largest ecological problem CIS countries - contamination of their territory with waste. Of particular concern are the waste generated during the cleanup of urban Wastewater, - sewer sludge and sewage sludge (hereinafter - WWS).

The main specificity of such waste is its two-component nature: the system consists of an organic and mineral component (80 and 20%, respectively, in fresh waste and up to 20 and 80% in waste after long-term storage). The presence of heavy metals in the composition of waste determines their IV hazard class. Most often, these types of waste are stored in the open air and are not subject to further processing.

For example, By now, more than 0.5 billion tons of WWS have been accumulated in Ukraine, the total area for storage of which is approximately 50 km 2 in suburban and urban areas.

The absence in world practice of effective methods of disposal of this type of waste and the resulting aggravation of the environmental situation (pollution of the atmosphere and hydrosphere, rejection of land areas for landfills for storing WWS) indicate the relevance of finding new approaches and technologies to involve WWS in economic circulation.

In accordance with Council Directive 86/278/EEC of 06/12/1986 "On the protection environment and in particular soils in agricultural use of sewage sludge” in countries European Union in 2005, WWS were used as follows: 52% - in agriculture, 38% - burned, 10% - stockpiled.

Russia's attempt to transfer Foreign experience incineration of WWS on domestic soil (construction of waste incineration plants) proved to be inefficient: the volume of the solid phase decreased by only 20% while simultaneously being released into atmospheric air a large number of gaseous toxic substances and combustion products. In this regard, in Russia, as in all other CIS countries, their storage remains the main way of handling WWS.

PERSPECTIVE SOLUTIONS

In the process of searching alternative ways recycling of WWS through theoretical and experimental studies and pilot testing, we have proved that the solution of the environmental problem - the elimination of accumulated waste - is possible through their active involvement in economic circulation in the following industries:

• road construction(production of organo-mineral powder instead of mineral powder for asphalt concrete);
• construction(production of expanded clay insulation and effective ceramic bricks);
• agricultural sector(production of high-humus organic fertilizer).

Experimental implementation of the results of the work was carried out at a number of enterprises in Ukraine:

• pavement of the heavy equipment storage area MD PMK-34 (Lugansk, 2005), section of the bypass road around Lugansk (at pickets PK220-PK221+50, 2009), pavement of the street. Malyutin in Anthracite (2011);

BY THE WAY

The results of observations of the condition and quality of the road surface indicate its good performance, exceeding traditional analogues in a number of indicators.

• production of a pilot batch of effective lightweight ceramic bricks at the Lugansk brick factory No. 33 (2005);
• production of biohumus based on WWS at the treatment facilities of Luganskvoda LLC.

COMMENTS ON THE INNOVATION OF THE USE OF WWS IN ROAD CONSTRUCTION

Analyzing our accumulated experience of waste disposal in the field of road construction, we can highlight the following: positive points:

• the proposed recycling method allows involving large-tonnage waste in the sphere of large-tonnage industrial production;
• the transfer of WWS from the category of waste to the category of raw materials determines their consumer value - the waste acquires a certain value;
• in ecological terms, waste of hazard class IV is placed in the roadbed, the asphalt concrete surface of which corresponds to hazard class IV;
• for the production of 1 m 3 of asphalt concrete mix, up to 200 kg of dry WWS can be disposed of as an analogue of mineral powder to obtain high-quality material that meets the regulatory requirements for asphalt concrete;
• the economic effect of the adopted method of disposal takes place both in the field of road construction (reducing the cost of asphalt concrete) and for Vodokanal enterprises (preventing payments for waste disposal, etc.);
• in the considered method of waste disposal, the technical, environmental and economic aspects are consistent.

Problem moments related to the need:

• cooperation and coordination of various departments;
• wide discussion and approval by specialists of the chosen method of waste disposal;
• development and implementation of national standards;
• amendments to the Law of Ukraine dated 05.03.1998 No. 187/98-ВР “On Waste”;
• development of technical specifications for products and certification;
• amendments to building codes and regulations;
• preparation of an appeal to the Cabinet of Ministers and the Ministry of Environmental Protection with a request to develop effective mechanisms for the implementation of waste disposal projects.

And finally, one more problematic point - can't solve this problem alone.

HOW TO SIMPLIFY ORGANIZATIONAL POINTS

On the way to the wide use of the considered method of waste disposal, organizational difficulties arise: cooperation of various departments with different visions of their production tasks is necessary - public utilities(in this case, Vodokanal, the owner of the waste) and a road construction organization. At the same time, they inevitably have a number of questions, incl. economic and legal ones, such as “Do we need it?”, “Is it a costly mechanism or profitable?”, “Who should bear the risks and responsibility?”

Unfortunately, there is no common understanding that the general environmental problem - the disposal of WWS (essentially waste from society accumulated by public utilities) - can be solved with the help of public utilities in the road construction industry by involving such waste in the repair and construction of public roads. That is, the whole process can be carried out within one communal department.

NOTE

What is the interest of all participants in the process?
1. The road construction industry receives sediment in the form of an analogue of mineral powder (one of the components of asphalt concrete) at a price much lower than the cost of mineral powder and produces high-quality asphalt concrete pavement at a lower cost.
2. Sewage treatment companies dispose of accumulated waste.
3. The society receives high-quality and cheaper road surfaces while improving the environmental situation in the territory of its residence.

Taking into account the fact that the disposal of WWS solves an important environmental problem of national importance, in this case the state should be the most interested participant. Therefore, under the auspices of the state, it is necessary to develop an appropriate legal framework that would meet the interests of all participants in the process. However, this will require a certain time interval, which in a bureaucratic system can be quite long. At the same time, as mentioned above, the problem of precipitation accumulation and the possibility of solving it are directly related to the utility industry, therefore it must be solved here, which will drastically reduce the time for all approvals, and narrow the list of necessary documentation to departmental standards.

