REPORT

  EcoEng Newsletter 3, December 2000 
 

1st World Water Congress of the International Water Association in Paris 3-7 July, 2000
 
 A personal report

by EcoEng Correspondent Caroline Höglund, Swedish Institute for Infectious Disease Control

E-mail: caroline.hoglund@smi.ki.se 
 

What is the IWA?
 
In September of 1999 IAWQ (International Association on Water Quality) and IWSA (International Water Services Association) merged into one organisation. IWA (International Water Association) is an international membership organisation, with members working in water and wastewater utilities, consulting companies, academia and research, manufacturers and suppliers, government departments and agencies in over 130 countries worldwide. A membership can be recommended since it can give you subscriptions of water-journals for a good price (at least if you are a student).
 

Paris in July 2000 - Not Only Water Guys
  The "Paris 2000” congress was the first international congress of the IWA and about 2'500 participants found their way to (a rainy) Paris in the middle of the summer. On the Sunday before the official opening day of the conference Paris was in chaos. Cars and people everywhere, later we could read in the paper that 500'000 had been on Champs Elyseés. France had won the World Cup in soccer!

A big conference also involves a bit of chaos: Where is the escalator? Where should I put up my poster (oh no, someone took it down and stole my spot!)? Where can I find those delicious-looking cakes and how about those walking sticks – are they free? What session should I go to now and where do we meet for lunch?
 

10th Health-Related Water Microbiology Symposium
 
I spent most of my time in the room where the 10th Health-related Water Microbiology Symposium was held (as a part of the IWA congress). Since microbiology is my special interest (workwise) and most speakers were interesting to listen to, I did not find any reason to switch to other sessions.

 

Cryptosporidium and Other Bugs
  As many of you may have heard, the Milwaukee outbreak of Cryptosporidium is the largest waterborne outbreak ever documented. An estimated 400'000 persons got infected from drinking water because the raw water was affected by agricultural land runoff and insufficiently treated. One presentation (P.R.Hunter & Q.Syed) explained how the 400'000 estimate could be overestimated by anything between 858-23'000%. Scary how statistics and risk modeling can provide varying results.

As with the massive outbreak of cryptosporidiosis it is difficult to estimate the number of people affected by a waterborne outbreak. The general opinion is that the numbers are underestimated and that some outbreaks are not even detected. From Finland it was reported (I.T.Miettinen et al.) that 14 outbreaks occurred during 1998-1999. Half of them were related to public water supplies and half to private water systems. However a significantly larger number of cases was attributable to the public supplies (7'400 cases) than to private (290 cases). Calicivirus was responsible for the majority of outbreaks.

Better detection methods have been developed and it seems that viruses are responsible for a large part of waterborne disease outbreaks. For foodborne outbreaks related to the consumption of shellfish, virus is also often the aetiological (= ill making) agent.

From Spain an outbreak of Hepatitis A with 180 people affected was reported (A.Bosch). However, within the EU as well as in other parts of the world regulations for waters used for shellfish breeding only include analysis of bacteria and how to change these regulations were discussed.

 

Emerging Waterborne Pathogens?
  The question mark here indicates that the role of some microorganisms still is unclear. Two of the pathogens debated in relation to drinking water were atypical (or environmental) mycobacteria (R.Schulze-Röbbecke et al. and A Vantarakis et al.) and Helicobacter pylori, the latter known to infect a large part of the world´s population and suggested to be responsible for ulcers as well as gastric cancer. In Mexico a sero-prevalence of 90% in adults was reported (M.Mazari-Hiriart et al.) and the bacteria was found in several of investigated water sources but the route of transmission is still unclear. The ongoing debate, e.g. in Sweden, about H. pylori include preventive medication for almost everyone which on the other hand could lead to problems with antibiotic resistant strains.

 

Drinking Water Quality
  Regarding drinking water the quality in developing countries and microbial disinfection were other issues presented and discussed. The approaches for developing and developed countries are quite different since water related problems are of completely different characteristics. The water quantity rather than quality is responsible for the health situation (especially regarding diarrhoeal disease) in developing countries according to a presenter from South Africa (I.Bailey & L.Archer).

