Maintaining the microbial quality in distribution systems and connected installations remains a challenge for water supply companies all over the world

On May 11-12 the conference Microbial Growth in Drinking Water Distribution Systems and Tap Water Installations is organized by KWR Watercycle Research Institute under the authority of the Dutch Joint Water Sector Research Programme, known as BTO. The regrowth issue is selected for this conference, because maintaining the microbial quality in distribution systems and connected installations remains a challenge for the water supply companies all over the world, despite many years of research. Exchange of information on this issue will be helpful in identifying the main concerns and knowledge gaps related to regrowth and stimulate cooperation in future research.

Topics of the conference include:

  • An overview of the regrowth issue in different countries;
  • Water quality problems related to regrowth;
  • Assessment and causes of regrowth in drinking water;
  • Prevention of regrowth by water treatment and distribution;
  • Research needs;
  • Technical programme: Visit to dune area and water treatment facility Heemskerk (PWN).

Invited speakers from Canada, Japan, USA, and European countries will present the latest information related to microbiological regrowth.

KWR-researchers Paul van der Wielen (editor) and Bart Wullings (photographer) will report from the conference in the next two days.

May 11-12, BTO Conference on Microbial growth in drinking water distribution systems and tap water installations

Click here to download:
Dick_vd_Kooij,_Conference_Announcement.pdf (1.1 MB)
The conference Microbial growth in drinking water distribution systems and tap water installations is organized by KWR in the framework of the Dutch Joint Water Sector Research Programme, known as BTO. The regrowth issue is selected for the conference, because maintaining the microbial quality in distribution systems and connected installations remains a challenge for the water supply companies all over the world, despite many years of research. Exchange of information on this issue will be helpful in identifying the main concerns and knowledge gaps related to regrowth and stimulate cooperation in future research.

Topics of the conference include: 

  • An overview of the regrowth issue in different countries;
  • Water quality problems related to regrowth;
  • Assessment and causes of regrowth in drinking water;
  • Prevention of regrowth by water treatment and distribution;
  • Research needs;
  • Technical programme: Visit to dune area and water treatment facility Heemskerk (PWN).

Invited speakers from Canada, Japan, USA, and European countries, most of them with many years of experience in applied research and water supply, will present the latest information related to microbiological regrowth. In a separate session, research needs will be discussed.

  

In addition to the scientific presentations, a welcoming reception at the evening of May 10 is organized as well as a social programme, including the conference dinner on May 11, and an optional technical programme on May 12. These events will provide opportunities to meet and network with your colleagues in an informal atmosphere.

 

 

Registration is possible until March 14th. For more information:
niels.dammers@kwrwater.nl , KWR, telephone +31 30 60 69 668
dieuwke.voorhoeve@kwrwater.nl, KWR,  telephone +31 30 60 69 724

We are looking forward to meeting you in May.

Prof.dr. ir. Dick van der Kooij

Principal Microbiologist, KWR Watercycle Research Institute

KWR peer reviewed: Quantifying the vulnerability of well fields towards anthropogenic pollution; The Netherlands as an example

Recentelijk publiceerden  Mendizabal, I. and Stuyfzand, P.J. in: Journal of Hydrology (2011) DOI 10.1016/j.jhydrol.2010.12.026 (in Press)

 

 Abstract

A new method is presented to asses the vulnerability of public supply well fields (PSWFs), other well fields or individual wells. The Intrinsic Vulnerability Index towards Pollution (VIP) is based on the age, redox level, alkalinity (or acidity), and surface water fraction of the pumped water, resulting in a score ranging from 0 for old, deeply anoxic, high alkalinity ground water to 30 for young, (sub)oxic, acid ground water.

The Specific Vulnerability Index towards Pollutant X (VIPX) combines VIP with four aspects: the current concentration of X in the pumped water; the mobility or mobilization potential of X in the hydrogeochemical environment as derived from the redox state and alkalinity of the raw water; the land use within the ground water catchment area; and the pollution risk for X, derived from its concentration in shallow groundwater and/or in the infiltrating surface water.

A national survey of all active PSWFs in the Netherlands revealed a low VIP in 50% and high VIP in 9% of them. Most PSWFs with a low VIP pump from very deep aquifers, and those with high VIP from either acidified, phreatic sandy aquifers, (sub)oxic, artificially recharged coastal dunes, (sub)oxic river banks or oxic limestone.

Research highlights: â–º We quantify the vulnerability of public supply well fields (PSWFs) and wells. â–º Both intrinsic vulnerability (VIP) and specific vulnerability (VIPX) are addressed. â–º VIP uses the age, redox level, alkalinity (or acidity), and surface water fraction. â–º VIPX also requires land use, capture zone, pollution risk and mobilization potential. â–º Our national survey of 241 PSWFs in the Netherlands revealed a good quality status.

Link: http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6C-51TYF9N-1&...

 

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KWR peer reviewed: Preliminary study on the occurrence and risk arising from bacteria internalized in zooplankton in drinking water

Recentelijk publiceerden Bichai, F., Hijnen, W., Baars, E., Rosielle, M., Dullemont, Y. and Barbeau, B. in: Water Science and Technology 63(2011)1, p. 108-114.

