Research project NM/A/10 (Research action NM)
CONTEXT
In Belgium, 15 to 30% of the buildings will not be connected to a collective wastewater treatment plant. The water of these buildings will have to be treated by small wastewater treatment plants. This solution is however only acceptable as far as one can be sure of the purification performance of the plants. The question arises whether the methods proposed by CEN do give reliable results.
THE PROJECT
In the European draft standard prEN 12566-3 "Small wastewater treatment systems (< 50PE) Part 3 -Packaged and/or site assembled domestic wastewater treatment plants", the fitness for use is evaluated on base of:
- a one year lasting test of the purification performance, done on a test platform or on site;
- an evaluation of the mechanical stability by testing the tank in laboratory or by calculation after verification of the material characteristics.
Concerning this approach the following comments can be made:
- There is no evidence that the purification results obtained in the lab will be confirmed by those on the site, as there is no validation of the tests.
- The purification tests, both on site and in a lab, are cumbersome and costly. Certain tests have to be repeated unnecessary and seem to be too complicated. The question arises whether the purification tests could not be simplified and whether they are realistic.
- The prEN proposes alternative tank tests, without indicating how to correlate the results of the different tests.
These comments lead to the establishment of the research aims:
- to validate, improve and simplify the fitness for use evaluation procedures of the draft European standard;
- to develop a purification test allowing to know rapidly whether a given plant has a chance to pass the long duration test of the prEN.
In order to realise these objectives, the research foresees the following steps:
1. To make operational a test platform (BBRI, CEBEDEAU and VITO)
This task comprises:
- the analysis of the prEN and of the documents upon which this draft standard relies;
- the conception of a test platform;
- the construction of the platform;
- getting the test rig into operation.
2. Determination of the treatment efficacy of some commercial treatment systems on the test platform (BBRI, CEBEDEAU and VITO)
As, within this task, the aim of both BBRI and VITO is to try to validate and improve the prEN test method, they proceed as follows:
- identification and choice of the plants to be tested. They opted for an active sludge system and for a submerged aerated filter (SAF);
- measuring the treatment efficacy of the considered systems evaluating meanwhile the prEN procedure.
CEBEDEAU follows also the working of a SAF, fed according to prEN, however monitoring the more closely the microbiological activity, in order to gain a better insight in the evolution of the base parameters of the system over time.
3. On site determination of the treatment efficacy of small wastewater plants (BBRI, FUL, VITO)
This task comprises:
- establishing a protocol for the on site monitoring;
- selection, equipment and monitoring of a number of sites.
In this task also, a distinction has to be made between the work of both BBRI and VITO and the one of FUL. For BBRI and VITO, it is to collect data allowing validating the tests on platform, while the FUL will especially focus on developing an appropriate “on site sampling routine”.
4. Evaluating the mechanical stability of the tanks of the plants (BBRI)
This task involves:
- an analysis of the methods proposed in the draft standard;
- the measurement of the deformation of some plastic tanks;
- the development of a stability assessment method based on calculation.
5. Drafting a procedure for assessing the fitness for use of small wastewater treatment plants (BBRI, CEBEDEAU, FUL and VITO).
THE PARTNERS
This research is conducted by 4 Belgian laboratories:
- CEBEDEAU (Centre Belge d’Etude et de Documentation de l’Eau),
- FUL (Fondation Universitaire Luxembourgeoise),
- VITO (Vlaamse Instelling voor Technologisch Onderzoek),
- CSTC (Centre Scientifique et Technique de la Construction).
EXPECTED PRODUCTS AND RESULTS
The results of the first year of research permitted to formulate a whole list of comments and modifications for the draft European standard. These proposals will be discussed at the June 2002 meeting in Helsinki of the working group CEN TC 165 WG 41, in charge of the standard. The first year results will thus already allow to improve the European draft standard.
USERS COMMITTEE
Establishing the quality the wastewater has to have before discharge in the environment, is of the competence of the regional authorities, while imposing requirements onto products is a federal competence. The users committee involves then as well delegates from the federal as from the regional administrations, besides a certain number of experts:
- G. Nelissen (The Federal Public Service Mobility and Transport)
- L. De Backer (The Flemish environmental agency)
- T. Gabriëls (The Flemish environmental administration)
- E. Halleux and J-P. Piret (The ministry of the Walloon region)
- M. Lemineur (The Namur inter-municipal public services agency)
- M. Lichosiek (The Brussels agency for environmental management)
- K. Rausch (The municipality of Bierbeek)
PROMOTERS
Karel DE CUYPER
Centre Scientifique et Technique de la Construction
Boulevard Poincaré 79
B-1060 BRUXELLES
Tel: +32 2 655.77.11
Fax: +32 2 653.07.29
E-mail: karel.de.cuyper@bbri.be
Jean-Luc VASEL
Fondation Universitaire Luxembourgeoise
Avenue de Longwy 185
B-6700 ARLON
Tel: +32 63 23.08.49
Fax: +32 63 23.08.00
E-mail: vasel@ful.ac.be
Stéphane NONET
Centre Belge d’Etude et de Documentation sur l’Eau A.S.B.L.
Rue Armand Stévart 2
B-4000 LIEGE
Tel: +32 4 252.12.33
Fax: +32 4 254.03.63
E-mail: snonet@cebedeau.be
Karen VANDERSTRAETEN
Vlaamse Instelling voor Technologisch Onderzoek
Boeretang 200
B-2400 MOL
Tel: +32 14 33.69.10
Fax: +32 14 32.65.86
E-mail: karen.vanderstraeten@vito.be
Fitness for use evaluation of small (<20PE) domestic wastewater treatment plants : final report
Brussels : Federal Science Policy, 2005 (SP1470)
[To download]
Fitness for use evaluation of small (<20PE) domestic wastewater treatment plants : annexes
Brussels : Federal Science Policy, 2005 (SP1471)
[To download]
