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Mohamed Hafidi - One of the best experts on this subject based on the ideXlab platform.
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Fate of pathogenic microorganisms during Lagooning sludge composting and exploration of bacteriophages as indicator of hygienization
Environmental Technology & Innovation, 2021Co-Authors: Bouchra El Hayany, Loubna El Fels, Yedir Ouhdouch, Mohamed HafidiAbstract:Abstract Composting is a suitable solution to reduce the high quantity of sewage sludge produced every year. Microbiological quality of compost should be evaluated before its use. In this circumstance, researching the faecal bacteria indicators becomes more interesting to confirm the compost safety in terms of pathogenic microorganisms, which can cause health risk for the soil–plant–human system. This work monitored the evolution of pathogenic bacteria (faecal coliforms, faecal streptococci, Shigella spp and Salmonella spp.) during windrows co-composting of three mixtures with different proportion of Lagooning sludge and green waste under semi-arid climate. It also investigated the evolution of two bacteriophages (Coliphages and Salmonella-phages) as an indicator of long-term compost hygienization. The final composts showed a high reduction that reached 99% for faecal coliforms, faecal streptococci; and 100% for Shigella spp. and Salmonella spp. These reductions revealed the efficiency of composting on bacteria inactivation. Comparison between the survivals of the two bacteriophages showed that Salmonella-phages have less tolerance to inactivation than coliphages, it was totally eliminated after 45 days of composting, while coliphages were completely inactivated after 200 days. The complete destruction of the bacteriophages showed the safety and the good microbial quality of the three co-composting trials. These findings revealed that in the case of composting on windrows, a maximum temperature about 50 °C and time which, exceeds 5 months are essential to decrease pathogenic bacteria and virus to a safe level. We conclude that co-composting conditions of mixtures containing half and one-third of the sludge were more adequate for a rapid destruction of pathogens, compared to mixture containing two-third of the sludge. Based on this study, we anticipate that the proposed analysis will yield a rapid indicator of co-composting hygienization design with less dependency simple and fast technique.
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microplastics from Lagooning sludge to composts as revealed by fluorescent staining image analysis raman spectroscopy and pyrolysis gc ms
Journal of Environmental Management, 2020Co-Authors: Bouchra El Hayany, Loubna El Fels, Katell Quenea, Mariefrance Dignac, Cornelia Rumpel, Vijay Kumar Gupta, Mohamed HafidiAbstract:Abstract Lagooning sludge (LS), which is used as soil amendment in Morocco, may contain microplastics (MPs). The aim of this study was to examine the effect of dewatering and co-composting of LS with green waste (GW) on the MPs’ evolution. In this context the present study proposes fast-preliminary steps to detect plastics in Lagooning sewage sludge before the extraction and identification process. We used pyrolysis GC/MS spectrometry to investigate the presence of chemical compounds possibly derived from plastics, and fluorescence staining by Nile Red to detect fluorescent particles suspected as plastics. Thereafter, we quantified the MPs particles after density fractionation and investigated their nature by Raman spectroscopy. Results indicated the presence of an average of 40.5 ± 11.9 × 103 MPs particles/kg (dry matter) and 36 ± 9.7 × 103 MPs particles/kg (dry matter) in fresh sludge and dewatered sludge respectively. Sludge dewatering in drying beds resulted a loss of small MPs (
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sludge nematodes cestodes and trematodes eggs variation from Lagooning activated sludge and infiltration percolation wastewater treatment system under semi arid climate
Environmental Science and Pollution Research, 2019Co-Authors: Loubna El Fels, Bouchra El Hayany, Abdelouahed El Faiz, Mustapha Saadani, Mustapha Houari, Mohamed HafidiAbstract:The prevalence and the identification of the helminth eggs load of raw sewage sludge was assessed of three different wastewater treatment systems. The results showed a variety of parasite species with following average concentrations; five taxa belonging to three classes nematodes, cestodes and trematodes were inventoried. The class of nematodes is the most diverse with 5 taxa. It is represented by the eggs of Ascaris sp., Capillaria sp., Trichuris sp., Toxocara sp., and Ankylostome sp., then comes the cestodes class, this is represented by the eggs of Taenia sp. The trematode class is represented by Schistosoma sp. The Lagooning station of Chichaoua shows the highest load 7 species with Ascaris 21 eggs/g; Capillaria sp., 11 eggs/g; Trichuris sp., 6 eggs/g; Toxocara sp., 2 eggs/g and Ankylostome sp., 1 egg/g; Taenia sp., 2eggs/g; and Schistosoma sp., 1 egg/g. Infiltration-percolation sludge show the presence of 4 species of helminths eggs in sludge from anaerobic settling with different rates: 15 eggs/g for Ascaris sp., 15 eggs/g for Trichuris sp., 13 eggs/g for Capillaria sp., and 8 eggs/g for Taenia sp. However, in sand filter pool, the sludge helminth eggs load was decreased by 47% of Ascaris sp., 85% of Capillaria sp., and 75% of Taenia sp., Nevertheless, an increase of Trichuris eggs load was noted in the second sludge by 17%. Five helminth eggs was detected in primary sludge coming from decantation pools in activated sludge plant in Marrakech, that is Ascaris sp., with a load of 16 eggs/g; Capillaria sp., with 3 eggs/g, Trichuris eggs with 2 eggs/g; Taenia sp., with 4 eggs/g; and Schistosoma sp., with 2 eggs/g. The abatement load of Ascaris sp. with 81% and Schistosoma and Taenia sp., with 100% was noted in biological sludge. Nevertheless, an increase load of Capillaria and Trichuris eggs 81% and 75% respectively was observed in this sludge coming from biological pools. The distribution of parasitic helminth eggs is linked to the differences in demographic and socio-economic status, seasonal variation, physico-chemical characteristic of helminth eggs, and the purification wastewater system performance.
