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Gabriela Dotro
Cranfield University, College Road, Cranfield, Bedfordshire, MK43 0AL, UK

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Book
Published: 15 June 2021 in उपचार आर्द्रभूमियााँ
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उपचार आर्द्रभूमियााँ ‘जैविक अपमिष्ट जल’ िें सातिाृं खृंड है उपचार श्ृंखर ला, जो सीिेज उपचार के विज्ञान और तकनीक की अत्याधुननक प्रस्तुनत देती है। आर्द्रभूमि प्रणामलयों के प्रिुख प्रकार इस खृंड िें िामिल हैं, नाितः: (i) क्षैनतज प्रिाह आर्द्रभूमि; (ii) ऊध्िारधर प्रिाह आर्द्रभूमि; (iii) फ्रें च ऊध्िारधर प्रिाह आर्द्रभूमि; (iv) सघन आर्द्रभूमि; (v) िुक्त जल सतह आर्द्रभूमि; (vi) उपचार आर्द्रभूमि के अन्य अनुप्रयोि। पुस्तक िुख्य अिधारणाओृं, कािकाजी मसद्धाृंतों, अपेक्षक्षत प्रदिरन, डडजाइन िानदृंड, डडजाइन उदाहरण, ननिारण पहलुओृं और पररचालन द्रदिाननदेिों को स्पष्ट और उपचारात्िक तरीके से प्रस्तुत करती है। पुस्तक को उपचार के क्षेत्र के िीर्र वििेर्ज्ञों की एक अृंतरराष्रीय टीि ने मलखा है। श्ृंखर ला के बारे िें: इस बहुप्रिृंमसत श्ृंखर ला िें सात पाठ्यपुस्तकें िामिल हैं - वप्रटृं िें या िुक्त-अमभिि ई-पुस्तकों के रूप िें उपलब्लध - जो जैविक अपमिष्ट जल उपचार के विज्ञान और तकनीक की एक अत्याधुननक प्रस्तुनत प्रदान करती हैं। विकमसत और विकासिील देिों िें छात्रों, िोधकतारओृं और अभ्यासकों द्िारा श्ृंखर ला के सभी खण्डों का व्यापक रूप से उपयोि...

ACS Style

Gabriela Dotro; Günter Langergraber; Pascal Molle; Jaime Nivala; Jaume Puigagut; Otto Stein; Marcos von Sperling. उपचार आर्द्रभूमियााँ. उपचार आर्द्रभूमियााँ 2021, 16, 1 .

AMA Style

Gabriela Dotro, Günter Langergraber, Pascal Molle, Jaime Nivala, Jaume Puigagut, Otto Stein, Marcos von Sperling. उपचार आर्द्रभूमियााँ. उपचार आर्द्रभूमियााँ. 2021; 16 ():1.

Chicago/Turabian Style

Gabriela Dotro; Günter Langergraber; Pascal Molle; Jaime Nivala; Jaume Puigagut; Otto Stein; Marcos von Sperling. 2021. "उपचार आर्द्रभूमियााँ." उपचार आर्द्रभूमियााँ 16, no. : 1.

Journal article
Published: 01 June 2019 in Water Science and Technology
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This study examined the dynamics of iron (Fe) and phosphorus (P) transformations from the surface sludge accumulated in tertiary horizontal flow (HF) treatment wetlands (TW) chemically dosed for P removal. Site surveys showed P was stored in HF TW with and without artificial aeration on average, with instances of P release in the non-aerated site. Controlled experiments revealed storing TW surface sludge for over 24 hours resulted in limited oxygen and nitrate concentrations, resulting in both P and Fe release. The rate of P release increased with increasing water-sludge P concentration gradients, and the reaction could take as little as 10 minutes. Convection had no impact on P transformation rates. The findings suggest mitigation strategies could include the manipulation of the biogeochemical environment by managing oxygen and nitrate concentrations within the wetlands. A better understanding of links between Fe, P, and nitrate is needed to test proactive mitigation strategies for small wastewater treatment plants.

ACS Style

Jan Barak; Gabriela Dotro; Bruce Jefferson. The role of concentrations gradients on phosphorus and iron dynamics from chemically-dosed horizontal flow wetlands for tertiary sewage treatment. Water Science and Technology 2019, 79, 2126 -2134.

AMA Style

Jan Barak, Gabriela Dotro, Bruce Jefferson. The role of concentrations gradients on phosphorus and iron dynamics from chemically-dosed horizontal flow wetlands for tertiary sewage treatment. Water Science and Technology. 2019; 79 (11):2126-2134.

Chicago/Turabian Style

Jan Barak; Gabriela Dotro; Bruce Jefferson. 2019. "The role of concentrations gradients on phosphorus and iron dynamics from chemically-dosed horizontal flow wetlands for tertiary sewage treatment." Water Science and Technology 79, no. 11: 2126-2134.

Correction
Published: 27 March 2018 in Clean Technologies and Environmental Policy
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ACS Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Luca Alibardi; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. Correction to: Coagulation–flocculation process with metal salts, synthetic polymers and biopolymers for the removal of trace metals (Cu, Pb, Ni, Zn) from municipal wastewater. Clean Technologies and Environmental Policy 2018, 20, 1119 -1119.

