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I.S.M. Pinel

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9 records found

Sialic acids

An important family of carbohydrates overlooked in environmental biofilms

Journal article - I.S.M. Pinel, H.B.C. Kleikamp, Martin Pabst, J.S. Vrouwenvelder, J.S. Vrouwenvelder, Mark C.M. van Loosdrecht, Y. Lin

Sialic acids in the structural matrix of biofilms developing in engineered water systems constitute a potential target in the battle against biofouling. This report focuses specifically on the presence of sialic acids as part of the extracellular polymeric substances (EPS) of bio ...

Biofouling in open recirculating cooling systems

Characterization and control of biofilms and Legionella pneumophila

Doctoral thesis - I.S.M. Pinel

Open recirculating cooling systems have been vital elements in industry since the early 20th century. Their purpose is to release excess heat from processes through water evaporation so that production can be carried out at optimal temperature. With the global development of industrial activities such as manufacturing, electricity and chemical production, the demand for cooling capacity keeps increasing. Biofouling is one of the main phenomena negatively affecting the performance of wet cooling systems. This phenomenon leads to: (i) loss of heat transfer efficiency, (ii) clogging, (iii) microbiologically influenced corrosion, and (iv) health risk associated to the development of pathogens. Controlling bacterial growth in open recirculating cooling systems is very challenging, and is generally performed via dosage of disinfectants such as sodium hypochlorite. Due to biofouling and the increasing concerns linked to chemical consumption and water discharge, attention has been given to investigate more sustainable approaches to cooling systems operation. Knowledge on the bacterial communities, disinfection impact and biofilm composition is however limited and a more in-depth characterization of biofouling is required to effectively establish new control strategies. The objectives of this thesis were to contribute to the available knowledge on biofouling in cooling systems and to investigate sustainable and predictable alternative operations, providing results of direct relevance to practice. Attention was given to the identification of factors selecting the microbiome of cooling water subjected to conventional operation, characterization of cooling tower biofilms without disinfection, and assessment of the impact of temperature on biofilm composition. Then, alternative approaches to biofouling control were tested at pilot-scale. Phosphorus depletion was investigated as a solution for limiting biofilm growth and high pH was considered as a Legionella pneumophila control method. These studies were performed with the use of recent analytical methods such as next generation amplicon sequencing (NGS), quantitative polymerase chain reaction (qPCR), and flow-cytometry, which allowed collection of valuable data and a better characterization of biofouling...@en

Efficient cooling tower operation at alkaline pH for the control of Legionella pneumophila and other pathogenic genera

Journal article - I.S.M. Pinel, P. M. Hankinson, D. H. Moed, L. J. Wyseure, J.S. Vrouwenvelder, J.S. Vrouwenvelder, Mark C.M. van Loosdrecht

Efficient control of pathogenic bacteria, specifically Legionella pneumophila, is one of the main concerns when operating industrial cooling towers. Common practices to limit proliferation involves use of disinfectants, leading to formation of disinfection by-product and increase in water corrosiveness. A disinfectant-free Legionella control method would make the industry more environmentally friendly. A pilot-scale cooling tower (1 m3/h) operated with demineralized water was used to investigate the potential of high-pH conditioning as a disinfectant-free alternative for control of L. pneumophila and other pathogens. One control experiment was performed under standard full-scale operation involving sodium hypochlorite dosage. Thereafter 3 alkaline pHs of the cooling water were tested: 9.0, 9.4 and 9.6. The tests lasted between 25 and 35 days. The cooling water from the basins were analysed for total cell count by flow cytometry, L. pneumophila concentration by plate count and occasional qPCR analyses targeting the mip-gene, bacterial and eukaryotic community analyses with 16S and 18S rRNA gene amplicon sequencing, relative abundance of eukaryotic to prokaryotic DNA by qPCR of the 16S and 18S rRNA gene. The L. pneumophila analyses showed considerable growth at pH 9.0 and pH 9.4 but was maintained below detection limit (< 100 CFU/L) at pH 9.6 without disinfection. Interestingly, the results correlated with the overall abundance of protozoa in the water samples but not directly with the relative abundance of specific reported protozoan hosts of Legionella. The pathogenicity based on 16S rRNA gene amplicon sequencing of the cooling water DNA decreased with increasing pH with a strong decline between pH 9.0 and pH 9.4, from 7.1% to 1.6% of relative abundance of pathogenic genera respectively. A strong shift in microbiome was observed between each tested pH and reproducibility of the experiment at pH 9.6 was confirmed with a duplicate test lasting 80 days. High-pH conditioning ≥ 9.6 is therefore considered as an efficient disinfectant-free cooling tower operation for control of pathogenicity, including L. pneumophila.@en

Assessment of the impact of temperature on biofilm composition with a laboratory heat exchanger module

Journal article - I.S.M. Pinel, R. Biskauskaite, E. Palova, J.S. Vrouwenvelder, J.S. Vrouwenvelder, Mark C.M. van Loosdrecht

Temperature change over the length of heat exchangers might be an important factor affect-ing biofouling. This research aimed at assessing the impact of temperature on biofilm accumulation and composition with respect to bacterial community and extracellular polymeric substances. ...