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effect of dewatering and composting on helminth eggs removal from Lagooning sludge under semi arid climate
Environmental Science and Pollution Research, 2018Co-Authors: Bouchra El Hayany, Mohamed Hafidi, Ghizlen El Mezouari El Glaoui, Mohammed Rihanni, Amine Ezzariai, Abdelouahed El Faiz, Mohamed El Gharous, Loubna El FelsAbstract:In this work, we assessed the drying and composting effectiveness of helminth eggs removal from sewage sludge of a lagoon wastewater treatment plant located in Chichaoua city. The composting was run after mixing sludge with green waste in different proportions: M1 (½ sludge + ½ green waste), M2 ([Formula: see text] sludge + [Formula: see text] green waste), and M3 ([Formula: see text] sludge + [Formula: see text] green waste) for 105 days. The analysis of the dewatered sewage sludge showed a load of 8-24 helminth eggs/g of fresh matter identified as Ascaris spp. eggs (5-19 eggs/g) followed by Toxocara spp. (0.2 to 2.4 eggs/g); Hookworm spp. and Capillaria spp. (0.4-1 egg/g); Trichuris spp., Taenia spp., and Shistosoma spp. (< 1 egg/g) in the untreated sludge. After 105 days of treatment by composting, we noted a total reduction of helminth eggs in the order of 97.5, 97.83, and 98.37% for mixtures M1, M2, and M3, respectively. The Ascaris spp. eggs were reduced by 98% for M1 and M3 treatments and by 97% for M2 Treatment. Toxocara spp., Hookworm spp., Trichuris spp., Capillaria spp., and Shistosoma spp. eggs were totally eliminated (100% decrease) and the Taenia spp. was absent from the first stage of composting. These results confirm the effectiveness of both dehydrating and composting processes on the removal of helminth eggs.
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Fate of phthalic acid esters during composting of both Lagooning and activated sludges
Process Biochemistry, 2005Co-Authors: Soumia Amir, Mohamed Hafidi, Georges Merlina, Hassan Hamdi, Abdelmajid Jouraiphy, Mohamed El Gharous, Jeanclaude RevelAbstract:Among the phthalic acid esters (PAEs) targeted by the United States Environmental Protection Agency (USEPA) as priority pollutants, di- ethyl-hexyl phthalate (DEHP) is the major pollutant identified at high concentration level in Lagooning sludge (LS), at about 28.67 mg/kg, and in activated sludge (AS), at about 6.26 mg/kg. Other phthalic acid esters, such as di-butyl phthalate (DBP) and di-methyl phthalate (DMP) show very low concentrations. During sludge composting, after the stabilization phase, the subsequent appearance of DEP and then DMP occurred indicating that microbial metabolism begins by alkyl side-chain degradation before aromatic ring-cleavage. The appearance and accumulation of PAEs with a short alkyl side-chain in the last stages of AS and LS composting is suggested originating from the degradation of phthalates with a much long side-chain. The DEHP showed a rate of biodegradation that follows a first-order kinetic model during composting of both AS and LS. The calculated DEHP half-lives are 45.4 days for LS and 28.9 days for AS. The better DEHP biodegradation rate (2.4 Â 10À2 dayÀ1) have been observed in the case of AS composting compared to LS compost (1.53 Â 10À2 dayÀ1). The mono-ethyl- hexyl phthalates MEHP has been shown to follow the same order of biodegradation as DEHP indicating that the same mechanism is followed (hydrolysis or dealkylation of each DEHP side-chain). Composting could be suggested as a detoxification process for the removal of PAEs (mainly DEHP) from sludges after a sufficient time of treatment to provide a safe end product.
