阅读说明：本技术 碱性物质中和测量酸性水体流量的方法 (Method for measuring flow of acidic water body by neutralizing alkaline substances ) 是由 孙静 吴攀 涂汉 张水 罗有发 于 2020-11-24 设计创作，主要内容包括：本方案公开了酸性水体流量测量技术领域的一种碱性物质中和测量酸性水体流量的方法,酸性矿山排水(AMD)作为全球最严峻的环境污染物问题之一,研究其水质变化特征、计算水体污染负荷、及评估污染修复效果等都与AMD的流量密不可分。AMD一般具有流路不规则和流量差异大的特点,很难满足常规流量测量方法所需的条件。因此,本发明公开了一种测量AMD流量的新方法：碱性物质与AMD发生中和反应,能快速降低水体电导率(EC),并在下游水体中准确测出EC,从而计算出AMD流量。根据其中和法的测量原理,同样适用于其它酸性水体流量的测量。该方法具有高精度、易操作、低成本、及对生态环境无害等优点。(The scheme discloses a method for neutralizing and measuring the flow of an acidic water body by using an alkaline substance, and belongs to the technical field of flow measurement of the acidic water body. AMD generally has the characteristics of irregular flow paths and large flow differences, and is difficult to meet the conditions required by conventional flow measurement methods. Therefore, the invention discloses a new method for measuring AMD flow, which comprises the following steps: the alkaline substance and the AMD are subjected to neutralization reaction, the conductivity (EC) of the water body can be quickly reduced, and the EC is accurately measured in the downstream water body, so that the AMD flow is calculated. The method is also suitable for measuring the flow of other acidic water bodies according to the measurement principle of the neutralization method. The method has the advantages of high precision, easy operation, low cost, no harm to ecological environment, etc.)

1. The method for measuring the flow of the acidic water body by neutralizing the alkaline substances is characterized by comprising the following steps: in a channel with any shape, taking an upstream point a as a throwing point of an alkaline substance, taking a downstream point b as a water conductivity measuring point, dividing the cross section of the water flow at the point b into n small sections with easily calculated areas, taking the cross section area of the water flow at the point b as S, and calculating the cross section area S of a flow path according to equation (1):

S＝ΣS₁+S₂+S₃+…+S_n(n is an integer not less than 1) -1;

the water flow velocity V is calculated according to equation (2): v is L/T; - (2)

Namely: the water velocity (V, m/s) is the ratio of the water velocity equal to the water length (L, m) to the measurement time (T, s); wherein L is the water flow length between a point a where the alkaline substance is put and a point b where the conductivity is measured; t is the corresponding time length from the beginning of the alkaline substance feeding at the point a to the time when the EC at the point b reaches the lowest value;

the water flow rate Q is calculated according to equation (3): q ═ V × S × 10³；——(3)

Namely: water flow (Q, liter/sec) -the cross-sectional area of the water flow S times the flow velocity of the water flow V.

2. The method for measuring the flow rate of the acidic water body by neutralizing the alkaline substances according to claim 1, wherein the method comprises the following steps: the cross section of the b-point water flow is divided into n trapezoidal or approximately trapezoidal small sections, n triangular small sections, n rectangular small sections, or a combination of n trapezoidal or approximately trapezoidal or triangular or rectangular small sections.

3. The method for measuring the flow rate of the acidic water body by neutralizing the alkaline substances according to claim 1, wherein the method comprises the following steps: the cross section of the point b water flow is divided into n trapezoidal or approximately trapezoidal small sections; the area S of the cross-section of the flow path is then:

S＝ΣS₁+S₂+S₃+…+S_n

＝ΣI₁×H₂+I₂×H₃+I₃×H₄+I₄×H₅+0.5×[I₁×(H₁–H₂)+I₂×(H₂–H₃)+I₃×(H₃–H₄)+I₄×(H₄–H₅)]where I is the length of each minor section and H is the height of each minor section.

4. The method for the neutralization measurement of the flow rate of the acidic water body by the alkaline substance according to any one of claims 1 to 3, wherein: and the water flow length between the points a and b is measured by using a measuring rope and a measuring tape.

5. The method for the neutralization measurement of the flow rate of the acidic water body by the alkaline substance according to any one of claims 1 to 3, wherein: the alkaline substance is quicklime.

6. The method for the neutralization measurement of the flow rate of the acidic water body by the alkaline substance according to any one of claims 1 to 3, wherein: the recording mode of the T is as follows: when alkaline substances are added to the upstream point a, recording time; and simultaneously recording EC corresponding to time at a downstream b point, stopping measurement after the value of EC is reduced to the minimum and rises back, and taking time from the start of recording to the stop of measurement as T.

