Chemical analysis of wastewater

Sampling and preparing them for analysis.

Since sampling
produced by hand, the quantity
places of constant control should be
as small as possible.

First point
control - selection of incoming for cleaning
waste water .

Selection is made
in collection duct or chamber after gratings
(you can take it in front of the bars, but in this
case, large suspensions distort the analysis
for suspended solids).

Second point
– clarified water after primary
settling tanks - characterizes the composition
wastewater after mechanical treatment
.

Third point
- after aeration facilities (aerotanks
, biofilters ) .

fourth point
— after secondary clarifiers, before
release water in a pond . In the presence of
post-treatment and disinfection facilities
purified water, sampling is required
after these facilities.

Sampling is done
at a depth of 0.5 m from the surface of the water.

Places for a fence
samples should have convenient approaches or
entrances and be illuminated.

Sampling errors
are not allowed because in the course of their analysis
fix is ​​impossible.

Correctness of selection
samples are determined:

place of selection;

periodicity
selection;

sample volume ;

vessel quality
for sampling.

Sampling frequency
— serial selection (selection every hour,
then mixing all samples and determining
average daily sample ) . This is applicable
not for all analyses. Sample volume depends
from the number of its components that you need
determine (for a complete analysis - 5 l,
for dissolved O₂
- 100 ml). The sampling vessel must
be of colorless resistant glass with
rubber or ground stoppers.
Dishes should be well washed
degreased (SMS or chrome mixture),
washed with distilled water and
dried.

Sample analysis
produced immediately after selection. If
sample storage is necessary, then it is stored
in the refrigerator (1 ... 3 C
) in a sealed container during the day .
Samples intended for determination
permanganate, bichromate oxidizability
, as well as various forms of nitrogen, canned
, adding 2 ml of 25% H to 1 liter of sample₂SO₄
.

Complete
or abbreviated chemical analysis.

With complete chemical
analysis (1 time per decade in the average daily
sample ) determine:

temperature,
color, smell, pH, transparency,
mass and volume of settled and suspended
substances, the amount of dense residue
taking into account losses on ignition,
amount of nitrogen (total, ammonium,
nitrite, nitrate) dichromate
oxidizability (COD) , BOD₅
, BOD_FULL
, the amount of dissolved oxygen
, chlorides, sulfates, heavy metals (
Fe
, Cu
, Cr
, Zn
, Pb
, Ni
etc. ) , phenols , cyanides , sulfides ,
Surfactants, ether-soluble substances,
petroleum products , free chlorine .

In addition to chemical
wastewater analysis is carried out:

bacteriological
(saprophytes, Coli
, pathogenic microorganisms ) ;

radiological
analysis (determination of radioactive
background of water and precipitation);

helminthological
analyses.

With reduced
chemical analysis of wastewater determine
:

temperature ;

transparency;

pH;

WITH_SVZ
, WITH_PROC
;

BOD₅
; COD ; O₂
.

Concepts and regulation

Before considering the issue of analysis, it is necessary to clearly define what wastewater is. Wastewater is all types of water, the properties of which have been degraded by use in production or as a result of other human activities. All these liquids are discharged into water bodies from enterprises or settlements directly or in the form of precipitation.

Wastewater analysis is aimed at accurately determining the presence of harmful substances and elements in it. Such activities can be aimed at various sources of possible pollution:

1. Production facilities.
2. Household or common sewer system.
3. Surface sewer systems that collect precipitation, melting snow.

What is the analysis for:

1. Determining the degree of pollution as a result of the enterprise's activities.
2. Evaluation of the effectiveness of the functioning of filtering and treatment facilities.
3. Development of an action plan for water treatment.

Analytical activities can only be carried out by licensed specialists who have at their disposal a full range of necessary equipment. The scope of activities for laboratory examination of the composition of effluents is strictly regulated. Instructions for sampling for wastewater analysis have been developed and adopted for use.

Despite the fact that it has been used for a long time, its main requirements meet modern realities. The instructions contain comprehensive information about the tasks of sampling, places of its performance, types, frequency (formula for calculating the timing), requirements for equipment and storage containers.

Important rules for sampling wastewater for analysis:

1. The collection is carried out in well-mixed flows, where the concentration of discharges will be as informative as possible.
2. The place of obtaining samples is determined depending on the tasks.
3. Simple, mixed, medium mixed selection can be used. A simple sample is taken in a "pure" form on the spot at a specific point in time. Mixed - several samples are combined at certain intervals.