Isabel Saraiva - One of the best experts on this subject based on the ideXlab platform.
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an innovative multistage treatment system for sanitary landfill leachate depuration studies at pilot scale
Science of The Total Environment, 2017Co-Authors: Tânia F C V Silva, Amelia Fonseca, Petrick A Soares, Diego Ricieri Manenti, Isabel SaraivaAbstract:In this work, an innovative methodology for the treatment of landfill leachates, after aerobic Lagooning, is proposed and adjusted at pilot-scale. This methodology involves an aerobic activated sludge biological pre-oxidation (ASBO), a coagulation/sedimentation step (240mgFe3+/L, at pH4.2) and a photo-oxidation through a photo-Fenton (PF) reaction (60mg Fe2+, at pH2.8) combining solar and artificial light. The ASBO process applied to a leachate after aerobic Lagooning, with high organic and nitrogen content (1.1-1.5gC/L; 0.8-3.0gN/L) and low biodegradability (BOD5/COD =0.07-0.13), is capable to oxidise 62-99% of the ammonium nitrogen, consuming only the affluent alkalinity (70-100%). The coagulation/sedimentation stage led to the humic acids precipitation, promoting a marked change in leachate colour, from dark-brown to yellowish-brown (related to fulvic acids), accompanied by a reduction of 60%, 58% and 88% on DOC, COD and TSS, respectively. The PF system promoted the degradation of the recalcitrant organic molecules into more easily biodegradable ones. According to Zahn-Wellens biodegradability test, a leachate with 419mg DOC/L after coagulation, would have to be photo-oxidized until DOC 60%. The PF step cost to treat 100m3/day of leachate was 6.41€/m3, combining 1339m2 of CPCs with 31 lamps.
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insights into solar photo fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab scale
Journal of Environmental Management, 2015Co-Authors: Tânia F C V Silva, Amelia Fonseca, Isabel Saraiva, Rui A R Boaventura, Petrick A Soares, Diego Ricieri Manenti, Rui Ferreira, Vitor J P VilarAbstract:This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated Lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe(2+)/L), solution pH (2.0-3.6), operating temperature (10-50 °C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH(2+), was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH(2+). The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 °C; [Fe(2+)] = 60 mg/L and UV irradiance = 44 WUV/m(2), achieving 72% mineralization after 25 kJUV/L of accumulated UV energy and 149 mM of H2O2 consumed.
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Insights into solar photo-Fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab-scale
'Elsevier BV', 2015Co-Authors: Tânia F C V Silva, Amelia Fonseca, Isabel Saraiva, Rui A R Boaventura, Petrick A Soares, Rui Ferreira, Diego R. Manenti, Vitor J P VilarAbstract:This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated Lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe2+/L), solution pH (2.0-3.6), operating temperature (10-50 degrees C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH2+, was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH2+. The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 degrees C; [Fe2+] = 60 mg/L and UV irradiance = 44 Wuv/m(2), achieving 72% mineralization after 25 kJuv/L of accumulated UV energy and 149 mM of H2O2 consumed
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sanitary landfill leachate treatment using combined solar photo fenton and biological oxidation processes at pre industrial scale
Chemical Engineering Journal, 2013Co-Authors: Tânia F C V Silva, Amelia Fonseca, Elisabete M F Silva, Cristina A Cunhaqueda, Isabel SaraivaAbstract:Abstract This work proposes a new strategy for the treatment of leachates from sanitary landfills after Lagooning pretreatment, using a solar photo-Fenton oxidation process to eliminate the most recalcitrant organic compounds, leading to a biodegradability enhancement of the leachate and promoting its subsequent oxidation in an activated sludge biological reactor. The integrated leachate treatment process was conducted in a pre-industrial plant, incorporating a photocatalytic system with 39.52 m2 of compound parabolic collectors (CPCs) and an activated sludge biological reactor, with 3.5 m3 capacity, operated under aerated and anoxic conditions. An extensive physico-chemical characterization of the leachate after Lagooning was performed during one year, from June 2010 to May 2011, showing its high recalcitrant character mainly associated with the presence of humic substances. The efficiency of the combined treatment was evaluated concerning the leachate characteristics’ variability after Lagooning, availability of solar radiation during the year, and different operational process variables, such as the amount of hydrogen peroxide necessary to reach the required COD target value, biodegradability enhancement during the photo-oxidation process, iron reutilization in consecutive oxidation processes, removal of acidic sludge resulting from the acidification process and leachate temperature/average solar power. The elimination of the remaining organic carbon fraction and nitrogen compounds after the pre-oxidation step was also assessed in an activated sludge biological reactor, under aerobic and anoxic conditions, considering the composition variability of photo-treated leachate. Nitrification and denitrification rates were also evaluated.