VODOKANAL AS A PRODUCER AND CONSUMER OF WASTE

Is cooperation of enterprises always necessary? Let us consider the option of disposing of accumulated WWS directly by Vodokanal enterprises in their production activities.

NOTE

Vodokanal enterprises after repair work on pipeline networks obliged to restore the damaged roadbed, which is not always done. So, according to the results of our approximate average annual assessment of the volume of such works in the Luhansk region, these volumes range from 100 to 1000 m 2 of the coverage area, depending on the locality. Considering that the structure of large enterprises, such as Luganskvoda LLC, includes dozens of settlements, the area of ​​restored coatings can reach tens of thousands of square meters, which requires hundreds of cubic meters of asphalt concrete.

The need to get rid of waste, the properties of which make it possible to obtain high-quality asphalt concrete as a result of its disposal, and, most importantly, the possibility of its use in the repair of disturbed road surfaces are the main reasons for the possible use of the considered method of waste disposal by Vodokanal enterprises.

It should be noted that the WWS of treatment facilities in various settlements are similar in their positive impact on asphalt concrete, despite some differences. chemical composition.

For example, Asphalt concrete modified by precipitation in Luhansk (Luganskvoda LLC), Cherkassy (Azot Production Association) and Kievvodokanal meets the requirements of DSTU B V.2.7-119-2003 “Asphalt concrete mixes and asphalt concrete for road and airfield. Specifications» (hereinafter - DSTU B V.2.7-119-2003) (Table 1).

Let's discuss. 1 m 3 of asphalt concrete has an average weight of 2.2 tons. With the introduction of 6-8% sediment as a substitute for mineral powder in 1 m 3 of asphalt concrete, 132-176 kg of waste can be disposed of. Let's take an average value of 150 kg/m 3 . So, with a layer thickness of 3-5 cm, 1 m 3 of asphalt concrete allows you to create 20-30 m 2 of the road surface.

As you know, asphalt concrete consists of crushed stone, sand, mineral powder and bitumen. Vodokanals are the owners of the first three components as artificial technogenic deposits: crushed stone - replaceable loading of biofilters; sand and deposited sediment are waste from sand and silt sites (Fig. 1). To turn this waste into asphalt concrete (useful disposal), only one additional component is needed - road bitumen, the content of which is only 6-7% of the planned output of asphalt concrete.

Existing waste (raw materials) and the need to carry out repair and restoration work with the possibility of using these wastes are the basis for creating a specialized enterprise or site within the structure of Vodokanal. The functions of this unit will be:

• preparation of asphalt concrete components from existing waste (stationary);
• production of asphalt mix (mobile);
• laying the mixture in the roadway and its compaction (mobile).

The essence of the technology for preparing the raw material component of asphalt concrete - mineral (organo-mineral) powder based on WWS - is shown in Fig. 2.

As follows from Fig. 2, feedstock (1) - sediment from dumps with a moisture content of up to 50% - is preliminarily sieved through a sieve with a mesh size of 5 mm (2) to remove foreign debris, plants and loosen lumps. The sifted mass is dried (in natural or artificial conditions) (3) to a moisture content of 10-15% and is fed for additional screening through a sieve with meshes of 1.25 mm (5). If necessary, additional grinding of lumps of mass (4) can be performed. The resulting powdered product (microfiller is an analogue of mineral powder) is packed into bags and stored (6).

Similarly, crushed stone and sand are prepared (drying and fractionation). Processing can be carried out at a specialized site located on the territory of the treatment plant, using improvised or special equipment.

Consider the equipment that can be used at the stage of preparation of raw materials.

vibrating screens

Vibrating screens from various manufacturers are used for screening WWS. So, vibrating screens can have the following characteristics: “The adjustable rotation speed of the vibration drive allows you to change the amplitude and frequency of vibration. Hermetic design allows the use of vibrating screens without an aspiration system and with the use of inert media. The material distribution system at the entrance to the vibrating screens allows you to use 99% of the screening surface. The vibrating screens are equipped with a split class wiring system. End replacement of screening surfaces. High reliability, easy setup and adjustment. Quick and easy deck replacement. Up to three screening surfaces .

Here are the main characteristics of the VS-3 vibrating screen (Fig. 3):

• dimensions - 1200 × 800 × 985 mm;
• installed power - 0.5 kW;
• supply voltage - 380 V;
• weight - 165 kg;
• productivity — up to 5 t/h;
• sieve mesh size - any on request;
• price - from 800 dollars.

Dryers

For drying bulk material - soil (sediment) and sand - in an accelerated mode (as opposed to natural drying), it is proposed to use drum dryers SB-0.5 (Fig. 4), SB-1.7, etc. Consider the principle of operation of such dryers and their characteristics (Table 2).

Through the loading hopper, wet material is fed into the drum and enters the internal nozzle located along the entire length of the drum. The nozzle provides uniform distribution and good mixing of the material over the drum section, as well as its close contact with the drying agent during pouring. Continuously mixing, the material moves to the exit from the drum. The dried material is removed through the discharge chamber.

Delivery set: dryer, fan, control panel. In dryers SB-0.35 and SB-0.5, the electric heater is built into the structure. Production time - 1.5-2.5 months. The cost of such dryers is from 18.5 thousand dollars.

Moisture meters

To control the moisture content of the material, various types of moisture meters can be used, for example, VSKM-12U (Fig. 5).