 

Abstract 
In this study, an environmental sampling campaign was conducted to detect internalized E. coli and C. jejuni bacteria in zooplankton and amoebae samples collected at various stages of three water treatment plants in Amsterdam, the Netherlands. Eight sampling locations were selected and sampling was performed twice, at a two-week interval, at each location. Chlorination was used to inactivate free (external) bacteria in the concentrated zooplankton samples and sonication was used to disrupt zooplankton organisms in order to release and recover internalized bacteria. Zooplankton enumeration was performed by microscopy. No internalized E. coli or C. jejuni bacteria were recovered from all of the samples analyzed. The occurrence of internalized E. coli or C. jejuni bacteria in drinking water was estimated to be lower than one internalized bacteria in 10(5) zooplankton organisms, as derived from the detection limit of the sampling campaign. By using the QMRA approach and the Beta-Poisson model, a risk of infection of less than 9.2E-6 and 5.9E-5 was estimated for internalized E. coli and C. jejuni in drinking water, respectively. This study remains preliminary due to the limited number of samples taken at each location.

 

Link: http://www.ncbi.nlm.nih.gov/pubmed/21245561

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KWR peer reviewed: Radial transport processes as a precursor to particle deposition in drinking water distribution systems

Recentelijk publiceerden van Thienen, P., Vreeburg, J.H.G. and Blokker, E.J.M. in: Water Resaerch 45(2011),4, p.1807-1817.


Abstract

Various particle transport mechanisms play a role in the build-up of discoloration potential in drinking water distribution networks. In order to enhance our understanding of and ability to predict this build-up, it is essential to recognize and understand their role. Gravitational settling with drag has primarily been considered in this context. However, since flow in water distribution pipes is nearly always in the turbulent regime, turbulent processes should be considered also. In addition to these, single particle effects and forces may affect radial particle transport. In this work, we present an application of a previously published turbulent particle deposition theory to conditions relevant for drinking water distribution systems. We predict quantitatively under which conditions turbophoresis, including the virtual mass effect, the Saffman lift force, and the Magnus force may contribute significantly to sediment transport in radial direction and compare these results to experimental observations. The contribution of turbophoresis is mostly limited to large particles (>50 μm) in transport mains, and not expected to play a major role in distribution mains. The Saffman lift force may enhance this process to some degree. The Magnus force is not expected to play any significant role in drinking water distribution systems.


Link: http://www.ncbi.nlm.nih.gov/pubmed/21186040

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KWR peer reviewed: "Formation and removal of genotoxic activity during UV/H2O2-GAC treatment of drinking water"

Recentelijk publiceerden M.B. Heringa a),*), D.J.H. Harmsen a), E.F. Beerendonk a), A.A. Reus b), C.A.M. Krul b), D.H. Metz c), G.F. IJpelaar a),1) Formation and removal of genotoxic activity during UV/H2O2-GAC treatment of drinking water in: Water Research 4 5 ( 2 0 1 1 ) 3 6 6 - 3 7 4
Abstract
The objective of this study was to determine the genotoxic activity of water after UV/H2O2 oxidation and GAC filtration. Pre-treated surface water from three locations was treated with UV/H2O2 with medium pressure (MP) lamps and passed through granulated activated carbon (GAC). Samples taken before and after each treatment step were extracted and concentrated by solid phase extraction (SPE) and analyzed for genotoxicity using the Comet assay with HepG2 cells and the Ames II assay. The Comet assay showed no genotoxic response in any of the samples. In the Ames II, no genotoxic response was obtained with the TAMix (a mix of six strains), but the TA98 strain showed an increase in genotoxic activity after MP-UV/H2O2 for all three locations. GAC post treatment effectively reduced the activities to control levels at two of the three locations and to below the level of the pre-treated water at one site. The results indicate that UV/H2O2 treatment may lead to the formation of genotoxic by-products, which can be removed by subsequent GAC filtration.

a) KWR Watercycle research institute, P.O. Box 1072, 3430 BB Nieuwegein, The Netherlands
b) TNO Quality of Life, P.O. Box 360, 3700 AJ Zeist, The Netherlands
c) Greater Cincinnati Water Works, 5651 Kellogg Avenue, Cincinnati, OH 45228, USA
*) Corresponding author. Tel.: +31 30 6069539; fax: +31 30 6061165. E-mail address: Minne.Heringa@kwrwater.nl (M.B. Heringa).
1) Present address: Royal Haskoning, P.O. Box 151, 6500 AD Nijmegen, The Netherlands.

Roberta Hofmans second report from the Water Quality Technology Conference 2010

Groot_hofman-caris_roberta

Today was the second day of the WQTC, and the final day of the exhibition. I attended a session on the impact of climate change. The first presentation showed the consequences of sea level rise on southeast Florida. The first consequences can already be noticed, but not everyone understands their impact. Some parts of the country will disappear within the next 50 years! Of course, this also has its consequences for the water availability in Florida, especially as the water sources tend to become salty.

The second presentation showed the first consequences of global warming for Alaska, where houses are collapsing as a result of the melting permafrost. As the water in Alaska is becoming warmer, the number of larves increases, which e.g. causes problems in the filters that are used to purify drinking water. Another presentation showed the problems that can be expected in the southwest part of the US. It was estimated that until the year 2050 the adaptations required for drinking water facilities in the US will cost between 326 and 692 billion dollars, whereas the costs for wastewater treatment plants adaptation will be between 123 and 252 billion dollars (these figures do not include the 500 billion required for maintenance of the present infrastructure).

In a session on endocrine disruptors, it was shown that the use of cocaine in a certain area can be estimated from the amount of its degradation product benzoylecgonine. Even in a creek in the Swiss mountains a notable amount of benzoylecgonine was detected!

Furthermore I attended several presentations on adsorption of NOM, mainly on activated carbon.At the end of the day there was a boat trip on the river. Unfortunately, it was too dark to see anything J.

Roberta Hofman-Caris