7. The method for the neutralization measurement of the flow rate of the acidic water body by the alkaline substance according to any one of claims 1 to 3, wherein: the acidic water body is formed by natural reasons from rocks, strata and the like or artificially from mining areas or factories.

8. The method for the neutralization measurement of the flow rate of the acidic water body by the alkaline substance according to any one of claims 1 to 3, wherein: the length L of water flow between the point a where the alkaline substances are put and the point b where the conductivity is measured is preferably 8-20 m.

Technical Field

The invention belongs to the technical field of acidic water flow measurement, and particularly relates to a method for measuring acidic water flow through neutralization of alkaline substances.

Background

Investigating natural and man-made causesThe water quality change characteristics of the acidic water body, the calculation of the water body pollution load, the evaluation of the pollution remediation effect and the like are inseparable from the flow of the acidic water body. Such as: acid Mine Drainage (AMD), the most serious global environmental pollution problem, destroys HCO in hydraulically connected bodies of water₃A buffer system to reduce the pH of the water and increase the concentration of soluble metals, leading to regional water quality degradation and water resource scarcity, which in turn affects the surrounding ecological systems and human health. However, AMD is often characterized by flow path irregularities and large flow differences, and conventional flow measurement methods often fail to obtain highly accurate values.

At present, according to the latest national standard "river discharge test Specification" (GB50179-2015), the river discharge is generally measured by the following methods: tracer method, flow meter method, buoy method, triangular weir method, pasteur bath method, drain coefficient method, volumetric method and flow meter method. A current meter method is generally used for measuring the river flow, and a buoy method with lower precision can be selected when the river flow cannot be measured well. The volumetric method is suitable for water bodies with small measurement flow and irregular pollution discharge channels. The buoy method is suitable for the condition that the length of the sewage discharge channel is not less than 10 meters, no bending exists, and the bottom wall is smooth. However, the acidic water body has the characteristics of chemical property, irregular natural flow path and large flow difference, so that the acidic water body of the natural flow path is difficult to meet the conditions required by the measuring method.

Disclosure of Invention

The invention aims to overcome the defects and provide a scientific, easy-to-operate, low-cost, high-precision and ecological environment-friendly method for measuring the flow of the acidic water body.

In the method for measuring the acid water flow by neutralizing the alkaline substances, in a channel with any shape, an upstream point a is taken as a feeding point of the alkaline substances, a downstream point b is taken as a water conductivity measuring point, the cross section of a water flow at the point b is divided into n small sections with easily calculated areas, the cross section area of the water flow at the point b is S, and the cross section area S of a flow path is calculated according to the equation (1):

S＝ΣS₁+S₂+S₃+…+S_n(n is an integer not less than 1) -1;

the water flow velocity V is calculated according to equation (2): v is L/T; - (2)

Namely: the water velocity (V, m/s) is the ratio of the water velocity equal to the water length (L, m) to the measurement time (T, s); wherein L is the water flow length between a point a where the alkaline substance is put and a point b where the conductivity is measured; t is the corresponding time length from the beginning of the alkaline substance feeding at the point a to the time when the EC at the point b reaches the lowest value;

the water flow rate Q is calculated according to equation (3): q ═ V × S × 10³；——(3)

Namely: water flow (Q, liter/sec) -the cross-sectional area of the water flow S times the flow velocity of the water flow V.

In the scheme, the conductivity (EC) is the conductivity of ions in the acidic water body, and can be measured by a high-precision conductivity meter and the like which are easy to operate. The principle of the scheme is that the basic substance and the acidic water body generate a neutralization reaction, the EC of the water body can be quickly reduced, and the EC can be quickly and accurately measured in the downstream water body, so that the flow of the acidic water body at the EC measuring point can be calculated. The method for measuring the flow of the acidic water body has the beneficial technical effects of easiness in operation, low cost, high precision and no harm to the ecological environment.

Further, the cross section of the b-point water flow is divided into n trapezoidal or approximately trapezoidal small sections, n triangular small sections, n rectangular small sections, or a combination of n trapezoidal or approximately trapezoidal or triangular or rectangular small sections.

Further, the cross section of the water flow at the point b is divided into n trapezoidal or approximately trapezoidal small sections; the area S of the cross-section of the flow path is then:

S＝ΣS₁+S₂+S₃+…+S_n

＝ΣI₁×H₂+I₂×H₃+I₃×H₄+I₄×H₅+0.5×[I₁×(H₁–H₂)+I₂×(H₂–H₃)+I₃×(H₃–H₄)+I₄×(H₄–H₅)]where I is the length of each minor section and H is the height of each minor section. Most of themAccording to the characteristics, the cross section of the water flow can be divided into a plurality of trapezoids or the trapezoids are carried out to calculate the total area as far as possible, and the operation is simple and easy to calculate.

