Browsing by Author "Pidou, Marc"
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Item Open Access Anaerobic co-digestion of sewage sludge and trade wastes: beneficial and inhibitory effects of individual constituents(MDPI, 2023-02-08) Berzal de Frutos, Olivia; Götze, Martin; Pidou, Marc; Bajón Fernández, YadiraAnaerobic digestion (AD) of sewage sludge can be optimised by adding trade wastes (TWs) because of their nutrient content and boost in biogas formation if non-inhibitory. However, some components in TWs might have an inhibitory impact, such as nitrogen compounds, sulphate, heavy metals, metalloids, halogens and organic pollutants (e.g., phenol). This study aimed to understand the impact of TWs on the co-digestion with sewage sludge to identify appropriate TW loads for sustainable AD operation. The composition of 160 TWs was evaluated and the constituents with potential to cause inhibition or toxicity were tested in bio-methane potential (BMP) tests. The compounds studied in BMP tests included ammonia, zinc, copper, aluminium, mercury, arsenic, chloride, sulphate and nitrate. An improvement was observed at concentrations 2–746 mg Zn/L, 1066–2821 mg Cl/L as zinc sulphate and sodium chloride in biogas production, and 2–746 mg Zn/L, 162 mg SO4/L, 25 mg Hg/L as zinc sulphate, sodium chloride and mercury sulphate in methane production, respectively. Considering the TWs characterised and the results of the BMP tests, a volumetric ratio of 10/90 of TWs and sewage sludge is proposed as a suitable feedstock for co-digestion.Item Open Access Biofouling and scaling control of reverse osmosis membrane using one-step cleaning - potential of acidified nitrite solution as an agent(Elsevier, 2015-08-17) Filloux, Emmanuelle; Wang, Jingshi; Pidou, Marc; Gernjak, Wolfgang; Yuan, ZhiguoBiofouling is generally regarded as a major issue in reverse osmosis (RO) membrane filtration. Two-step chemical cleanings with alkaline and acidic agents are typically applied to restore the treatment capacity. In this study, the feasibility of one-step cleaning using free nitrous acid (FNA) was investigated as a novel low cost cleaning agent. The FNA cleaning solution was prepared by acidification of a sodium nitrite solution with hydrochloric acid. Seven fouled RO membranes collected from full-scale wastewater recycling and desalination plants were used to perform lab-scale cleaning trials. Membrane fouling characterisation revealed six of out of seven membranes were mainly bio-fouled, while one membrane was severely fouled by calcium carbonate. This study showed the feasibility of using FNA at pH 3.0 for biomass removal as well as for calcium carbonate scaling removal. The results from the lab-scale cleaning tests suggested that FNA can be used as a single cleaning agent for both biofouling and scaling removal. Cost analysis showed that FNA is a cost-effective solution for biofouling and scaling removal in RO filtration applications.Item Open Access CO2 absorption into aqueous ammonia using membrane contactors: Role of solvent chemistry and pore size on solids formation for low energy solvent regeneration(Elsevier, 2022-03-16) Bavarella, S.; Luqmani, Ben; Thomas, Navya; Brookes, Adam; Moore, A.; Vale, P.; Pidou, Marc; McAdam, Ewan J.Solids formation can substanitally reduce the energy penalty for ammonia solvent regeneration in carbon capture and storage (CCS), but has been demonstrated in the literature to be difficult to control. This study examines the use of hollow fibre membrane contactors, as this indirect contact mediated between liquid and gas phases in this geometry could improve the regulation of solids formation. Under conditions comparable to existing literature, NH4HCO3 was evidenced to primarily crystallise in the gas-phase (lumen-side of the membrane) due to the high vapour pressure of ammonia, which promotes gaseous transmission from the solvent. Investigation of solvent reactivity demonstrated how equilibria dependent reactions controlled the onset of NH4HCO3 nucleation in the solvent, and limited ‘slip’ through transfomation of ammonia into its protonated form which occurs prior to the phase change. Crystallisation in the solvent was also dependent upon ammonia concentration, where sufficient supersaturation must develop to overcome the activation energy for nucleation. However, this has to be complemented with a reduction in solvent temperature to offset vapour pressure and limit the risk of gas-phase crystallisation. While changes to the solvent chemistry were sufficient to shift from gas-phase to liquid phase crystallisation, wetting was observed immediately after nucleation in the solvent. This was explained by a local region of