Skip to main content

Natural biofilms as high-tech conditioners for drinking water

Objective

Problems to be solved
Drinking water companies in Europe have installed sophisticated treatment facilities to prepare drinking water from moderate quality surface water. However, the quality of the 'raw' water remains important, because increasing urbanisation enhances the load of pathogens and substances with suspected hormonal, mutagenic or other health risks. Shortage of water, especially in the Mediterranean countries, implies that surface water of any quality is to be exploited. In view of these problems it is imperative for the drinking water sector to improve environmental technologies increasing water quality prior to treatment. Bio films are sites of biological activity, that abound in all natural rivers and lakes, as well as in all stages of the drinking water system. The aim of the research planned is to develop the knowledge needed to exploit bio films upstream of the water plant and to optimise their capacity to regulate organic matter content in water, to retain noxious compounds and to trap potential pathogens.
Scientific objectives and approach
Analysing the practical problems of the drinking water companies and considering the basic functioning of bio films, the following research activities will be undertaken.
· Construction of a dynamic model for the exchange of solutes and particles between autotrophic/heterotrophic bio films and water. The model facilitates the application of ecological, ecotoxicological and chemical information to water technology.
· The basic architecture of bio films, composed of micro-algae, bacteria and their mucus envelope, and the sites of major biological activity are described and localised. Confocal microscopy is one of the tools used.
· Analysis of bio film development and quantification of its capacity to trap particles from the water. These particles are detritus flocks, invading natural microorganisms, but also bacteria of hygienic interests. Fluorescent labelled particles and genetic probes for pathogens are used.
· To quantify the budget of carbon production in bio films by micro-algae and the carbon consumption by bacteria. The resulting net production or consumption is specified for dissolved compounds, exchangeable with overlying water, and particulate carbon increasing or decreasing total density of the organic mass. Pulse-amplitude modulated fluorometry (PAM) is used for micro-algae production and thymidine or leucine based production estimates for bacteria are combined with chemical determinations of organic carbon. Total DOC and TOC will be measured as well as main classes of protein, carbohydrates (in mucus), and fatty acids.
· The production of the odorous compound geosmin will be measured in an actual river system (Spain) and the seasonal occurrence will be correlated to bio film parameters to assess the causal factors for odour production. These metabolites will be measured with GC-MS.
· The capacity of bio films to transform organic matter from natural or man made sources is based mainly on the enzymatic machinery of the complex microbial consortia making up these bio films. The transformation and detoxification of key compounds will be tested using bio films and an existing test battery of photometric and fluorometric methods.
· The microbial consortium of the bio film is highly responsive to variable exposure to natural products and toxicants. Changes in various stages of the processing of surface water into drinking water will be described using genetic methods (DGGE). For selected classes of hygienically relevant bacteria (enterococci, Mycobacterium, Legionella) genetic probes are used.
· The transformation rate of the cyan toxin microcystein through bio films is measured in experiments. Microsystein is determined using HPLC with PDA detection. To estimate the health risk of transformation products of organic compounds formed in contact with bio films an existing test battery for cytotoxity, hepatotoxicity and immunotoxicity will be applied. All these biological processes in bio films are studied in conjunction with management problems of drinking water companies in four countries and are actually carried out at drinking water facilities. The observations (made under 2-8) will be expressed in process-kinetic terms (1). These process formulations are basic to adapted practices for drinking water companies.
Expected impacts
The project will result in a coherent concept on bio films functioning as conditioner for water quality. This functioning is expressed in quantitative terms as calculation routines (dynamic model) that are likely to find widespread application at European drinking water companies. Also, the close observations of very relevant variables such as DOC, cyan toxins, odorous compounds, toxicants and transformation products and hygienically important bacteria is likely to help finding detailed solutions for water quality problems. At several stages of the project the research is expected to induce adapted procedures at the drinking water facilities.

Drinking water companies in Europe have installed sophisticated treatment facilities to prepare drinking water from moderate quality surface water. However, the quality of the 'raw' water remains important, because increasing urbanisation enhances the load of pathogens and substances with suspected hormonal, mutagenic or other health risks. Shortage of water, especially in the Mediterranean countries, implies that surface water of any quality is to be exploited.

In view of these problems it is imperative for the drinking water sector to improve environmental technologies increasing water quality prior to treatment. Biofilms are sites of biological activity, that abound in all natural rivers and lakes, as well as in all stages of the drinking water system. The aim of the research planned is to develop the knowledge needed to exploit biofilms upstream of the water plant and to optimise their capacity to regulate organic matter content in water, to retain noxious compounds and to trap potential pathogens.

Expected impacts
The project will result in a coherent concept on biofilms functioning as conditioner for water quality. This functioning is expressed in quantitative terms as calculation routines (dynamic model) that are likely to find wide-spread application at European drinking water companies. Also, the close observations of very relevant variables such as DOC, cyanotoxins, odorous compounds, toxicants and transformation products and hygienically important bacteria is likely to help finding detailed solutions for water quality problems. At several stages of the project the research is expected to induce adapted procedures at the drinking water facilities.

Call for proposal

Data not available

Coordinator

UNIVERSITEIT VAN AMSTERDAM
Address
Kruislaan 320
1098 SM Amsterdam
Netherlands
 

Participants (3)

INSTITUTE OF BOTANY - ACADEMY OF SCIENCES OF THE CZECH REPUBLIC
Czechia
Address
Zamek 1
252 43 Pruhonice
 
UNIVERSITAT DE BARCELONA
Spain
Address
645,Avinguda Diagonal 645
08028 Barcelona
 
WFM-WASSERFORSCHUNG MAINZ GMBH
Germany
Address
41,Rheinallee 41
55118 Mainz