Pollutants in wastewater

Pollution of natural resources has a negative impact on the environment. This includes not only emissions into the atmosphere, but also into water bodies. Pollutants, including biologically hazardous ones, when released into water, penetrate into the sewer systems of public and residential buildings, as well as into the soil. Therefore, it is so important to promptly analyze the composition of wastewater for the presence of harmful substances and to ensure timely safety measures.

 

Wastewater - Definition and Standards

 

Water pollution by industrial waste occurs as a result of any industrial, agricultural, manufacturing, household activity. As a result, waste water is formed with altered biological, chemical, physical characteristics after the entry of gaseous, solid, liquid components in high concentrations. This causes not only an uncharacteristic taste and aroma, but also the formation of a new dangerous compound in the water due to the chemical interaction of substances.

There are several categories of stocks:

 

• technological (industrial);
• household;
• atmospheric.

 

The main potentially dangerous sources include:

• livestock complexes;
• chemical, oil refining, paper and pulp production;
• mining, metallurgical enterprises;
• food processing plants;
• uncontrolled use of pesticides and mineral fertilizers in agricultural activities;
• emissions of synthetic detergents into sewers;
• radioactive pollution caused by violations of uranium and nuclear fuel purification technologies;
• rail transport.

 

It is important to conduct timely analysis of pollutants in wastewater, clean facilities and wastewater systems.

 

The danger is that irreparable harm is caused to the environment. Timely measures to clean up waste can prevent negative consequences for nature and people.

 

Industrial pollutants

 

Industrial wastewater is one of the most dangerous. It is a variety of emissions depending on the area of activity of the organizations, the types of raw materials, equipment, and technological processes they use. They are characterized by a high concentration of the following substances:

• sulfuric acid;
• resins;
• chlorides;
• oils;
• metals;
• sulfates;
• ammonia;
• cyanides;
• phenols;
• inorganic acids.

Each type of industrial water pollution is specific and is determined both by the change in odor and by the methods of wastewater treatment at the local treatment facility, which require an integrated approach.

Types of wastewater categories

 

There are several types of SV:

• mechanical (increased amount of mechanical particles);
• chemical (with presence of toxic components of organic and inorganic origin);
• biological/bacterial (with high concentration of harmful bacteria, fungi, microorganisms);
• thermal (arising due to the entry of heated liquid from the power plant into the aquatic environment);
• radioactive (containing high concentration of radioactive substances).

Main types of SV

 

Monitoring water pollution by industrial wastewater for chemical analysis assessments is the most important event in the design and operation of any treatment facility. Types of wastewater differ in physical properties and origin.

By physical characteristics, they may include colloidal substances, soluble/insoluble impurities.

By origin – bacterial, organic, mineral type.

Mixed type. Containing inorganic and organic impurities.

 

Suspended solids

 

Components consisting of silicon rock, sand, clay and other large particles that are unable to pass through a paper filter. When washed into a reservoir, they can:

 

• change transparency;
• reduce water aeration, photosynthesis;
• cause siltation;
• lead to the death of aquatic organisms;
• heat up other substances, leading to secondary pollution.

Wastewater discharge standards differ for water users. For the highest categories of enterprises – no more than 0.25 mg/dm3, for the second categories – up to 0.75 mg/dm3.

 

Petroleum products

 

A group of mixtures of hydrocarbons of various types (bitumen, oils, fuel, etc.). They enter water bodies from enterprises, during transportation, and leaks during extraction. They contain residual fraction, cycloparaffin, paracin, naphthene-aromatic carbon. They move quickly with the ebb/flow of the tide, and with gusts of wind. This leads to:

 

• oil film on the surface;
• harmful fumes;
• death of living microorganisms;
• formation of emulsion;
• precipitation.
• surfactants in SW

Surface-active substances are products contained in detergents. The components present in their composition are adsorbed in liquids and air. Result:

 

• slowing down of the water process;
• deterioration of organoleptic properties, gas exchange;
• loss of self-purification up to 15%;
• reduction in the functioning of biofilters;
• toxic effects at surfactant levels above 10 mg/l.

