RU2782889C1 - Decontamination unit - Google Patents

Abstract

FIELD: wastewater treatment.

SUBSTANCE: invention relates to the field of wastewater treatment. Sewage treatment plant contains a water disinfection unit, including an ultraviolet radiation lamp located in a quartz case. The cover with the lamp is inserted into the gravity flow in the treatment plant housing, located between the last sump of the sewage treatment plant and the forced pumping chamber or the outlet of the treated water gravity discharge. The UV lamp is a low pressure ozone free amalgam lamp.

EFFECT: increased efficiency of wastewater disinfection.

4 cl, 2 dwg

Description

The invention relates to the field of wastewater treatment.

Wastewater, which is a product of human life, at the outlet of sewage treatment plants must contain a normalized amount of chemical pollutants in certain concentrations that do not cause any environmental damage to the environment.

In addition to chemicals, wastewater contains pathogenic microorganisms, the concentration of which is also regulated by the current legislation in order to prevent deterioration of the sanitary situation in the area of wastewater discharge into the environment.

According to the coverage of users of the wastewater system, all sewage treatment plants (STP) can be divided into two fundamentally different groups:

1. KOS for collective use, located on specially designated sites, as a rule, remote from the settlement. The construction of the WWTP of this group is associated with the passage of all stages of the implementation of capital construction projects, including the passage of an examination for compliance with environmental and sanitary and epidemiological requirements;

2. WWTP for individual use - local treatment facilities (VOC) located directly on the site of the owner (user). The construction of the WWTP of this group, as a rule, is carried out by the owner without any project, therefore, the issues of compliance with environmental and sanitary and epidemiological requirements are within the competence of the developer and manufacturer of this equipment.

In contrast to WWTPs of settlements, the discharge of treated wastewater from which, as a rule, is carried out into water bodies, the main methods of disposal of wastewater treated at individual WWTPs are:

• discharge into the ground through various types of filtering facilities (underground filtration fields, filtering wells, etc.) - possible only if the facility is located in close proximity to the water body;

• dumping on the terrain, ditch - the vast majority of cases;

• Irrigation of green plantings in summer is a special case of discharge onto the terrain.

The discharge of treated wastewater into water bodies and underground layers excludes direct contact of treated wastewater with a person, while the release of the same water to the surface is associated with the possibility of such interaction.

Thus, the issues of disinfection are of the greatest relevance for individual VOCs. Currently, all VOCs are sold without a mandatory disinfection step.

The main methods of decontamination used at the WWTP for collective use are:

- chlorination (liquefied, gaseous chlorine, hypochlorite, bleach);

- oxidation with oxygen (ozonation);

- treatment with ultraviolet rays (UV disinfection).

Chlorination

Chlorination, as the simplest and most reliable method of disinfection, was widespread in collective sewage treatment plants at the end of the last century.

However, the costs associated with ensuring the industrial safety of the facility when using gaseous or liquefied chlorine necessitated the transition to disinfection with a hypochlorite solution, or the search for alternative methods of disinfection.

Moreover, since chlorine has a prolonged effect, its discharge with treated wastewater has a negative impact on the natural environment. To minimize this effect, it is necessary to carry out a dechlorination process, which increases the cost of wastewater treatment.

On individual WWTPs, this method has limited application in the form of a unit with chlorine tablets installed at the outlet of the WWTP.

Ozonation

The ozonation technology is widely used in water treatment facilities for the oxidation of organic substances and disinfection, as well as in the preparation of water in swimming pools.

However, this method is practically not used at WWTP due to the high cost of purchasing and maintaining equipment - ozonizers.

UV disinfection

UV disinfection is the main disinfection method that has replaced chlorination.

The positive properties of this method include the high efficiency of the process and the safety of treated wastewater, as well as the absence of reagents.

However, there are also disadvantages - high power consumption, high cost of equipment and consumables, as well as increased requirements for the quality of treated wastewater entering the UV treatment.

The problem of existing UV disinfection

Currently, a number of large manufacturers offer disinfection units as additional equipment supplied at the request of the Customer.

As a rule, such nodes are called "sterilizers", which is not entirely correct, but reflects the main purpose of this equipment.

Almost all sterilizers on the market are installed on the pressure line for the removal of treated wastewater.

In order to save the life of the lamp, it is switched on at the time of the flow of the treated water, i.e. when the forced pump is turned on.

This solution for organizing a disinfection unit has a number of significant drawbacks, which are exacerbated by the small volume of the treated wastewater chamber:

• the need to frequently turn on the purified water pump leads to the rapid exhaustion of the lamp life in terms of the number of starts - which, along with the total number of lamp hours, is normalized by the manufacturer. That is, there is a need for frequent replacement of UV lamps, which leads to an increase in operating costs;

• the life of the lamps used is about 10,000 hours of operation and 1,000 on/off cycles;

• any lamp needs a certain period of time to reach the specified parameters of UV radiation power, therefore, when the supply pump is turned on, the first portion of purified water is not irradiated, or it is irradiated less intensively, which leads to the discharge of insufficiently disinfected water into the environment. Moreover, if the period of "ignition" of the lamp is longer than the period of pumping out the purified water chamber, the use of UV disinfection generally loses its meaning;

• taking into account the high performance of the pump for supplying treated wastewater to the lamps, the “exposure” time (contact of water and UV radiation) may not be enough;

• This equipment is not applicable to WWTP with gravity discharge of treated wastewater, or requires the use of WWTP with pressure pumping, which also increases both capital and operating costs.

Considering the foregoing, it can be concluded that the equipment for UV disinfection of wastewater offered on the market in most cases does not operate in normal mode, not providing the full required functionality, therefore, the known equipment has a low efficiency of wastewater disinfection.

