This paper presents a comparative analysis of 5 systems for the treatment of greywater for reuse.... more This paper presents a comparative analysis of 5 systems for the treatment of greywater for reuse. The systems investigated were a biological system: a membrane bioreactor(MBR), a chemical system: a membrane chemical reactor(MCR) and three constructed wetlands: ...
A modelling study has been developed in which the energy requirements of aerobic and anaerobic me... more A modelling study has been developed in which the energy requirements of aerobic and anaerobic membrane bioreactors (MBRs) are assessed in order to compare these two wastewater treatment technologies. The model took into consideration the aeration required for biological oxidation in aerobic MBRs (AeMBRs), the energy recovery from methane production in anaerobic MBRs (AnMBRs) and the energy demands of operating submerged and sidestream membrane configurations. Aeration and membrane energy demands were estimated based on previously developed modelling studies populated with operational data from the literature. Given the difference in sludge production between aerobic and anaerobic systems, the model was benchmarked by assuming high sludge retention times or complete retention of solids in both AeMBRs and AnMBRs. Analysis of biogas production in AnMBRs revealed that the heat required to achieve mesophilic temperatures (35°C) in the reactor was only possible with influent wastewater strengths above 4–5 g COD L−1. The general trend of the submerged configuration, which is less energy intensive than the sidestream configuration in aerobic systems, was not observed in AnMBRs, mainly due to the wide variation in gas demand utilized in anaerobic systems. Compared to AeMBRs, for which the energy requirements were estimated to approach 2 kWh m−3 (influent up to 1 g COD L−1), the energy demands associated with fouling control in AnMBRs were lower (0.80 kWh m−3 for influent of 1.14 g COD L−1), although due to the low fluxes reported in the literature capital costs associated with membrane material would be three times higher than this.
Pathogen Reed bed Wetland Membrane bioreactor Water reuse Pseudomonas aeruginosa Indicator bacter... more Pathogen Reed bed Wetland Membrane bioreactor Water reuse Pseudomonas aeruginosa Indicator bacteria a b s t r a c t
Fouling in membrane coupled photocatalytic reactors was investigated in the case of greywater tre... more Fouling 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 mm pore sized polyethylene membrane. Rapid fouling occurred only with shower gels and conditioners and was linked to changes in the organo-TiO 2 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 reactor. (B. Jefferson).
The toxicity of individual products has been measured in relation to a marine luminescent bacteri... more The toxicity of individual products has been measured in relation to a marine luminescent bacteria and a biological community within a grey water treatment technology. The results demonstrate that brand labeling provides no evidence about the relative toxicity of a product including those labeled as environmentally friendly. Overall, the only products seen to be a potential risk to reuse treatment technology is bleach and car oil with secondary risks associated with washing powder and vegetable oil.
Greywater recycling is now accepted as a sustainable solution to the general increase of the fres... more Greywater recycling is now accepted as a sustainable solution to the general increase of the fresh water demand, water shortages and for environment protection. However, the majority of the suggested treatments are biological and such technologies can be affected, especially at small scale, by the variability in strength and flow of the greywater and potential shock loading. This investigation presents the study of alternative processes, coagulation and magnetic ion exchange resin, for the treatment of greywater for reuse. The potential of these processes as well as the influence of parameters such as coagulant or resin dose, pH or contact time were investigated for the treatment of two greywaters of low and high organic strengths. The results obtained revealed that magnetic ion exchange resin and coagulation were suitable treatment solutions for low strength greywater sources. However, they were unable to achieve the required level of treatment for the reuse of medium to high strength greywaters. Consequently, these processes could only be considered as an option for greywater recycling in specific conditions that is to say in case of low organic strength greywater or less stringent standards for reuse.
A three-element microfiltration (MF) hollow fiber (HF) membrane module has been evaluated for tre... more A three-element microfiltration (MF) hollow fiber (HF) membrane module has been evaluated for treating municipal wastewater by an immersed membrane bioreactor (iMBR) based on a pilot-scale plant. The flux-step method, classically used to identify the critical flux, was ...
The treatment of spent metalworking fluids (MWFs) is difficult due to their complex and variable ... more The treatment of spent metalworking fluids (MWFs) is difficult due to their complex and variable composition. Small businesses often struggle to meet increasingly stringent legislation and rising costs as they need to treat this wastewater on site annually over a short period. Larger businesses that treat their wastewater continuously can benefit from the use of biological processes, although new MWFs designed to resist biological activity represent a challenge. A three-stage treatment is generally applied, with the oil phase being removed first, followed by a reduction in COD loading and then polishing of the effluent's quality in the final stage. The performance of advanced oxidation processes (AOPs), which could be of benefit to both types of businesses was studied. After assessing the biodegradability of spent MFW, different AOPs were used (UV/H2O2, photo-Fenton and UV/TiO2) to establish the treatability of this wastewater by hydroxyl radicals (•OH). The interactions of both the chemical and biological treatments were also investigated. The wastewater was found to be readily biodegradable in the Zahn–Wellens test with 69% COD and 74% DOC removal. The UV/TiO2 reactor was found to be the cheapest option achieving a very good COD removal (82% at 20 min retention time and 10 L min−1 aeration rate). The photo-Fenton process was found to be efficient in terms of degradation rate, achieving 84% COD removal (1 M Fe2+, 40 M H2O2, 20.7 J cm−2, pH 3) and also improving the wastewater's biodegradability. The UV/H2O2 process was the most effective in removing recalcitrant COD in the post-biological treatment stage.