AMA Style

Andrew J. Hargreaves, Peter Vale, Jonathan Whelan, Luca Alibardi, Carlos Constantino, Gabriela Dotro, Elise Cartmell, Pablo Campo. Correction to: Coagulation–flocculation process with metal salts, synthetic polymers and biopolymers for the removal of trace metals (Cu, Pb, Ni, Zn) from municipal wastewater. Clean Technologies and Environmental Policy. 2018; 20 (5):1119-1119.

Chicago/Turabian Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Luca Alibardi; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. 2018. "Correction to: Coagulation–flocculation process with metal salts, synthetic polymers and biopolymers for the removal of trace metals (Cu, Pb, Ni, Zn) from municipal wastewater." Clean Technologies and Environmental Policy 20, no. 5: 1119-1119.

Original paper
Published: 07 February 2018 in Clean Technologies and Environmental Policy
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To ensure compliance with regulatory standards, it is important to examine the potential of treatment technologies to enhance trace metal removal from wastewater. This study investigated the effectiveness of coagulation–flocculation at removing trace metals from humus effluent with ferric chloride (FeCl3), the synthetic polymer polyethyleneimine (PEI) and the biopolymers chitosan and floculan. Effluent samples were collected from a trickling filter treatment works operating in the UK and contained 21 ± 4 μg/L Cu, 0.8 ± 0.1 μg/L Pb, 4 ± 1 μg/L Ni and 43 ± 9 μg/L Zn. The influence of coagulant dosage and the velocity and time of the slow mixing stage were studied via a series of jar tests. Chitosan and PEI had a moderate effect on the removal of trace metals (≤ 35%). FeCl3 removed 48% Cu, 56% Pb and 41% Zn at the optimised dose of 0.10 mg/L. At the optimised dose of 0.25 mg/L, floculan removed 77% Cu, 68% Pb and 42% Zn. The dominant mechanism for particle removal by FeCl3 was enmeshment in the precipitates (i.e. sweep flocculation), whereas, for floculan, inter-particle bridging was the dominant removal mechanism. Overall, FeCl3 and floculan were found to be most effective at removing trace metals from wastewater.

ACS Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Luca Alibardi; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. Coagulation–flocculation process with metal salts, synthetic polymers and biopolymers for the removal of trace metals (Cu, Pb, Ni, Zn) from municipal wastewater. Clean Technologies and Environmental Policy 2018, 20, 393 -402.

AMA Style

Andrew J. Hargreaves, Peter Vale, Jonathan Whelan, Luca Alibardi, Carlos Constantino, Gabriela Dotro, Elise Cartmell, Pablo Campo. Coagulation–flocculation process with metal salts, synthetic polymers and biopolymers for the removal of trace metals (Cu, Pb, Ni, Zn) from municipal wastewater. Clean Technologies and Environmental Policy. 2018; 20 (2):393-402.

Chicago/Turabian Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Luca Alibardi; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. 2018. "Coagulation–flocculation process with metal salts, synthetic polymers and biopolymers for the removal of trace metals (Cu, Pb, Ni, Zn) from municipal wastewater." Clean Technologies and Environmental Policy 20, no. 2: 393-402.

Review
Published: 09 January 2018 in Environmental Technology Reviews
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Municipal effluents contain heavy metals in particular copper, lead, nickel, zinc and mercury. The concern regarding the impact of these contaminants in the aquatic environment is reflected in the latest criteria revisions to water-related legislation, such as the Clean Water Act in the US and the Water Framework Directive in Europe. These revisions may lower metal concentrations considered acceptable in final effluents. The study of metal behaviour within the wastewater treatment process is crucial to develop and optimise systems to achieve acceptable metal concentrations in effluent discharges. To comply with more stringent environmental quality standards, utilities may require the implementation of additional treatment technologies. This review evaluates the performance of conventional municipal wastewater treatment processes, that is, primary sedimentation and biological treatment via the activated sludge and trickling filter processes. The mechanisms and parameters influencing metal removal are discussed to evaluate how an understanding of metal behaviour within wastewater treatment processes may allow optimisation and enhancement of conventional treatment processes, or inform the selection of new technologies to enhance trace metal removal. The performance of advanced treatment technologies capable of removing metals from municipal wastewater under real-world conditions has also been evaluated.

ACS Style

Andrew J. Hargreaves; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. Fate and removal of metals in municipal wastewater treatment: a review. Environmental Technology Reviews 2018, 7, 1 -18.

AMA Style

Andrew J. Hargreaves, Carlos Constantino, Gabriela Dotro, Elise Cartmell, Pablo Campo. Fate and removal of metals in municipal wastewater treatment: a review. Environmental Technology Reviews. 2018; 7 (1):1-18.

Chicago/Turabian Style

Andrew J. Hargreaves; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. 2018. "Fate and removal of metals in municipal wastewater treatment: a review." Environmental Technology Reviews 7, no. 1: 1-18.