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biodegradability enhancement of a leachate after biological Lagooning using a solar driven photo fenton reaction and further combination with an activated sludge biological process at pre industrial scale
Water Research, 2013Co-Authors: Tânia Silva, Amelia Fonseca, Isabel SaraivaAbstract:Abstract This work proposes an integrated leachate treatment strategy, combining a solar photo-Fenton reaction, to enhance the biodegradability of the leachate from an aerated lagoon, with an activated sludge process, under aerobic and anoxic conditions, to achieve COD target values and nitrogen content according to the legislation. The efficiency and performance of the photo-Fenton reaction, concerning a sludge removal step after acidification, defining the optimum phototreatment time to reach a biodegradable wastewater that can be further oxidized in a biological reactor and, activation sludge biological process, defining the nitrification and denitrification reaction rates, alkalinity balance and methanol dose necessary as external carbon source, was evaluated in the integrated system at a scale close to industrial. The pre-industrial plant presents a photocatalytic system with 39.52 m 2 of compound parabolic collectors (CPCs) and 2 m 3 recirculation tank and, an activated sludge biological reactor with 3 m 3 capacity. Leachate biodegradability enhancement by means of a solar driven photo-Fenton process was evaluated using direct biodegradability tests, as Zahn–Wellens method, and indirect measure according to average oxidation state (AOS), low molecular carboxylic acids content (fast biodegradable character) and humic substances (recalcitrant character) concentration. Due to high variability of leachate composition, UV absorbance on-line measurement was established as a useful parameter for photo-Fenton reaction control.
Tânia F C V Silva - One of the best experts on this subject based on the ideXlab platform.
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an innovative multistage treatment system for sanitary landfill leachate depuration studies at pilot scale
Science of The Total Environment, 2017Co-Authors: Tânia F C V Silva, Amelia Fonseca, Petrick A Soares, Diego Ricieri Manenti, Isabel SaraivaAbstract:In this work, an innovative methodology for the treatment of landfill leachates, after aerobic Lagooning, is proposed and adjusted at pilot-scale. This methodology involves an aerobic activated sludge biological pre-oxidation (ASBO), a coagulation/sedimentation step (240mgFe3+/L, at pH4.2) and a photo-oxidation through a photo-Fenton (PF) reaction (60mg Fe2+, at pH2.8) combining solar and artificial light. The ASBO process applied to a leachate after aerobic Lagooning, with high organic and nitrogen content (1.1-1.5gC/L; 0.8-3.0gN/L) and low biodegradability (BOD5/COD =0.07-0.13), is capable to oxidise 62-99% of the ammonium nitrogen, consuming only the affluent alkalinity (70-100%). The coagulation/sedimentation stage led to the humic acids precipitation, promoting a marked change in leachate colour, from dark-brown to yellowish-brown (related to fulvic acids), accompanied by a reduction of 60%, 58% and 88% on DOC, COD and TSS, respectively. The PF system promoted the degradation of the recalcitrant organic molecules into more easily biodegradable ones. According to Zahn-Wellens biodegradability test, a leachate with 419mg DOC/L after coagulation, would have to be photo-oxidized until DOC 60%. The PF step cost to treat 100m3/day of leachate was 6.41€/m3, combining 1339m2 of CPCs with 31 lamps.
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insights into solar photo fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab scale
Journal of Environmental Management, 2015Co-Authors: Tânia F C V Silva, Amelia Fonseca, Isabel Saraiva, Rui A R Boaventura, Petrick A Soares, Diego Ricieri Manenti, Rui Ferreira, Vitor J P VilarAbstract:This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated Lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe(2+)/L), solution pH (2.0-3.6), operating temperature (10-50 °C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH(2+), was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH(2+). The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 °C; [Fe(2+)] = 60 mg/L and UV irradiance = 44 WUV/m(2), achieving 72% mineralization after 25 kJUV/L of accumulated UV energy and 149 mM of H2O2 consumed.