supersaturation within the coarse membrane pores that promoted a high nucleation rate, altering the material contact angle of the membrane sufficient for solvent to breakthrough into the gas phase. Adoption of a narrower pore size membrane was shown to dissipate wetting after crystallisation in the solvent, illustrating membrane contactors as a stable platform for the sustained separation of CO2 coupled with its simultaneous transformation into a solid. Through resolving previous challenges experienced with solids formation in multiple reactor configurations, the cost benefit of using ammonia as a solvent can be realised, which is critical to enabling economically viable CCS for the transition to net zero, and can be exploited within hollow fibre membrane contactors, eliciting considerable process intensification over existing reactor designs for CCS.Item Open Access A comparative evaluation of reverse osmosis membrane performance when combined with anaerobic or aerobic membrane bioreactors for indirect potable reuse applications(Elsevier, 2022-11-18) Huang, Yu; Jeffrey, Paul; Pidou, MarcThe filtration performance and fouling behaviour of reverse osmosis (RO) membranes was investigated for the post-treatment of aerobic (Ae) and anaerobic (An) MBR effluents treating municipal wastewater for potable reuse. Both MBR effluents followed by RO can produce a water quality sufficient for indirect potable water reuse, while fluorescence excitation-emission scan suggests RO can effectively remove disinfection by-products precursors, ensuring the safety for chlorine based reuse water distribution by rejecting the dissolved organic matters in MBR effluents. AnMBR effluent leads to more fouling when compared to the AeMBR effluent with an average membrane fouling resistance of 12.35 × 1013 m−1 and 8.97 × 1013 m−1. Elemental analysis and membrane surface imaging results demonstrate that the foulant deposition sequence is organic and colloidal at first, followed by inorganic substances, while TOC and Ca are the most deposited foulants from both effluents. The unremoved ammonia in the AnMBR effluent may partially go through in the RO permeate and exceed the threshold in Singapore's PUB NEWater standard, while experiencing a significantly higher deposition rate of 13.8 % than the nitrate (0.02 %) from the AeMBR effluent. The findings suggest that the combination of AnMBR with RO offers a more sustainable approach than with the AeMBR but nutrients removal, with the potential of recovery, is recommended before the RO membranes to limit the fouling propensity and achieve a permeate of sufficient quality.Item Open Access Consequences of pH change on wastewater depth filtration using a multimedia filter(Elsevier, 2017-10-21) Ncube, Philani; Pidou, Marc; Stephenson, Tom; Jefferson, Bruce; Jarvis, PeterDifferent media materials in a multimedia filter have the potential to trap particles of different characteristics dependent on the media-suspension particle interactions. However, the removal of particles from wastewater secondary effluent using granular media filtration is relatively poorly understood because of the complexity of the wastewater matrix. Often the wastewater treatment process is liable to undergo pH changes due to removal or addition of chemicals in the treatment chain or from biological instability which in turn may alter the wastewater characteristics. Wastewater contains a mixture of organic and inorganic components, dissolved or particulate which may influence the aggregation and deposition of suspension solids during depth filtration. Changes in wastewater pH has the potential to change the wastewater matrix and media surface properties hence affecting aggregation and deposition in wastewater filtration. This study investigated how pH change affects wastewater filtration by monitoring zeta potential, aggregation and deposition of solids. The wastewater and filter media were also characterised over a range of pH from 1 to 13. Aggregation and deposition of wastewater solids was found to be most efficient near neutral pH. This was not concurrent with the conditions of lowest net charge in the system.Item Open Access Data for the paper "Influence of light regime on the performance of an immobilised microalgae reactor for wastewater nutrient removal"(Cranfield University, 2019-10-31 18:14) Whitton, Rachel; Ometto, Francesco; Villa, Raffaella; Pidou, Marc; Jefferson, BruceWastewater nutrient remediation data using immobilised microalgae under differing light regimes including wavelength (nm), duty cycles and photoperiods (on:off cycles), light transmittance and attenuation depths.Item Open Access Data for the paper "What is the impact of personal care products selection on grey water characteristics and reuse?"