Let's bring specifications such a moisture meter:

• humidity measurement range - from dry state to full moisture saturation (real ranges for specific materials are indicated in the device passport);
• relative measurement error - ± 7% of the measured value;
• depth of the control zone from the surface - up to 50 mm;
• calibration dependences for all materials controlled by the device are stored in non-volatile memory for 30 materials;
• the selected type of material and measurement results are displayed on a two-line display directly in humidity units with a resolution of 0.1%;
• the duration of a single measurement is no more than 2 s;
• duration of holding indications - not less than 15 s;
• universal power supply: autonomous from the built-in battery and from the mains ~ 220 V, 50 Hz via a network adapter (it is also a charger);
• dimensions of the electronic unit - 80 × 145 × 35 mm; sensor — Æ100×50 mm;
• total weight of the device - no more than 500 g;
• full service life - at least 6 years;
• price - from 100 dollars.

NOTE

According to our calculations, the organization of a stationary point for the preparation of asphalt concrete aggregates will require equipment in the amount of 20-25 thousand dollars.

Production of asphalt concrete with OSV filler and its laying

Consider the equipment that can be used directly in the process of manufacturing asphalt concrete with OSV filler and its laying.

Small Asphalt Mixing Plant

For the production of asphalt concrete mixtures from the production waste of Vodokanal and their use in the road surface, the smallest possible complex in terms of capacity is proposed - a mobile asphalt concrete plant (mini-APZ) (Fig. 6). The advantages of such a complex are low price, low operating and depreciation costs. The small dimensions of the plant allow not only its convenient storage, but also energy-efficient instant start-up and production of finished asphalt concrete. At the same time, the production of asphalt concrete is carried out at the place of laying, bypassing the stage of transportation, using a mixture of high temperature, which ensures a high degree of compaction of the material and excellent quality of the asphalt concrete pavement.

The cost of a mini-assembly plant with a capacity of 3-5 tons/hour is 125-500 thousand dollars, and with a capacity of up to 10 tons/hour - up to 2 million dollars.

Here are the main characteristics of mini-ABZ with a capacity of 3-5 t / h:

• outlet temperature — up to 160 °С;
• engine power - 10 kW;
• generator power - 15 kW;
• volume of bitumen tank - 700 kg;
• fuel tank volume - 50 kg;
• fuel pump power - 0.18 kW;
• bitumen pump power - 3 kW;
• exhaust fan power - 2.2 kW;
• skip hoist motor power - 0.75 kW;
• dimensions - 4000 × 1800 × 2800 mm;
• weight - 3800 kg.

In addition, to carry out a full cycle of work on the production and laying of asphalt concrete, it is necessary to purchase a container for transporting hot bitumen and a mini-skating rink for laying asphalt (Fig. 7).

Vibratory tandem road rollers weighing up to 3.5 tons cost 11-16 thousand dollars.

Thus, the entire complex of equipment required for the preparation of materials, production and placement of asphalt concrete can cost about 1.5-2.5 million dollars.

FINDINGS

1. The application of the proposed technological scheme will solve the problem of waste disposal from sewerage stations by involving them in economic circulation at the local level.

2. The implementation of the method of waste disposal considered in the article will make it possible to bring water utilities into the category of low-waste enterprises.

3. Through the use of WWS in the production of asphalt concrete, the list of services provided by Vodokanal can be expanded (the possibility of repairing intra-quarter roads and driveways).

Literature

1. Drozd G.Ya. Utilization of mineralized sewage sludge: problems and solutions // Ecologist's Handbook. 2014. No. 4. S. 84-96.
2. Drozd G.Ya. Problems in the sphere of treatment with deposited sewage sludge and methods for their solution // Water Supply and Water Supply. 2014. No. 2. S. 20-30.
3. Drozd G.Ya. New technologies for sludge disposal - a way to low-waste sewage treatment facilities // Vodoochistka. Water treatment. Water supply. 2014. No. 3. S. 20-29.
4. Drozd G.Ya., Breus R.V., Bizirka I.I. Deposited sludge from urban sewage. Recycling Concept // Lambert Academic Publishing. 2013. 153 p.
5. Drozd G.Ya. Proposals for the involvement of deposited sewage sludge in the economic turnover // Mater. International Congress "ETEVK-2009". Yalta, 2009. C. 230-242.
6. Breus R.V., Drozd G.Ya. A method for utilizing sediments from local sewage waters: Patent for the core model No. 26095. Ukraine. IPC CO2F1 / 52, CO2F1 / 56, CO4B 26/26 - No. U200612901. Appl. 12/06/2006. Published 09/10/2007. Bull. No. 14.
7. Breus R.V., Drozd G.Ya., Gusentsova E.S. Asphalt-concrete sumish: Patent for coris model No. 17974. Ukraine. IPC CO4B 26/26 - No. U200604831. Appl. 05/03/2006. Published 10/16/2006. Bull. No. 10.

• Sewage treatment facilities: issues of operation, economics, reconstruction

• Decree of the Government of the Russian Federation of 01/05/2015 No. 3 "On Amendments to Certain Acts of the Government of the Russian Federation in the Sphere of Water Disposal": what's new?

Wastewater coming from businesses or homes must be treated before being discharged into the ground or water bodies. A prerequisite is the degree of purity, which is 95-98%. During processing, a precipitate appears, which is reused or disposed of. The method of disposal of sewage sludge is determined by the composition and source.

Types of sewage sludge:

• deposits from the surface of the gratings;
• deposits with sandy elements;
• heavy forms of waste from primary clarifiers;
• components from the bottom, obtained by interaction with coagulating substances;
• activated sludge used for biochemical water purification in aerotanks;
• a film of biological origin, located on the surface of wastewater in biofilters;
• a mixture of activated sludge and heavy components of wastewater.

Components of sewage sludge (SSW):

1. 80-85% - components of fat, protein and carbohydrate nature.
2. 60-80% - solid organic matter.
3. The residual volume is the elements of lignin and humus.

Depending on the predominant component of WWS, there are:

• mineral;
• organic;
• mixed.