Journal article
Published: 01 January 2018 in Water Research
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This study investigated the impact of coagulation-flocculation treatment on metal form and bioavailability in municipal wastewater. Real humus effluent samples were separated into particulate, colloidal and truly dissolved fractions before and after treatment with either ferric chloride (FeCl) or the biopolymer Floculan. Results revealed that both reagents effectively (≥48%) eliminated Cu, Pb and Zn from the particulate fraction and removed Cu and Zn from the colloidal fraction in conjunction with colloidal organic carbon (COC). Although organics in the truly dissolved fraction were resistant to removal, Floculan reduced Cu in this fraction by 72% owing to the complexation of free Cu ions to phenol and amino groups along the polymeric chains, revealing an additional removal pathway. In fact, COC removed in the CF process by Floculan was replaced with truly dissolved compounds, input as a result of this reagents organic composition. Floculan, therefore, reduced the soluble concentration of Cu and Zn without changing the DOC concentration, thus reducing the bioavailability of these metals in treated effluent. FeCl did not reduce the bioavailability of target metals, thus did not deliver any environmental benefit. This work provides important information for the selection and development of high performance coagulants to improve metal removal.

ACS Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Luca Alibardi; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. Impacts of coagulation-flocculation treatment on the size distribution and bioavailability of trace metals (Cu, Pb, Ni, Zn) in municipal wastewater. Water Research 2018, 128, 120 -128.

AMA Style

Andrew J. Hargreaves, Peter Vale, Jonathan Whelan, Luca Alibardi, Carlos Constantino, Gabriela Dotro, Elise Cartmell, Pablo Campo. Impacts of coagulation-flocculation treatment on the size distribution and bioavailability of trace metals (Cu, Pb, Ni, Zn) in municipal wastewater. Water Research. 2018; 128 ():120-128.

Chicago/Turabian Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Luca Alibardi; Carlos Constantino; Gabriela Dotro; Elise Cartmell; Pablo Campo. 2018. "Impacts of coagulation-flocculation treatment on the size distribution and bioavailability of trace metals (Cu, Pb, Ni, Zn) in municipal wastewater." Water Research 128, no. : 120-128.

Journal article
Published: 01 May 2017 in Chemosphere
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The distribution of Cu, Pb, Ni and Zn between particulate, colloidal and truly dissolved size fractions in wastewater from a trickling filter treatment plant was investigated. Samples of influent, primary effluent, humus effluent, final effluent and sludge holding tank returns were collected and separated into particulate (i.e. > 0.45 μm), colloidal (i.e. 1 kDa to 0.45 μm), and truly dissolved (i.e. < 1 kDa) fractions using membrane filters. In the influent, substantial proportions of Cu (60%), Pb (67%), and Zn (32%) were present in the particulate fraction which was removed in conjunction with suspended particles at the works in subsequent treatment stages. In final effluent, sizeable proportions of Cu (52%), Pb (32%), Ni (44%) and Zn (68%) were found within the colloidal size fraction. Calculated ratios of soluble metal to organic carbon suggest the metal to be adsorbed to or complexed with non-humic macromolecules typically found within the colloidal size range. These findings suggest that technologies capable of removing particles within the colloidal fraction have good potential to enhance metals removal from wastewater.

ACS Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Carlos Constantino; Gabriela Dotro; Pablo Campo; Elise Cartmell. Distribution of trace metals (Cu, Pb, Ni, Zn) between particulate, colloidal and truly dissolved fractions in wastewater treatment. Chemosphere 2017, 175, 239 -246.

AMA Style

Andrew J. Hargreaves, Peter Vale, Jonathan Whelan, Carlos Constantino, Gabriela Dotro, Pablo Campo, Elise Cartmell. Distribution of trace metals (Cu, Pb, Ni, Zn) between particulate, colloidal and truly dissolved fractions in wastewater treatment. Chemosphere. 2017; 175 ():239-246.

Chicago/Turabian Style

Andrew J. Hargreaves; Peter Vale; Jonathan Whelan; Carlos Constantino; Gabriela Dotro; Pablo Campo; Elise Cartmell. 2017. "Distribution of trace metals (Cu, Pb, Ni, Zn) between particulate, colloidal and truly dissolved fractions in wastewater treatment." Chemosphere 175, no. : 239-246.

Proceedings article
Published: 01 April 2017 in Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering
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ACS Style

Andrew Hargreaves; Peter Vale; Jonathan Whelan; Carlos Constantino; Gabriela Dotro; Pablo Campo. Removal of Trace Metals from Municipal Wastewater by Coagulation-Flocculation. Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering 2017, 1 .

AMA Style

Andrew Hargreaves, Peter Vale, Jonathan Whelan, Carlos Constantino, Gabriela Dotro, Pablo Campo. Removal of Trace Metals from Municipal Wastewater by Coagulation-Flocculation. Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering. 2017; ():1.

Chicago/Turabian Style

Andrew Hargreaves; Peter Vale; Jonathan Whelan; Carlos Constantino; Gabriela Dotro; Pablo Campo. 2017. "Removal of Trace Metals from Municipal Wastewater by Coagulation-Flocculation." Proceedings of the 2nd World Congress on Civil, Structural, and Environmental Engineering , no. : 1.

Journal article
Published: 01 January 2017 in Ecological Engineering
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ACS Style

Gabriela Dotro; Ülo Mander; Diederik Rousseau. WETPOL 2015: Closing the gap between natural and constructed wetlands research. Ecological Engineering 2017, 98, 286 -289.

