The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Zhiguo Yuan - One of the best experts on this subject based on the ideXlab platform.
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overcoming nitrite oxidizing bacteria adaptation through alternating Sludge Treatment with free nitrous acid and free ammonia
Environmental Science & Technology, 2019Co-Authors: Haoran Duan, Zhiguo YuanAbstract:Stable suppression of nitrite oxidizing bacteria (NOB) is one of the major bottlenecks for achieving mainstream nitrite shunt or partial nitritation/anammox (PN/A). It is increasingly experienced that NOB could develop resistance to suppressions over an extended time, leading to failure of nitrite shunt or PN/A. This study reports and demonstrates the first effective strategy to overcome NOB adaptation through alternating Sludge Treatment with free nitrous acid (FNA) and free ammonia (FA). During over 650 days of reactor operation, NOB adaptation to both FNA and FA was observed, but the adaptation was successfully overcome by deploying the alternate Treatment strategy. Microbial community analysis showed Nitrospira and Nitrobacter, the key NOB populations in the reactor, have the ability to adapt to FNA and FA, respectively, but do not adapt to the alternation. Stable nitrite shunt with nitrite accumulation ratio over 95% and excellent nitrogen removal were maintained for the last 10 months with only one ...
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effects of free nitrous acid Treatment conditions on the nitrite pathway performance in mainstream wastewater Treatment
Science of The Total Environment, 2018Co-Authors: Haoran Duan, Qilin Wang, Dirk V Erler, Zhiguo YuanAbstract:Inline Sludge Treatment using free nitrous acid (FNA) was recently shown to be effective in establishing the nitrite pathway in a biological nitrogen removal system. However, the effects of FNA Treatment conditions on the nitrite pathway performance remained to be investigated. In this study, three different FNA Treatment frequencies (daily Sludge Treatment ratios of 0.22, 0.31 and 0.38, respectively), two FNA concentrations (1.35 mgN/L and 4.23 mgN/L, respectively) and two influent feeding regimes (one- and two-step feeding) were investigated in four laboratory-scale sequencing batch reactors. The nitrite accumulation ratio was positively correlated to the FNA Treatment frequency. However, when a high Treatment frequency was used e.g., daily Sludge Treatment ratio of 0.38, a significant reduction in ammonia oxidizing bacteria (AOB) activity occurred, leading to poor ammonium oxidation. AOB were able to acclimatise to FNA concentrations up to of 4.23 mgN/L, whereas nitrite oxidizing bacteria (NOB) were limited by an FNA concentration of 1.35 mgN/L over the duration of the study (up to 120 days). This difference in sensitivity to FNA could be used to further enhance nitrite accumulation, with 90% accumulation achieved at an FNA concentration of 4.23 mgN/L and a daily Sludge Treatment ratio of 0.31 in this study. However, this high level of nitrite accumulation led to increased N2O emission, with emission factors of up to 3.9% observed. The N2O emission was mitigated (reduced to 1.3%) by applying two-step feeding resulting in a nitrite accumulation ratio of 45.1%. Economic analysis showed that choosing the optimal FNA Treatment conditions depends on a combination of the wastewater characteristics, the nitrogen discharge standards, and the operational costs. This study provides important information for the optimisation and practical application of FNA-based Sludge Treatment technology for achieving the mainstream stable nitrite pathway.
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achieving stable mainstream nitrogen removal via the nitrite pathway by Sludge Treatment using free ammonia
Environmental Science & Technology, 2017Co-Authors: Qilin Wang, Andrew Elohim Laloo, Haoran Duan, Wei Wei, Zhiguo YuanAbstract:Biological nitrogen removal through the nitrite pathway (NH4+→NO2-→N2) is favorable for the wastewater Treatment plants without sufficient carbon source. This study demonstrates an innovative approach for attaining the nitrite pathway based on Sludge Treatment using free ammonia (FA i.e. NH3). This approach is based on our innovative discovery in this study that FA at 210 mg NH3-N/L is far less biocidal to ammonium oxidizing bacteria (AOB) than to nitrite oxidizing bacteria (NOB). Twenty-two percent of the activated Sludge from the sequencing batch reactor (SBR) receiving synthetic domestic wastewater was treated in an FA Treatment unit at 210 mg NH3-N/L for one day. The FA treated Sludge was afterwards recirculated back to the SBR. A nitrite accumulation ratio of above 90% was quickly achieved (in 40 d) and maintained stable in the SBR, indicating the establishment of the nitrite pathway. The NOB population and activity after implementing FA Treatment was less than 5% of those without FA Treatment, sugge...