The sludge, which consists of wet sediments remaining at the bottom of the treatment plant, contains nitrogen, potassium, phosphorus. Trace elements are often used in agriculture as fertilizers. Long-term presence of such substances leads to decay, release of biogas. They also provoke a paradoxical reaction, when the sediment, instead of falling out, floats to the surface of the water. Therefore, containers need to be cleaned regularly.

Characteristics

The sludge obtained from wastewater treatment has certain characteristics:

The largest volume of WWS (90-99%) is water. It is divided into hygroscopic, free and colloidally bound.

Treatment and stabilization of sediments

Processing includes several stages:

• thickening with the removal of 60% moisture, reducing the total volume by 50%;
• seal;
• stabilization;
• conditioning.

Processing aims to remove the liquid and get the sludge. The latter is represented by fine particles, recycled pollutants.

To carry out compaction, the following technological approaches are used:

• vibration;
• gravity;
• flotation;
• filtration;
• a combination of several methods.

The most common and in a simple way compaction is considered a gravity technique. Designed to compress activated sludge and precipitation. Settling tanks of vertical and radial orientation are used. Duration - from 5 to 24 hours. If necessary, speed up the procedure, use:

• coagulation with ferric chloride;
• heating up to 90 degrees;
• mixing with other precipitates.

The flotation method is based on the ability of air bubbles to lift sediment fragments to the surface of the water. The speed is controlled by changing the air flow.

After processing, the stabilization phase begins. It is necessary for the separation of complex organic compounds into water, methane and carbon dioxide. Carried out under anaerobic and aerobic conditions. If aerobic stabilization is used, then the degree of decay is low, but WWS is characterized by stability. The disadvantage of oxygen treatment is the preservation of helminth eggs, which requires additional disinfestation of wastewater.

Wastewater sludge disposal technologies

Today, there are several methods of disposal - deposition, incineration, pyrolysis, use in the form of fertilizers. Each option has advantages and disadvantages. But everyone does important task- Recycle sludge. Some are able to provide raw materials for recycling.

From an environmental point of view, recycling approaches that allow the reuse of the resulting substances are considered promising.

Deposit at sludge sites

Up to 90% of all precipitation is utilized at sludge sites today. The disadvantage of the technique is evaporation, polluting the atmospheric air. The released biogas exceeds the allowable limits and worsens the air quality. Therefore, additional conditioning of sludge obtained from wastewater is required. When it enters the ground, it slags groundwater and reservoirs.

Disposal as fertilizer

According to the hazard class, they belong to the 4th group, as the least dangerous. Therefore, they are allowed to be disposed of as fertilizers for agricultural land.

The exception is precipitation containing heavy metals, toxic substances. To control pollution, regulatory documents are created that set the permissible limits for the concentration of hazardous components.

In Western European countries, farms specializing in the cultivation of organic plants have refused to use such fertilizers on their lands.

Incineration of sewage sludge

The disposal method by incineration of sewage sludge is implemented as follows:

• hot sand torch activation;
• location above the air flow;
• conducting liquid with precipitation through the torch;
• combustion with the formation of gas;
• gas purification.

The beginning of the construction of recycling plants operating under the incineration program dates back to 1980 in the USA, Japan, and European countries. The negative impact on the environment suspended the further use of this technique already in 1990.

AT European countries the technology of sludge disposal with the production of raw materials for recycling is popular. Also, such methods reduce operating costs.

Pyrolysis

Pyrolysis is considered the most advanced recycling method. Pyrolysis is based on the decomposition of organic components under the influence of high temperatures (700 degrees) without the participation of oxygen (anaerobic method).

The advantage over direct combustion is the elimination of harmful substances that enter the atmosphere along with gas. The reason for this phenomenon lies in the recycling technology, because only organic components are processed with the help of pyrolysis.

Thermal decomposition result:

• 55% combustible gas;
• 35% char;
• 15% liquid organic elements.

The organic matter flies away with the gas, and the semi-coke undergoes further processing (gasification) to produce combustible gas. After gasification, metal oxides remain in the form of purified slag available for further use.

Use of slag

The slag obtained as a result of recycling is successfully used in the construction and repair of roads. Several reuse methods have been proposed:

1. If you mix slag with cement, subject it to vibrocompression, then the output is paving slabs. The thickness of each plate is 10 cm. The configuration and color are variable, depending on the desire of the buyer.
2. Also, with the help of slag, dumps are filled, damaged sections of the roadway are repaired.

Recycling is reaching a new level today, when they seek to find a way to maximize the complete processing of WWS. The use of recycled materials is an indicator of a healthy country that wants to preserve the environment for itself and future generations.

The state of the environment directly depends on the degree of purification of industrial wastewater from nearby enterprises. Recently environmental issues are very sharp. Over the past 10 years, many new effective technologies for industrial wastewater treatment have been developed.

Treatment of industrial wastewater from different facilities can occur in one system. Representatives of the company can agree with utilities on the discharge of their wastewater into the general centralized sewerage of the settlement where it is located. To make this possible, a chemical analysis of effluents is preliminarily carried out. If they have an acceptable degree of pollution, then industrial wastewater will be discharged together with domestic wastewater. It is possible to pre-treat wastewater from enterprises with specialized equipment for the elimination of pollution of a certain category.

Standards for the composition of industrial effluents for discharge into the sewer

Industrial waste waters may contain substances that will destroy sewer lines and city treatment plants. If they get into water bodies, they will negatively affect the mode of water use and life in it. For example, if the MPC is exceeded, toxic substances will harm surrounding water bodies and, possibly, humans.

To avoid such problems, before cleaning, the maximum permissible concentrations of various chemical and biological substances are checked. Such actions are preventive measures for the proper operation of the sewer pipeline, the functioning of treatment facilities and environmental ecology.