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Insights into solar photo-Fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab-scale
'Elsevier BV', 2015Co-Authors: Tânia F C V Silva, Amelia Fonseca, Isabel Saraiva, Rui A R Boaventura, Petrick A Soares, Rui Ferreira, Diego R. Manenti, Vitor J P VilarAbstract:This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated Lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe2+/L), solution pH (2.0-3.6), operating temperature (10-50 degrees C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH2+, was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH2+. The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 degrees C; [Fe2+] = 60 mg/L and UV irradiance = 44 Wuv/m(2), achieving 72% mineralization after 25 kJuv/L of accumulated UV energy and 149 mM of H2O2 consumed
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sanitary landfill leachate treatment using combined solar photo fenton and biological oxidation processes at pre industrial scale
Chemical Engineering Journal, 2013Co-Authors: Tânia F C V Silva, Amelia Fonseca, Elisabete M F Silva, Cristina A Cunhaqueda, Isabel SaraivaAbstract:Abstract This work proposes a new strategy for the treatment of leachates from sanitary landfills after Lagooning pretreatment, using a solar photo-Fenton oxidation process to eliminate the most recalcitrant organic compounds, leading to a biodegradability enhancement of the leachate and promoting its subsequent oxidation in an activated sludge biological reactor. The integrated leachate treatment process was conducted in a pre-industrial plant, incorporating a photocatalytic system with 39.52 m2 of compound parabolic collectors (CPCs) and an activated sludge biological reactor, with 3.5 m3 capacity, operated under aerated and anoxic conditions. An extensive physico-chemical characterization of the leachate after Lagooning was performed during one year, from June 2010 to May 2011, showing its high recalcitrant character mainly associated with the presence of humic substances. The efficiency of the combined treatment was evaluated concerning the leachate characteristics’ variability after Lagooning, availability of solar radiation during the year, and different operational process variables, such as the amount of hydrogen peroxide necessary to reach the required COD target value, biodegradability enhancement during the photo-oxidation process, iron reutilization in consecutive oxidation processes, removal of acidic sludge resulting from the acidification process and leachate temperature/average solar power. The elimination of the remaining organic carbon fraction and nitrogen compounds after the pre-oxidation step was also assessed in an activated sludge biological reactor, under aerobic and anoxic conditions, considering the composition variability of photo-treated leachate. Nitrification and denitrification rates were also evaluated.
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evaluation of solar photo fenton parameters on the pre oxidation of leachates from a sanitary landfill
Solar Energy, 2012Co-Authors: Tânia F C V Silva, Amelia Fonseca, Marcos A N Santos, Isabel SaraivaAbstract:Abstract The main purpose of this work is to study the treatment of a leachate after preliminary aerated Lagooning by a solar photo-Fenton process, using a photocatalytic reactor with compound parabolic collectors (CPCs). The influence of different process parameters in the reaction rate was evaluated, such as, the type of acid used in the acidification step (H 2 SO 4 , HCl, H 2 SO 4 + HCl); type of iron salt (FeSO 4 , FeCl 3 ) and respective iron concentration (60, 80, 100 and 140 mg Fe 2+ /L); temperature; and ratio of illuminated to total volume (25 L/35 L; 25 L/72 L). DOC abatement in the acidification procedure is independent of the type of acid used and temperature, and is related principally with the precipitation of humic acids. The use of HCl alone or in combination with H 2 SO 4 leads to a substantially increase of the chloride ions, leading to the formation of less reactive chloride radicals when compared with sulfate radicals, decreasing the photo-Fenton reaction rate. The use of ferrous ions instead of ferric ions influenced positively the photo-Fenton reaction. Meteorological conditions favoring higher temperature of the leachate enhance the photo-Fenton reaction. Alternating dark and illumination intervals has shown a negligible effect on the illumination time needed to achieve the same mineralization, indicating that the Fenton process that takes place in dark zones is not efficient, even in the degradation of intermediate compounds resulting from the light-enhanced reaction. According to biodegradability tests, the optimum energy dose, necessary to obtain a biodegradable effluent, is 57.4 kJ UV /L, consuming 120 mM of H 2 O 2 and leading to a final DOC of 284 mg/L which corresponds to approximately 66% of mineralization.
Loubna El Fels - One of the best experts on this subject based on the ideXlab platform.
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Fate of pathogenic microorganisms during Lagooning sludge composting and exploration of bacteriophages as indicator of hygienization
Environmental Technology & Innovation, 2021Co-Authors: Bouchra El Hayany, Loubna El Fels, Yedir Ouhdouch, Mohamed HafidiAbstract:Abstract Composting is a suitable solution to reduce the high quantity of sewage sludge produced every year. Microbiological quality of compost should be evaluated before its use. In this circumstance, researching the faecal bacteria indicators becomes more interesting to confirm the compost safety in terms of pathogenic microorganisms, which can cause health risk for the soil–plant–human system. This work monitored the evolution of pathogenic bacteria (faecal coliforms, faecal streptococci, Shigella spp and Salmonella spp.) during windrows co-composting of three mixtures with different proportion of Lagooning sludge and green waste under semi-arid climate. It also investigated the evolution of two bacteriophages (Coliphages and Salmonella-phages) as an indicator of long-term compost hygienization. The final composts showed a high reduction that reached 99% for faecal coliforms, faecal streptococci; and 100% for Shigella spp. and Salmonella spp. These reductions revealed the efficiency of composting on bacteria inactivation. Comparison between the survivals of the two bacteriophages showed that Salmonella-phages have less tolerance to inactivation than coliphages, it was totally eliminated after 45 days of composting, while coliphages were completely inactivated after 200 days. The complete destruction of the bacteriophages showed the safety and the good microbial quality of the three co-composting trials. These findings revealed that in the case of composting on windrows, a maximum temperature about 50 °C and time which, exceeds 5 months are essential to decrease pathogenic bacteria and virus to a safe level. We conclude that co-composting conditions of mixtures containing half and one-third of the sludge were more adequate for a rapid destruction of pathogens, compared to mixture containing two-third of the sludge. Based on this study, we anticipate that the proposed analysis will yield a rapid indicator of co-composting hygienization design with less dependency simple and fast technique.