Sources

• https://vodakanazer.ru/kanalizaciya/analiz-stochnyx-vod.html
• http://oskada.ru/analiz-i-kontrol-kachestva-vody/analiz-kanalizacionnoj-vody-stochnyx-vod.html
• http://fb.ru/article/185826/analiz-vodyi-stochnyih-vod-kogda-on-neobhodim
• http://VtorOthodi.ru/ecology/analyz-stochnyih-vod
• http://oskada.ru/analiz-i-kontrol-kachestva-vody/analiz-stochnyx-vod-predpriyatiya.html
• https://vodospec.ru/stochnye-vody/analiz-stochnoj-vody.html

State regulation of water balance

There are a number of GOSTs adopted at the state level for the quality of drinking water, as well as norms for effluents and maximum allowable concentrations of pollutants.

When carrying out production activities, water management passports are developed, including to take into account risk factors: they take into account not only the balance of water consumption and water disposal, sources of water supply, but also possible pollutants, as well as their maximum permissible concentrations and methods of purification.

Wastewater analysis is a must when conducting economic activities, as well as for enterprises involved in water treatment: they need to periodically check the quality of the effluents entering the treatment plant.

Dry residue

Its value is determined by analyzing an unfiltered sample. This indicator informs about the amount of impurities present in water, both suspended (scale, ore, coke, limestone, etc.) and dissolved. Depending on the content of these impurities, all industrial effluents are divided into 4 categories:

• the first - the value of the dry residue is less than 500 mg / l (this includes municipal wastewater);
• the second and third categories are separated by an indicator of 5000 mg / l;
• the fourth - more than 30,000 mg / l.

Identified suspended impurities can be removed by mechanical cleaning methods. The simplest of them is elementary settling.

The need to identify dry residue is important because industrial effluents require treatment using bacteria (biological treatment). In addition, at this stage, the amount of suspended solids cannot exceed 10 g/l. Otherwise, cleaning will not achieve the required efficiency.

It is more accurate to say that we are not talking about dry, but about dense residue, which is the amount of solids contained in the filtered sample.

What is the concept of wastewater

Wastewater from a private house, by general definition, is water polluted by human activities, as well as water that penetrates into the ground as a result of precipitation.

Once in the ground, wastewater can change the composition of groundwater that we use as drinking water. Water can acquire an unpleasant odor, the purity of the water changes, i.e. various impurities and sediment may appear in it. In addition, the chemical composition of water also changes.

The nature of groundwater pollution can be divided into the following types:

• Mechanical - when the wastewater contains a high content of insoluble particles;

Chemical - involves the content in wastewater of products of organic and inorganic origin, both toxic and non-toxic;
Biological and bacterial - when various pathogenic microorganisms, algae and fungi are present in wastewater;
Radioactive - the presence of radioactive substances in wastewater (this most likely does not apply to private ownership).

Contaminated wastewater poses a health hazard not only to the owner of the site, but also to neighboring sites.

At present, it is possible to carry out any analysis and take all measures to treat wastewater, while maintaining not only your health, but also the environment.

How sampling is done

If the check is not planned and is not done by state control bodies, then sampling is your responsibility. To do this, you need to do the following:

• Find a clean glass or plastic container with a volume of at least 1 liter. Rinse thoroughly with tap water. So you exclude the possibility of accidental ingress of substances and bacteria that can distort the true results of the tests.
• If bacteriological analysis will be carried out, then the water container must be sterile with an airtight lid. Usually such containers can be taken in the laboratory, where you will do the test.
• Before taking a water sample, rinse the sample container with this liquid.
• The container must be filled almost to the top, leaving a small gap between the water level and the lid.
• Water samples should be delivered to the laboratory within two hours. At the same time, try to transport the sample not in a warm place and not in the sun.

How wastewater is tested and by whom

In order to use your autonomous sewer system in a country house with full confidence in the safety of wastewater, you need to know the composition of these waters.

This is determined by conducting numerous analyses:

• sanitary and chemical,
• biological.

A complete chemical analysis of wastewater is essential to select the optimal water treatment system. But sometimes an abbreviated type of analysis is also possible. In general, analyzes, even carried out several dozen times, cannot provide a complete and accurate picture of wastewater. All conclusions are, in principle, conditional.