Effluent requirements are taken into account during the design of the installation or reconstruction of all industrial facilities.

Factories should strive to operate on technologies with little or no waste. Water must be reused.

Wastewater discharged into the central sewer system must comply with the following standards:

• BOD 20 must be less than the allowable value of the design documentation of the treatment plant sewer network;
• drains should not cause failures or stop the operation of the sewerage and treatment plant;
• wastewater should not have a temperature above 40 degrees and a pH of 6.5-9.0;
• waste water should not contain abrasive materials, sand and chips, which can form sediment in sewerage elements;
• there should be no impurities that clog pipes and grates;
• drains should not have aggressive components that lead to the destruction of pipes and other elements of treatment stations;
• wastewater should not contain explosive components; non-biodegradable impurities; radioactive, viral, bacterial and toxic substances;
• COD should be less than BOD 5 by 2.5 times.

If the discharged water does not meet the specified criteria, then local wastewater pre-treatment will be organized. An example would be the treatment of wastewater from the galvanizing industry. The quality of cleaning must be agreed by the installer with the municipal authorities.

Types of industrial wastewater pollution

Water treatment should remove environmentally harmful substances. The technologies used must neutralize and dispose of the components. As can be seen, treatment methods must take into account the initial composition of the effluent. In addition to toxic substances, water hardness, its oxidizability, etc. should be controlled.

Each harmful factor (HF) has its own set of characteristics. Sometimes one indicator can indicate the existence of several WFs. All WFs are divided into classes and groups that have their own cleaning methods:

• coarsely dispersed suspended impurities (suspended impurities with a fraction of more than 0.5 mm) - screening, sedimentation, filtration;
• coarse emulsified particles - separation, filtration, flotation;
• microparticles - filtration, coagulation, flocculation, pressure flotation;
• stable emulsions - thin-layer sedimentation, pressure flotation, electroflotation;
• colloidal particles - microfiltration, electroflotation;
• oils - separation, flotation, electroflotation;
• phenols - biological treatment, ozonation, sorption activated carbon, flotation, coagulation;
• organic impurities - biological treatment, ozonation, activated carbon sorption;
• heavy metals - electroflotation, settling, electrocoagulation, electrodialysis, ultrafiltration, ion exchange;
• cyanides - chemical oxidation, electroflotation, electrochemical oxidation;
• tetravalent chromium - chemical reduction, electroflotation, electrocoagulation;
• trivalent chromium - electroflotation, ion exchange, precipitation and filtration;
• sulfates - settling with reagents and subsequent filtration, reverse osmosis;
• chlorides - reverse osmosis, vacuum evaporation, electrodialysis;
• salts - nanofiltration, reverse osmosis, electrodialysis, vacuum evaporation;
• Surfactants - activated carbon sorption, flotation, ozonation, ultrafiltration.

Types of wastewater

Effluent pollution is:

• mechanical;
• chemical - organic and inorganic substances;
• biological;
• thermal;
• radioactive.

In every industry, the composition of wastewater is different. There are three classes that contain:

1. inorganic pollution, including toxic ones;
2. organics;
3. inorganic impurities and organic matter.

The first type of pollution is present in soda, nitrogen, sulfate enterprises that work with various ores with acids, heavy metals and alkalis.

The second type is characteristic of enterprises oil industry, organic synthesis plants, etc. There is a lot of ammonia, phenols, resins and other substances in the water. Impurities during oxidation lead to a decrease in oxygen concentration and a decrease in organoleptic qualities.

The third type is obtained in the process of electroplating. There are a lot of alkalis, acids, heavy metals, dyes, etc. in the drains.

Wastewater treatment methods for enterprises

Classical cleaning can occur using various methods:

• removal of impurities without changing their chemical composition;
• modification of the chemical composition of impurities;
• biological cleaning methods.

Removal of impurities without changing their chemical composition includes:

• mechanical cleaning using mechanical filters, settling, filtering, flotation, etc.;
• at a constant chemical composition, the phase changes: evaporation, degassing, extraction, crystallization, sorption, etc.

The local wastewater treatment system is based on many treatment methods. They are selected for a certain type of wastewater:

• suspended particles are removed in hydrocyclones;
• fine impurities and sediment are removed in continuous or batch centrifuges;
• flotation plants are effective in removing fats, resins, heavy metals;
• gaseous impurities are removed by degassers.

Wastewater treatment with a change in the chemical composition of impurities is also divided into several groups:

• transition to sparingly soluble electrolytes;
• the formation of fine or complex compounds;
• decay and synthesis;
• thermolysis;
• redox reactions;
• electrochemical processes.

The effectiveness of biological treatment methods depends on the types of impurities in the effluent, which can accelerate or slow down the destruction of waste:

• the presence of toxic impurities;
• increased concentration of minerals;
• biomass nutrition;
• structure of impurities;
• biogenic elements;
• environment activity.

In order for industrial wastewater treatment to be effective, a number of conditions must be met:

1. Existing impurities must be biodegradable. The chemical composition of wastewater affects the rate of biochemical processes. For example, primary alcohols oxidize faster than secondary ones. With an increase in oxygen concentration, biochemical reactions proceed faster and better.
2. The content of toxic substances should not adversely affect the operation of the biological installation and treatment technology.
3. PKD 6 also should not disrupt the vital activity of microorganisms and the process of biological oxidation.

Stages of wastewater treatment of industrial enterprises

Wastewater treatment takes place in several stages using different methods and technologies. This is explained quite simply. It is impossible to carry out fine purification if coarse substances are present in the effluents. In many methods, limiting concentrations are provided for the content of certain substances. Thus, wastewater must be pre-treated before the main treatment method. The combination of several methods is the most economical in industrial enterprises.

