RU2710358C1 - Method for interpolation control of waste water and industrial wastes pollution - Google Patents

Abstract

FIELD: ecology.

SUBSTANCE: invention relates to methods of monitoring the environment and can be used to control contamination of sewage water or surface water of natural water bodies. Method of interpolation control of contamination of waste water and industrial effluents involves measurement of concentration of contamination in sewage pipe at inlet and outlet of controlled section and comparison of measurement result with maximum permissible value of MAC. Measurement of concentration of contamination and comparison of measurement result with maximum permissible value of MAC is carried out using posts analyzing contamination of waste water or industrial wastes, installed at inlet and outlet of sewage pipe, made in the form of measuring modules connected through switchboard to computer unit. Additionally determining probability of detecting P_DET. contamination in the absence of its fixation by said analysis stations, representing a sequence of measurements as a stationary Poisson flow, calculating probability P_DET. by formula:

where λ is average amount of occurrence of contamination of certain type per unit time; T₀ – time of waste water flow from the beginning of observations to the analysis post installed at the sewer pipe inlet; T₁ is the time required to obtain information on the type and degree of contamination from the analysis post installed at the inlet of the sewage pipe; T₂ is the waste water flow time along the sewage pipe; T₃ is the time required to obtain information on the type and degree of contamination from the analysis post installed at the outlet of the sewage pipe.

EFFECT: invention provides higher reliability of pollution control of waste water in natural-industrial territorial complexes.

1 cl, 1 dwg

Description

The invention relates to methods and means of environmental monitoring and can be used to control pollution of wastewater or surface water of natural reservoirs.

As you know, studies of the qualitative and quantitative composition of wastewater are often difficult due to their complex composition, a wide range of impurity concentrations, and changes in the composition of wastewater over time. Many substances already in very small concentrations cause changes in water quality, and the determination of their amount in water is associated with significant difficulties.

In the analytical control of the operation of treatment facilities, the time taken to conduct the analysis is of no small importance. Often when analyzing wastewater there are difficulties associated with the presence of concomitant and interfering substances that are not provided for in standard methods.

The use of automatic devices is of particular importance, which allows not only to increase the productivity of analytical chemists and reduce the cost of analysis, but also to continuously monitor the composition of wastewater and the operation of treatment facilities, as well as to quickly record any violations.

In modern production with increased (forced) parameters of technological processes, conditions periodically arise that lead to the destruction of buildings, structures, equipment and vehicles, failure of machines, aggregates, communications or their components, discharges into the sewer or surface water bodies of aggressive liquids and strong toxic substances, oil spills. Such phenomena are called accidents.

In accordance with the current GOST 12.1.004-91 and GOST R 12.3.047-98 production processes should be designed so that the probability of emergency situations at any site (facility) during the year does not exceed 10 ^-6 ⋅ year ^-1 .

In design practice, three areas are considered as criteria for admissibility of an individual risk level R _e [1]:

• R _e less than 5.0⋅10 ^-5 - low risk area; measures to reduce them are not required;

• R _e from 5.0⋅10 ^-5 to 10 ^-3 - an area requiring the adoption of certain measures to reduce risks, taking into account the economic (financial) feasibility of these measures;

• R _e more than 10 ^-3 - an area of unacceptable risk, requiring mandatory implementation of measures to reduce it, regardless of the size of financial costs.

The provision of these requirements is possible only with the appropriate reliability of control.

Existing methods to increase the objectivity of control are based on increasing the number of analyzes and installing more stationary or mobile environmental monitoring stations. These methods are expensive and do not provide reliable analysis, since the dump can still pass by them and not be identified. In this regard, it is important to create effective quick forecast systems based on a priori information about the appearance of contaminants and mathematical processing of the dynamics of changes in the control results, which is implemented in the invention.