Fats

 

This is a group of substances that are formed by fatty acid or glycerin. Characteristics: insolubility in water, solid acid content. They arise as a result of the activities of catering establishments, fish processing, meat, dairy, oil and fat factories.

 

Organic mixtures

 

Includes various impurities (alcohol, protein, fat, fiber, carbohydrates and other organic waste from food products, human/animal life). Concentration is determined by biochemical and chemical oxygen requirements. Composition:

• organochlorine compound (low-volatile/volatile);
• toluenes, xylenes, benzenes;
• pesticides.

They enter water bodies from sewers and industrial waste.

Persistent organic pollutants

 

POPs are one of the dangerous groups of processing by-products. These are impurities: polychlorinated biphenyl, dichlorodiphenyltrichloroethane, chemically stable compound, etc. A distinctive feature is that they are not susceptible to decomposition.

Pesticides

 

Category containing toxic artificial organophosphorus and organochlorine particles used to control rodents and weeds.

The danger is in cumulative and mutagenic irreversible changes and the difficulty of cleaning.

Heavy metals

 

In stable water, the metal turns into a complex chemical compound. The most common are: zinc, chromium, copper, manganese, lead. They are present in different forms - colloidal, suspended, soluble. They come from chemical plants, mining, energy enterprises.

 

Phenols

 

Type of anthropogenic pollution of SV, penetrating during the production of tannin, dye, building materials, glue, rubber products, processing of petrochemical products, etc.

Xylenol, resorcinol, cresol greatly change the characteristics of water resources. It is important to carry out biological treatment in a timely manner.

 

Bacterial contamination

 

With a high content of viruses and bacteria. Drainage may contain brucellosis, tuberculosis bacteria, cholera virus, intestinal bacteria, helminth eggs and much more. A characteristic feature is high resistance to chlorine. The main bacteriological characteristics: coli-indices, coli-titers, the amount of coliphagen, the presence of lactose-positive intestinal bacteria.

 

Hazard classes in wastewater

 

The classification is determined taking into account the limiting indicators of harmfulness of substances, their toxic effects, and mutagenicity.

There are several classes:

 

• low hazard;
• moderately hazardous;
• high risk;
• extremely hazardous.

 

The class is established on the basis of sanitary and epidemiological standards and rules (1.2.3685-21). Taking into account the standards, a design for a treatment facility is developed that guarantees the effective removal of wastewater from specific organizations.

 

Wastewater Treatment Methods

 

Methods of wastewater treatment are selected individually. The most common is combined.

 

Separately used:

 

• mechanical purification (for insoluble impurities);
• biological (without the use of chemicals);
• biochemical (a combination of microorganisms and a chemical reagent);
• chemical (using alkali/acid);
• chemical-physical.

Treatment plant

 

A large group of structures/devices that vary in scale (from a private plot to a metropolis).

At the initial stages, grates, sand traps, sieves, grease traps, settling tanks, septic tanks, etc. are used.

In more complex cases, step-by-step purification will be required. These are aeration tanks, secondary settling tanks, biofilters, bioreactors, post-treatment filters, ultrasound, etc. The choice of method (biological or physical) depends on the type of pollution and the activities of the enterprise.

 

Rules

 

The rules for receiving wastewater and operating sewerage systems are regulated by the Legislation of the Republic of Kazakhstan on water supply and sanitation, the rules for operating sewerage systems, as well as sanitary norms and methods for determining emission standards into the environment.

The procedure for standards for the composition of wastewater has been developed taking into account the activities of organizations.

Analysis of the content of harmful substances includes:

 

• provision of opportunities for visual inspections and sampling;
• provision of free access to water bodies and sewers;
• organization of sampling sites, installation of special signs identifying control zones;
• timely monitoring of characteristics and concentrations of effluents (with completion of statistical reports);
• checking the operation of the treatment facility and timely troubleshooting;
• submission of reports to the supervisory authority within the established timeframes.

Penalties

 

The amount of fines depends on the degree of violation by water users. For an official - up to 20 monthly calculation indices, for a legal entity - from 20 to 100.

In case of a serious (irreversible) violation, criminal liability is provided.

You can avoid fines by observing all the standards established by environmental legislation, having permits, and conducting timely monitoring of the water supply system.