A modelling study has been developed in which the energy requirements of aerobic and anaerobic me... more A modelling study has been developed in which the energy requirements of aerobic and anaerobic membrane bioreactors (MBRs) are assessed in order to compare these two wastewater treatment technologies. The model took into consideration the aeration required for biological oxidation in aerobic MBRs (AeMBRs), the energy recovery from methane production in anaerobic MBRs (AnMBRs) and the energy demands of operating submerged and sidestream membrane configurations. Aeration and membrane energy demands were estimated based on previously developed modelling studies populated with operational data from the literature. Given the difference in sludge production between aerobic and anaerobic systems, the model was benchmarked by assuming high sludge retention times or complete retention of solids in both AeMBRs and AnMBRs. Analysis of biogas production in AnMBRs revealed that the heat required to achieve mesophilic temperatures (35°C) in the reactor was only possible with influent wastewater strengths above 4–5 g COD L−1. The general trend of the submerged configuration, which is less energy intensive than the sidestream configuration in aerobic systems, was not observed in AnMBRs, mainly due to the wide variation in gas demand utilized in anaerobic systems. Compared to AeMBRs, for which the energy requirements were estimated to approach 2 kWh m−3 (influent up to 1 g COD L−1), the energy demands associated with fouling control in AnMBRs were lower (0.80 kWh m−3 for influent of 1.14 g COD L−1), although due to the low fluxes reported in the literature capital costs associated with membrane material would be three times higher than this.
Urban water recycling is now becoming an important issue where water resources are becoming scarc... more Urban water recycling is now becoming an important issue where water resources are becoming scarce. This paper looks at reusing grey water; the preference is treatment processes based on biological systems to remove the dissolved organic content. Here, an alternative process, photocatalysis is discussed as it is an attractive technology that could be well-suited for treating the recalcitrant organic compounds found in grey water. The photocatalytic process oxidises organic reactants at a catalyst surface in the presence of ultraviolet light. Given enough exposure time, organic compounds will be oxidized into CO2 and water. The best contact is achieved in a slurry reactor but a second step to separate and recover the catalyst is need. This paper discusses a new membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.
This paper presents a comparative analysis of 5 systems for the treatment of greywater for reuse.... more This paper presents a comparative analysis of 5 systems for the treatment of greywater for reuse. The systems investigated were a biological system: a membrane bioreactor(MBR), a chemical system: a membrane chemical reactor(MCR) and three constructed wetlands: ...
A modelling study has been developed in which the energy requirements of aerobic and anaerobic me... more A modelling study has been developed in which the energy requirements of aerobic and anaerobic membrane bioreactors (MBRs) are assessed in order to compare these two wastewater treatment technologies. The model took into consideration the aeration required for biological oxidation in aerobic MBRs (AeMBRs), the energy recovery from methane production in anaerobic MBRs (AnMBRs) and the energy demands of operating submerged and sidestream membrane configurations. Aeration and membrane energy demands were estimated based on previously developed modelling studies populated with operational data from the literature. Given the difference in sludge production between aerobic and anaerobic systems, the model was benchmarked by assuming high sludge retention times or complete retention of solids in both AeMBRs and AnMBRs. Analysis of biogas production in AnMBRs revealed that the heat required to achieve mesophilic temperatures (35°C) in the reactor was only possible with influent wastewater strengths above 4–5 g COD L−1. The general trend of the submerged configuration, which is less energy intensive than the sidestream configuration in aerobic systems, was not observed in AnMBRs, mainly due to the wide variation in gas demand utilized in anaerobic systems. Compared to AeMBRs, for which the energy requirements were estimated to approach 2 kWh m−3 (influent up to 1 g COD L−1), the energy demands associated with fouling control in AnMBRs were lower (0.80 kWh m−3 for influent of 1.14 g COD L−1), although due to the low fluxes reported in the literature capital costs associated with membrane material would be three times higher than this.
Pathogen Reed bed Wetland Membrane bioreactor Water reuse Pseudomonas aeruginosa Indicator bacter... more Pathogen Reed bed Wetland Membrane bioreactor Water reuse Pseudomonas aeruginosa Indicator bacteria a b s t r a c t
Fouling in membrane coupled photocatalytic reactors was investigated in the case of greywater tre... more Fouling 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 mm pore sized polyethylene membrane. Rapid fouling occurred only with shower gels and conditioners and was linked to changes in the organo-TiO 2 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 reactor. (B. Jefferson).
The toxicity of individual products has been measured in relation to a marine luminescent bacteri... more The toxicity of individual products has been measured in relation to a marine luminescent bacteria and a biological community within a grey water treatment technology. The results demonstrate that brand labeling provides no evidence about the relative toxicity of a product including those labeled as environmentally friendly. Overall, the only products seen to be a potential risk to reuse treatment technology is bleach and car oil with secondary risks associated with washing powder and vegetable oil.
