Wastewater comprehensive toxicity detection and water quality risk evaluation method

Abstract

The invention discloses a wastewater comprehensive toxicity detection and water quality risk evaluation method which comprises the following steps: S1, determining an ammonia nitrogen index of a to-be-detected wastewater sample, and judging whether the to-be-detected wastewater needs to be diluted or not according to an ammonia nitrogen concentration value; s2, measuring and calculating the algae cell activity index value of the to-be-measured wastewater / diluted to-be-measured wastewater; s3, determining the water quality risk grade of the to-be-detected wastewater according to the algae cell activity index value of the to-be-detected wastewater. The method evaluates the water quality toxicity by determining the algae cell activity index, has the advantages of high speed, low cost and the like, and can be applied to comprehensive toxicity detection and water quality risk evaluation of industrial wastewater.

Description

Technical Field

[0001] The present invention relates to the field of water quality risk control, and in particular to a method for comprehensive wastewater toxicity detection and water quality risk assessment. Background Art

[0002] With the rapid development of my country's economy, industrial and domestic wastewater are increasing, seriously exceeding nature's natural purification capacity and posing a serious challenge to aquatic ecosystems and the human living environment. Sewage is commonly found with a large number of known and unknown pollutants. The complexity of their chemical composition, structure, and sources, as well as the interactions between various substances, lead to significant limitations in traditional chemical analysis methods for assessing the toxicity of pollutants in sewage. Compared to chemical analysis, biological toxicity testing methods can integrate the interactions of multiple pollutants and establish a dose-response relationship between pollutant concentration and biological effects, thereby intuitively reflecting the comprehensive toxicity of polluted water to organisms.

[0003] Microalgae, as typical model organisms for aquatic ecotoxicology, are widely used in the study of the toxic effects of pollutants due to their direct exposure to the aquatic environment, short generation cycles, and sensitive environmental responses. Among them, Lunaea capricornifolia is one of the species recommended by the International Organization for Standardization for use in ecotoxicological biological assays. This single-celled green alga is generally more sensitive to various pollutants than other species. Furthermore, Lunaea capricornifolia is not only widely adaptable to freshwater environments, but also offers experimental biological advantages such as simple culture conditions and a short generation cycle.

[0004] At present, the microalgae toxicity biological detection system mainly uses algae growth inhibition rate, cell viability, photosynthesis efficiency and changes in physiological indicators (such as reactive oxygen species generation, cell membrane integrity, etc.) as toxicity endpoint indicators. Among them, the half-maximal effect concentration (EC50) determined based on the algae growth inhibition experiment is the most effective concentration of the microalgae. 50 ) and toxicity unit (TU) are the most commonly used indicators to judge the toxicity level and risk level of water bodies. However, the algae growth inhibition experiment is time-consuming (usually 72h or 96h) and cannot be used for high-throughput detection. Therefore, it has limitations in actual wastewater toxicity determination and risk assessment. Summary of the Invention

[0005] In order to solve the technical problems provided by the above background, the method of the present invention is based on a microplate and a multifunctional microplate reader to quickly determine cell viability toxicity indicators to evaluate the comprehensive toxicity and risk level of water quality. Compared with the growth inhibition method, it has the advantages of fast speed, simple operation, and the ability to perform high-throughput detection on microplates.

[0006] A method for comprehensive wastewater toxicity detection and water quality risk assessment comprises the following steps:

[0007] S1. Determine the ammonia nitrogen concentration of the wastewater to be tested, and determine whether the wastewater to be tested needs to be diluted according to the ammonia nitrogen concentration of the wastewater to be tested. If dilution is required, dilute the wastewater to be tested with pure water to obtain diluted wastewater to be tested. If dilution is not required, perform the next step of treatment on the wastewater to be tested;

[0008] S2. Adding the wastewater to be tested that does not require dilution or the diluted wastewater to be tested into the algae cell culture system and exposing it to the poison for 20 to 48 hours, and then measuring and calculating the algae cell activity index value of the wastewater to be tested;

[0009] S3. Determine the water quality risk level of the wastewater to be tested based on the algae cell activity index value of the wastewater to be tested.