AMA Style

Gabriela Dotro, Ülo Mander, Diederik Rousseau. WETPOL 2015: Closing the gap between natural and constructed wetlands research. Ecological Engineering. 2017; 98 ():286-289.

Chicago/Turabian Style

Gabriela Dotro; Ülo Mander; Diederik Rousseau. 2017. "WETPOL 2015: Closing the gap between natural and constructed wetlands research." Ecological Engineering 98, no. : 286-289.

Journal article
Published: 24 August 2016 in Water
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A comparison of the performance of four full-scale aerated horizontal flow constructed wetlands was conducted to determine the efficacy of the technology on sites receiving high and variable ammonia loading rates not yet reported in the literature. Performance was assessed in terms of ammonia and solids removal, hydraulic conductivity and mixing patterns. The capability of systems to produce ammonium effluent concentrations <3 mgNH4+-N/L was observed across all sites in systems receiving variable loadings between 0.1 and 13.0 gNH4+-N/m2/d. Potential resilience issues were observed in relation to response to spike loadings posited to be due to an insufficient nitrifying population within the beds. Hydraulic conductivity and flow mixing patterns observed suggested deterioration of the reactor effective volume over time. Overall, the study demonstrates the efficacy of the technology where ammonium removal is required on small sites receiving high and variable flow rates, with adequate removal of organics and solids, but no significant benefit to the long term hydraulics of the system.

ACS Style

Eleanor Butterworth; Andrew Richards; Mark Jones; Gabriella Mansi; Ezio Ranieri; Gabriela Dotro; Bruce Jefferson. Performance of Four Full-Scale Artificially Aerated Horizontal Flow Constructed Wetlands for Domestic Wastewater Treatment. Water 2016, 8, 365 .

AMA Style

Eleanor Butterworth, Andrew Richards, Mark Jones, Gabriella Mansi, Ezio Ranieri, Gabriela Dotro, Bruce Jefferson. Performance of Four Full-Scale Artificially Aerated Horizontal Flow Constructed Wetlands for Domestic Wastewater Treatment. Water. 2016; 8 (9):365.

Chicago/Turabian Style

Eleanor Butterworth; Andrew Richards; Mark Jones; Gabriella Mansi; Ezio Ranieri; Gabriela Dotro; Bruce Jefferson. 2016. "Performance of Four Full-Scale Artificially Aerated Horizontal Flow Constructed Wetlands for Domestic Wastewater Treatment." Water 8, no. 9: 365.

Journal article
Published: 06 June 2016 in Environmental Technology
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This paper demonstrates that utilising a vertical flow (VF) wetland after a conventional activated sludge (CAS) delivers equivalent or better effluent quality to a membrane bioreactor (MBR) based on a side-by-side pilot trial. The CAS was operated under the solids retention times (SRT) of 6, 12, and 20 days, with the effluent from each pilot plant fed onto a soil aquifer treatment column to better understand their water reuse application potential. Results showed an upgraded CAS + VF system could deliver effluents with median values of 34 mgO2.L–1, 7 mg.L–1 and 1.9 mg.L–1 for organics, solids and ammonia nitrogen, respectively, which were statistically similar to those from the MBR. Water reuse standards were achieved by the upgraded system for most parameters, with the exception of total coliform removal. The upgraded system delivered superior metal removal when compared to the CAS. An economic analysis showed upgrading a CAS with a VF wetland was more favourable than investing in an MBR system for example works of 5000 and 50,000 population equivalents if the VF system was operated at hydraulic loading rates of 0.03 m.d–1 and 0.08 m.d–1, respectively. This was delivered for a tenth of the carbon footprint of the MBR treatment.

ACS Style

A. Besançon; K. S. Le Corre; G. Dotro; Bruce Jefferson. Assessment of activated sludge, membrane bioreactors and vertical flow wetlands for upgrading sewage treatment works. Environmental Technology 2016, 38, 154 -162.

AMA Style

A. Besançon, K. S. Le Corre, G. Dotro, Bruce Jefferson. Assessment of activated sludge, membrane bioreactors and vertical flow wetlands for upgrading sewage treatment works. Environmental Technology. 2016; 38 (2):154-162.

Chicago/Turabian Style

A. Besançon; K. S. Le Corre; G. Dotro; Bruce Jefferson. 2016. "Assessment of activated sludge, membrane bioreactors and vertical flow wetlands for upgrading sewage treatment works." Environmental Technology 38, no. 2: 154-162.

Journal article
Published: 27 February 2016 in Ecological Engineering
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The effect of artificial aeration on plant growth in constructed wetlands in terms of above and below ground biomass and nutrient uptake of two macrophyte species Phragmites australis and Typha latifolia was carried out to provide quantitative, mechanistic evidence to support any differences between the plant species establishment. Pilot scale systems were built and supplied with different intensities of aeration and corresponding controls, with supporting evidence from two full scale operational sites. Results show T. latifolia was more impacted by aeration than P. australis when comparing against their respective non-aerated controls, evidenced in reduced height, growth rate and leaf length. However, the impact was less visible due to T. latifolia's faster growth rate compared to P. australis. Micro and macronutrient uptake by each species had no discernible pattern, preventing the identification of a definitive mechanism to explain the retarded growth. However, results suggest a synergy between iron and manganese may be at play.

