Water is a unique raw material, the foundation for spiritual and human development. Since this substance is a valuable natural resource, plays a role in metabolic processes, determining the color of water is an important parameter in the analysis of its quality.
Significance of Water Quality Analysis
Man is an element of the biosphere. The main resources - water, food, air - people get from the biosphere. Accumulating and dumping industrial and household waste, for a long time people upset the equilibrium of the biosphere.
What are the consequences
Such processes lead to the fact that organoleptic and physical indicators change significantly (the color of the water changes, an unpleasant odor appears), the quantitative content of chlorides, sulfates, toxic heavy metals, nitrates increases, the amount of air oxygen in the water decreases, pathogenic bacteria and radioactive elements appear.
Direct contact and the use of contaminated water can lead to serious problems. A variety of parasites penetrate the skin, can provoke serious diseases. Currently, the risk of epidemic diseases is increasing: cholera, dysentery, typhoid fever.
In order to stop the spontaneous development of such events, it is necessary to carry out special treatment of water from the water supply system, wells.
Major pollutants
There are about four hundred different types of substances that can cause pollution, affect the color of water, reduce its organoleptic characteristics. Exceeding the permissible norm of the following indicators is possible:
- organoleptic;
- general sanitary;
- toxicological.
In this case, the water is considered contaminated, unfit for consumption. It cannot be used without prior cleaning.
Among the chemical compounds that can affect the color of water, it is necessary to mention oil and its many products, surfactants (surfactants), heavy metals, pesticides, dioxins.
Biological components (viruses and pathogens) and physical (radioactive compounds) pollute water substantially.
Pollution factors
The determination of color and turbidity of water is carried out to analyze its suitability for use. Among the factors that negatively affect the quality of surface waters, note:
- discharge of untreated effluents into water bodies;
- flushing with rainfall pesticides;
- leakage of oil products and oil;
- gas and smoke emissions.
In addition to surface waters, groundwater is also systematically polluted, in particular, near large industrial centers. Penetrate harmful compounds in a variety of ways:
- seepage from household and industrial wastewater storage facilities;
- through pipes of faulty wells;
- from storage ponds.
Among the natural sources of pollution, underground mineralized or seawater is introduced into the uncontaminated fresh water sources during the operation of water intake facilities, as well as during pumping of water from functioning wells.
Impurities that degrade quality
The color index of water allows you to identify some impurities that adversely affect its quality. For example, insoluble emulsions, suspensions, which are suspended in water, give a similar effect. Their presence is evidence of contamination of the water source by algae, sand, clay.
Also, the color of the water is affected by organic compounds: particles of soil humus, decomposition and vital products of animals and plant organisms.
Analyzing the sources of deterioration in water quality, one cannot ignore the compounds of technogenic origin: fats, organic acids, phenols, proteins, viruses, carbohydrates. GOST "Water. Methods for the determination of color" defines the requirements for sampling water selected for research. It also regulates the basic principles and procedures.
The color and turbidity of drinking water is associated with microorganisms: viruses, bacteria, plankton. The increase in turbidity is evidence of contamination, the inability to use for drinking and household purposes.
Organic substances can give water certain odors: putrefactive, earthy, fishy, marsh, oil, pharmacy, increase its color, adversely affect the human body.
Due to microorganisms, the risk of cholera, dysentery, typhoid, poliomyelitis is significantly increased, so it is important to determine the color of water. The analysis methods currently in use make it possible to identify various pathogens with a high degree of probability and to carry out timely and high-quality water purification.
Quality requirements
What is the color of water? SanPin's norm for this indicator is 20 degrees. By this parameter is meant its color caused by substances dissolved in it. Among the main components that cause a color change, humic acids and various iron compounds are distinguished.
Determining the color of water is an important component of a comprehensive physico-chemical analysis, the purpose of which is to determine the suitability of drinking water for use. This indicator is determined on a platinum-cobalt color scale of the solution.
