Many parts of our planet have become so polluted that government agencies and research institutions are making desperate attempts to reduce sources of pollution and return to proven methods that existed before. The automotive industry has not been immune to these stringent regulations, and professionals have worked hard to reduce pollutant emissions from spraying and evaporating solvents.

These are chemical substances that rise into the atmosphere when paint is sprayed, when solvents evaporate, combining with nitrogen oxide and ozone. Ozone is the main component of smog. Volatile organic compounds (VOCs)- those elements in containers with paints that evaporate. If the pigment and binders (resins) harden, forming a film on the surface, then VOCs in this case are chemical solvents. Thinner is a general term for all materials in paint that allow the mixture to remain in liquid form; the varnish contains its own thinner, enamel and urethane paints - a reducing agent. Each gallon of paint can contain up to 90% solvent. Thinners and reducing agents are 100% solvent.

It should be noted that in addition to environmental pollution, volatile organic compounds have an extremely negative impact on human health, causing diseases of the upper respiratory tract.

New laws have been passed in states such as California, New York, Texas and New Jersey to reduce the use of VOCs by local companies, including auto paint shops. In addition to requiring stores to be equipped with high-tech paint booths with ventilation systems, the law requires a special filter system to be incinerated or otherwise destroyed. volatile organic compounds (VOCs).

To reduce release to the atmosphere volatile organic compounds (VOC) when spraying, many companies, such as DeVilbiss, have developed low pressure volumetric paint sprayers (HVLP). These units are capable of producing 64 lb 3 /m (cubic feet per minute) of air at 5 lb/d 2 (psi). They also heat the air up to about 90° Fahrenheit. Such systems can reduce the consumption of paints and varnishes by a quarter.

Paint companies directed all the efforts of their laboratories to the development of new types of paints that would contain a minimum amount of ) evaporating daily into the atmosphere. Water-based paints have been developed with mixed success, but research will continue until all possible options have been explored. Bob Inglis, Director of New Development at BASF-Refinish, said: “By 1992 we will be either a solid system or water. As I see it, most likely it will be a water-based base coat, a high-density one-step paint system, a dense base base and transparent paints. Since all varnish variants have already been invented and it is impossible to reduce their content volatile organic compounds (VOC) to the level dictated by the new laws, then manufacturers will have to gradually reduce their production, and stores will have to accept this fact.

As shady as this path may be, the best way to stay up to date on new products is to maintain a relationship with a nearby auto paint shop. Their employees are always the first to know about global changes in the auto industry. They are also the first to receive new and updated technical material on new paints and systems that are compatible with legacy products that need to be adjusted. Rest assured, any technological novelty is developed with an eye on previously manufactured products and tries to be compatible with it so that buyers do not have difficulties with repairs.

The importance of wastewater treatment systems is undeniable. No building that is used by man can do without them. New manufacturing enterprises, gas stations, bars and restaurants, other establishments from the service sector, apartment buildings or country houses are constantly emerging, and the problem of high-quality wastewater treatment remains relevant. To solve it, enterprises, local authorities, owners of residential real estate are building local treatment systems of various types.

The concept of VOC

Devices, structures, complexes of structures with various engineering communications and various combined systems, the main purpose of which is the complete or ultra-deep purification of household, industrial, rain and other sewage, are called local treatment facilities (VOCs).

Many put an equal sign between VOCs and autonomous sewers - this is not true, since autonomous sewers are one of the types of VOCs that function independently and exist separately from the central sewer line.

Interesting to know. The most important task that such structures, structures and their complexes must solve is the purification of wastewater to a level that is described in the legislative rules and regulations of the relevant services, which guarantees the absolute safety of the surrounding flora and fauna, the health and life of people.

VOC types

Local facilities for the purification of sewage water by location can be divided into the following types:

1. Treatment systems that are part of the municipal central sewerage system, which, after processing wastewater, send it to the city sewer network;
2. Cleaning systems that serve buildings or building complexes separately from the central sewer line, as they are removed at a decent distance from it or without the possibility of connecting to it (autonomous sewerage).