Bacterial community dynamics and disinfection impact in cooling water systems

Journal article - I.S.M. Pinel, D. H. Moed, J.S. Vrouwenvelder, J.S. Vrouwenvelder, Mark C.M. van Loosdrecht

Understanding the bacterial dynamics in cooling towers is imperative for the assessment of disinfection efficiency and management of microbial risks linked to aerosol formation. The objective of this study was to evaluate the impact of feed water on the cooling water bacterial microbiome and investigate the survival ability of its members when exposed to continuous chlorine disinfection. Water from an industrial cooling water system (2600 m3/h) was collected over a 5-month period at 3 locations along the feed water line and 3 locations in the cooling tower. ATP measurements suggested that the average ATP-per-cell in the cooling tower evolved independently from the average ATP-per-cell in the feed water. Flow cytometry and 16S rRNA gene amplicon sequencing were then combined to quantify the bacterial dynamics in the whole system. A mass balance based equation was established to determine net growth and net decay of the cooling tower bacterial communities in order to evaluate the impact of continuous chlorination (0.35–0.41 mg Cl2/L residual chlorine). The results indicated that cooling tower main community members were determined by the input feed water microbiome and the bacterial community structure was further shaped by varying decay rates of the microorganisms. Notably, the order Obscuribacterales showed to be growing in the cooling tower in the presence of residual chlorine up to 0.4 mg Cl2/L, with a recurrent net growth of 260 ± 95%, taking into account the impact of the concentration factor. This conclusion was only possible thanks to the systematic analysis described in this paper and generates discussion about the resistance of Obscuribacterales to residual chlorine. The described mass balance approach provides a high level of understanding on bacterial dynamics and should be considered for future characterization studies of cooling towers in which accurate investigation of microbiome changes is essential.@en

Enhanced biofilm solubilization by urea in reverse osmosis membrane systems

Journal article - H. Sanawar, H. Sanawar, I.S.M. Pinel, I.S.M. Pinel, Nadia M. Farhat, Sz S. Bucs, J. Zlopasa, J. Zlopasa, J. C. Kruithof, J. C. Kruithof, G.J. Witkamp, G.J. Witkamp, G.J. Witkamp, Mark C.M. van Loosdrecht, Mark C.M. van Loosdrecht, J.S. Vrouwenvelder, J.S. Vrouwenvelder, J.S. Vrouwenvelder

Chemical cleaning is routinely performed in reverse osmosis (RO) plants for the regeneration of RO membranes that suffer from biofouling problems. The potential of urea as a chaotropic agent to enhance the solubilization of biofilm proteins has been reported briefly in the literature. In this paper the efficiency of urea cleaning for RO membrane systems has been compared to conventionally applied acid/alkali treatment. Preliminary assessment confirmed that urea did not damage the RO polyamide membranes and that the membrane cleaning efficiency increased with increasing concentrations of urea and temperature. Accelerated biofilm formation was carried out in membrane fouling simulators which were subsequently cleaned with (i) 0.01M sodium hydroxide (NaOH) and 0.1M hydrochloric acid (HCl) (typically applied in industry), (ii) urea (CO(NH 2 ) 2 ) and hydrochloric acid, or (iii) urea only (1340 g/L water ). The pressure drop over the flow channel was used to evaluate the efficiency of the applied chemical cleanings. Biomass removal was evaluated by measuring chemical oxygen demand (COD), adenosine triphosphate (ATP), protein, and carbohydrate content from the membrane and spacer surfaces after cleaning. In addition to protein and carbohydrate quantification of the extracellular polymeric substances (EPS), fluorescence excitation−emission matrix (FEEM) spectroscopy was used to distinguish the difference in organic matter of the remaining biomass to assess biofilm solubilization efficacy of the different cleaning agents. Results indicated that two-stage CO(NH 2 ) 2 /HCl cleaning was as effective as cleaning with NaOH/HCl in terms of restoring the feed channel pressure drop (>70% pressure drop decrease). One-stage cleaning with urea only was not as effective indicating the importance of the second-stage low pH acid cleaning in weakening the biofilm matrix. All three chemical cleaning protocols were equally effective in reducing the concentration of predominant EPS components protein and carbohydrate (>50% reduction in concentrations). However, urea-based cleaning strategies were more effective in solubilizing protein-like matter and tyrosine-containing proteins. Furthermore, ATP measurements showed that biomass inactivation was up to two-fold greater after treatment with urea-based chemical cleanings compared to the conventional acid/alkali treatment. The applicability of urea as an alternative, economical, eco-friendly and effective chemical cleaning agent for the control of biological fouling was successfully demonstrated. @en

Effect of phosphate availability on biofilm formation in cooling towers

Journal article - I.S.M. Pinel, L. H. Kim, Vitor R. Proença Borges, Nadia M. Farhat, Geert J. Witkamp, Mark C.M. van Loosdrecht, J.S. Vrouwenvelder, J.S. Vrouwenvelder

Phosphate limitation has been suggested as a preventive method against biofilms. P-limited feed water was studied as a preventive strategy against biofouling in cooling towers (CTs). Three pilot-scale open recirculating CTs were operated in parallel for five weeks. RO permeate wa ...