ACS Style

Eleanor Butterworth; Andrew Richards; Mark Jones; Hans Brix; Gabriela Dotro; Bruce Jefferson. Impact of aeration on macrophyte establishment in sub-surface constructed wetlands used for tertiary treatment of sewage. Ecological Engineering 2016, 91, 65 -73.

AMA Style

Eleanor Butterworth, Andrew Richards, Mark Jones, Hans Brix, Gabriela Dotro, Bruce Jefferson. Impact of aeration on macrophyte establishment in sub-surface constructed wetlands used for tertiary treatment of sewage. Ecological Engineering. 2016; 91 ():65-73.

Chicago/Turabian Style

Eleanor Butterworth; Andrew Richards; Mark Jones; Hans Brix; Gabriela Dotro; Bruce Jefferson. 2016. "Impact of aeration on macrophyte establishment in sub-surface constructed wetlands used for tertiary treatment of sewage." Ecological Engineering 91, no. : 65-73.

Reviews
Published: 01 January 2016 in Environmental Technology Reviews
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The challenge of how to maintain or improve wastewater treatment performance without causing an excessive increase in energy or costs is increasingly focussed towards ammonia. On small sewage treatment works, solutions have historically been energy intensive: to divert waste to a larger plant, add a polishing step to the end of the process flow sheet or upgrade and replace upstream processes. Constructed wetlands (CWs) offer a low energy alternative to meet these challenges. This review explores oxygen transfer theory; nitrification performance of existing CW systems, and the key affecting factors to be considered when implementing the technology for tertiary treatment upgrades. Future perspectives include the use of artificial aeration and greater consideration of vertical sub-surface flow systems as they achieve the nitrification capacity in a smaller footprint than horizontal flow systems and, where suitable hydraulics permit, can be operated under very low energy demand.

ACS Style

Eleanor Butterworth; Andrew Richards; Mark Jones; Gabriela Dotro; Bruce Jefferson. Assessing the potential for tertiary nitrification in sub-surface flow constructed wetlands. Environmental Technology Reviews 2016, 5, 68 -77.

AMA Style

Eleanor Butterworth, Andrew Richards, Mark Jones, Gabriela Dotro, Bruce Jefferson. Assessing the potential for tertiary nitrification in sub-surface flow constructed wetlands. Environmental Technology Reviews. 2016; 5 (1):68-77.

Chicago/Turabian Style

Eleanor Butterworth; Andrew Richards; Mark Jones; Gabriela Dotro; Bruce Jefferson. 2016. "Assessing the potential for tertiary nitrification in sub-surface flow constructed wetlands." Environmental Technology Reviews 5, no. 1: 68-77.

Chapter
Published: 19 July 2014 in The Role of Natural and Constructed Wetlands in Nutrient Cycling and Retention on the Landscape
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Fourteen full-scale wastewater treatment plants (WwTPs) owned and operated by Severn Trent Water, a major UK water utility, were assessed to determine the long-term efficiency of using chemical dosing upstream of biofilm processes followed by horizontal flow wetlands to remove phosphorus and any residual metals. Results showed that the flowsheets used are an effective strategy to remove BOD, solids, ammonia, nitrate, and phosphorus, with all sites meeting their discharge consents for the past 10 years. Wetland removal rates of up to 6.7, 3.8, 0.24, 2.4, and 0.5 mg m−2 d−1 were found for solids, nitrate, ammonia, phosphorus, and iron, respectively. Under flooded conditions, settling mechanisms dominated as evidenced by average surface sludge accumulation rates of 2 cm year−1. Subsurface flow resulted in lower or no sludge accumulation on top of the gravel. The average concentration of P and Fe in the sludge per site was in the range of 17–48 and 9–178 g kg−1, respectively, much higher than sediment concentrations found in non-dosed wetlands and river sediments. Analysis of suspended, colloidal, and dissolved fractions showed a change in phase for P from particulate to dissolved after the wetland, suggesting release. Phosphorus release was observed under low P conditions in wastewater (<1 mg L−1) and high sludge P levels, with release rates of 12–52 44 mg m−2 d−1 in the field and 44 mg m−2 d−1 under laboratory conditions. Iron release was observed under controlled experiments but not detected in the field, indicating additional transformation reactions take place in full-scale wetlands. Further research is required to provide adequate data for modifying the design and improving the operation and maintenance recommendations to ensure wetlands continue to deliver environmental benefit at WwTPs required to remove phosphorus.

ACS Style

Gabriela Dotro; Raul Prieto Fort; Jan Barak; Mark Jones; Peter Vale; Bruce Jefferson. Long-Term Performance of Constructed Wetlands with Chemical Dosing for Phosphorus Removal. The Role of Natural and Constructed Wetlands in Nutrient Cycling and Retention on the Landscape 2014, 273 -292.

AMA Style

Gabriela Dotro, Raul Prieto Fort, Jan Barak, Mark Jones, Peter Vale, Bruce Jefferson. Long-Term Performance of Constructed Wetlands with Chemical Dosing for Phosphorus Removal. The Role of Natural and Constructed Wetlands in Nutrient Cycling and Retention on the Landscape. 2014; ():273-292.