The prior art method for measuring river pollution by sampling water, including measuring the concentration of pollutants in various river sections and compiling a table of measurement data. In this case, the quality of river water is evaluated in relation to the maximum permissible concentration of a polluting substance (MPC) [2].

The disadvantage of this method is the low reliability of the control, manifested in the impossibility of differential diagnosis of foci of water pollution.

An automatic station for monitoring the quality of natural and waste waters (SU 1134547 A1, IPC C02F 1/00, G01N 33/18, G05D 27/00, C02F 103/02, publ. January 15, 1985) is also known in the art, which implements a method for controlling pollution by measuring the concentration of a polluting component in water using portable devices or stationary multi-parameter analyzers [3].

However, when controlling pollution using an automatic station for monitoring the quality of natural and wastewater, the process history is not taken into account, which does not allow to establish the cause and place of pollution, which reduces the reliability of the control.

Closest to the claimed invention, the method selected as a prototype, recognized as a method of controlling river pollution (RU 2058270 C1, IPC C02F 5/00, publ. 04/20/1996). In this method of pollution control, the difference in time-synchronized values of the concentration of the polluting component at the input and output of the controlled section is additionally calculated, after which the calculated value of the concentration difference is compared with the marginal error of the applied concentration control method. If the difference between the threshold value of the marginal error of the control method is exceeded with a simultaneous exceeding of the concentration limits at the outlet of the site, it is concluded that there is water pollution in the area of the controlled site. When the values of the difference are less than the established marginal error of the control method with a simultaneous excess of the maximum concentration limits at the inlet and outlet of the site, a conclusion is drawn about surface water pollution to the border of the controlled site. If the MPC exceeds the concentrations at the inlet and outlet of the controlled area with a simultaneous excess of the difference in concentration values of the marginal error of the control method, a conclusion is made about the simultaneous presence of contaminants both at the entrance and within the controlled area [4].

The disadvantage of this method is its low reliability due to the fact that the sampling frequency is not regulated. The latter can lead to the fact that pollution may not be recorded at all.

The technical problem to which the claimed invention is directed is to increase the reliability of control by creating an interpolation control system for wastewater pollution from natural industrial territorial complexes.

This problem is solved in that the method of interpolation control of pollution of wastewater and industrial effluents, includes measuring the concentration of pollution in the sewer pipe at the inlet and outlet of the controlled area and comparing the measurement result with the maximum permissible MAC value. The method differs from the known analogues in that the measurement of the concentration of pollution and the comparison of the measurement result with the maximum permissible MPC value is carried out using the posts for analysis of pollution of wastewater or industrial effluents installed at the inlet and outlet of the sewer pipe, made in the form of measuring modules connected via a switch to the computing unit, while additionally determining the probability of detecting contamination in the absence of its fixation by the mentioned analysis posts, presenting after ovatelnost measurements as stationary Poisson stream.

A positive technical result provided by the above set of features of the method is to increase the reliability of control by measuring the concentration of contaminants at the inlet and outlet of the sewer pipe and additionally calculating the probability of detecting pollution.

The method is illustrated in the drawing, where the figure shows a simplified block diagram of an automated system with which the method is carried out.

The implementation of the method is based on the use of an instrumental method for studying the characteristics of the processes of movement of pollutants in a liquid medium. To develop the algorithm of the system according to the reference measurements and current analysis results, the basis was taken as the method of stochastic interpolation, used as a means of solving problems of recognition, identification, training and adaptation.

An automated control system that implements the method includes a control object, which is a sewer pipe 1, pollution analysis stations for wastewater or industrial effluents 2.1 and 2.2, installed at the inlet and outlet of the pipe, switch 3, clock generator 4, computing unit 5, master MPC for a controlled pollutant and the intensity of occurrence of this type of pollution 6, the controller setting the reliability of monitoring for the observation time 7, logical unit 8, indicator 9.