When conducting a complete chemical analysis of wastewater, determine:

• Discoloration of sewage. Usually, domestic wastewater has a weak coloration. If it changes to strongly pronounced, then the wastewater needs strong treatment;
• The smell of domestic waste water is peculiar. Obtained from the breakdown of organic compounds and feces;
• temperature. This indicator indicates how quickly the biological treatment of wastewater occurs;
• Transparency, which serves as an indicator of the degree of pollution of effluents;
• The pH level in wastewater that meets the standards must be neutral;
• Dense sediment, which should not exceed 10g/l;
• CBO and BOD values ​​(chemical oxygen demand and biological oxygen demand);
• The toxicity of wastewater, which is a negative indicator, since when the norm is exceeded, bacteria do a poor job of treating wastewater. Toxic substances include many detergents, dyes, copper, mercury, cadmium, sulfides, cyanides and other substances;
• Suspended substances, which normally should be 100-500 mg / l;
• Forms of nitrogen, phosphorus;
• Chlorides, sulfates;
• Dissolved oxygen, which is necessary for the life of bacteria;
• biological pollution.

When conducting analyzes for wastewater, GOST divides the results into two types: maximum permissible concentrations and unacceptable ones, that is, exactly what should not be, and which is the reason for the immediate adoption of appropriate measures.

Naturally, such analyzes can only be done by specialized laboratories that are licensed to conduct such analyzes for the population.

 

Types of septic tanks, allowing to reduce the maximum allowable norms of wastewater

Many owners of country houses do not think about the consequences of their savings when they decide to make a simple cesspool instead of a septic tank. They should do an analysis of their drinking water if it comes from a well or well located in the immediate vicinity of the cesspool. In this case, we can say with confidence that the analysis of drinking water will be far from the normative indicators. There is a risk of infection with helminthic invasions and other infectious diseases.

In addition, an aquifer that has been contaminated by sewage will require a decade of effort to clean it up.

And on the contrary, those who have a sewer septic tank equipped in accordance with all the rules should not be afraid of a negative analysis of wastewater, since a well-thought-out septic tank system, in combination with the use of biological wastewater treatment, will give positive results in analyzes of drinking water.

This is due to the fact that wastewater, being in the first chamber of the septic tank for a long time, is freed from suspended particles that precipitate.

In the second chamber, further purification and filtration of wastewater takes place. And the water discharged into the drainage well or into the ground is practically safe for the environment. According to the statistics of the analyzes carried out, the owners of septic tanks have better indicators than the owners of cesspools.

Currently, there are many ways of biological wastewater treatment. These include drugs that are directly poured into septic tanks and biological treatment plants, devices where microbes are released into the septic tank when a certain level of wastewater in the septic tank is reached.

The septic tank must have a permanent organic substrate for microbes. With a long absence of owners, microbes, without receiving a fresh portion of organic matter, can simply die.

The conclusion suggests itself - to make a modern septic tank is of course difficult, but our health is more important than the investment and physical effort.

Specifics of carrying out and main indicators of wastewater analysis

The determination of the main indicators is carried out by an accredited laboratory. Samples are brought by the customer, but according to the contract, the representatives of the contractor will do the sampling themselves. When carrying out, the sanitary-chemical and biological parameters of wastewater are determined. There are two methods of wastewater analysis: complete and reduced.

Chemical research determines:

• the content of harmful substances;
• oxygen level;
• suspension concentration;
• temperature;
• color, transparency;

With the reduced method, specific indicators are examined. The results obtained should be included in the maximum allowable value according to GOST. If the maximum concentration is higher than the permissible one, then the effluent is treated.

When is sample analysis required?

Industrial enterprises, gas stations, car washes are required to check for compliance with MPC. The frequency depends on the type of activity of the organization. The following companies are under control:

• paint and varnish;
• food;
• printing;
• metallurgical;
• chemical.

Determination of the composition of natural wastewater is recommended for owners of country estates when installing a volley discharge septic tank. Research data is used to draw up an environmental declaration, develop acceptable standards.

What indicators are being studied?

In the laboratory analysis of wastewater, bacterial, chemical and biological indicators are examined. Toxicity, content of copper, mercury, sulfides is determined. Drains are checked for smell, color, density. An important indicator is neutrality.They are examined for the content of heavy metals, surfactants.

Water intake method

According to the guidelines for sampling for wastewater analysis, samples are taken with a sampler. The type of device depends on the parameters being studied. Samplers are stationary and mobile. When sampling for the determination of suspended solids, the sampling is done once without overflow.

On open water bodies, the fence is carried out above and below the discharge points. A bathometer is used to take deep natural water samples, but collection directly into hermetically sealed containers is also allowed.

How is the analysis carried out?

The owner is responsible for the analysis of wastewater. In order for the results to be reliable, the sampling rules are followed.

1. The volume of the container for samples is not less than a liter.
2. The sample container must be sterile and tightly closed.
3. The container is filled completely.
4. The container is protected from ultraviolet radiation.
5. The sample is delivered to the laboratory within two hours.