Chicago/Turabian Style

Gabriela Dotro; Raul Prieto Fort; Jan Barak; Mark Jones; Peter Vale; Bruce Jefferson. 2014. "Long-Term Performance of Constructed Wetlands with Chemical Dosing for Phosphorus Removal." The Role of Natural and Constructed Wetlands in Nutrient Cycling and Retention on the Landscape , no. : 273-292.

Original articles
Published: 25 June 2014 in Environmental Technology
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As regulatory requirements for contaminants in wastewater discharged to the environment get stricter, alternative or additional treatment processes to those already being used are necessary. One contaminant of particular concern associated with discharging treated municipal wastewater to a receiving water body is phosphorus (P). A continuous scale electrocoagulation (EC) system was investigated as an alternative to conventional chemical addition for P removal from municipal wastewater. The EC process was optimized for iron dose delivery by changing the electrical current, electrode spacing and the reactor contact time, and a comparison was made with conventional ferric dosing through jar testing. Results showed that EC could achieve P removal to meet a P consent of 1 mg L−1 at a dose of 154 mg L−1 Fe. The process was shown to provide a supplementary benefit for chemical and biological oxygen demand removal of 86% and 82%, respectively, but gave no significant removal of other sanitary pollutants. When compared directly with conventional iron dosing, EC required approximately twice the iron dose. When electrical costs were also factored into the comparison, EC was shown to be approximately double the cost of conventional dosing and at present is not a feasible alternative to conventional coagulation using ferric chloride.

ACS Style

B. Stafford; Gabriela Dotro; P. Vale; Bruce Jefferson; Peter Jarvis. Removal of phosphorus from trickling filter effluent by electrocoagulation. Environmental Technology 2014, 35, 3139 -3146.

AMA Style

B. Stafford, Gabriela Dotro, P. Vale, Bruce Jefferson, Peter Jarvis. Removal of phosphorus from trickling filter effluent by electrocoagulation. Environmental Technology. 2014; 35 (24):3139-3146.

Chicago/Turabian Style

B. Stafford; Gabriela Dotro; P. Vale; Bruce Jefferson; Peter Jarvis. 2014. "Removal of phosphorus from trickling filter effluent by electrocoagulation." Environmental Technology 35, no. 24: 3139-3146.

Review
Published: 01 May 2014 in Ecological Engineering
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A literature analysis of 158 papers published in international peer-reviewed journals indexed by the Thomson Reuters Web of Knowledge from 1994 to 2013 showed that CO2C emission was significantly lower in free water surface (FWS) constructed wetlands (CW) than in subsurface flow (SF) CWs (median values from 95.8 to 137.0 mg m−2h−1, respectively). In vertical subsurface flow (VSSF) CWs the CH4Cemission was significantly lower than in horizontal subsurface flow (HSSF) CWs (median values 3.0, 6.4,and 4.0 mg m−2h−1, respectively). There were no significant differences in N2O N emission in various Cw types (median for FWS, VSSF and HSSF CWs: 0.09, 0.12, and 0.13 mg m−2h−1correspondingly).The highest value of emission factor (EF) of CH4((CH4C/inflow TOCin) * 100%) was found for FWSCWs (median 18.0%), followed by HSSF CWs (3.8%), and VSSF CWs (1.28%). Median values of N2O EFs((N2O N/inflow TNin) * 100%) differed significantly in all three CW types: 0.34% for HSSF, 0.11% for FWS,and 0.018% for VSSF CWs.We found a significant correlation between TOCin and CH4C emission and between the TNinandN2O N emission values for all of the types of CWs we studied.Hybrid CWs (e.g., the subsequent combination of VSSF, HSSF and FWS CWs) are beneficial from thepoint of view of both water purification and minimization of greenhouse gas (GHG) emissions. Likewise,intermittent loading in VSSF CWs and macrophyte harvesting in HSSF and FWS CWs can mitigate GH Gemissions.201

ACS Style

Ülo Mander; Gabriela Dotro; Yoshitaka Ebie; Sirintornthep Towprayoon; Chart Chiemchaisri; Sandra Furlan Nogueira; Baasansuren Jamsranjav; Kuno Kasak; Jaak Truu; Julien Tournebize; William Mitsch. Greenhouse gas emission in constructed wetlands for wastewater treatment: A review. Ecological Engineering 2014, 66, 19 -35.

AMA Style

Ülo Mander, Gabriela Dotro, Yoshitaka Ebie, Sirintornthep Towprayoon, Chart Chiemchaisri, Sandra Furlan Nogueira, Baasansuren Jamsranjav, Kuno Kasak, Jaak Truu, Julien Tournebize, William Mitsch. Greenhouse gas emission in constructed wetlands for wastewater treatment: A review. Ecological Engineering. 2014; 66 ():19-35.

Chicago/Turabian Style

Ülo Mander; Gabriela Dotro; Yoshitaka Ebie; Sirintornthep Towprayoon; Chart Chiemchaisri; Sandra Furlan Nogueira; Baasansuren Jamsranjav; Kuno Kasak; Jaak Truu; Julien Tournebize; William Mitsch. 2014. "Greenhouse gas emission in constructed wetlands for wastewater treatment: A review." Ecological Engineering 66, no. : 19-35.