Analysis posts 2.1 and 2.2 can be measuring modules based on pH converters, conductivity sensors and oxygen meters ¹ ( ¹ Measurement of water and other liquids // RusAutomation. URL: https://rusautomation.ru/datchiki_parametrov_zhidkosti (accessed: 01/18/2019).). Switch 3 can be a multiplex input of an industrial measuring transducer ² ( ² T201 // KIP-Service. URL: https://rusautomation.ru/datchiki_parametrov_zhidkosti (accessed: 01/18/2019).). Clock generator 4 can be built on the basis of a DS1302 real-time clock chip with a serial interface ³ ( ³ Real-time clock with a serial interface // Microelectronics Market. URL: http://www.gaw.ru/html.cgi/txt/ic/ Maxim / timing / rtc / serial / start.htm (accessed: 01/18/2019).). Blocks 5, 6, 7, 8, and 9 can be implemented on the basis of an industrial controller built on the basis of an eight- or thirty-two-bit microcontroller of the STM8 or STM32 series, containing a microprocessor core connected via a system bus with program FLASH memory, SRAM data memory , a twelve-bit analog-to-digital converter, non-volatile electrically reprogrammable EEPROM memory and universal eight-bit bi-directional I / O ports. In this case, the computing unit 5 and the logical unit 8 are implemented by the microprocessor core of the microcontroller. The controllers 6 and 7 are realized by an electrically reprogrammable memory with the possibility of changing them using a programmer or a microcontroller control program stored in the FLASH memory. The output of switch 3 through a measuring input equipped with an operational amplifier is connected to the input of the analog-to-digital converter of the microcontroller, and indicator 9 is connected to the output of one of the input-output ports, which can be an indication module based on an LCD display or a line of seven-segment indicators .

The proposed control method is implemented as follows.

Information about the type and degree of pollution from the stations for analysis of pollution of wastewater or industrial effluents 2.1 and 2.2 through the switch 3, in a certain sequence, in accordance with the commands of the clock generator 4, is sent to the computing unit 5. Next, using the computing unit 5, the measured pollution concentrations are compared with MPC values. Here, the probability of skipping wastewater contamination is calculated and a comparison is made with the reliability of the control specified by the control setting reliability controller 7. Then, using block 8, a differential assessment of the control results is made by comparing and logically analyzing the measured and calculated values with the maximum deviations. The control results are displayed on indicator 9.

The flow time of wastewater from the beginning of observations to the post of analysis 2.1 is T ₀ . From the post of analysis of pollution of wastewater or industrial effluents 2.1 installed on the sewer pipe 1, the time for obtaining information about the type and degree of pollution is T ₁ . The flow time of wastewater inside the sewer pipe is T ₂ . At the outlet of the sewer pipe, wastewater enters the analysis post 2.2, the time for obtaining information on the type and degree of pollution from which is T ₃ .

When sewage flows through the sewer during the observation time T _H , two incompatible events are possible, forming a complete group of incompatible events.

Event 1. There were no pollution at the inlet of the pipe exceeding the MPC, and, accordingly, the pollution analysis post 2.1 did not record them, there were no pollution in the sewer pipe and the pollution analysis post 2.2 did not record them either. During sewage flowing through the sewer from station 2.1 to station 2.2, there was no pollution. The time of the sewage flowing through the sewer pipe to the pollution analysis post from post 2.1 to post 2.2 will be T ₀ , the probability of such an event is denoted by P ₁ .

Event 2. There were pollution in excess of the MPC, the probability of such an event is denoted as P ₂ .

As you know, the probability of a complete group of incompatible events is equal to one.

The probability of the event P _{2 is} the sum of the probabilities of several joint events:

Event 2.1. During the flow of wastewater through the sewer pipe to the post of analysis of pollution of wastewater or industrial effluents 2.1, one or more pollutants exceeding the MPC occurred. The probability of such an event is P ₂₀ .