In the laboratory, samples are examined for specified parameters using wastewater analyzers. Then a conclusion is drawn up, on the basis of which a protocol is issued. If excesses are found, recommendations are made to eliminate violations.

Who performs sewer analysis?

Sampling is carried out either independently or by representatives of the laboratory or water utility. Waste water analysis for the enterprise is allowed to be carried out by certified laboratories.

Key indicators for quality assessment

When studying samples, indicators are determined that should not exceed the MPC of wastewater.

• The value of acidity and alkalinity in the range of pH 6.5-9.
• Temperature from +35 to +45 C.
• The content of phosphorus is 12 mg/dm3, and that of nitrogen-containing compounds is 50 mg/dm3.
• The content of oil products is 10 mg/dm3.

In the course of work, the dry residue, the quantitative composition of bacteria are determined. The level of oxidizability determines the degree of pollution of wastewater with organic and non-organic matter. Visually determine physical characteristics such as color and smell.

Synthetic surfactants surfactants

Natural water bodies suffer the most from these types of pollution. Synthetic surfactants lead to eutrophication of lakes and rivers, inhibit the processes due to which water bodies are self-purifying, and inhibit any biochemical processes in them. Surfactants initiate a decrease in the percentage of oxygen in water bodies and other processes that are detrimental to any biocenosis.

During the treatment of industrial effluents, surfactants slow down the processes that cause the sedimentation of solid suspensions and provoke the appearance of foam in the treatment facilities, as well as hinder the high-quality biological treatment of discharged effluents.

Therefore, the content of surfactants in industrial effluents, at the time of their entry into the biological treatment zone, cannot exceed 20 mg/l. And individual fractions (for example, hard surfactants) must first be completely removed by any methods.

Conducting an analysis

All wastewater discharged into natural water bodies has a strong impact on this biosphere:

• Stimulate eutrophication;
• Change in biocenosis;
• The death of individual biological individuals;
• Other negative manifestations.

Sources of wastewater generation - housing, industrial, social and other purposes (apartments, schools, medical institutions, gas stations, etc.).

Environmental supervision is constantly improving the regulatory framework for monitoring compliance with sanitary cleaning standards by enterprises. These measures are necessary to preserve the hydrosphere, maintain the ecological balance of a particular area.

Most often, samples of domestic and industrial effluents are examined, which come directly to treatment plants and facilities. The quality of the effluents is determined by samples from the end streams that are sent for treatment.

The simplest sample analyzes determine the following effluent parameters:

1) color;

2) the level of transparency;

3) temperature;

4) the presence of smell.

All wastewater has an elevated temperature, low transparency and a specific odor. The more harmful the production, the more intense the discharges are colored.

Chemical indicators of wastewater sample analysis:

• pH level. Municipal effluents are neutral, and the pH level of industrial sewage can vary from strongly acidic to strongly alkaline. After filtering and cleaning, all discharges must be neutral;
• Dry residue, which is taken from unfiltered samples. This criterion shows the content of suspended (lime, ore, etc.) and dissolved impurities in wastewater. Removal of suspended impurities occurs by mechanical methods of water treatment, for example, by standing. All urban sewage has a level of settling substances from 65 to 75%;
• Determination of the ash content of solid types of impurities. It is found by the calculation method: the dry residue calcined to +600ºС is divided by the initial weight of the analyzed sample. The ash content is calculated as a percentage. City sewer discharges have from 25 to 35% ash content of solid impurities;
• The value of oxidizability, determined by the action of aerobic bacteria and chemical reactions on wastewater.

Also, the key parameters of wastewater purity are the level of nitrogen and phosphorus compounds, sulfates and chlorides, surfactants and toxic substances. Biological pollutants of wastewater - bacteria, viruses, pathogenic protozoa, helminth eggs.

The last indicator detected during the analysis of wastewater samples is the level of dissolved oxygen. The parameter standard is 8 mg / liter of wastewater.

Conclusions: analysis of wastewater samples is required when drawing up a plan for a treatment plant, assessing the effectiveness of its work and checking the quality of treatment of incoming effluents. All studies are carried out by specialists in special laboratories using precise equipment.