VOC of the centralized sewerage

The first group mainly consists of large-scale systems, which include a number of large-scale treatment facilities that form an automatic complex for the processing of large volumes of industrial effluents from factories, industrial production, plants and domestic effluents from cities, towns, and other settlements.

Such sewer systems are usually built outside the city line. The territory allocated for their construction and operation is a sanitary zone where it is forbidden to live and hold various recreational activities.

They are serviced by specially trained personnel, and they operate through special devices and equipment, control panels and automation systems.

Independent VOCs

Autonomous VOCs have smaller dimensions. They are installed to treat industrial wastewater from small industrial organizations and factories, as well as wastewater from human activities. They have a simpler design and cleaning technology with lower power and throughput.

Often, local sewage treatment systems of an autonomous type serve service industries, small villages and individual residential buildings that are far from the municipal sewage treatment network.

How does the LOS work?

The vast majority of local treatment facilities operate on a multi-level method of wastewater treatment, which consists in their passage of the following stages:

• mechanical (rough);
• bacterial (biological);
• chemical-physical.

Rough cleansing

As a result of mechanical treatment, household and fecal waters are passed through various filter systems that trap large inclusions in them. The stage at which the effluents pass through the first filter system is called rough cleaning. After this stage, the wastewater passes the next set of filters, designed to remove smaller inclusions from the drains. Upon completion of the passage through the filters, the water enters specialized storage tanks, where the process of clarification takes place.

Chemical cleaning

Since wastewater is affected by various chemical reagents, inorganic and organic compounds that have a detrimental effect on the state of the environment, it is necessary to carry out the process of their chemical neutralization before discharging such water into a reservoir or river. This process is based on oxidation-reduction reactions. For example, if you want to get rid of impurities in the water caused by alkaline solutions, you need to treat the liquid with various acids, and vice versa.

Bacterial cleansing

This stage consists in the purification of wastewater from various organic contaminants by means of special bacteria, which, processing such contaminants, start the process of their decomposition with further removal from the VOC. This cleaning step can take place in an anoxic or oxygen environment, against which a distinction is made between anaerobic and aerobic cleaning.

Varieties of autonomous treatment systems

Autonomous local treatment systems include the following types of facilities:

• septic tanks with sedimentation tanks;
• biofilters;
• aerotanks.

These systems differ from each other in design features and the method of wastewater treatment.

Important! Any of the above facilities must necessarily be equipped with filtering installations or facilities, since on their own they will not be able to organize a full processing cycle, in which water will be purified by 97-100%.

Septic tanks

Constructions for organizing sewage, consisting of accumulation tanks, divided into chambers for cleaning and settling waste inclusions, are called septic tanks. They can include several storage tanks in their design. The most popular for organizing a sewer system in summer cottages and personal plots, as they have a low cost and a high level of practicality.

Septic tanks are small in size and contain all the necessary devices for organizing the processing of sewage water.

Such septic tanks are produced on an industrial scale mainly from high-strength plastic. This material is light in weight, which makes the installation of a septic tank quick and easy. Such systems perfectly withstand sharp temperature fluctuations, exposure to various aggressive environments, onslaughts and mechanical loads.

The construction of a septic tank can be carried out from concrete and other materials.

Note! Septic tanks are not able to treat wastewater by 100%, as they are part-cycle VOCs. Be sure to create special filter fields together with them, which contributes to almost complete soil purification.

On the market of local treatment systems, you can find ultra-deep cleaning stations, which are a kind of septic tank, where all kinds of filtering devices and other cleaning agents have already been installed. Such devices have compact dimensions and provide almost one hundred percent purification of sewage water.

Aerotanks

Specialized open storage tanks in the shape of a rectangle, where the filtration process and the sedimentation of abrasive fractions of wastewater are carried out, are called aerotanks.

