POTABLE WATER QUALITY CONTROL
Physical and Chemical Control
|
|
The quality control of the potable water, for the protection of Public Health, is carried out at the Water Supply Laboratory of E.Y.A.Th S.A., in conformity to the sanitary legislation Õ 2/2600/2001 (Gov. Gazette 892/11.7.2001), in compliance to the directive 98/83 E.C. of the European Community Council on the “quality of water for human consumption”, and the Ministerial Ordinance G3 á /761/6.3.68 (Gov. Gazette 189/volume II/1968).
For a more efficacious Public Health protection, the water quality control is carried out through samplings from the water supply system. |
Specifically :
- In conformity to the new directive are examined at the Laboratory test, on a daily basis and during the entire year length, samples from the sources water intake and the distribution network for parameters like odor, taste, turbidity, colour, pH, conductivity, ammonium, aluminum and micro-organisms.
- In an annual program, a controlling monitoring of the water is performed. Among others, are checked the parameters concerning heavy metals and organic compounds (pesticides, chlorination by-products, etc). Analyses are carried out on about 100 samples, annually, during control monitoring, originating from the water intakes (Aravissos sources, Aliakmon refinery, water-bores) and from the distribution network.
- Also, during the supplementary monitoring, which is carried out at least twice annually on samples from the urban network and the intake sources, analyses are carried out for other parameters, like mineral oils, detergents, phenols, other heavy metals, etc, pathogenic bacteria and parasitic organisms.
Sanitary control – Microbiologic examination
A very important factor for the suitability of the potable water is the fact that the potable water should not contain, among others, pathogenic microorganisms. For this reason, systematic sanitary controls and identifications are carried out at the water intakes and the distribution network.
The Water Supply Laboratory carries out microbiological analyses on about 2000 samples, annually, which include examinations on the total bacteria at 22? and 37? C, the total coliforms and Escherichia coli number. The samples originate from points of the distribution network and points where the water is put at the consumers' disposal.
Disinfection
The disinfection of the potable water with chlorination is imposed by the sanitary legislation ÕÌ 5673/4.12.57 (Govern. Gazette 5/ vol . II /9.1.58) “on disinfection of the water of water supply” for an efficacious protection of Public Health and securing the water quality from microbiological and sanitary prospect
The disinfection is a measure for the maintaining of hygienic conditions, it fights off pestilential diseases and the formation of a biologic mass on the internal walls of the conveyance and distribution network ducts.
There are many disinfection methods, among which chlorination is a universally applied method, till this day. Chlorination is carried out at the central treatment installations and at points where the water is put at the consumers disposal, from the central pump stations. The main chlorine form being used is the anhydrous liquid chlorine (chlorine gas). |
|
 |
The disinfection of the distribution network of the Thessaloniki urban compound is daily controlled by the Water Supply Laboratory, measuring the residues of free chlorine at about 70-80 points of the distribution network. The presence of residual chlorine is continuous and a minimal concentration level of 0,2 ppm ( or mg / l ) is detected in the entire network till its extreme points
Water control using electronic microscope.
The only electronic microscope existing in Greece , measures the water content in asbestos fibers and operates at the Electronic Microscopy Laboratory of the Aristotle University of Thessaloniki. The Laboratory represents a social offering of the University and cooperates with many BODIES in Greece and abroad.
E.Y.A.Th. cooperates with the Laboratory and has under development a program of permanent water monitoring on a daily basis. E.Y.A.Th. is determined to invest continuously on the subject of water control.
Water pipe-lines control in cooperation with the Aristotle University of Thessaloniki.
The good quality of the materials used for the construction of the water supply ducts is an essential precondition for securing the Public Health. For this reason, E.Y.A.Th. has initiated a cooperation with the Scanning Microscope Laboratory of the Aristotle University of Thessaloniki and started its efforts for the creation of a data base, for the quality features of the manufacturing materials of the pipes it respectively uses and acquires.
Five years ago, the Scanning Microscope Laboratory made a study on asbestos-cement pipes of the E.Y.A.Th. network, which shows that in the first 56 days after their installation, they get covered a thin layer of carbonic calcium, fact that equalizes the quality of the transiting water with the quality of water passing through pipes made of marble.
In the present stage of the water supply network extension, E.Y.A.Th. uses plastic, metallic and rarely asbestos-cement pipes. For this reason, the establishment of a data base started with the study of metallic pipes, in two directions. First, for the verification of the degree of oxidation in used pipes and in continuation, by examining the material from the angle of composition and homogenization of the material during the casting stage. The analysis and photographing of the material and in continuation its comparison with international catalogues will offer E.Y.A.Th. the possibility to control the offered pipes and to foresee eventual faults.