Specifics of carrying out and main indicators of wastewater analysis

Analysis of sewage wastewater is performed to determine the level and specificity of pollution of the reservoir, which is polluted by industrial enterprises or by natural means. If sanitary conditions are not met, the liquid is re-sampled. As a rule, water is collected at the outlet of the industrial cleaning complex. After re-analysis, the wastewater composition should be completely free of specific pollutants. In the process of studying wastewater, they are guided by such indicators as:

• Physical - necessary to determine the color, smell, transparency and temperature. All of these indicators are determined superficially, without the use of special equipment or chemicals. It is known that waste water has an overestimated temperature regime, a pronounced odor and a low transparency index.
• Chemical - is necessary to determine the level of change in the pH of the reaction, which changes in industrial effluents.

• Determination of dry residue - necessary to identify sanitary standards and the amount of impurities in the liquid. In the process of its implementation, unfiltered samples are used, which allow determining the level of dry runoff. The main purpose of determining dry effluent is that all industrial effluents need to be treated using special bacteria. It should be noted that the number of suspended bacteria in the area under study should not exceed 10 l / g; if the indicator is too low, cleaning will not be effective.
• The level of oxidizability is a sanitary indicator that makes it possible to determine the level of water pollution by organic and inorganic substances. The level of water oxidation is determined by the consumption of chemical and biochemical oxygen.Indicators of chemistry and biochemistry help to determine and predict the amount of contaminants in wastewater that can be removed using a biological cleaning method.
• Phosphorus and nitrogen content - this indicator is one of the main ones, which is responsible for the effectiveness of biological cleaning and the preservation of the hydrosphere. At enterprises where industrial effluents are used, this indicator is responsible for the level of presence of nitrates, nitrites and ammonium nitrogen, all these components affect the level of biological treatment.

• Toxins - they are determined exclusively in industrial effluents, according to their composition they are divided into organic and inorganic. The rules for conducting analysis with the determination of toxins in industrial effluents are carried out based on the specifics of the production process.
• Surface-synthetic active substances - this indicator affects the level of oxygen in the water, with its underestimated value, the environment suffers.

Pure water natural wealth

Man consists of 60 percent water, which means that water is one of the most important resources on our planet. But here's the paradox - it is exposed to the greatest pollution by man. Of course, the time has passed when people strived to “turn the rivers back”, but the time for true respect for nature has not yet come. Manufacturing enterprises continue to be guided solely by considerations of economy and profit, ignoring the preservation of the environmental cleanliness of the space in which we live and our children will live.

The state is trying to regulate the ecological balance with the help of rules and responsibility, however, as Professor Preobrazhensky said: "The devastation begins in the heads." The purity of nature and water can only be ensured by starting with one's own behavior.

Classification and degree of pollution of sewer water

Depending on the origin, sewage flows are:

• industrial;
• household;
• atmospheric.

Industrial discharge through the industrial sewerage, household - through the household, and surface - through the storm drain. In addition, regardless of the species, they can be dumped into the common alloy.

Household contain mineral, organic, biological substances. Industrial classify:

• by the composition of the pollutant;
• concentration of harmful substances;
• according to the properties of pollution;
• acidity;
• toxicity.

Storm drains are contaminated with minerals and have a constant composition. Therefore, the analysis of storm sewage is done to determine the degree of impact of pollution on the environment.

Research types

To determine the quality of sewage, various types of studies are used that help determine the composition of pollutants and their concentration. The results of the study help to correctly assess the sanitary and environmental situation, to choose a treatment system.

Sewer discharges are analyzed using the following methods:

• chemical;
• microbiological;
• toxicological;
• sanitary and hygienic;
• radiological.

Not only industrial, but also sewage household plots are subject to research. To quickly determine the chemical composition, an express method is used.

microbiological method

In microbiological research, the ATP method, titration, plate count, membrane filtration are used. With the help of BAC analysis, the number of pathogenic microorganisms, coliform bacteria, staphylococci is determined. The test results are used to determine the cleaning method.

chemical method

In chemical research, a weight and volume method is used. With the help of chemical analysis determine:

• acidity;
• toxicity;
• transparency;
• weighted balance.

COD, BOD data are used to determine the oxygen demand.In the course of a chemical study, compliance with MPC standards is determined.

Chemical analysis of wastewater

Analysis of drains on a personal plot

Household runoff causes soil pollution. They carry a potential danger not only to this site, but also to neighboring ones. Therefore, homeowners are advised to do a complete chemical method.

The results will help to avoid contamination, select and equip a suitable septic tank. This eliminates unpleasant odors.

Express analysis

If it is necessary to urgently determine the chemical composition, then an express study is done. To do this, use a device for the analysis of waste water. Using the express method, the level of alkalinity, the content of chlorine and phosphorus compounds are determined.

Express method allows you to determine the organoleptic characteristics. The disadvantage of the method is the low accuracy.