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technologies for reducing Sludge production in wastewater Treatment plants state of the art
Science of The Total Environment, 2017Co-Authors: Qilin Wang, Wei Wei, Yanyan Gong, Jing Sun, Zhiguo YuanAbstract:This review presents the state-of-the-art Sludge reduction technologies applied in both wastewater and Sludge Treatment lines. They include chemical, mechanical, thermal, electrical Treatment, addition of chemical un-coupler, and predation of protozoa/metazoa in wastewater Treatment line, and physical, chemical and biological preTreatment in Sludge Treatment line. Emphasis was put on their effect on Sludge reduction performance, with 10% Sludge reduction to zero Sludge production in wastewater Treatment line and enhanced TS (total solids) or volatile solids removal of 5–40% in Sludge Treatment line. Free nitrous acid (FNA) technology seems good in wastewater Treatment line but it is only under the lab-scale trial. In Sludge Treatment line, thermal, ultrasonic (< 4400 kJ/kg TS), FNA preTreatment and temperature-phased anaerobic digestion (TPAD) are promising if pathogen inactivation is not a concern. However, thermal preTreatment and TPAD are superior to other preTreatment technologies when pathogen inactivation is required. The new wastewater Treatment processes including SANI®, high-rate activated Sludge coupled autotrophic nitrogen removal and anaerobic membrane bioreactor coupled autotrophic nitrogen removal also have a great potential to reduce Sludge production. In the future, an effort should be put on the effect of Sludge reduction technologies on the removal of organic micropollutants and heavy metals.
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reducing n2o emission from a domestic strength nitrifying culture by free nitrous acid based Sludge Treatment
Environmental Science & Technology, 2016Co-Authors: Dongbo Wang, Qilin Wang, Andrew Elohim Laloo, Zhiguo YuanAbstract:An increase of nitrite in the domestic-strength range is generally recognized to stimulate nitrous oxide (N2O) production by ammonia-oxidizing bacteria (AOB). It was found in this study, however, that N2O emission from a mainstream nitritation system (cyclic nitrite = 25–45 mg of N/L) that was established by free nitrous acid (FNA)-based Sludge Treatment was not higher but much lower than that from the initial nitrifying system with full conversion of NH4+-N to NO3–-N. Under dissolved oxygen (DO) levels of 2.5–3.0 mg/L, N2O emission from the nitritation stage was 76% lower than that from the initial stage. Even when the DO level was reduced to 0.3–0.8 mg/L, N2O emission from the nitritation stage was still 40% lower. An investigation of the mechanism showed that FNA Treatment caused a shift of the stimulation threshold of nitrite on N2O emission. At the nitritation stage, the maximal N2O emission factor occurred at ∼16 mg of N/(L of nitrite). However, it increased with increasing nitrite in the range of 0...
Qilin Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of free nitrous acid Treatment conditions on the nitrite pathway performance in mainstream wastewater Treatment
Science of The Total Environment, 2018Co-Authors: Haoran Duan, Qilin Wang, Dirk V Erler, Zhiguo YuanAbstract:Inline Sludge Treatment using free nitrous acid (FNA) was recently shown to be effective in establishing the nitrite pathway in a biological nitrogen removal system. However, the effects of FNA Treatment conditions on the nitrite pathway performance remained to be investigated. In this study, three different FNA Treatment frequencies (daily Sludge Treatment ratios of 0.22, 0.31 and 0.38, respectively), two FNA concentrations (1.35 mgN/L and 4.23 mgN/L, respectively) and two influent feeding regimes (one- and two-step feeding) were investigated in four laboratory-scale sequencing batch reactors. The nitrite accumulation ratio was positively correlated to the FNA Treatment frequency. However, when a high Treatment frequency was used e.g., daily Sludge Treatment ratio of 0.38, a significant reduction in ammonia oxidizing bacteria (AOB) activity occurred, leading to poor ammonium oxidation. AOB were able to acclimatise to FNA concentrations up to of 4.23 mgN/L, whereas nitrite oxidizing bacteria (NOB) were limited by an FNA concentration of 1.35 mgN/L over the duration of the study (up to 120 days). This difference in sensitivity to FNA could be used to further enhance nitrite accumulation, with 90% accumulation achieved at an FNA concentration of 4.23 mgN/L and a daily Sludge Treatment ratio of 0.31 in this study. However, this high level of nitrite accumulation led to increased N2O emission, with emission factors of up to 3.9% observed. The N2O emission was mitigated (reduced to 1.3%) by applying two-step feeding resulting in a nitrite accumulation ratio of 45.1%. Economic analysis showed that choosing the optimal FNA Treatment conditions depends on a combination of the wastewater characteristics, the nitrogen discharge standards, and the operational costs. This study provides important information for the optimisation and practical application of FNA-based Sludge Treatment technology for achieving the mainstream stable nitrite pathway.
