did not lead to obvious negative effects on the endpoints investigated for L.variegatus and only a slight trend of a reduced growth was detected. Conclusion We did not detect harmful effects on L. variegatus caused by the presence of MP-loaded PAC from a WWTP which gives an auspicious perspective for PAC as an advanced treatment option.

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Section: Discussionmentioning

confidence: 99%

Micropollutant-loaded powdered activated carbon released from waste water treatment plants: a risk for sediment-dwelling organisms?

2021

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“…As the PAC particles may accumulate over time at certain hot spots in aquatic ecosystems, the chosen lowest exposure concentration of 1 mg/L PAC in water (or 0.0005% PAC in sediment) is assumed to be a more or less realistic worst-case scenario. In WWTP full-scale applications, PAC is typically dosed in concentrations ranging from 5 to 30 mg/L [23], and retention rates are considered to be greater than 98% [20]. However, the exact amount of PAC that is emitted by WWTPs and reaches the environment is still unknown but is estimated to be rather low.…”

Section: Discussionmentioning

confidence: 99%

“…The PAC can be applied in the effluent from the biological treatment and can be kept in contact reactors to ensure well mixing with the wastewater and to make use of the adsorption capacity at the best possible rate [16][17][18]. Subsequently, the PAC needs to be separated from the effluent and may be used again during a recirculation process in the WWTP [19][20][21]. This concept has already been deployed in pilot and full scale in several WWPTs [16,19,22].…”

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confidence: 99%

Is micropollutant-loaded powdered activated carbon from a wastewater treatment plant toxic to the bivalve Corbicula sp.?

2020

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Background In order to reduce emissions of micropollutants (MPs) via effluents of wastewater treatment plants (WWTPs), additional treatment steps are suggested and already deployed in selected WWTPs. Next to advanced oxidation processes, the application of powdered activated carbon (PAC) is considered a promising and suitable option as MP removal rates of 80% and more can be achieved. However, this method might also hold a drawback as a complete retention of PAC applied within the WWTP cannot always be guaranteed. Hence, small amounts of MP-loaded PAC can enter receiving waters with potentially negative consequences for aquatic organisms. The present study investigated possible effects of MP-loaded PAC from a WWTP as compared to unloaded, native PAC on the bivalve Corbicula sp. in a 10-week exposure experiment. The PAC types were administered in concentrations of 1, 10 and 100 mg/L in a semi-static sediment–water system. Results Molecular biomarker responses for xenobiotic metabolism (i.e., glutathione-S-transferase (GST)) and oxidative stress (i.e., catalase (CAT) activity and lipid peroxidation) were analyzed and in none of the treatments, significant differences to the control could be detected, except for the CAT activity in the 1 mg/L PACWWTP treatment. Moreover, the filtration rate of individual bivalves was measured after 5 and 10 weeks of exposure and compared to the initial filtration rate with the result that the presence of PAC did not affect the filtration rate of Corbicula sp. In summary, despite the selection of sensitive endpoints and a comparatively long exposure period, no significant effects were detected for unloaded and MP-loaded PAC even at the highest test concentration, which is far away from environmental relevance. Conclusions These results give an auspicious perspective for the application of PAC in WWTPs. Even when small PAC leakages from WWTPs occur, adverse effects for aquatic organisms appear to be neglectable based on our findings.

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“…Deep purification of oil-containing wastewater from petroleum products and suspended substances is carried out in filters with granular loading [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Treatment of oil-containing wastewater of machine-building enterprises using pressure hydrocyclones

Busarev

Selyugin

2021

E3S Web Conf.

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Wastewater treatment of machine-building enterprises contaminated with oils, petroleum products and mechanical impurities is an urgent task. A promising direction in the field of treatment of such wastewater is the use of pressure hydrocyclones and hydrocyclone installations. The article presents the results of research on the treatment of oil-containing wastewater of machine-building enterprises in pressure of hydrocyclones, conducted on an experimental hydrocyclone installation, which includes the pressure hydrocyclone under test, a sedative tank, and tanks for receiving water from the upper and lower drains of the hydrocyclone. The studies were carried out in two stages: the first stage was used to determine the diameter of the pressure of hydrocyclone suitable for the treatment of oily wastewater, and the second stage was used to study its geometric characteristics. At the first stage, seven modifications of pressure hydrocyclones with a diameter of 40 to 100 mm with different diameters of the upper and lower drain pipes were tested. A 75 mm diameter hydrocyclone is recommended for the treatment of oily wastewater. At the second stage, nine pressure hydrocyclones with a diameter of 75 mm with different diameters of the upper and lower drain pipes were tested. As a result of the experiments, the design parameters of the hydrocyclone that showed the best results were determined. The results of the research were used in the design of industrial hydrocyclone installations.

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Characterizing solids retention, head loss development and micropollutant removal in the case of direct powdered activated carbon dosage upstream of deep bed filtration

Abstract: The dynamics of micropollutant removal and powdered activated carbon (PAC) separation were studied in a combined PAC/deep bed filtration process.

Cited by 9 publications

References 39 publications

Micropollutant-loaded powdered activated carbon released from waste water treatment plants: a risk for sediment-dwelling organisms?

Micropollutant-loaded powdered activated carbon released from waste water treatment plants: a risk for sediment-dwelling organisms?

Is micropollutant-loaded powdered activated carbon from a wastewater treatment plant toxic to the bivalve Corbicula sp.?

Treatment of oil-containing wastewater of machine-building enterprises using pressure hydrocyclones

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