Greywater recycling is now accepted as a sustainable solution to the general increase of the fres... more Greywater recycling is now accepted as a sustainable solution to the general increase of the fresh water demand, water shortages and for environment protection. However, the majority of the suggested treatments are biological and such technologies can be affected, especially at small scale, by the variability in strength and flow of the greywater and potential shock loading. This investigation presents the study of alternative processes, coagulation and magnetic ion exchange resin, for the treatment of greywater for reuse. The potential of these processes as well as the influence of parameters such as coagulant or resin dose, pH or contact time were investigated for the treatment of two greywaters of low and high organic strengths. The results obtained revealed that magnetic ion exchange resin and coagulation were suitable treatment solutions for low strength greywater sources. However, they were unable to achieve the required level of treatment for the reuse of medium to high strength greywaters. Consequently, these processes could only be considered as an option for greywater recycling in specific conditions that is to say in case of low organic strength greywater or less stringent standards for reuse.
A three-element microfiltration (MF) hollow fiber (HF) membrane module has been evaluated for tre... more A three-element microfiltration (MF) hollow fiber (HF) membrane module has been evaluated for treating municipal wastewater by an immersed membrane bioreactor (iMBR) based on a pilot-scale plant. The flux-step method, classically used to identify the critical flux, was ...
The treatment of spent metalworking fluids (MWFs) is difficult due to their complex and variable ... more The treatment of spent metalworking fluids (MWFs) is difficult due to their complex and variable composition. Small businesses often struggle to meet increasingly stringent legislation and rising costs as they need to treat this wastewater on site annually over a short period. Larger businesses that treat their wastewater continuously can benefit from the use of biological processes, although new MWFs designed to resist biological activity represent a challenge. A three-stage treatment is generally applied, with the oil phase being removed first, followed by a reduction in COD loading and then polishing of the effluent's quality in the final stage. The performance of advanced oxidation processes (AOPs), which could be of benefit to both types of businesses was studied. After assessing the biodegradability of spent MFW, different AOPs were used (UV/H2O2, photo-Fenton and UV/TiO2) to establish the treatability of this wastewater by hydroxyl radicals (•OH). The interactions of both the chemical and biological treatments were also investigated. The wastewater was found to be readily biodegradable in the Zahn–Wellens test with 69% COD and 74% DOC removal. The UV/TiO2 reactor was found to be the cheapest option achieving a very good COD removal (82% at 20 min retention time and 10 L min−1 aeration rate). The photo-Fenton process was found to be efficient in terms of degradation rate, achieving 84% COD removal (1 M Fe2+, 40 M H2O2, 20.7 J cm−2, pH 3) and also improving the wastewater's biodegradability. The UV/H2O2 process was the most effective in removing recalcitrant COD in the post-biological treatment stage.
A modelling study has been developed in which the energy requirements of aerobic and anaerobic me... more A modelling study has been developed in which the energy requirements of aerobic and anaerobic membrane bioreactors (MBRs) are assessed in order to compare these two wastewater treatment technologies. The model took into consideration the aeration required for biological oxidation in aerobic MBRs (AeMBRs), the energy recovery from methane production in anaerobic MBRs (AnMBRs) and the energy demands of operating submerged and sidestream membrane configurations. Aeration and membrane energy demands were estimated based on previously developed modelling studies populated with operational data from the literature. Given the difference in sludge production between aerobic and anaerobic systems, the model was benchmarked by assuming high sludge retention times or complete retention of solids in both AeMBRs and AnMBRs. Analysis of biogas production in AnMBRs revealed that the heat required to achieve mesophilic temperatures (35°C) in the reactor was only possible with influent wastewater strengths above 4–5 g COD L−1. The general trend of the submerged configuration, which is less energy intensive than the sidestream configuration in aerobic systems, was not observed in AnMBRs, mainly due to the wide variation in gas demand utilized in anaerobic systems. Compared to AeMBRs, for which the energy requirements were estimated to approach 2 kWh m−3 (influent up to 1 g COD L−1), the energy demands associated with fouling control in AnMBRs were lower (0.80 kWh m−3 for influent of 1.14 g COD L−1), although due to the low fluxes reported in the literature capital costs associated with membrane material would be three times higher than this.
Urban water recycling is now becoming an important issue where water resources are becoming scarc... more Urban water recycling is now becoming an important issue where water resources are becoming scarce. This paper looks at reusing grey water; the preference is treatment processes based on biological systems to remove the dissolved organic content. Here, an alternative process, photocatalysis is discussed as it is an attractive technology that could be well-suited for treating the recalcitrant organic compounds found in grey water. The photocatalytic process oxidises organic reactants at a catalyst surface in the presence of ultraviolet light. Given enough exposure time, organic compounds will be oxidized into CO2 and water. The best contact is achieved in a slurry reactor but a second step to separate and recover the catalyst is need. This paper discusses a new membrane chemical reactor (MCR) combining photocatalysis and microfiltration for grey water treatment.
Uploads
Papers by Marc Pidou