Legionella growth potential of drinking water produced by a reverse osmosis pilot plant
Learbuch, K.L.G. ; Lut, M.C. ; Liu, G. ; Smidt, H. ; Wielen, P.W.J.J. van der - \ 2019
Water Research 157 (2019). - ISSN 0043-1354 - p. 55 - 63.
Drinking water quality - Legionella pneumophila - Regrowth - Reverse osmosis
Treatment processes, such as membrane filtration with reverse osmosis (RO), are used to produce drinking water with a high degree of biostability. To our knowledge, the influence of RO water on biofilm formation and growth of L. pneumophila has not yet been investigated. Therefore, this study aimed (i) to determine the Legionella growth potential of (remineralised) RO-water produced by a pilot plant and to compare this to conventional treated groundwater, and (ii) to determine if different pipe materials, in contact with remineralised RO-water, can cause growth of L. pneumophila. The Legionella growth potential of water was determined with the boiler biofilm monitor (BBM) that mimics the flow of water in a premise plumbing system. The Legionella growth potential of materials in contact with remineralised RO-water was determined by using the biomass production potential (BPP)-test. ATP concentrations in the biofilm on the glass rings from the BBM fed with (remineralised) RO water fluctuated around 100 pg ATP cm −2 . In contrast, BBMs fed with conventionally treated water resulted in ten-fold higher ATP concentrations in the biofilm. Moreover, conventionally treated water had a Legionella growth potential that was 1000-fold higher than that of (remineralised) RO-water. Furthermore, glass, copper and PVC-C had the lowest biofilm concentrations and Legionella growth potential in the BPP-test, followed by PE-Xb, PE-Xc and PE-100. The highest biofilm concentration and Legionella growth potential were with PVC-P. Hence, our study demonstrated that remineralised RO-water did not enhance growth of L. pneumophila in the BBM that mimics the premises plumbing system. However, when PE or PVC-P materials are used growth of L. pneumophila can still occur in the premises plumbing system despite the high quality of the supplied remineralised RO-water.
Public participation in science : The future and value of citizen science in the drinking water research
Brouwer, Stijn ; Wielen, Paul W.J.J. van der; Schriks, Merijn ; Claassen, Maarten ; Frijns, Jos - \ 2018
Water 10 (2018)3. - ISSN 2073-4441
Amsterdam - Citizen science - Drinking water quality - Knowledge generation - Participation
This paper explores the value of involving citizens in the generation of knowledge in drinking water research. To this end, the significance of the 'Freshness of Water' citizen science project on the microbiological stability of drinking water was analyzed, supplemented with a series of expert interviews. In this project, citizens of Amsterdam participated in taking samples from their own kitchen tap and testing the water using test strips. The subsequent monitoring of bacteria revealed that the total number of bacterial species in all of the Amsterdam drinking water samples was high. For the participants, the presence of ten thousands of bacterial species in their drinking water, as well as the interpretation that this is perfectly normal and not a health concern, was obviously new. However, instead of causing concern or worry, this transparency clearly functioned as a strong confidence-inducing signal. A majority of the citizen scientists state that, as a result of their participation, their confidence in the quality of drinking water and the water company has increased. This study suggests that citizen science can raise the participant's water awareness and that, with the appropriate support, non-professionals can make a valuable contribution to scientific drinking water research.