Aerotanks have an elongated shape, reminiscent of water channels through which household and fecal liquid moves, mixing with activated sludge (a community of protozoa) with the help of air pressure, which is responsible for their processing.

Various substances appearing on the surface, for example, oil products, fatty inclusions, can also be removed in aeration tanks.

These structures do not exist in isolation, but are part of a complex of municipal sewer systems or, in a reduced form, are built into a septic tank with settling tanks and ultra-deep cleaning stations.

Design for biological treatment

Biofilters are special containers or structures that serve for deep purification of wastewater with the help of colonies of certain bacteria launched into them. Just like in aerotanks, they are part of municipal sewer systems or, in a reduced and simplified version, are built into septic tanks.

In addition to microorganisms, filter materials are placed in biofilters, which provide mechanical wastewater treatment, for example, expanded clay.

VOC for industrial enterprises

Local treatment facilities for industrial enterprises operate according to a progressive and more complex structure for processing wastewater with more complex pollution.

Treatment systems serving large or complex technological enterprises, in their structure contain:

• Mechanical cleaning line. The waste liquid enters the storage tank, from which it is distributed to biofilters, getting rid of large inclusions;
• Simultaneous processing of industrial effluents by the chemical method. After getting rid of large fractions, effluents enter various sedimentation tanks containing certain chemicals and solvents that bind to organic and inorganic water pollutants, forming feathers or lumps that settle at the bottom of the tank;
• Specialized greenhouses with aerotanks that contain activated sludge and water hyacinth, which rids the water of organic fractions;
• Biological ponds for post-treatment of wastewater, in which the last stage of work with fractions takes place by exposing them to special microorganisms;
• Disinfection station for sewage treatment by means of ultraviolet radiation.

Usually, each stage of processing industrial wastewater is carried out in a separate building or room, which makes it possible to avoid the release of polluting compounds or substances from these sewage effluents into the atmosphere, as well as to comfortably control the entire technological process.

VOCs in this structure provide processing of sewer lines at the following enterprises:

• poultry farms;
• meat processing plants;
• factories for the production of glass and other products from it;
• canning factories;
• car washes;
• factories of fat-containing products and vegetable oils;
• and other industrial enterprises.

VOC for rain (stormwater) runoff

Systems for the processing of storm water have their own characteristics in terms of structure and treatment methods, which is due to the presence in their composition of a significant content of suspensions of natural origin, chemical compounds and large particles.

These VOCs can successfully function for the treatment of storm water from the following facilities:

• car washes;
• factories;
• territories of industrial enterprises;
• large parking lots and car parks;
• adjacent territories to business centers and shopping facilities;
• household plot.

So a standard storm sewer system should contain the following elements:

• sump;
• trap of sand and other abrasive particles;
• trap of oil-containing substances (oil trap);
• absorbent filter;
• UV disinfection system;
• control container for approbation of the purified liquid.

VOCs for storm sewer systems have a high level of wastewater treatment (up to 98%) and productivity, as they must be ready to process a large volume of liquid, for example, during prolonged rains.

In the design of such sewer systems, there are sedimentation tanks, where effluents are separated from large fractions such as branches, street litter, glass, cobblestones and other particles washed up with water from melting snow or rain.

VOCs for storm drains must contain sand and oil traps in their system, as storm drains contain a large amount of abrasive substances and petroleum products emitted by cars and gas stations.

The final stage of purification of such effluents is their disinfection by means of ultraviolet rays, after which the purified liquid can be sent to natural reservoirs.

Local treatment facilities for sewage of any type provide those technological solutions that reliably provide high-quality wastewater treatment without adversely affecting the environment, making human life easier and more comfortable.