(Cranfield University, 2020-05-27 19:59) Le Corre Pidou, Kristell; Jeffrey, Paul; Jefferson, Bruce; Pidou, MarcThis unique study explores the question as to whether consumers’ product selection could affect the treatability and reuse of bathroom greywater. Fifty five personal care and household products (PCHP) were analysed for their effects on a range of water quality parameters including their aquatic and soil toxicity using Microtox® and MicroRespTM. Data used in the manuscript are compiled in the attached data file. Material and methods used to generate the data can be found in the manuscriptItem Open Access Data related to "Examining disruptive gas-phase reactions during CO2 capture in membrane contactors: CO2-NH3-H2O as a model ternary system"(Cranfield University, 2024-05-23 17:10) Luqmani, Ben; Pidou, Marc; McAdam, EwanData related to figures for "Examining disruptive gas-phase reactions during CO2 capture in membrane contactors: CO2-NH3-H2O as a model ternary system"Item Open Access Data related to "The role of solvent temperature and gas pressure on CO2 mass transfer during biogas upgrading within porous and dense-skin hollow fibre membrane contactors"(Cranfield University, 2023-04-14 14:37) Luqmani, Ben; McAdam, Ewan; Pidou, MarcSource data for published works: 'The role of solvent temperature and gas pressure on CO2 mass transfer during biogas upgrading within porous and dense-skin hollow fibre membrane contactors'.Item Open Access Data related to figures from "Transitioning through the vapour-liquid equilibrium for low energy thermal stripping of ammonia from wastewater..."(Cranfield University, 2023-04-21 14:29) Luqmani, Ben; Pidou, Marc; McAdam, EwanSupporting dataset related to figures in the following work : "Transitioning through the vapour-liquid equilibrium for low energy thermal stripping of ammonia from wastewater...".Item Open Access Data supporting: 'CO2 absorption into aqueous ammonia using membrane contactors: Role of solvent chemistry and pore size on solids formation for low energy solvent regeneration'(Cranfield University, 2022-10-13 16:42) Bavarella, Salvatore; Luqmani, Ben; Thomas, Navya; Brookes, Adam; Moore, Andrew; Vale, Peter; Pidou, Marc; McAdam, EwanSolids formation can substantially reduce the energy penalty for ammonia solvent regeneration in carbon capture and storage (CCS), but has been demonstrated in the literature to be difficult to control. This study examines the use of hollow fibre membrane contactors, as this indirect contact mediated between liquid and gas phases in this geometry could improve the regulation of solids formation. Adoption of a narrower pore size membrane was shown to dissipate wetting after crystallisation in the solvent, illustrating membrane contactors as a stable platform for the sustained separation of CO2 coupled with its simultaneous transformation into a solid. Through resolving previous challenges experienced with solids formation in multiple reactor configurations, the cost benefit of using ammonia as a solvent can be realised, which is critical to enabling economically viable CCS for the transition to net zero, and can be exploited within hollow fibre membrane contactors, eliciting considerable process intensification over existing reactor designs for CCS.Item Open Access Demonstrating commercial hollow fibre membrane contactor performance at industrial scale for biogas upgrading at a sewage treatment works(MDPI, 2021-01-13) Houlker, Sam; Rutherford, Tony; Herron, Daniel; Brookes, Adam; Moore, Andrew; Vale, Peter; Pidou, Marc; McAdam, Ewan J.Hollow fibre membrane contactor (HFMC) technology has been developed for CO2 absorption primarily using synthetic gas, which neglects the critical impact that trace contaminants might have on separation efficiency and robustness in industrial gases. This study, therefore, commissioned a demonstration-scale HFMC for CO2 separation at a full-scale anaerobic digester facility to evaluate membrane integrity over six months of operation on real biogas. The CO2 capture efficiency identified using real biogas was benchmarked at comparable conditions on synthetic gas of an equivalent partial pressure, and an equivalent performance identified. Two HFMC were subsequently compared, one with and one without a pre-treatment stage that targeted particulates, volatile organic compounds (VOCs) and humidity. Similar CO2 separation efficiency was again demonstrated, indicating limited impact within the timescale evaluated. However, gas phase pre-treatment is advised in order to ensure robustness in the long term. Over longer-term operation, a decline in CO2 separation efficiency