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achieving stable mainstream nitrogen removal via the nitrite pathway by Sludge Treatment using free ammonia
Environmental Science & Technology, 2017Co-Authors: Qilin Wang, Andrew Elohim Laloo, Haoran Duan, Wei Wei, Zhiguo YuanAbstract:Biological nitrogen removal through the nitrite pathway (NH4+→NO2-→N2) is favorable for the wastewater Treatment plants without sufficient carbon source. This study demonstrates an innovative approach for attaining the nitrite pathway based on Sludge Treatment using free ammonia (FA i.e. NH3). This approach is based on our innovative discovery in this study that FA at 210 mg NH3-N/L is far less biocidal to ammonium oxidizing bacteria (AOB) than to nitrite oxidizing bacteria (NOB). Twenty-two percent of the activated Sludge from the sequencing batch reactor (SBR) receiving synthetic domestic wastewater was treated in an FA Treatment unit at 210 mg NH3-N/L for one day. The FA treated Sludge was afterwards recirculated back to the SBR. A nitrite accumulation ratio of above 90% was quickly achieved (in 40 d) and maintained stable in the SBR, indicating the establishment of the nitrite pathway. The NOB population and activity after implementing FA Treatment was less than 5% of those without FA Treatment, sugge...
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technologies for reducing Sludge production in wastewater Treatment plants state of the art
Science of The Total Environment, 2017Co-Authors: Qilin Wang, Wei Wei, Yanyan Gong, Jing Sun, Zhiguo YuanAbstract:This review presents the state-of-the-art Sludge reduction technologies applied in both wastewater and Sludge Treatment lines. They include chemical, mechanical, thermal, electrical Treatment, addition of chemical un-coupler, and predation of protozoa/metazoa in wastewater Treatment line, and physical, chemical and biological preTreatment in Sludge Treatment line. Emphasis was put on their effect on Sludge reduction performance, with 10% Sludge reduction to zero Sludge production in wastewater Treatment line and enhanced TS (total solids) or volatile solids removal of 5–40% in Sludge Treatment line. Free nitrous acid (FNA) technology seems good in wastewater Treatment line but it is only under the lab-scale trial. In Sludge Treatment line, thermal, ultrasonic (< 4400 kJ/kg TS), FNA preTreatment and temperature-phased anaerobic digestion (TPAD) are promising if pathogen inactivation is not a concern. However, thermal preTreatment and TPAD are superior to other preTreatment technologies when pathogen inactivation is required. The new wastewater Treatment processes including SANI®, high-rate activated Sludge coupled autotrophic nitrogen removal and anaerobic membrane bioreactor coupled autotrophic nitrogen removal also have a great potential to reduce Sludge production. In the future, an effort should be put on the effect of Sludge reduction technologies on the removal of organic micropollutants and heavy metals.
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reducing n2o emission from a domestic strength nitrifying culture by free nitrous acid based Sludge Treatment
Environmental Science & Technology, 2016Co-Authors: Dongbo Wang, Qilin Wang, Andrew Elohim Laloo, Zhiguo YuanAbstract:An increase of nitrite in the domestic-strength range is generally recognized to stimulate nitrous oxide (N2O) production by ammonia-oxidizing bacteria (AOB). It was found in this study, however, that N2O emission from a mainstream nitritation system (cyclic nitrite = 25–45 mg of N/L) that was established by free nitrous acid (FNA)-based Sludge Treatment was not higher but much lower than that from the initial nitrifying system with full conversion of NH4+-N to NO3–-N. Under dissolved oxygen (DO) levels of 2.5–3.0 mg/L, N2O emission from the nitritation stage was 76% lower than that from the initial stage. Even when the DO level was reduced to 0.3–0.8 mg/L, N2O emission from the nitritation stage was still 40% lower. An investigation of the mechanism showed that FNA Treatment caused a shift of the stimulation threshold of nitrite on N2O emission. At the nitritation stage, the maximal N2O emission factor occurred at ∼16 mg of N/(L of nitrite). However, it increased with increasing nitrite in the range of 0...
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achieving stable nitritation for mainstream deammonification by combining free nitrous acid based Sludge Treatment and oxygen limitation
Scientific Reports, 2016Co-Authors: Dongbo Wang, Qilin Wang, Andrew Elohim Laloo, Philip L Bond, Zhiguo YuanAbstract:Stable nitritation is a critical bottleneck for achieving autotrophic nitrogen removal using the energy-saving mainstream deammonification process. Herein we report a new strategy to wash out both the Nitrospira sp. and Nitrobacter sp. from the Treatment of domestic-strength wastewater. The strategy combines Sludge Treatment using free nitrous acid (FNA) with dissolved oxygen (DO) control in the nitritation reactor. Initially, the nitrifying reactor achieved full conversion of NH4+ to NO3−. Then, nitrite accumulation at ~60% was achieved in the reactor when 1/4 of the Sludge was treated daily with FNA at 1.82 mg N/L in a side-stream unit for 24 h. Fluorescence in-situ hybridization (FISH) revealed FNA Treatment substantially reduced the abundance of nitrite oxidizing bacteria (NOB) (from 23.0 ± 4.3 to 5.3 ± 1.9%), especially that of Nitrospira sp. (from 15.7 ± 3.9 to 0.4 ± 0.1%). Nitrite accumulation increased to ~80% when the DO concentration in the mainstream reactor was reduced from 2.5–3.0 to 0.3–0.8 mg/L. FISH revealed the DO limitation further reduced the abundance of NOB (to 2.1 ± 1.0%), especially that of Nitrobacter sp. (from 4.9 ± 1.2 to 1.8 ± 0.8%). The strategy developed removes a major barrier for deammonification in low-strength domestic wastewater.