Article
Published: 18 January 2014 in Water, Air, & Soil Pollution
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Wastewater treatment works can receive toxic substances that can kill microorganisms responsible for waste degradation. Implementation of toxicity monitors in-sewer, as part of an early warning system to help prevent toxic substances entering treatment works, is, however, very rare. This work presents results from a pilot-scale study using an in-sewer early warning system based on detection of nitrous oxide (N2O) gas emitted by nitrifying bacteria naturally present in sewer biofilm. Nitrous oxide has potential to be an indicator of nitrification inhibition as it is typically emitted when nitrifiers are under stress. The biofilm was allowed to develop over 14 days under fixed wastewater flow and level. Presence of nitrifying bacteria was verified on day 13 followed by a 90 min toxic shock on day 14 by four different known nitrification inhibitors. Pre-shock nitrification rates averaged 0.78 mg-NH4+-N mg-VS−1 d−1 and were significantly reduced post shock to <0.2 mg-NH4+-N mg-VS−1 d−1. Nitrous oxide emissions were found to vary with influent wastewater quality, suggesting a more complex data processing algorithm is needed instead of a simple threshold emission value. The extent of nitrification inhibition differed from the recorded response for suspended growth biomass with allylthiourea resulting in a 77 and 81 % nitrification inhibition for literature suspended growth EC50 and EC75 concentrations, respectively. Results from this study suggest nitrifying biofilms in closed pipes can be used as part of an early warning system but will likely require amplification of the response to be of practical use. Further research is required to better understand the biofilm response and calibrate the early warning system for differentiating its unique baseline from true toxicity events.

ACS Style

G. Black; M. Jones; P. Vale; N. Johnson; A. Nocker; Elise Cartmell; Gabriela Dotro. Biofilm Responses to Toxic Shocks in Closed Pipes: Using Nitrous Oxide Emissions as an Early Warning of Toxicity Ahead of a Wastewater Treatment Works. Water, Air, & Soil Pollution 2014, 225, 1837 .

AMA Style

G. Black, M. Jones, P. Vale, N. Johnson, A. Nocker, Elise Cartmell, Gabriela Dotro. Biofilm Responses to Toxic Shocks in Closed Pipes: Using Nitrous Oxide Emissions as an Early Warning of Toxicity Ahead of a Wastewater Treatment Works. Water, Air, & Soil Pollution. 2014; 225 (2):1837.

Chicago/Turabian Style

G. Black; M. Jones; P. Vale; N. Johnson; A. Nocker; Elise Cartmell; Gabriela Dotro. 2014. "Biofilm Responses to Toxic Shocks in Closed Pipes: Using Nitrous Oxide Emissions as an Early Warning of Toxicity Ahead of a Wastewater Treatment Works." Water, Air, & Soil Pollution 225, no. 2: 1837.

Journal article
Published: 06 December 2013 in Water, Air, & Soil Pollution
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Methane (CH4) formation in wastewater treatment is linked to long residence times under anaerobic conditions such as those in sewers and primary treatment units. Emissions of this methane to the atmosphere can occur under turbulent flows and, potentially, during aeration in an activated sludge plant. An online, 8-week monitoring campaign of CH4 emissions and operational conditions was conducted to study emissions from a full-scale nitrifying activated sludge plant (ASP). Significant emissions were found throughout the aerated lane, with the highest values observed two thirds down the lane. Emissions had high diurnal and spatial variability, with values ranging from 0.3 to 24 g CH4/h. No significant correlations were found between dissolved oxygen, aeration or influent loads. The results suggest that emissions are linked to upstream process conditions, with potential for methane generation in-lane due periods of limited oxygen availability. The dynamic oxygen profile observed suggests that aerobic and anoxic conditions coexist in the lane, leading to limited oxygen diffusion from the bulk liquid to the inner regions of the floc where anoxic/anaerobic layers may allow methanogenic microorganisms to survive. The average emission factor was 0.07 % of removed chemical oxygen demand, giving a total of 668 kg CH4/year and 14,000 CO2 equivalents/year. The operational carbon associated with the energy requirements of the ASP increased by 5 %. With emerging legislation requiring the reporting of greenhouse gas emissions, the carbon impact may be significant, particularly as the industry moves towards a carbon-reducing future. Therefore, an adequate profiling of full-scale emissions is critical for future proofing existing treatment technologies.

ACS Style

Amina Aboobakar; Mark Jones; Peter Vale; Elise Cartmell; Gabriela Dotro. Methane Emissions from Aerated Zones in a Full-Scale Nitrifying Activated Sludge Treatment Plant. Water, Air, & Soil Pollution 2013, 225, 1 .

AMA Style

Amina Aboobakar, Mark Jones, Peter Vale, Elise Cartmell, Gabriela Dotro. Methane Emissions from Aerated Zones in a Full-Scale Nitrifying Activated Sludge Treatment Plant. Water, Air, & Soil Pollution. 2013; 225 (1):1.