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To reduce the amount of pollutants and runoff from roads directly on the carriageway, the following measures are taken:

• Collection of storm water from roads through catchment trays and pre-curb recesses for further discharge to wastewater treatment plants.
• Prevention of erosion of earthen slopes and roadside areas, timely cleaning of drainage ditches, roadsides and slopes.
• Regular cleaning of the road surface, cleaning of drainage systems.
• Timely repair of the roadway.
• Control over the use of anti-icing reagents.
• A ban on the dumping of snow removed in winter into water bodies or onto the ice surface.
• Selection of environmentally friendly road marking materials.

Pollutants and particles of asphalt material accumulate on the road sections with destroyed pavement, which spread in the form of a suspension during rain and enter the surface sewage. In order to prevent polluted construction effluents - for example, during the repair of the roadway - from falling into water collection devices, it is necessary to organize the discharge of polluted effluents into a specially arranged infiltration trench.

Minimization of the use of anti-icing reagents to reduce the harmful effects on the environment is possible with the correct calculation of the rate of use of reagents. If the road passes near a reservoir, it makes sense to install special barriers that divert polluted effluents from the water body. Screens made of polymeric materials are the most promising for this.

The search for new anti-icing products that combine efficiency, economy and environmental safety is an urgent problem of today.

Engineering wastewater treatment

The storm and melt runoff collected from the surface of the road in the most favorable variant is directed to the treatment plant. When choosing the type of treatment plant, it is necessary to take into account its interface with the road drainage system.

The choice of treatment plant design depends on the climatic and hydrological characteristics of the area, as well as on the characteristics of pollutants.

Pollutants are separated by physical state (soluble, insoluble, colloidal systems) and by chemical composition. An important characteristic of suspended particles that affects the choice of treatment equipment is dispersion (particle size and shape).

Types of treatment facilities

At the treatment plant, all or several of the following stages of wastewater treatment are sequentially implemented: mechanical treatment, chemical treatment, physicochemical and biological treatment.

Mechanical wastewater treatment from pollutants is carried out using mechanical gratings, sand traps, settling tanks, oil traps, hydrocyclones, filters, plant strips, etc.

Mechanical treatment facilities open the way for effluents entering the treatment facilities. Mechanical cleaning removes large debris from wastewater, significantly reduces the content of suspended solids and prepares wastewater for further treatment stages.

Next view - chemical wastewater treatment. Chemical methods are used after mechanical treatment and before effluents enter biological treatment, or are used as the final stage of post-treatment (chlorination, ozonation).

Neutralization (for acidic or alkaline effluents) and oxidation are used as chemical treatment methods on an industrial scale.

Physical and chemical cleaning methods belong to the deep cleaning stages. These are methods of flotation, coagulation (clarification), adsorption, ion exchange, extraction, etc. The use of these methods allows you to remove most of the toxic chemical compounds that are in dissolved form from the water.

For the treatment of high flow rates of wastewater by adsorption, the following types of structures are used: non-pressure adsorbers, infiltration trenches, drainage wells.

Biochemical cleaning methods based on the ability of some microorganisms to process dissolved chemical compounds.

Biological treatment methods have their own characteristics associated with the normal functioning of microorganisms - it is necessary that the concentrations of chemicals be within the specified limits, and that there are no heavy metals in the effluents. Biological treatment can be aerobic (with active air access) and anaerobic (oxygen-free).

Aerobic treatment is carried out in the following types of treatment facilities: aeration tanks, oxygen tanks, biofilters, biological ponds.

Anaerobic purification (methane fermentation or fermentation) is carried out without air access in specially equipped reactors (methane tanks, septic tanks, anoxicators) and makes it possible to biologically process even the most difficult-to-oxidize chemical compounds.

The combination of aerobic and anaerobic treatment methods gives the greatest effect of improving water quality.

If the installation of treatment facilities near the road is not possible, structures in the form of reinforced concrete shield fences should be installed.

For the treatment of surface runoff from roads and bridges, the most promising is the installation of complex treatment facilities that give the maximum effect on the treatment of polluted effluents.