Nicky Eshtiaghi - One of the best experts on this subject based on the ideXlab platform.
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a review of wet air oxidation and thermal hydrolysis technologies in Sludge Treatment
Bioresource Technology, 2014Co-Authors: Kevin Hii, Saeid Baroutian, Raj Parthasarathy, Daniel J Gapes, Nicky EshtiaghiAbstract:With rapid world population growth and strict environmental regulations, increasingly large volumes of Sludge are being produced in today's wastewater Treatment plants (WWTP) with limited disposal routes. Sludge Treatment has become an essential process in WWTP, representing 50% of operational costs. Sludge destruction and resource recovery technologies are therefore of great ongoing interest. Hydrothermal processing uses unique characteristics of water at elevated temperatures and pressures to deconstruct organic and inorganic components of Sludge. It can be broadly categorized into wet oxidation (oxidative) and thermal hydrolysis (non-oxidative). While wet air oxidation (WAO) can be used for the final Sludge destruction and also potentially producing industrially useful by-products such as acetic acid, thermal hydrolysis (TH) is mainly used as a pre-Treatment method to improve the efficiency of anaerobic digestion. This paper reviews current hydrothermal technologies, roles of wet air oxidation and thermal hydrolysis in Sludge Treatment, and challenges faced by these technologies.
Saeid Baroutian - One of the best experts on this subject based on the ideXlab platform.
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a review of wet air oxidation and thermal hydrolysis technologies in Sludge Treatment
Bioresource Technology, 2014Co-Authors: Kevin Hii, Saeid Baroutian, Raj Parthasarathy, Daniel J Gapes, Nicky EshtiaghiAbstract:With rapid world population growth and strict environmental regulations, increasingly large volumes of Sludge are being produced in today's wastewater Treatment plants (WWTP) with limited disposal routes. Sludge Treatment has become an essential process in WWTP, representing 50% of operational costs. Sludge destruction and resource recovery technologies are therefore of great ongoing interest. Hydrothermal processing uses unique characteristics of water at elevated temperatures and pressures to deconstruct organic and inorganic components of Sludge. It can be broadly categorized into wet oxidation (oxidative) and thermal hydrolysis (non-oxidative). While wet air oxidation (WAO) can be used for the final Sludge destruction and also potentially producing industrially useful by-products such as acetic acid, thermal hydrolysis (TH) is mainly used as a pre-Treatment method to improve the efficiency of anaerobic digestion. This paper reviews current hydrothermal technologies, roles of wet air oxidation and thermal hydrolysis in Sludge Treatment, and challenges faced by these technologies.
Francesc Hernández-sancho - One of the best experts on this subject based on the ideXlab platform.
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Selecting sewage Sludge Treatment alternatives in modern wastewater Treatment plants using environmental decision support systems
Journal of Cleaner Production, 2015Co-Authors: Manel Garrido-baserba, M. Molinos-senante, J. M. Abelleira-pereira, L. A. Fdez-güelfo, Manel Poch, Francesc Hernández-sanchoAbstract:The importance of the sewage Sludge Treatment within the field of wastewater Treatment plants (WWTPs) suggests new dimensions of analysis where the relevance of economic criteria combined with the associated environmental issues are increasing the Sludge management complexity. For supporting the decision process and for comparative purposes, this study assesses five alternative configurations for Sludge Treatment, namely: mesophilic and termophilic anaerobic digestion plus composting, incineration, gasification, and supercritical water oxidation (SCWO). The global warming potential (GWP) and the annual cash flow of each alternative are used to estimate a composite indicator for each alternative. Stakeholders' preferences are integrated into the assessment through the development of five scenarios prioritizing economic or environmental aspects. A case study for a 1 million person equivalent WWTP proved that SCWO is the most adequate option if economic and environmental criteria are considered equally important. However, if the economic assessment is prioritized over the environmental one, thermophilic anaerobic digestion followed by composting turned out to be the most appropriate option. The proposed approach contributes to the implementation of more suitable sewage Sludge Treatment lines since it provides an indicator for each alternative embracing economic and GWP issues.