[0010] Note: The above method controls the exposure concentration range by adjusting the ammonia nitrogen concentration to avoid high-concentration wastewater directly causing acute death of algal cells and masking the chronic toxic effects, thereby ensuring the accuracy and repeatability of the experiment. Combined with the algal cell viability index, it can not only quickly, cost-effectively and sensitively reflect the comprehensive impact of complex pollutants in wastewater on the ecological functions of algae, but also provide a scientific basis for water quality management and pollution control.

[0011] Furthermore, before determining the ammonia nitrogen index of the wastewater to be tested in S1, the wastewater to be tested is filtered through a 0.22 μm water filter membrane.

[0012] Note: The above-mentioned filtration can effectively intercept suspended particles, algae, bacteria and macromolecular organic matter in the wastewater, preventing them from interfering with the chemical analysis process of ammonia nitrogen, and ensuring the accuracy of the ammonia nitrogen concentration test results; at the same time, the clarified filtrate obtained after filtering out the particulate matter can reduce the physical interference of impurities on the growth of algal cells in subsequent algal cell exposure experiments, so that the changes in algal cell viability toxicity indicators are completely attributed to dissolved ammonia nitrogen and other pollutants that can pass through the filter membrane, thereby improving the accuracy of toxicity assessment and the interpretability of the results.

[0013] Furthermore, the method of judging whether the wastewater to be tested needs to be diluted according to the ammonia nitrogen concentration value in S1 includes: when the ammonia nitrogen concentration is >30 mg / L, using pure water to dilute the ammonia nitrogen concentration of the water sample to ≤30 mg / L; when the ammonia nitrogen concentration is ≤30 mg / L, no dilution is required.

[0014] Note: When the ammonia nitrogen concentration exceeds 30 mg / L, diluting it with pure water to reduce the concentration to below the threshold can avoid the acute toxicity of high-concentration ammonia nitrogen to algal cells (such as osmotic pressure imbalance, metabolic enzyme inhibition, etc.), thereby ensuring that the changes in algal cell viability indicators in the exposure experiment mainly reflect the chronic toxic effects of low-concentration ammonia nitrogen or other pollutants; when the ammonia nitrogen concentration is ≤30 mg / L, directly conducting the experiment can reduce unnecessary dilution operations, improve experimental efficiency and reduce the risk of dilution error.

[0015] Furthermore, in S2, the algal cells are Capricornis horned algae in the logarithmic growth phase.

[0016] Note: The tolerance threshold of S. capillaris to pollutants such as ammonia nitrogen and heavy metals is clear, which can ensure that the toxicity changes are mainly driven by other pollutants in the wastewater to be tested, avoiding the single interference of ammonia nitrogen; in addition, its single-cell morphology and rapid proliferation characteristics facilitate experimental operations (such as counting, fluorescence detection) and result quantification, significantly improving the sensitivity and reliability of toxicity assessment.

[0017] Furthermore, the cell concentration in the algae cell culture system is 10 5 ~10 6 pieces / mL.

[0018] Note: This concentration range ensures that algal cells are at an appropriate population density, avoiding both the lack of significant toxicity response after pollutant exposure due to too low a cell concentration and the interference of experimental results with the cell self-shading effect, the intensification of nutrient competition or the accumulation of metabolites due to too high a concentration.

[0019] Furthermore, in said S2, the method for determining the algal cell viability index of the wastewater to be tested is any one of a cell density determination method, a fluorescence parameter determination method and a cell activity staining determination method.