Furthermore, the water flow length between the points a and b is measured by using a measuring rope and a measuring tape. The measuring rope or the tape is a length measuring tool which can be bent or folded according to the irregularity of the river, and the use is more convenient.

Further, the alkaline substance is quicklime. The quicklime is produced artificially, and is low in price and easy to obtain compared with natural alkaline substances.

Further, the recording mode of T is: when alkaline substances are added to the upstream point a, recording time; and simultaneously recording EC corresponding to time at a downstream b point, stopping measurement after the value of EC is reduced to the minimum and rises back, and taking time from the start of recording to the stop of measurement as T.

Further, the acidic water body is formed by natural reasons from rocks, strata and the like or artificially from mines or factories.

Further, the length L of water flow between the point a where the alkaline substance is put and the point b where the conductivity is measured is preferably 8-20 m.

Drawings

FIG. 1 is a schematic diagram of measuring the flow rate of an acidic water body;

FIG. 2 is a diagram of a case analysis of the measurement of the flow rate of an acidic water body based on the method for measuring the flow rate of an acidic water body by neutralization of an alkaline substance according to the present invention;

in fig. 1 and 2, the X-axis is the length direction of the water flow cross section; the Y-axis represents the depth direction of the water flow cross section; the Z axis is the water flow direction.

Detailed Description

The following is further detailed by way of specific embodiments:

reference numerals in the drawings of the specification include: s: a cross-sectional area of the flow path; i: length of flow path cross section; h: height of flow path cross section; l: length of water flow.

The Jiale coal mining area is located in Xingren county of Guizhou province in China and is a famous karst coal mining area seriously polluted by mine activities. AMD continuously flows from waste coal holes, randomly stacked tailing slag and coal gangue as a source, has the characteristics of irregular flow path, large flow change, low pH value, high concentration of trace elements and the like, seriously pollutes ecological systems of water, soil and the like in a mining area, and influences the health of local residents. The method for measuring the flow of the acidic water body by neutralizing the alkaline substances takes the coal mine area as an example, and selects cheap and pollution-free quicklime as an alkaline material to measure the flow of AMD; the specific implementation mode is as follows:

measurement tools and materials:

quicklime, stopwatch, tape, measuring rope, measuring rod (or plumb line), EC measuring instrument.

Measurement procedure, shown in conjunction with fig. 1 and 2:

(i) selecting a point a as a lime feeding point and a point b as an EC and water flow cross-sectional area measuring point along the AMD water flow direction;

(ii) measuring the length (L) of the water flow between the points a and b by using a measuring rope and a tape measure;

(iii) properly dividing the irregular water flow cross section at the downstream b point into a plurality of trapezoidal or approximately trapezoidal small sections, measuring the length (I) and the height (H) corresponding to each small section by using a measuring rod (or a plumb line), and calculating the water flow cross section area according to the equation (1);

(iv) when quicklime is added at a point a on the upstream of AMD, the time is recorded; simultaneously recording EC (table 1) corresponding to time at a downstream point b, stopping measurement after the value of the EC is reduced to the lowest value and starts to rise, selecting the time length corresponding to the lowest value of the EC as measurement time (T), and calculating the flow rate of water flow according to equation (2);

(v) the flow rate of AMD at point b is calculated by substituting the values obtained in (iii) and (iv) into equation (3).

Equation (1): s ═ Σ S₁+S₂+S₃+…+S_n＝ΣI₁×H₂+I₂×H₃+I₃×H₄+I₄×H₅+0.5×[I₁×(H₁–H₂)+I₂×(H₂–H₃)+I₃×(H₃–H₄)+I₄×(H₄–H₅)]；

Equation (2): v is L/T

Equation (3): q ═ V × S × 10³。

TABLE 1 relationship of EC and T at b-Point downstream of AMD

And (3) measuring results:

as shown in Table 1, the duration corresponding to the lowest EC value (600. mu.S/cm) was selected as the measurement time T (27.71 seconds). The measurements of Table 1 and FIG. 2 were taken into equations (1), (2) and (3) and the flow at point b downstream of AMD was calculated to be 58.32 liters/second.

Based on the method, the cross section of the water flow at the point b can be divided into n triangles or rectangles or the combination of the triangles, the rectangles and the trapezoids according to the actual situation, and the corresponding areas are calculated according to the area formulas of the shapes and then added to obtain the area S of the cross section of the water flow at the point b. In addition, the length L of water flow between the point a where the alkaline substances are put and the point b where the conductivity is measured is preferably 8-20 m; the alkaline substance may also be a natural alkaline substance or another artificially produced and inexpensive alkaline substance.