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microplastics from Lagooning sludge to composts as revealed by fluorescent staining image analysis raman spectroscopy and pyrolysis gc ms
Journal of Environmental Management, 2020Co-Authors: Bouchra El Hayany, Loubna El Fels, Katell Quenea, Mariefrance Dignac, Cornelia Rumpel, Vijay Kumar Gupta, Mohamed HafidiAbstract:Abstract Lagooning sludge (LS), which is used as soil amendment in Morocco, may contain microplastics (MPs). The aim of this study was to examine the effect of dewatering and co-composting of LS with green waste (GW) on the MPs’ evolution. In this context the present study proposes fast-preliminary steps to detect plastics in Lagooning sewage sludge before the extraction and identification process. We used pyrolysis GC/MS spectrometry to investigate the presence of chemical compounds possibly derived from plastics, and fluorescence staining by Nile Red to detect fluorescent particles suspected as plastics. Thereafter, we quantified the MPs particles after density fractionation and investigated their nature by Raman spectroscopy. Results indicated the presence of an average of 40.5 ± 11.9 × 103 MPs particles/kg (dry matter) and 36 ± 9.7 × 103 MPs particles/kg (dry matter) in fresh sludge and dewatered sludge respectively. Sludge dewatering in drying beds resulted a loss of small MPs (
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sludge nematodes cestodes and trematodes eggs variation from Lagooning activated sludge and infiltration percolation wastewater treatment system under semi arid climate
Environmental Science and Pollution Research, 2019Co-Authors: Loubna El Fels, Bouchra El Hayany, Abdelouahed El Faiz, Mustapha Saadani, Mustapha Houari, Mohamed HafidiAbstract:The prevalence and the identification of the helminth eggs load of raw sewage sludge was assessed of three different wastewater treatment systems. The results showed a variety of parasite species with following average concentrations; five taxa belonging to three classes nematodes, cestodes and trematodes were inventoried. The class of nematodes is the most diverse with 5 taxa. It is represented by the eggs of Ascaris sp., Capillaria sp., Trichuris sp., Toxocara sp., and Ankylostome sp., then comes the cestodes class, this is represented by the eggs of Taenia sp. The trematode class is represented by Schistosoma sp. The Lagooning station of Chichaoua shows the highest load 7 species with Ascaris 21 eggs/g; Capillaria sp., 11 eggs/g; Trichuris sp., 6 eggs/g; Toxocara sp., 2 eggs/g and Ankylostome sp., 1 egg/g; Taenia sp., 2eggs/g; and Schistosoma sp., 1 egg/g. Infiltration-percolation sludge show the presence of 4 species of helminths eggs in sludge from anaerobic settling with different rates: 15 eggs/g for Ascaris sp., 15 eggs/g for Trichuris sp., 13 eggs/g for Capillaria sp., and 8 eggs/g for Taenia sp. However, in sand filter pool, the sludge helminth eggs load was decreased by 47% of Ascaris sp., 85% of Capillaria sp., and 75% of Taenia sp., Nevertheless, an increase of Trichuris eggs load was noted in the second sludge by 17%. Five helminth eggs was detected in primary sludge coming from decantation pools in activated sludge plant in Marrakech, that is Ascaris sp., with a load of 16 eggs/g; Capillaria sp., with 3 eggs/g, Trichuris eggs with 2 eggs/g; Taenia sp., with 4 eggs/g; and Schistosoma sp., with 2 eggs/g. The abatement load of Ascaris sp. with 81% and Schistosoma and Taenia sp., with 100% was noted in biological sludge. Nevertheless, an increase load of Capillaria and Trichuris eggs 81% and 75% respectively was observed in this sludge coming from biological pools. The distribution of parasitic helminth eggs is linked to the differences in demographic and socio-economic status, seasonal variation, physico-chemical characteristic of helminth eggs, and the purification wastewater system performance.