was observed. Membrane autopsy identified shell-side deposition, where the structural morphology and confirmation of amide I and II groups, indicated biofouling. Separation efficiency was reinstated via chemical cleaning, which demonstrated that proactive maintenance could minimise process risk.Item Open Access The effect of high hydraulic loading rate on the removal efficiency of a quadruple media filter for tertiary wastewater treatment(IWA Publishing, 2016-10-24) Ncube, Philani; Pidou, Marc; Stephenson, Tom; Jefferson, Bruce; Jarvis, PeterIt is well known that filtration removal efficiency falls with an increase in flow rate; however, there is limited supporting experimental data on how removal efficiency changes for filters with multiple layers of media and for wastewater filtration, a practice that is becoming more common. Furthermore, information is not available on the characteristics of particles that are removed at different flow rates. Here, a quadruple media filter was operated at hydraulic loading rates (HLRs) between 5 and 60 mh−1 with subsequent measurement of total suspended solids, turbidity and particle size distribution (PSD). Samples were collected from the filter influent, effluent and also from between media layers. Pressure changes across the filter layers were also measured. The solids removal efficiency of the filter varied inversely with the increase in filtration rate. However, the multiple media layers reduced the negative impact of increased HLR in comparison to a single media filter. High filtration rates were shown to transport solids, such that particle retention and headloss development was distributed across the entire depth of the multi-media filter. There was also a progressive decrease in the suspension particle size leaving each of the filter layers. The particle hydrodynamic force simulation was consistent with the changes in measured PSD through the filter layers.Item Open Access Energy recovery from immobilised cells of Scenedesmus obliquus after wastewater treatment(Springer, 2017-05-05) Gomez San Juan, Marta; Ometto, F.; Whitton, Rachel; Pidou, Marc; Jefferson, Bruce; Villa, RaffaellaBiomethane batch test of alginate beads and beads with algae at different stages of utilisation in the wastewater treatment plants showed that immobilised S. obliquus yield similar biogas and biomethane than freely suspended algae (between 60.51 ± 4.19 and 82.32 ± 2.17 mL g-1 VSadd) and that a pre-treatment stage was not necessary for the digestion process.Item Open Access Figures and tables from "Hybrid membrane distillation reverse electrodialysis configuration for water and energy recovery from human urine: An opportunity for off-grid decentralised sanitation."(Cranfield University, 2019-05-15 14:12) Mercer, Edwina; McAdam, Ewan; Davey, Chris; Pidou, Marc; Tyrrel, Sean; Williams, Leon; Jiang, Ying; Parker, Alison; Tierney, Ross; Azzini, Daniele; Eusebi, AnnaThis data compiles the dataset required to generate the tables and figures for the paper - "Hybrid membrane distillation reverse electrodialysis configuration for water and energy recovery from human urine: An opportunity for off-grid decentralised sanitation."Item Open Access Fouling control of a membrane coupled photocatalytic process treating greywater(Elsevier Science B.V., Amsterdam., 2009-09-01T00:00:00Z) Pidou, Marc; Parsons, Simon A.; Raymond, Gaelle; Jeffrey, Paul; Stephenson, Tom; Jefferson, BruceFouling in membrane coupled photocatalytic reactors was investigated in the case of greywater treatment by establishing the link between product type, dose, irradiation time and fouling rates in a cross flow membrane cell fitted with a 0.4 μm pore sized polyethylene membrane. Rapid fouling occurred only with shower gels and conditioners and was linked to changes in the organo-TiO2 aggregate size postulated to be caused by polymers within the products. Fouling was reduced to a negligible level when sufficient irradiation was applied demonstrating that the membrane component of the process is not the issue and that scale up and implementation of the process relates to effective design of the UV reactorItem Open Access Greywater recycling: A review of treatment options and applications(Thomas Telford, 2007-01-01T00:00:00Z) Pidou, Marc; Memon, Fayyaz Ali; Stephenson, Tom; Jefferson, Bruce; Jeffrey, PaulWastewater is an immense resource which could have significant applications in regions of water scarcity. Greywater has particular advantages in that it is a large source with a low organic content. Through critical analysis of data from existing greywater recycling applications this paper presents a review of existing technologies and applications; collating