Each production has a certain number of stages. It depends on the type of treatment plant, treatment methods and composition of wastewater.

The most appropriate way is a four-stage water treatment.

1. Removal of large particles and oils, neutralization of toxins. If the wastewater does not contain this type of impurities, then the first stage is skipped. It is a pre-cleaner. It includes coagulation, flocculation, mixing, settling, screening.
2. Removal of all mechanical impurities and preparation of water for the third stage. It is the primary stage of purification and may consist of settling, flotation, separation, filtration, demulsification.
3. Removal of contaminants up to a certain predetermined threshold. Secondary processing includes chemical oxidation, neutralization, biochemistry, electrocoagulation, electroflotation, electrolysis, membrane cleaning.
4. Removal of soluble substances. It is a deep cleaning - activated carbon sorption, reverse osmosis, ion exchange.

The chemical and physical composition determines the set of methods at each stage. It is allowed to exclude some stages in the absence of certain contaminants. However, the second and third stages are mandatory in the treatment of industrial wastewater.

If you comply with the listed requirements, then the disposal of wastewater from enterprises will not cause damage environmental situation environment.

Description:

Recycling building effluent, after appropriate treatment, can successfully help solve crises that exist in regions with insufficient supplies. water resources.

Waste water recycling

The recycling of building waste, after appropriate treatment, can successfully contribute to the solution of crisis situations that exist in regions with insufficient water resources.

In many regions of our country, there are serious problems with water supply due to insufficient water resources, and, as a result, water-saving technologies are becoming extremely important here.

Measures that could help save money natural resources and make a significant contribution to solving the problem, or at least alleviate its severity, seem to be as follows:

– encouragement to reduce consumption;

– water regeneration (if possible);

– reuse of runoff and rainwater (usually requires additional treatment).

In particular, the secondary utilization of already used water reduces the level of pollution of natural areas that receive wastewater. The collection of rainwater in bathtubs or catch basins, followed by planned use, prevents overloading the sewer network in case of heavy rainfall. In addition, if domestic and sewage drains merge into one sewer channel, this makes it possible not to dilute sewage so much, since otherwise this would disrupt the biological phase of treatment. In terms of the reuse of such water for the protection of public health, certain requirements are established in relation to sanitary, hygienic and chemical parameters. Depending on the required quality of the final product, cleaning can be more or less difficult.

Picture 1.

Normative documents

Regulatory requirements for the recycling of municipal wastewater in different countries different and more or less restrictive. In Europe, the main document is the European regulation 91/271. In Italy, in terms of the recycling of wastewater within the framework of the policy of conservation and stimulation of the saving of natural resources, the republican legislation in the field of nature protection is considered to be the guiding one (law of 01/05/1994 No. 36, legislative act of 05/11/1999 No. 2003 No. 185), as well as legislative acts at the regional level (having their own powers in this area). Regulatory requirements for the quality of water reclaimed for reuse in various fields of activity have been drawn up by several authorities. These are, first of all, the main directions that determine the maximum permissible parameters: WHO regulations ( world organization Health), EEA (European Environment Agency), EPA (Environmental Protection Agency).

Areas of use

For secondary use, both domestic wastewater, as well as urban and industrial wastewater, can be sent. Reuse is permitted provided that complete environmental safety is ensured (i.e. such use should not damage the existing ecosystem, soil and cultivated plants), and any risk to the local population in terms of sanitary and hygienic terms is excluded. Thus, it is essential that any such project carefully adheres to the requirements of existing regulations. normative documents in terms of health and safety, as well as current industry codes and regulations for industry and agriculture.

In most cases, in order for water to be recycled, it must first be treated. The choice of the degree of such purification is determined by the established requirements for sanitary and hygienic safety and cost parameters. To organize the supply of secondary regenerated water after treatment, a dedicated distribution pipeline is required.

According to regulation 185/2003, there are three main categories for the use of reclaimed water:

– irrigation systems: watering cultivated plants, intended for the production of food products for human and pet consumption, as well as non-food products, by watering green areas, landscape gardening areas and sports facilities;

- civil purpose: washing of bridges and sidewalks of settlements, water supply of heating networks and air conditioning networks, water supply of secondary water distribution networks (separate from drinking water supply) without the right to directly use such water in civil buildings, with the exception of drain systems for toilets and bathrooms;

– industrial purpose: supply of fire extinguishing systems, production circuits, washing systems, thermal cycles of production processes, with the exception of applications that involve contacting recycled water with food, pharmaceutical and cosmetic products.

Before the reuse of reclaimed water, a certain level of quality must be ensured, especially with regard to sanitary and hygienic requirements. Traditional Methods water treatment sent for discharge are insufficient to ensure such quality. Today, new alternative technologies for cleaning and disinfection are emerging, with the help of which it is possible to reduce the level of microbes, nutrients, toxic substances in water and reach the required level of water quality at a relatively low cost. The regulatory documentation contains the minimum acceptable quality parameters that water must have after regeneration if it is supposed to be sent for recycling. The indicated requirements (chemical-physical and microbiological) for reclaimed water destined for reuse for irrigation or civil purposes are given in the table in the annex to regulation 185/2003. For water intended for industrial use, limit values ​​are set depending on the specific production cycles. The construction of wastewater recovery systems and their subsequent use must be carried out with the authorization of the competent authorities and are subject to periodic inspection control. Distribution networks for reclaimed water must be specifically marked and distinguished from drinking water networks in order to completely eliminate any risk of contamination of the drinking water distribution network. The tapping points of such networks must be appropriately marked and clearly distinguished from drinking points.

At the same time, with all the advantages that modern technology provides, in addition to direct benefits, the implementation of measures to save water resources may entail certain risks.