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effect of dewatering and composting on helminth eggs removal from Lagooning sludge under semi arid climate
Environmental Science and Pollution Research, 2018Co-Authors: Bouchra El Hayany, Mohamed Hafidi, Ghizlen El Mezouari El Glaoui, Mohammed Rihanni, Amine Ezzariai, Abdelouahed El Faiz, Mohamed El Gharous, Loubna El FelsAbstract:In this work, we assessed the drying and composting effectiveness of helminth eggs removal from sewage sludge of a lagoon wastewater treatment plant located in Chichaoua city. The composting was run after mixing sludge with green waste in different proportions: M1 (½ sludge + ½ green waste), M2 ([Formula: see text] sludge + [Formula: see text] green waste), and M3 ([Formula: see text] sludge + [Formula: see text] green waste) for 105 days. The analysis of the dewatered sewage sludge showed a load of 8-24 helminth eggs/g of fresh matter identified as Ascaris spp. eggs (5-19 eggs/g) followed by Toxocara spp. (0.2 to 2.4 eggs/g); Hookworm spp. and Capillaria spp. (0.4-1 egg/g); Trichuris spp., Taenia spp., and Shistosoma spp. (< 1 egg/g) in the untreated sludge. After 105 days of treatment by composting, we noted a total reduction of helminth eggs in the order of 97.5, 97.83, and 98.37% for mixtures M1, M2, and M3, respectively. The Ascaris spp. eggs were reduced by 98% for M1 and M3 treatments and by 97% for M2 Treatment. Toxocara spp., Hookworm spp., Trichuris spp., Capillaria spp., and Shistosoma spp. eggs were totally eliminated (100% decrease) and the Taenia spp. was absent from the first stage of composting. These results confirm the effectiveness of both dehydrating and composting processes on the removal of helminth eggs.
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an innovative multistage treatment system for sanitary landfill leachate depuration studies at pilot scale
Science of The Total Environment, 2017Co-Authors: Tânia F C V Silva, Amelia Fonseca, Petrick A Soares, Diego Ricieri Manenti, Isabel SaraivaAbstract:In this work, an innovative methodology for the treatment of landfill leachates, after aerobic Lagooning, is proposed and adjusted at pilot-scale. This methodology involves an aerobic activated sludge biological pre-oxidation (ASBO), a coagulation/sedimentation step (240mgFe3+/L, at pH4.2) and a photo-oxidation through a photo-Fenton (PF) reaction (60mg Fe2+, at pH2.8) combining solar and artificial light. The ASBO process applied to a leachate after aerobic Lagooning, with high organic and nitrogen content (1.1-1.5gC/L; 0.8-3.0gN/L) and low biodegradability (BOD5/COD =0.07-0.13), is capable to oxidise 62-99% of the ammonium nitrogen, consuming only the affluent alkalinity (70-100%). The coagulation/sedimentation stage led to the humic acids precipitation, promoting a marked change in leachate colour, from dark-brown to yellowish-brown (related to fulvic acids), accompanied by a reduction of 60%, 58% and 88% on DOC, COD and TSS, respectively. The PF system promoted the degradation of the recalcitrant organic molecules into more easily biodegradable ones. According to Zahn-Wellens biodegradability test, a leachate with 419mg DOC/L after coagulation, would have to be photo-oxidized until DOC 60%. The PF step cost to treat 100m3/day of leachate was 6.41€/m3, combining 1339m2 of CPCs with 31 lamps.
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insights into solar photo fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab scale
Journal of Environmental Management, 2015Co-Authors: Tânia F C V Silva, Amelia Fonseca, Isabel Saraiva, Rui A R Boaventura, Petrick A Soares, Diego Ricieri Manenti, Rui Ferreira, Vitor J P VilarAbstract:This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated Lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe(2+)/L), solution pH (2.0-3.6), operating temperature (10-50 °C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH(2+), was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH(2+). The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 °C; [Fe(2+)] = 60 mg/L and UV irradiance = 44 WUV/m(2), achieving 72% mineralization after 25 kJUV/L of accumulated UV energy and 149 mM of H2O2 consumed.