However, the lack of sanitation has an even larger impact and joint efforts on water and sanitation is necessary. Mark Sobsey gave one example from Bangladesh where the chlorination of the water source was implemented and prevalence of diarrhoea decreased by 17%, and another from India where septic tanks were installed, resulting in a decrease of diarrhoea with 50%. From New Zealand a roof water supply was reported (G.Lewis) to result in problems with Aeromonas which are quite common in water systems including tanks and pipes.

 

Microbial Survival...
  ....is a topic related to any water and sanitary system. One interesting project presented (M.Storey) concerns a housing area outside Sydney, Australia, where a dual reticulation (= distribution) system soon will be in use. The idea is to have two separate pipes; one supplying drinking water and the other one supplying reclaimed (tertiary treated effluent) water for other use like flushing of toilets and irrigation. What is investigated is the potential differences in virus accumulation within biofilms.

Another study comparing the adsorption and survival of bacteria (faecal coliforms) and viruses (bacteriophages) in wastewater irrigated soil confirmed previous results. Viruses were less adsorbed to soil particles and are able to be transported longer distances than bacteria (C.Gantzer). They also had a better survival than bacteria. The overall survival was longer in wastewater than in soil. These are issues important to consider in reuse systems.

In France there is a long history of using wastewater for irrigation of crops. In epidemiological investigations of risk a case study was presented where tertiary pond treated wastewater was reused. No particular sanitary problem was associated with the wastewater reuse, but workers had skin problems. The paper presented (I.Devaux) stated that these results could not guarantee safety of the practice in a long term and that recommendations had been established.

 

Wetlands
  Wetlands were discussed in another session. The reduction of indicator organisms as well as pathogens have been studied in Tucson, Arizona and was reported to vary widely, from 52% to >99.9% (A.Oswald). Wetlands are quite difficult to study, e.g. in order to estimate microbial reduction and risks related to the effluent in the recipient or the wetland itself. In Sweden Anneli Carlander has shown that a major part of microbial reduction in the water phase is due to sedimentation.

Health and the recreational use of water was another issue of concern. Among other things the appropriateness of the EU bathing water directive and the WHO guidelines were discussed (I.Leenen, J.A.Juanes et al., M.A.Mugglestone, D.Kay and J.Fleischer). One conclusion was that monitoring results and compliance to guidelines will vary largely depending on discontinuous contaminant events and weather.

 

The "Real" IWA Conference
  The themes of the "real” IWA conference were 1) Industrial wastewater treatment, 2) Drinking water treatment, 3) Wastewater treatment plants, 4) Small wastewater treatment plants - management of sludges and leachates, 5) Water resources and waste management, 6) Administration - Management and 7) Wastewater reclamation, recycling and reuse.

 

The Two Poster Sessions Were a Disaster.
  It was hopeless to find the posters you were interested in and time was short. The place where the congress was held had no chairs outside the lecture halls, so we sat on the floor eating our sandwiches for lunch. This environment did not provide for fruitful discussions and meeting new people, which I think was a greater problem than where to have lunch. I remember…yes, it was actually much better organised in Vancouver 1998 where the previous congress was held (then by IAWQ). However, the quality of the research presented was, from what I can judge, very good.

 

Last But Not Least...
  A translation was necessary during one of the social events when politicians and other important people welcomed us to Paris and explained the excellent function of the wastewater treatment plant where we had a superb cocktail party while artists were flying above our heads. The final was one of the longest (in time) and loudest fireworks I have ever seen. A six-course dinner and a guided visit in the Louvre were also provided for during the week (if you had paid).
 

The Next Congress Will Be in Berlin in October 2001,
  It will be even bigger. 5'000 participants are expected. Maybe I will see you there somewhere in the crowd...
 
© 2000, International Ecological Engineering Society, Wolhusen, Switzerland