Application of DBNPA dosage for biofouling control in spiral wound membrane systems

Journal article - Amber Siddiqui, I.S.M. Pinel, E.I.E.D. Prest, Sz S. Bucs, Mark C.M. van Loosdrecht, J. C. Kruithof, J.S. Vrouwenvelder, J.S. Vrouwenvelder, J.S. Vrouwenvelder

Biocides may be used to control biofouling in spiral-wound reverse osmosis (RO) and nanofiltration (NF) systems. The objective of this study was to investigate the effect of biocide 2,2-dibromo-3-ni-trilopropionamide (DBNPA) dosage on biofouling control. Preventive biofouling con ...

Application of DBNPA dosage for biofouling control in spiral wound membrane systems

Journal article - Amber Siddiqui, I.S.M. Pinel, E.I.E.D. Prest, Sz S. Bucs, Mark C.M. van Loosdrecht, J. C. Kruithof, J.S. Vrouwenvelder, J.S. Vrouwenvelder, J.S. Vrouwenvelder

Contributed

1 records found

Ion Exchange as Pretreatment of Municipal Wastewater Effluent for Reverse Osmosis Desalination

Assessment of treatment performance and prediction of fouling potential on downstream reverse osmosis

Master thesis - I. Gkoutzamani, H. Spanjers, J.P. van der Hoek, D.G. Weissbrodt, I.S.M. Pinel, Otto Schepers, Peter van Hartingsveldt

Biofouling and scaling are ongoing challenges for reverse osmosis (RO) membranes application in wastewater reclamation. Adequate RO feed pretreatment is necessary for biofouling and scaling control. The objective of this thesis was evaluated the effectiveness of ion exchange treatment with weak acid cation (WAC) and strong base anion (SBA) resins columns, in series, after ultrafiltration (UF) treatment for the pretreatment of municipal wastewater treatment plant effluent in order to be used for RO desalination. Specifically, the performance of two SBA resins, the Amberlite SCAV4 Cl (SCAV4) and the Amberlite IRA458 Cl (IRA458) was assessed at three regeneration levels (120, 100 and 80 g NaCl/Lr). The effect of the different regeneration levels on anions removal (sulfate, phosphate and nitrate), total organic carbon (TOC) removal and the operational exchange capacity was researched. Moreover, the subsequent effect on RO biofouling and scaling potential was investigated based on the product water quality of the two SBA resins with bio-growth potential tests and software tests (WAVE design, PHREEQC 3 and Avista Ci), respectively. Phosphate and sulfate removal was above 97% for both resins at all regeneration levels. TOC removal of about 70% was achieved in all cases. It was also observed that sulfate, phosphate and TOC removal remained the same up to the point where product nitrate concentration reached its feed concentration. The removal of nitrate was influenced by the regeneration level. For both SBA resins, a lower regeneration level caused a higher nitrate baseline leakage in product water, hence to a lower removal. The macroporous SCAV4 found to have higher selectivity towards nitrate compared to the gel IRA458. Nevertheless, the anion selectivity order for both SCAV4 and IRA458 was HCO3- < NO3- < HPO42- < SO42-. A minor increase in the operational exchange capacity for both SBA resins was observed at higher regeneration levels. Overall, the influence of the different regeneration levels was found to be limited towards the product water quality and the operational exchange capacity. Also, both SBA resins resulted to similar product water quality. The operational exchange capacity of IRA458 at each regeneration level was higher than that of SCAV4, due to the former’s greater total exchange capacity. The RO feed water quality produced without ion exchange pretreatment (only UF) supported bacterial growth up to 54 ± 1.5 × 106 cells/mL. The RO feed water qualities produced with ion exchange pretreatment in the cases of SCAV4 and IRA458 supported bacterial growth up to 3.4 ± 0.3 × 106 cells/mL and to 1.25 ± 0.2 × 106 cells/mL, respectively. The resulted reduction in the bacterial growth potential was above 90% after ion exchange treatment with either one of the tested SBA resins. The growth-limiting nutrient for the RO feed water qualities produced by either SBA resin was phosphorus. The bacterial growth supported by the two RO feed water qualities produced with ion exchange pretreatment after extra phosphorus addition was 80% lower than that supported by the RO feed water quality produced without ion exchange. This difference suggests that both SBA resins removed a considerable fraction of assimilable organic carbon (AOC). It was concluded that ion exchange pretreatment with either one of the tested SBA resins resulted in nutrients removal (P and C) in the RO feed that lowers the biofouling potential compared to RO feed pretreatment with only UF. The software results suggest lower scaling potential for several scalant types in the RO feed after ion exchange treatment with either one of the tested SBA resins. Among them was calcium phosphate, which was found to have high scaling potential in RO feed without ion exchange treatment (only UF) either with or without anti-scalant dosing. However, the scaling potential of some silica and iron based minerals was high, thus anti-scalant dosing might be required.