Water is a unique raw material, the foundation for spiritual and human development. Since this substance is a valuable natural resource, plays an important role in metabolic processes, the determination of water color is an important parameter for analyzing its quality.
The importance 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 disturb the balance of the biosphere.
What are the consequences
bacteria, radioactive elements.
Direct contact and drinking contaminated water can lead to serious problems. Diverseparasites penetrate the skin, can provoke serious diseases. Currently, the danger of epidemic diseases is increasing: cholera, dysentery, typhoid fever.
In order to stop the spontaneity of the development of such events, it is necessary to carry out special treatment of water from the water supply system, wells.
Main pollutants
There are about four hundred different types of substances that can cause pollution, affect the color of water, and reduce its organoleptic characteristics. It is possible to exceed the permissible norm of the following indicators:
- organoleptic;
- general sanitary;
- toxicological.
In this case, the water is considered polluted, unfit for consumption. It cannot be used without first 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), physical (radioactive compounds) significantly pollute water.
Pollution factors
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 are:
- discharge of untreated sewage into water bodies;
- rainfall washoutpesticides;
- leakage of oil products and oil;
- gas and smoke emissions.
In addition to surface water, underground water is also systematically polluted, in particular, near large industrial centers. Harmful compounds penetrate in a variety of ways:
- leakage from domestic and industrial effluents;
- through pipes of faulty wells;
- from storage ponds.
Among the natural sources of pollution are underground mineralized or sea waters introduced into unpolluted fresh sources during the operation of water intake facilities, as well as during the pumping of water from functioning wells.
Quality degrading impurities
The color index of water allows you to identify some impurities that adversely affect its quality. For example, insoluble emulsions, suspensions that are suspended in water give a similar effect. Their presence is evidence of contamination of the water source with algae, sand, clay.
Organic compounds also affect the color of water: particles of soil humus, decomposition products and vital activity of animals and plant organisms.
When analyzing the sources of water quality deterioration, one cannot ignore the compounds of technogenic origin: fats, organic acids, phenols, proteins, viruses, carbohydrates. GOST "Water. Methods for determining color" defines the requirements for sampling water selected for research. It also regulates the mainprinciples and procedures.
The color and turbidity of drinking water is associated with microorganisms: viruses, bacteria, plankton. An increase in turbidity is evidence of contamination, impossibility of use for drinking and household purposes.
Organic substances can give water certain odors: putrefactive, earthy, fishy, swampy, oily, pharmaceutical, increase its color, adversely affect the human body.
Due to microorganisms, the risk of cholera, dysentery, typhoid, poliomyelitis is significantly increased, which is why it is so important to determine the color of water. The methods of analysis currently used make it possible to identify various pathogens with a high degree of probability, to carry out timely and high-quality water purification.
Quality requirements
What is the color of water? The SanPina norm for this indicator is 20 degrees. This parameter refers to its color caused by the substances dissolved in it. Among the main components that cause discoloration are humic acids, as well as various iron compounds.
Determining the color of water is an important component of a comprehensive physical and chemical analysis, the purpose of which is to determine the suitability of drinking water for use. This indicator is determined according to the platinum-cob alt color scale of the solution.
What is important to know
Drinking and household water should be absolutely harmless to humans, havehigh sanitary, chemical, physical indicators. That is why GOST was developed. The color of water, its smell, turbidity - these parameters are mandatory elements analyzed in laboratory studies.
If the water has an initial turbidity, and after a long settling brightens, therefore, it contains an increased amount of clay and sand. What are the requirements for this indicator GOST? Determination of color, turbidity, smell is carried out in accordance with the standards specified in SanPin. For example, for turbidity, there is the following requirement - this indicator should not be more than 1.5 mg of suspended particles per 1 dm3 of water.
Acidity
It is determined by the pH value. Depending on its value, water can be alkaline or acidic. The optimal pH value according to SanPin is in the range of 6-9.
Water hardness
This indicator is important for the analysis. It characterizes the presence of magnesium and calcium s alts in water. If the quantitative content of these cations exceeds normal levels, the water is considered hard (according to SanPin, the limit is 7 mmol / l).
Allocate temporary and permanent stiffness. The latter indicator is otherwise called non-carbonate, and the first option is called 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, adding baking soda(sodium bicarbonate).
Methods for the purification of drinking and domestic water are selected taking into account its initial indicators, identified in laboratory studies.
Cleaning options
In our time of industrial progress, wastewater emissions into water bodies from industrial plants have increased significantly. There is an urgent need to process them in order to destroy or remove harmful substances of organic and inorganic nature.
Waste water acts as a raw material, and its purified streams are the finished product. Cleaning activities 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 gaseous form or remain in the water without harming living organisms.
The essence of regenerative methods is the treatment of wastewater, as well as the disposal of harmful substances generated in waste. Today, the following methods of water neutralization are used:
- hydrochemical;
- mechanical;
- electrochemical;
- biological;
- physical and chemical.
When combined, several methods are talking about combined water purification. 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 of mechanical impurities by filtering. Large particles are captured by sieves, gratings, septic tanks, sand trapsvaried designs. Surface impurities are removed from water samples by settling tanks, oil traps, oil traps.
Due to mechanical treatment, 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 consists in adding certain chemical compounds to wastewater. They, interacting with impurities, precipitate them in the form of a precipitate. Thanks to this purification method, it is possible to reduce the percentage of insoluble impurities in wastewater up to 80%, soluble - up to 25%.
Hydromechanical methods are used in cases where it is necessary to extract insoluble coarse impurities of inorganic and organic type from wastewater. For this, filtering, settling, centrifugation, filtration with the help of structural materials and devices is performed. For example, centrifuges, settling tanks, screens, sieves, hydrocyclones are used.
Terms in water analysis
SanPin uses the following designations:
- MAC - maximum allowable concentrations;
- TAD - indicative allowable level of connections;
- hazard class.
According to regulatory documents, the following hazard classes are distinguished:
- 1K (most dangerous elements);
- 2K (substances of high danger);
- 3K (hazardous substances);
- 4K (moderate hazard compounds).
Also, the analysis of water samples takes into accountsuch as toxicity. In the group of organoleptic indicators, the designations are used:
- ZAP - a substance with a smell;
- OKR - the presence of an element that colors water;
- OP is a compound that causes opalescence.
Summarize
Water is the most important chemical compound, without which the full existence of man, his industrial activity is impossible. Depending on the quantitative content of microorganisms in drinking, waste, utility water, as well as heavy metal cations, we can talk about its suitability (unsuitability) for use, select effective treatment technologies.