a disparate information base and comparing / contrasting the strengths and weaknesses of different approaches. Findings suggest that simple technologies and sand filters have been shown to achieve only a limited treatment of the greywater whereas membranes were reported to provide good removal of the solids but could not efficiently tackle the organic fraction. Alternatively, biological and extensive schemes achieved good general treatment of greywater with a particularly good removal of the organics. The best overall performances were observed within the schemes combining different types of treatment to ensure effective treatment of all the fractions.Item Open Access Hybrid membrane distillation reverse electrodialysis configuration for water and energy recovery from human urine: an opportunity for off-grid decentralised sanitation(Elsevier, 2019-05-06) Mercer, Edwina; Davey, Christopher; Azzini, D.; Eusebi, Anna L.; Tierney, Ross; Williams, Leon; Jiang, Ying; Parker, Alison; Tyrrel, Sean; Pidou, Marc; McAdam, EwanThe integration of membrane distillation with reverse electrodialysis has been investigated as a sustainable sanitation solution to provide clean water and electrical power from urine and waste heat. Reverse electrodialysis was integrated to provide the partial remixing of the concentrate (urine) and diluate (permeate) produced from the membrane distillation of urine. Broadly comparable power densities to those of a model salt solution (sodium chloride) were determined during evaluation of the individual and combined contribution of the various monovalent and multivalent inorganic and organic salt constituents in urine. Power densities were improved through raising feed-side temperature and increasing concentration in the concentrate, without observation of limiting behaviour imposed by non-ideal salt and water transport. A further unique contribution of this application is the limited volume of salt concentrate available, which demanded brine recycling to maximise energy recovery analogous to a battery, operating in a ‘state of charge’. During recycle, around 47% of the Gibbs free energy was recoverable with up to 80% of the energy extractable before the concentration difference between the two solutions was halfway towards equilibrium which implies that energy recovery can be optimised with limited effect on permeate quality. This study has provided the first successful demonstration of an integrated MD-RED system for energy recovery from a limited resource, and evidences that the recovered power is sufficient to operate a range of low current fluid pumping technologies that could help deliver off-grid sanitation and clean water recovery at single household scale.Item Open Access The impact of filter bed depth and solids loading using a multimedia filter(Taylor and Francis, 2018-02-23) Ncube, Philani; Pidou, Marc; Jarvis, PeterDesign and operation of tertiary wastewater filters are not always well understood because of the inherent complexities of the wastewater matrix. Here, comparison of single, dual, triple and quadruple media (anthracite, flint, alumina and magnetite) filters were made to understand how the depth, media type and solids concentration influenced performance. The filter was improved by making the media deeper; however, the top 0.1 m of the filter retained the most solids. Additional layers of filter materials from single, dual, triple to quadruple improved the filter performance for the same depth of filter bed.Item Open Access The impact of polymer selection and dose on the incorporation of ballasting agents onto wastewater aggregates(Elsevier, 2019-11-28) Murujew, Olga; Geoffroy, Jordan; Fournie, Emeline; Gioacchini, Elisa Socionovo; Wilson, Andrea; Vale, Peter; Jefferson, Bruce; Pidou, MarcBallasted flocculation is an efficient high-rate sedimentation process getting more attention as an advanced P removal technology for levels below 0.1 mg/L. The process is well-known yet only very few studies have investigated the interactions, within the matrix of wastewater, of coagulant, polymer and ballast, especially when it comes to polymer doses and types which are, in the industry, rather based on recommendations than scientific evidence. In this work, the impact of anionic and cationic polymers has been investigated on P removal and floc properties. Anionic polymers showed to be superior to cationic ones when it comes to P removal and doses even as low as 0.01 mg/L yield better results than coagulant alone. There appears to be a “best-case” floc size with which very good P removal (>90%) can be achieved and flocs of sufficient strength can be generated.
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