The closest analogue, chosen as a prototype of the claimed technical solution, is a plant for treating wastewater from organic and mineral substances by ultraviolet irradiation, including a pre-treatment unit, a mechanical filter, an ultraviolet irradiation chamber, a circulation pipeline and pipes for inlet of treated and outlet of treated water ( see RU 65042 U1, published 07/27/2007). At the same time, the pretreatment unit consists of a settling tank-clarifier with a built-in mixing-flocculation chamber with nozzles for introducing reagents, communicated with a clarified water tank. The clarified water tank is connected in series with a circulation pipeline to a pump, a mechanical filter, an ejector for introducing oxidizers and catalysts, a UV irradiation chamber, and a sorption filter connected, in turn, to the clarified water tank. Moreover, the purified water outlet pipe is installed on the circulation pipeline after the sorption filter.

The disadvantages of the prototype are:

- the location of the UV disinfection module placed outside the WWTP body, which leads to bulkiness and high cost of the installation as a whole;

- high labor intensity of replacing the UV lamp and the need for this additional special tool;

- small resource of the used UV lamp;

- turning on the UV lamp only at the moment of wastewater pumping.

These shortcomings, as mentioned above, lead to low efficiency of wastewater disinfection.

The technical result of the claimed invention is to increase the efficiency of wastewater disinfection.

This technical result is achieved due to the fact that the sewer treatment plant contains a water disinfection unit, including an ultraviolet radiation lamp located in a quartz case, while, according to the invention, the case with the lamp is inserted into a gravity overflow in the treatment facility housing, located between the last sump of the sewer treatment plant and a forced pumping chamber or a gravity discharge of treated water.

In this case, the lamp cover can be made in such a way that it can be removed from the overflow without additional tools.

In this case, the ultraviolet radiation lamp may be a low-pressure ozone-free amalgam lamp.

In this case, the lamp can have a service life of 16,000 hours and 2,000 on-off cycles.

In this case, the lamp with a cover can be in a permanently immersed in water position.

Embodiments of the invention are schematically shown in Fig.1, 2.

Figure 1 shows an embodiment of the invention with gravity discharge of treated wastewater.

Figure 2 shows an embodiment of the invention in the forced discharge of treated wastewater.

Figures 1 and 2 contain the following positions: 1 - treated wastewater, 2 - wastewater after UV disinfection, 3 - gravity flow between the last sump of the treatment plant and the outlet of the gravity discharge of treated water (in Fig.1) or a forced pumping chamber ( figure 2), 4 - UV lamp in a quartz case.

The invention works as follows.

In any well-known sewage treatment plant, a water disinfection unit is equipped. This assembly is an ultraviolet lamp located in a quartz case. In this case, a quartz case with a UV lamp (4) is inserted into a gravity overflow (3) in the body of the treatment plant. The specified overflow (3) is located between the last sump of the sewage treatment plant and the forced pumping chamber (figure 2) or the outlet of the gravity discharge (figure 1) of treated water.

The lamp cover is designed in such a way that it can be removed from the overflow without additional tools.

The UV lamp is a low pressure ozone free amalgam lamp. The lamp has a lifespan of 16,000 hours and 2,000 on-off cycles. The lamp with the case is in a permanently immersed position in water.

Advantages of the invention: 1) the UV disinfection module is located in the WWTP body and is inserted into the gravity flow between the last settling tank and the forced pumping chamber / outlet of the treated water gravity discharge. Thus, this module is applicable both on models with forced discharge of treated wastewater, and on gravity ones; 2) the lamp is in a quartz case, constantly immersed in water, which is natural cooling; 3) the lamp cover can be easily removed from the flow without special tools, which allows you to quickly service the cover or replace the lamp if it malfunctions; as a working element of the module, an ozone-free low-pressure amalgam lamp was used, which has a service life of 16,000 hours or about 2 years and 2000 on / off cycles (a feature of these lamps is a long operating time, which allows you not to turn off the lamp during continuous operation of the WWTP); 4) lamp power depends on VOC performance; 5) the use of this module is possible both on newly manufactured WWTPs and on WWTPs produced earlier and already assembled, currently in operation.

All of the above advantages are achieved thanks to the claimed design, which allows to achieve a technical result, which consists in increasing the efficiency of wastewater disinfection.

The achievement of the claimed technical result is due to the fact that the treated waste water, passing through a gravity flow, is subjected to complete and sufficient UV treatment.

As a result of the work, a fundamentally new UV disinfection module was manufactured and tested, devoid of the main drawbacks of the equipment on the market, and having a number of additional advantages.

It should be understood that after considering the above description with an example implementation of the proposed technical solution, as well as the accompanying drawings, other changes, modifications and embodiments of the invention will become apparent to the specialist. Thus, all such changes, modifications and implementations, as well as other applications that do not depart from the essence of the present invention, should be considered protected by the present invention within the scope of the appended claims.

Claims (4)

1. Sewage treatment plant containing a water disinfection unit, including an ultraviolet radiation lamp located in a quartz case, characterized in that the case with the lamp is inserted into a gravity flow in the treatment facility housing, located between the last sump of the sewage treatment facility and the forced pumping or outlet chamber gravity discharge of purified water, while the UV lamp is an ozone-free low pressure amalgam lamp. 2. Sewage treatment plant according to claim 1, characterized in that the lamp cover is made in such a way that it can be removed from the overflow without additional tools. 3. Sewage treatment plant according to any one of paragraphs. 1, 2, characterized in that the lamp has a service life of 16,000 hours and 2,000 on-off cycles. 4. Sewage treatment plant according to any one of paragraphs. 1-3, characterized in that the lamp with a cover are in a permanently immersed in water position.

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