Control of water quality

Water characterized by composition and properties which determine its convenience for the concrete types of water consumption. The estimation of water quality is given on signs, elected and rationed depending on the type of water consumption. One of water indexes is considered as limiting. For limiting sign is elected those which is characterized the least harmless concentration of matter in water. The total numerical estimation of water quality is given on an index which is the aggregate of basic indexes by the types of water consumption. Quality, composition and properties of water in reservoirs is regulated by hygienic requirements and sanitary norms.

For the hygienic evaluation of water such indexes are used (табл.3.З):

· a mass of hangings up matters;

· a mass of floating matters;

· a temperature;

· a hydrogen index of ;

· a mineral composition;

· a soluble oxygen;

· a biologically complete consumption of oxygen ();

· a chemical consumption of oxygen (CCO);

· a presence of diseases exciters;

· an amount of lactone-positive intestinal sticks (LIS);

· an amount of kaliphag in thrombus-constitutive units;

· a presence of viable eggs of helminth and simplest intestinal bacteria;

· an amount of chemical matters.

Table 3.3 − Hygienic requirements in relation to composition and properties of water

Indexes of composition and properties of water	Category of water consumption
for an economic-drinkable water-supply	for bathing, sport and rest of population
Hangings up matters	Maintenance of hangings up matters must not be increased more than on:
0,25	0,75
Floating admixtures	On a surface of reservoir must not be floating tapes, the spots of mineral butters and accumulations of other admixtures
Smells	Water must not acquire unusual its smells by intensity an over 1 mark
Color	Must not appear in a column
20 cm	10 cm
Temperature	Summer temperature of water as a result of lowering of sewages must not rise more than on 3°С comparatively with average monthly temperature
Hydrogen index	6,5	8,5
Mineral composition	Must not exceed by the dry remain of 1000 , in the that number of chlorides − 350 , sulfates are 500
Soluble oxygen	Must not be less than after 4 of any period of the year in a test, taken at 12 o'clock of day
Exciters of diseases	Water must not contain the exciters of diseases

Such indexes are utilized for the sanitary evaluation of water as:

• maximum possible concentrations of matters in water;

• orientation possible levels of matters in water (OPL);

• limiting the signs of harmfulness (sanitation-toxicological, pantosanitary, organoleptic with decoding of its properties: smell, influence on a color, formation of suds and tape, infusion of taste).

Chemical matters in water are divided into four classes of danger: I class − extraordinarily dangerous; II class − high-dangerous; III − dangerous; IV class − reasonably dangerous.

Ascription harmful matters to the class of danger depends on their toxicity, shaped-charge, capability to cause remote effects, the type of limiting index of harmfulness (табл.3.4).

Table 3.4 − Maximum possible concentrations of harmful matters in water of water objects household, cultural and welfare water use

Name of matters	Class of dangerous	Maximum possible concentration mg/l
Ammonia (by nitrogen)	III	2,0
Active chlorine	III	Absents
Acetone	III	2,2
Benzol	II	0,5
Cadmium	II	0,001
Cobalt	II	0,1
Manganese	III	0,1
Copper	III	1,0
Oil products	IV	0,1
Nitrates	III	45,0
Nitrites	II	3,0
Mercury	III	0,0005
Lead	II	0,03
Turpentine	IV	0,2
Phenol	IV	0,001
Chrome	III	0,05
Zinc	III	1,0

Except of state control, the state of water is controlled by enterprises which utilize water and throw down flows to the reservoirs. For this purpose posts, equipped a necessary apparatus for conducting of analyses, are created on enterprises at factory or special laboratories.

During conducting of control of waters state and flows physical, chemical, biological and organoleptic methods are utilized.

Physical methods are utilized for determination of transparency, lees, amount of hangings-up particles and conductivity of water and flows. Amount of hangings-up particles is determined by diaphragm and paper filters through which skipped test of volume 100...500 ml. Transparency, lees are determined by devices or by organoleptic comparison of specimens.

Chemical methods are utilized for determination of acidity, alkali of metals, salts, organic and synthetic matters in water.

A bacterial analysis is executed by the special methods in the laboratories of the sanitary epidemiology stations. Control of muddiness by a help of bacteria − biotesting deserves on attention. Some bacteria at appearances of pollutions begin to shine. The larger toxic matters in water, the bacteria shine stronger.

Дата добавления: 2015-10-31