What is important to know
Drinking and household water should be absolutely harmless to humans, have high sanitary, chemical, physical indicators. That is why GOST was developed. The color of water, its smell, turbidity - these parameters are mandatory elements that are analyzed in the framework of laboratory research.
If the water has an initial turbidity, and after prolonged settling, it brightens, therefore, it contains an increased amount of clay and sand. What are the requirements for this indicator GOST? The determination of color, turbidity, odor is carried out in accordance with the standards specified in SanPin. For example, due to turbidity, there is the following requirement - this indicator should not be more than 1.5 mg of suspended particles per 1 dm 3 of water.
Acidity
It is determined by pH. Depending on its value, water can be alkaline or acidic. The optimal pH is SanPin pH in the range of 6-9.
Hardness of water
This indicator is important for analysis. It characterizes the presence of magnesium and calcium salts in water. If the quantitative content of these cations exceeds normal values, the water is considered hard (according to SanPin, a limit of 7 mmol / l is set).
Allocate temporary and permanent stiffness. The latter indicator is otherwise called non-carbonate, and the first option - carbonate. Hard water makes electrical appliances unusable, causes dry skin and hair, and contributes to urolithiasis. The following methods are used to remove it: boiling, the addition of drinking soda (sodium bicarbonate).
The methods of purification of drinking and household water are selected taking into account its initial indicators, identified in the framework of laboratory research.
Cleaning options
In our time of industrial progress, wastewater emissions to water from industrial plants have increased significantly. There was an urgent need for their processing in order to destroy or remove harmful substances of organic and inorganic nature.
Wastewater acts as a raw material, and the purified product is its finished product. Cleaning-related measures are usually divided into two groups: destructive, regenerative. In the first case, we are talking about the destruction of pollutants. Those products that are formed after cleaning are removed in a gaseous form or remain in water without harming living organisms.
The essence of regenerative methods consists in wastewater treatment, as well as in the disposal of harmful substances generated in waste. Nowadays, the following water treatment methods are used:
- hydrochemical;
- mechanical;
- electrochemical;
- biological;
- physical and chemical.
When combined, several techniques at once are talking about combined water treatment. The choice of method depends on the nature and degree of contamination, as well as on the chemical composition of the impurities present.
Mechanical cleaning involves the removal by filtering of mechanical impurities. Large particles are captured by sieves, gratings, septic tanks, sand traps of various designs. Surface impurities are removed from water samples by sedimentation tanks, oil traps, oil traps.
Thanks to mechanical cleaning, more than 70% of insoluble impurities can be removed from wastewater, and many of them are then additionally used in chemical production.
The chemical method is to add certain chemical compounds to the wastewater. They, interacting with impurities, precipitate them in the form of a precipitate. Thanks to this cleaning method, it is possible to reduce the percentage of insoluble impurities in wastewater to 80%, soluble to 25%.
Hydromechanical methods are used in cases where it is necessary to extract insoluble coarse dispersed inorganic and organic species from wastewater. To do this, filtering, settling, centrifuging, filtering using structural materials and devices. For example, centrifuges, sumps, grids, sieves, hydrocyclones are used.
Water Analysis Terms
SanPin uses the following notation:
- MPC - maximum permissible concentration;
- ODE - approximate acceptable level of connections;
- Hazard Class.
According to regulatory documents, the following hazard classes are distinguished:
- 1K (the most dangerous elements);
- 2K (high hazard substances);
- 3K (hazardous substances);
- 4K (moderate hazard compounds).
Also in the analysis of water samples, an indicator such as toxicity is taken into account. In the group of organoleptic indicators, the following notations are used:
- ZAP - a substance with a smell;
- OCD - the presence of an element staining water;
- OP is a compound that causes opalescence.
To summarize
Water is the most important chemical compound, without which the full-fledged existence of man, his industrial activity is impossible. Depending on the quantitative content of microorganisms in drinking, wastewater, household water, as well as heavy metal cations, we can talk about its suitability (unsuitability) for use, and select effective treatment technologies.