Figure 3 Water treatment facilities

Wastewater Treatment Methods

The wastewater treatment method in each specific case, depending on the required final quality of the product, may include the following types of treatment:

– pre-cleaning: includes passing through a sieve (removal of large solids), sand removal (through sedimentation baths), pre-aeration, extraction of oil particles (most oils and fats are driven to the surface by air blowing), screening (removal of suspended particles using rotating sieves);

– primary purification is carried out by sedimentation: in the sedimentation bath, a significant part of the settling solids is separated by mechanical decantation. The process can be accelerated by the use of chemical additives (flocculators): in the flocculation clarification baths, the precipitation of solid particles increases, as well as the precipitation of non-settling suspended particles;

– secondary treatment with the use of aerobic bacteria that ensure the biological destruction of the organic load, thus the biological oxidation of suspended biodegradable organic matter dissolved in wastewater. Cleaning methods can include suspended biomass processes (active dirt), where the dirt is kept in a state of constant mixing with sewage, and adhesive biomass processes (providing a percolator base or a spinning biodisk substrate), during which decontaminating bacteria are attached to a fixed base;

– purification of the third level is used after primary and secondary in the case when, in accordance with the quality requirements for purified water, nutrients (nitrates and phosphates) must be removed from it;

- nitrification, denitritification, dephosphorization: purification processes that ensure, respectively, the conversion of organic nitrogen into nitrates, the decomposition of nitrates with the formation of gaseous nitrogen, the removal of soluble phosphorus salts from wastewater;

- final disinfection is used when it is required to ensure complete sanitary and hygienic safety of wastewater. The technique involves the use of chlorine-based reagents or ozonation or ultraviolet irradiation. In addition to the above methods, there are two more natural wastewater treatment technologies that can be used as second or third level treatment. These are phytocleaning and biological settling (or lagooning). Both technologies are mainly used in small wastewater treatment plants or in areas where large areas can be used. The essence of phyto-purification is that waste water is gradually poured into baths or channels, where the surface (water depth 40–60 cm) is directly under the open sky, and the bottom, which is always under water, serves as the basis for the roots of a special plant species. The task of plants is to contribute to the creation of a microenvironment suitable for the reproduction of microbial flora, which biological treatment. After passing the cleaning bath, the water is slowly, and in a volume equal to the filled volume of water, is sent for further use.

Biological sedimentation requires large pools (lagoons), where sewage fecal water is periodically poured. There is a gradual biological decomposition of pollution by microbial colonies living in the pool (due to aerobic or anaerobic metabolism) or algae.

Purification to drinking water quality

In certain cases, when there is insufficient supply of drinking resources, wastewater that has undergone appropriate treatment can be used as such. There are no such treatment facilities in Italy yet, but they have been built in a number of countries. Treated wastewater can be supplied directly to the drinking water supply or to a storage reservoir (natural or artificial). Alternatively, such water can be directed to feed aquifers by direct injection directly into the aquifer or by natural infiltration through permeable soils. From the horizon saturated in this way, water is taken through wells arranged far from the site where infiltration is organized. In order to purify wastewater to the state of drinking water suitable for direct supply to a drinking water supply, or for injection into an aquifer, it is necessary that it successively undergo the following types of treatment:

clarification by flocculation - filtration - absorption by activated carbon - membrane purification (reverse osmosis) - final disinfection.

More easy cleaning(filtration - activated carbon absorption - disinfection) is carried out for wastewater intended to feed aquifers by infiltration through permeable soils, since in this case the natural ability of the soil to serve as a filter pad is used.

Reuse of wastewater for technical (non-potable) purposes

The most popular technology today is the so-called dual systems. Next to normal water supply network for drinking purposes, a second dedicated network for the delivery of treated wastewater is organized.

This water can be used for the following purposes:

- domestic process water for sanitary facilities in cases where there is no direct contact with a person (i.e., mainly for flushing toilet bowls);

– watering of green spaces of landscape gardening areas, sports fields, golf courses, etc.;

– washing of streets, sidewalks, pedestrian crossings, etc.;

– water supply for decorative fountains;

- car wash.

Purification of water for technical use provides for successive passage through clarification by flocculation, filtration and disinfection. Basically, domestic wastewater is sent for such treatment, most often in order not to create an unnecessarily cumbersome network, the so-called “gray” drain, excluding fecal water containing urine and feces.

At the same time, in parallel with common dual systems, today there are effective technologies for treating water already used in individual bathroom units for subsequent secondary use, when, for example, wastewater from washbasins, bathtubs and showers is filtered, soap and dirt are removed from it, and it is sent to a toilet cistern or for other technical needs, for example, for washing a car or watering a garden. Such systems are suitable for individual houses, individual apartments, small hotels, clubs, etc. The results of the experiments have shown that in terms of actual resource consumption, such systems provide savings of up to 50% in ordinary residential buildings and up to 40% in the hotel business and trade. The main advantages are the complete autonomy of the water supply system with the absolute impossibility of cross-contamination of drinking and industrial water, the absence of chemicals and harmful by-products, significant energy efficiency (a 12 W direct current source is used to power the electric pump), the possibility of using solar energy, a fully automatic cleaning cycle.

Reuse of wastewater for general purposes

Treated wastewater can be successfully used for general purposes in both civil and industrial areas. These can be, in particular, heating systems (power circuits for heating boilers), cooling systems (cooling towers, condensers, heat exchangers), fire safety (fire extinguishing systems with water). For use in heating boilers, waste water should be passed through a clarification by flocculation, then filtered and demineralized.

The last type of treatment involves passing water through an ion exchange resin pad. Use in cooling circuits typically involves clarification by flocculation, filtration and usually disinfection.

Recycled water in industry

In industrial processes, many operations require the use of water. Among them:

– preparation of steam in boilers and air humidifiers;

- heat exchange in heating systems, vapor condensation, cooling of liquid and solids;

– particulate washing and gas cleaning;

– surface treatment baths of various kinds.