You're probably used to buying paint either by brand or by color like Benjamin Moore or blue.

But when it comes to coating your walls and ceiling, there's a much bigger decision you need to make that has to do with the chemicals actually used to make the paint itself.

One of the most toxic is actually a group referred to as "Volatile Organic Compounds" or VOCs.

VOCs are a large group of carbon-based chemicals that evaporate easily at room temperature, making them easily inhalable. Some of the most common sources of VOCs in our homes are household paints. VOCs are used as solvents or thinners that work together with resins to bind together all the paint ingredients and make them adhere to the wall. In other words, they can improve performance and durability.

However, the VOC "gases off" into the air while the paint dries. Most people can smell high concentrations of some VOCs, although other VOCs are odorless. The smell doesn't indicate how dangerous the chemicals are, says the Minnesota Department of Health. No matter how strong they smell, many VOCs, which can include formaldehyde, acetone, benzene, and perchlorethylene, can make you sick in a variety of ways.

That's why I've put together this list of 6 reasons why you should never use paint that contains VOCs.

1) Worsening of asthma symptoms. If you already suffer from asthma, breathing air contaminated with VOCs can trigger an asthmatic reaction. Scientists studied 400 toddlers and preschoolers and found that children who inhaled smoke from water-based paints and solvents were two to four times more likely to suffer from allergies or asthma.

2) The appearance of flu-like symptoms. Even if you don't suffer from asthma, you may experience a runny nose, itchy eyes, joint pain, and other flu-like symptoms from inhaling paint fumes. Solvents that evaporate into the air from paint are absorbed into the lungs when inhaled and then into the bloodstream. They can irritate your eyes, nose, and throat and make you feel as if you've contracted the flu.

3) Potential cancer causing. Many chemicals in the VOC family are considered carcinogenic by the US Environmental Protection Agency. According to the World Health Organization, professional painters face a 20 percent increased risk of contracting a number of cancers, especially lung cancer.

4) Dizziness and loss of consciousness. Sometimes the chemicals that release gas in VOC paints are so overwhelming that they make people feel very dizzy and, in extreme cases, pass out. This can be especially dangerous if you were at the top of the stairs, perhaps while painting the ceiling, where you inhaled paint fumes very close to the source.

5) Problems of infertility. A study from the University of Sheffield and Manchester suggests that men who are regularly exposed to chemicals in paint may be more prone to fertility problems. Painters and decorators are the main victims. However, researchers found a 250 percent increase in "sperm motility risk" among men exposed to chemicals widely used as thinners for water-based paints, which would give any guy a break from using paints containing VOCs.

6) The problem of "dementia painter". In addition to an increased risk of lung cancer, painters can develop a neurological condition triggered by long-term exposure to paint thinners called painter's dementia.

What can you use instead

You might decide to ditch paints that contain VOCs because that would be right for your painter!

Increasingly, you can buy VOC-free paint online and in stores that specialize in supplying healthy and environmentally friendly building materials. Consumer Reports offers this helpful guide to VOC content to choose from when you're shopping; if you are a subscriber, you can see how they rate the various no or low VOC paints that are available on the market.

Most of the major brands, including Home Depot, Benjamin Moore, and Pittsburgh Paints, have made VOC-free choices. Just be careful when the paints are mixed, as the base paint may be VOC-free, but the pigment color may contain VOCs. You want the entire mixture to be VOC-free.

Water-based paints will have fewer VOCs than oil-based paints. However, there is no guarantee that just because the paint is water based, it will be VOC free. You must explicitly ask for VOC-free paint before you buy.

Whatever paint you use, make sure the room or house is well ventilated while painting. Turn on fans and open windows and doors. If possible, don't sleep in a room that has been freshly painted; especially don't sleep or use the room if the paint on the walls isn't completely dry. If you wake up with a headache or discomfort, stay out of the room for several days until you are sure it is odor free.