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Insights into solar photo-Fenton reaction parameters in the oxidation of a sanitary landfill leachate at lab-scale
'Elsevier BV', 2015Co-Authors: Tânia F C V Silva, Amelia Fonseca, Isabel Saraiva, Rui A R Boaventura, Petrick A Soares, Rui Ferreira, Diego R. Manenti, Vitor J P VilarAbstract:This work evaluates the effect of the main photo-Fenton (PF) reaction variables on the treatment of a sanitary landfill leachate collected at the outlet of a leachate treatment plant, which includes aerated Lagooning followed by aerated activated sludge and a final coagulation-flocculation step. The PF experiments were performed in a lab-scale compound parabolic collector (CPC) photoreactor using artificial solar radiation. The photocatalytic reaction rate was determined while varying the total dissolved iron concentration (20-100 mg Fe2+/L), solution pH (2.0-3.6), operating temperature (10-50 degrees C), type of acid used for acidification (H2SO4, HCl and H2SO4 + HCl) and UV irradiance (22-68 W/m(2)). This work also tries to elucidate the role of ferric hydroxides, ferric sulphate and ferric chloride species, by taking advantage of ferric speciation diagrams, in the efficiency of the PF reaction when applied to leachate oxidation. The molar fraction of the most photoactive ferric species, FeOH2+, was linearly correlated with the PF pseudo-first order kinetic constants obtained at different solution pH and temperature values. Ferric ion speciation diagrams also showed that the presence of high amounts of chloride ions negatively affected the PF reaction, due to the decrease of ferric ions solubility and scavenging of hydroxyl radicals for chlorine radical formation. The increment of the PF reaction rates with temperature was mainly associated with the increase of the molar fraction of FeOH2+. The optimal parameters for the photo-Fenton reaction were: pH = 2.8 (acidification agent: H2SO4); T = 30 degrees C; [Fe2+] = 60 mg/L and UV irradiance = 44 Wuv/m(2), achieving 72% mineralization after 25 kJuv/L of accumulated UV energy and 149 mM of H2O2 consumed
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sanitary landfill leachate treatment using combined solar photo fenton and biological oxidation processes at pre industrial scale
Chemical Engineering Journal, 2013Co-Authors: Tânia F C V Silva, Amelia Fonseca, Elisabete M F Silva, Cristina A Cunhaqueda, Isabel SaraivaAbstract:Abstract This work proposes a new strategy for the treatment of leachates from sanitary landfills after Lagooning pretreatment, using a solar photo-Fenton oxidation process to eliminate the most recalcitrant organic compounds, leading to a biodegradability enhancement of the leachate and promoting its subsequent oxidation in an activated sludge biological reactor. The integrated leachate treatment process was conducted in a pre-industrial plant, incorporating a photocatalytic system with 39.52 m2 of compound parabolic collectors (CPCs) and an activated sludge biological reactor, with 3.5 m3 capacity, operated under aerated and anoxic conditions. An extensive physico-chemical characterization of the leachate after Lagooning was performed during one year, from June 2010 to May 2011, showing its high recalcitrant character mainly associated with the presence of humic substances. The efficiency of the combined treatment was evaluated concerning the leachate characteristics’ variability after Lagooning, availability of solar radiation during the year, and different operational process variables, such as the amount of hydrogen peroxide necessary to reach the required COD target value, biodegradability enhancement during the photo-oxidation process, iron reutilization in consecutive oxidation processes, removal of acidic sludge resulting from the acidification process and leachate temperature/average solar power. The elimination of the remaining organic carbon fraction and nitrogen compounds after the pre-oxidation step was also assessed in an activated sludge biological reactor, under aerobic and anoxic conditions, considering the composition variability of photo-treated leachate. Nitrification and denitrification rates were also evaluated.
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biodegradability enhancement of a leachate after biological Lagooning using a solar driven photo fenton reaction and further combination with an activated sludge biological process at pre industrial scale
Water Research, 2013Co-Authors: Tânia Silva, Amelia Fonseca, Isabel SaraivaAbstract:Abstract This work proposes an integrated leachate treatment strategy, combining a solar photo-Fenton reaction, to enhance the biodegradability of the leachate from an aerated lagoon, with an activated sludge process, under aerobic and anoxic conditions, to achieve COD target values and nitrogen content according to the legislation. The efficiency and performance of the photo-Fenton reaction, concerning a sludge removal step after acidification, defining the optimum phototreatment time to reach a biodegradable wastewater that can be further oxidized in a biological reactor and, activation sludge biological process, defining the nitrification and denitrification reaction rates, alkalinity balance and methanol dose necessary as external carbon source, was evaluated in the integrated system at a scale close to industrial. The pre-industrial plant presents a photocatalytic system with 39.52 m 2 of compound parabolic collectors (CPCs) and 2 m 3 recirculation tank and, an activated sludge biological reactor with 3 m 3 capacity. Leachate biodegradability enhancement by means of a solar driven photo-Fenton process was evaluated using direct biodegradability tests, as Zahn–Wellens method, and indirect measure according to average oxidation state (AOS), low molecular carboxylic acids content (fast biodegradable character) and humic substances (recalcitrant character) concentration. Due to high variability of leachate composition, UV absorbance on-line measurement was established as a useful parameter for photo-Fenton reaction control.