Event 2.2. A post for analysis of wastewater or industrial effluent pollution 2.1 found pollution exceeding the MPC. The probability of such an event is P ₂₁ .

Event 2.3. Between receiving information about the type and degree of pollution from the posts for analysis of pollution of wastewater or industrial effluents 2.1 and 2.2, one or more pollutants appeared in the sewer pipe in excess of the MPC. The probability of such an event is P ₂₂ .

Event 2.4. A post for analysis of wastewater or industrial effluent pollution 2.2 has detected pollution exceeding the MPC. The probability of such an event is P ₂₃ .

The appearance of wastewater pollution in excess of the MPC, in the general case, is random in nature and is presented in the form of a random flow, ordinary, stationary and without aftereffect. For the mathematical formalization, the Poisson flow is used, and the time between adjacent pollutants has an exponential distribution, taking into account daily (morning, lunch and evening), seasonal (spring, summer, autumn and winter) and other changes in the parameters of the flow of pollution.

The intensity of the appearance of pollution λ is the average number of occurrence of pollution of a certain type per unit time, the reciprocal of the average time interval between pollution. The following approaches are used to assess the expected intensity of occurrence:

- a statistical approach, which consists in the maximum use of statistics on the presence of pollution, as well as data on the appearance of pollution at similar facilities;

- graphoanalytical approach, consisting in the use of logical methods of analysis of "event trees" or design, simulation, user models;

- an expert approach consisting in the development of an assessment by taking into account the views of specialists in this field.

Different sources of pollution are characterized by a clear lack of representative statistical data on failures, errors and technical malfunctions in the technological process, accidents at analogous facilities, uniqueness of production cycles, lack of exhaustive initial data on production, equipment placement and operation conditions. Therefore, it is advisable to use a combination of these approaches and procedures adapted to the specific goals and objectives of the analysis of the risk of accidental emissions from a particular production.

The likelihood that during the flow of sewage through the sewer before the post of analysis of pollution of sewage or industrial effluents 2.1 was not, is determined by the following expression:

The likelihood that the post of analysis of pollution of sewage or industrial effluents 2.1 pollution is not found, is determined by the following expression:

The probability that there was no contamination between the analyzes of the sewer pipe is determined by the expression:

The probability that the post of analysis of pollution of wastewater or industrial effluents 2.2 pollution is not found, is determined by the expression:

Events are independent, therefore the probability of their simultaneous origin is determined by their product:

The probability that during the flow of wastewater through the sewer pipe before the post of analysis of pollution of wastewater or industrial effluents 2.1 there was one or more pollution, is determined by the expression:

The probability that the post of analysis of pollution of wastewater or industrial effluents 2.1 detected pollution, taking into account the small time interval for obtaining information about the type and degree of pollution T ₁ with the entire observation time, is approximately determined by the expression:

The probability that between the posts for analysis of pollution of wastewater or industrial effluents 2.1 and 2.2 in the sewer pipe appears one or more pollution is determined by the expression:

The likelihood that the post analysis of pollution of wastewater or industrial effluent 2.2 detected one or more contaminants, taking into account the short time to obtain information about the type and degree of pollution T ₃ with the entire observation time, is determined by the expression:

Using the well-known expression for calculating the sum of four joint events, we obtain an expression for calculating the probability of the presence of pollution:

On the other hand:

Equating expressions (10) and (11), we obtain:

Selecting the works, which include the probability of simultaneous execution of independent events, we obtain the following expression:

According to expression (13), the probability of detecting pollution by posts 2.1 or 2.2 when one or more wastewater contaminants flows through the sewer pipe before or after the post of analysis of pollution of wastewater or industrial effluents 2.1 can be calculated. Finally, the probability of detection can be determined based on the following expression:

From literary sources it is known that a major accident occurs on average after 175.2 hours, the case of an oil spill - on average after 26.3 minutes. The average time before pollution can vary from 0.5 to 150 hours, the average value is approximately 50 hours. The average time to eliminate the effects of pollution in most cases varies from several days to several years. The average time for the presence of pollution is 240 hours (10 days) [5].