In many cases where production requires large volumes of water, treated wastewater is also quite suitable for this purpose, for example, in the textile industry, pulp and paper, dye shops and metallurgy. Given the extreme variety and variety of industrial processes, the quality of secondary water is required for them to be very different and, therefore, in each specific case, different treatment systems are used for wastewater treatment.

Secondary water in agriculture

Recycled water in agriculture provides tangible savings in water consumption. Indeed, water consumption in the agro-zootechnical sector significantly exceeds the consumption in the civilian sector and industry. For Italy, these figures are respectively 60%, 15% and 25%. Pursuant to the European regulation (recognizing the provisions of the European Directive 91/271 as valid), at present, preference is given to recycled water, and connection to the main water supply - if the water is not intended for drinking purposes or the ichthyogenic sphere - is limited to cases where it is not possible to use treated wastewater or when these economic costs are obviously prohibitive. Waste water is released free of charge, and capital expenses for the organization of treatment systems are deducted from the taxable base.

It should be taken into account that the use of recycled water in agriculture is not always possible, but only, for example, if the agricultural land where this technology is supposed to be used is located in a very remote area or at a lower altitude level.

Waste water should not be used when its chemical composition is incompatible with agriculture (excess sodium and calcium compared to potassium and magnesium). It is important to note that the ridiculously low current price of ordinary tap water released for irrigation (as measured by the cost of a connection or drilling license) does not encourage a switch to reclaimed wastewater. Wastewater treatment technology for Agriculture varies depending on the types of crops for which they are intended. To irrigate crops intended for raw consumption, water must be clarified by flocculation, filtration and disinfection (sometimes lagoon). For irrigation of gardens and pastures - only clarification by flocculation (or biological sedimentation) and disinfection, for irrigation of fields with non-food crops - biological sedimentation (and, if necessary, reservoir baths).

Rain water recovery

In individual houses, condominiums, hotels, rainwater collected in storage tanks can be successfully used in the working circuits of sanitary appliances, washing machines, for cleaning, watering plants, washing cars. It is estimated in the private sector that up to 50% of the daily water requirement can be converted to the use of reclaimed rainwater.

Due to its characteristics (very soft), rainwater, compared to tap water, gives best results if used for watering plants and washing clothes. In particular, such water does not leave deposits on the pipes, cuffs and heating elements of washing machines and reduces the amount detergent not to mention that no one has to pay for it. In the municipal sector, it can be recommended for watering landscape gardening areas and washing streets. In industry, rainwater can also be used in a variety of production areas, resulting in significant savings in water costs and a significant impact on the cost of processes.

It should be borne in mind that rainwater does not require any special treatment at all: just a simple filtration is enough while it flows down the roofs of buildings and enters storage tanks.

In a rainwater recovery system, depending on where the storage tank is located (for example, buried in the ground), a water pressure pump may be required. On fig. 5 shows a diagram of such a system.

Rainwater is considered unsuitable for drinking, therefore the supply pipeline and water points (water taps, points of connection to household appliances) must be marked with a clearly visible warning sign: "water not suitable for drinking".

Reprinted with abridgements from the RCI Journal No. 2/2006

Translation from Italian S. N. Bulekova

In domestic and industrial water supply systems, special treatment facilities have been installed, in which the remains of dirty effluents accumulate over time. Silt deposits contain a huge amount of hazardous chemicals. If they get into the soil, they cause irreparable harm not only to the soil, but also groundwater. Therefore, pouring contaminated liquids without prior neutralization is prohibited.

Disposal of wastewater from industrial enterprises is a mandatory measure, since liquid waste is classified as hazard class 4. They can poison the water used by people and permanently upset the balance of land and water resources in the area. Therefore, in order to competently disinfect liquid products, responsible entrepreneurs are increasingly turning to recycling professionals.

How is sewage sludge disposed of?

For efficient processing of dirty suspensions, specialists use a complex of specialized equipment. Sediments are taken to a high-tech site for their neutralization. As a result, valuable material can be obtained from liquid impurities for land irrigation, heat generation, construction and other purposes. Unsuitable sludge is burned or used as fertilizer after processing.

Methods for the disposal of sewage sludge are selected taking into account the concentration and chemical composition of the suspension. Skilled workers resort exclusively to environmentally friendly methods of neutralization and disposal. The pyrolysis method is widely used. It provides for the decomposition of organic compounds under thermal influence. Harmful substances are not emitted.

Properly executed waste disposal provides:

preservation of a favorable environmental background on the ground, without the presence of odor and toxic emissions into the air, soil and water;

obtaining useful energy, industrial, construction and other resources;

proper functioning of the water supply system and local treatment facilities;

execution of production processes without the risk of being penalized for improper disposal of dirty liquid.

At the legislative level, the need for disinfection and processing of sludge is controlled federal law"On production and consumption waste". Failure to comply with sanitary and epidemiological and environmental requirements entails significant penalties.

Domestic and industrial wastewater: recycling is profitable at ECOUMWELT

Qualified employees from the ECOUMWELT company have extensive experience in the field of industrial waste and the processing of dirty effluents of any type. They have modern equipment and know perfectly how to neutralize sewage deposits without harming the environment.

If you contact ECOUMWELT, then the disposal of sewage sludge will be carried out on the most favorable terms for you:

with the conclusion of an agreement and the execution of official reporting documentation confirming the processing in accordance with the regulations;

with payment for professional service at the lowest rates available to all;

with the provision by the company of its own specialized transport and equipment for recycling procedures.

If you want to consult on the processing of wastewater and quickly order the service, call us or write an e-mail. Disposal of liquid waste is carried out on time, in Moscow and with a trip to the region!