Chicago/Turabian Style

Amina Aboobakar; Mark Jones; Peter Vale; Elise Cartmell; Gabriela Dotro. 2013. "Methane Emissions from Aerated Zones in a Full-Scale Nitrifying Activated Sludge Treatment Plant." Water, Air, & Soil Pollution 225, no. 1: 1.

Journal article
Published: 06 March 2013 in Ecological Engineering
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A full scale comparison of a newly commissioned artificially aerated horizontal subsurface flow constructed wetland and a non-aerated bed of identical design was conducted to determine the efficacy of artificial aeration on tertiary nitrification. The works serves a population equivalent of 400; each bed is 100 m2 and has a mean hydraulic loading rate of 0.27 m3/m2/d. During the first 9 months of operation the wetlands received inlet loadings of NH4-N: 3.1 ± 2.4 g/m2/d, CBOD5: 2.8 ± 2.0 gO2/m2/d, chemical oxygen demand (COD): 19.4 ± 11.2 g/m2/d and total suspended solids (TSS): 6.6 ± 5.0 g/m2/d (mean ± standard deviation, n = 17). Results demonstrated enhanced nitrification in the aerated bed with 99% mass removal up to the maximum tested loading rate of 10.1 gNH4+-N/m2/d. In comparison, an ammonia removal of 59% was observed in the non-aerated bed up to a loading rate of 1.6 gNH4+-N/m2/d beyond which performance deteriorated. Carbonaceous biochemical oxygen demand and suspended solids removal were seen to be statistically similar between the beds while a significant difference was observed in terms of mixing pattern, quantity and characteristics of the accumulated solids and hydraulic conductivity. The suitability of the technology was also assessed through comparison of cost, carbon footprint and land area relative to alternative upgrading options. Retrofitting existing horizontal subsurface flow wetlands was shown to be the most cost effective solution delivering the required treatment at 38% of the cost of the least expensive alternatives.

ACS Style

E. Butterworth; G. Dotro; M. Jones; A. Richards; P. Onunkwo; Y. Narroway; Bruce Jefferson. Effect of artificial aeration on tertiary nitrification in a full-scale subsurface horizontal flow constructed wetland. Ecological Engineering 2013, 54, 236 -244.

AMA Style

E. Butterworth, G. Dotro, M. Jones, A. Richards, P. Onunkwo, Y. Narroway, Bruce Jefferson. Effect of artificial aeration on tertiary nitrification in a full-scale subsurface horizontal flow constructed wetland. Ecological Engineering. 2013; 54 ():236-244.

Chicago/Turabian Style

E. Butterworth; G. Dotro; M. Jones; A. Richards; P. Onunkwo; Y. Narroway; Bruce Jefferson. 2013. "Effect of artificial aeration on tertiary nitrification in a full-scale subsurface horizontal flow constructed wetland." Ecological Engineering 54, no. : 236-244.

Comparative study
Published: 01 February 2013 in Water Research
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This paper reports findings from online, continuous monitoring of dissolved and gaseous nitrous oxide (N2O), combined with dissolved oxygen (DO) and ammonia loading, in a full-scale nitrifying activated sludge plant. The study was conducted over eight weeks, at a 210,000 population equivalent sewage treatment works in the UK. Results showed diurnal variability in the gaseous and dissolved N2O emissions, with hourly averages ranging from 0 to 0.00009 kgN2O-N/h for dissolved and 0.00077–0.0027 kgN2O-N/h for gaseous nitrous oxide emissions respectively, per ammonia loading, depending on the time of day. Similarly, the spatial variability was high, with the highest emissions recorded immediately after the anoxic zone and in the final pass of the aeration lane, where ammonia concentrations were typically below 0.5 mg/L. Emissions were shown to be negatively correlated to dissolved oxygen, which fluctuated between 0.5 and 2.5 mgO2/L, at the control set point of 1.5 mgO2/L. The resulting dynamic DO conditions are known to favour N2O production, both by autotrophic and heterotrophic processes in mixed cultures. Average mass emissions from the lane were greater in the gaseous (0.036% of the influent total nitrogen) than in the dissolved (0.01% of the influent total nitrogen) phase, and followed the same diurnal and spatial patterns. Nitrous oxide emissions corresponded to over 34,000 carbon dioxide equivalents/year, adding 13% to the carbon footprint associated with the energy requirements of the monitored lane. A clearer understanding of emissions obtained from real-time data can help towards finding the right balance between improving operational efficiency and saving energy, without increasing N2O emissions.

ACS Style

Amina Aboobakar; Elise Cartmell; Tom Stephenson; Mark Jones; Peter Vale; Gabriela Dotro. Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant. Water Research 2013, 47, 524 -534.

AMA Style

Amina Aboobakar, Elise Cartmell, Tom Stephenson, Mark Jones, Peter Vale, Gabriela Dotro. Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant. Water Research. 2013; 47 (2):524-534.

Chicago/Turabian Style

Amina Aboobakar; Elise Cartmell; Tom Stephenson; Mark Jones; Peter Vale; Gabriela Dotro. 2013. "Nitrous oxide emissions and dissolved oxygen profiling in a full-scale nitrifying activated sludge treatment plant." Water Research 47, no. 2: 524-534.