The implementation of the method will consider the example of detecting pollution.

Initial data: observation time is one month, the average time interval between pollution is fifty hours (in the form of suspended solids), the average time for obtaining information about the type and degree of pollution by both posts is the same and is 12 minutes. The time from the beginning of observations to the first analysis is one hour, between analyzes, with the alternation of posts - ten hours. In total, during the observation period, one analysis was performed by each of the posts; no pollution was found that exceeded the maximum permissible concentration. According to the results of calculation by expression (14), a low probability of detecting pollution by posts 2.1 or 2.2 was obtained, amounting to P = 7.58 × 10 ^-3 , which indicates the absence of pollution. If the probability of detection of pollution by posts 2.1 or 2.2 were high, but the posts did not fix it, then, in accordance with the requirements for ensuring the above risks, it would be concluded that there were contaminants in excess of the MPC that were missed, which would require protective measures .

In the practical implementation of the proposed method, it is necessary to make an assessment for each of the mandatory controlled wastewater pollution: biochemical oxygen consumption, suspended solids, ammonium nitrogen, sulfates, nitrates, oil products, chromium, copper, nickel, zinc, lead, phosphorus, nitrites, iron, chlorides.

List of sources of information

1. Gabrichidze T.G. The basics of an integrated security system for critical (potentially dangerous) objects of the municipal and regional levels: Samara monograph: Samara Scientific Center RAS, 2011. - 391 p.

2. Molokov M.V., Shifrin V.N. Surface runoff treatment from the territories of cities and industrial sites. M., Stroyizdat, 1977 .-- 104 p.

3. SU 1134547 A1 USSR, IPC C02F 1/00, G01N 33/18, G05D 27/00, C02F 103/02. Automatic station for monitoring the quality of natural and waste waters / Belogurov V.P., Popov L.E., Mikotkin B.G .; Applicant All-Union Scientific Research Institute for Water Protection No. 3542717; declared 01/25/1983; publ. 01/15/1995, Bull. No. 2. 6 s .; silt.

4. RU 2058270 C1 Russian Federation, IPC C02F 5/00. A method of controlling river pollution / Yastremsky Yu.N., Vinokurov Yu.I., Kozlov VV, Krasnov Yu.G .; Applicant Barnaul Innovation and Ecological Firm “BINEF” No. 91 4919533; declared 03/14/1991.

5. Usoltsev V.P., Juran S.I. The reliability of the sanitary-epidemiological analysis of wastewater with a large number of random influences and the absence of a dominant factor // Theoretical and Applied Ecology. - 2016, No. 3. - S. 19-24.

Claims (3)

The method of interpolation control of pollution of wastewater and industrial effluents, including measuring the concentration of pollution in the sewer pipe at the inlet and outlet of the controlled area and comparing the measurement result with the maximum permissible MPC value, characterized in that measuring the concentration of pollution and comparing the measurement result with the maximum permissible MPC value using the posts for analysis of wastewater pollution or industrial effluents installed at the inlet and outlet of sewer pipes Made in the form of measuring modules are connected through a switch to a computing unit, wherein further comprising determining the probability of detection P _OPL. pollution in the absence of its fixation by the mentioned analysis posts, representing the measurement sequence as a stationary Poisson flow, calculating the probability P _OBN. according to the formula:

where λ is the average number of occurrences of pollution of a certain type per unit time; T ₀ - wastewater flow time from the beginning of the observations to the analysis post installed at the inlet of the sewer pipe; T ₁ - the time required to obtain information about the type and degree of contamination from the analysis post installed at the inlet of the sewer pipe; T ₂ - time flow of wastewater through the sewer; T ₃ - the time required to obtain information about the type and degree of contamination from the analysis post installed at the outlet of the sewer pipe.

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