[0020] Furthermore, in S2, the cell viability staining assay is used for determination, and the determination steps include:

[0021] Fluorescein diacetate is added to the wastewater to be tested that does not require dilution or the diluted wastewater to be tested to a concentration of 25 μM; the mixture is then incubated at room temperature in a dark environment for 30 to 60 minutes to obtain fluorescently stained algal cells;

[0022] The fluorescence intensity of the algal cells after fluorescence staining was obtained using a multifunctional microplate reader, and the algal cell viability index value f0 was obtained by calculating the fluorescence intensity of the algal cells after exposure to the poison and the fluorescence intensity of the algal cells without exposure to the poison.

[0023] According to the algae cell activity index measurement value f0, the algae cell activity index value f1 of the wastewater to be tested is determined.

[0024] Note: The above method achieves high efficiency, sensitivity and standardization of algal cell viability toxicity assessment through FDA-approved live cell-specific fluorescent labeling and quantitative detection by microplate reader, providing a powerful tool for rapid screening of wastewater toxicity and mechanism research.

[0025] Furthermore, the algae cell viability index value f0 is calculated by the following formula (1):

[0026]

[0027] Where f0 is the measured value of algal cell viability index, f0 includes the measured value of algal cell viability index of the wastewater to be tested without dilution The algae cell activity index of the diluted wastewater to be tested is measured Two values: F1 is the average fluorescence intensity of algal cells after exposure to poisons, and F0 is the average fluorescence intensity of algal cells after no exposure to poisons.

[0028] Note: The above method uses the fluorescence intensity of unexposed algal cells as a benchmark and normalizes the fluorescence intensity of the exposed group. This can eliminate experimental errors such as instrument fluctuations and cell seeding density, and directly reflect the proportion of decreased cell metabolic activity caused by pollutants.

[0029] Furthermore, the method for determining the algae cell viability index value f1 of the wastewater to be tested based on the algae cell viability index measurement value f0 is:

[0030] When the wastewater to be tested does not need to be diluted, the algae cell activity index value of the wastewater to be tested

[0031] When the wastewater to be tested needs to be diluted, the algal cell activity index value of the wastewater to be tested is calculated as f1 by the following formula (2):

[0032]

[0033] Where f1 is the algal cell activity index value of the wastewater to be tested, and S is the dilution multiple.

[0034] Explanation: Calculating the algal cell viability index value of the wastewater to be tested by the above formula (2) can unify the toxicity assessment standards and truly reflect the toxicity intensity of the pollutants. For wastewater that needs to be diluted, the activity value is corrected by weighting the dilution multiple to ensure the comparability of the toxic effects of wastewaters of different concentrations and avoid underestimation or overestimation of toxicity due to dilution operations. The dilution multiple correction mechanism associates the final activity index value with the original concentration of the wastewater, retains the integrity of the toxic effect of high-concentration wastewater, and facilitates subsequent risk classification. This method takes into account the needs of direct experiments on high-concentration wastewater and dilution experiments on super-concentration wastewater. Through formula standardization, the interference of dilution multiple differences on toxicity assessment is eliminated, ensuring that the experimental results truly reflect the ecological toxicity of wastewater to algal cells and providing a reliable basis for water quality safety evaluation.

[0035] Furthermore, the method for determining the water quality risk level of the wastewater to be tested according to the algal cell viability index value of the wastewater to be tested in S3 is: when the algal cell viability index value of the wastewater to be tested is greater than 73.00%, the toxicity level of the water sample is non-toxic or slightly toxic, and the risk level is low risk; when 73.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 48.00%, the toxicity level of the water sample is low toxicity, and the risk level is medium risk; when 48.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 4.00%, the toxicity level of the water sample is moderately toxic, and the risk level is high risk; when 4.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 0.00%, the toxicity level of the water sample is highly toxic, and the risk level is extremely high risk.

[0036] Explanation: The above method divides water quality risk levels into a four-level toxicity system (non-toxic / slightly toxic, low toxicity, moderate toxicity, and high toxicity) based on the value of algal cell viability index, covering the full range of effects from sublethal to acute toxicity, ensuring the continuity and gradient of risk assessment; directly linking toxicity levels with low / medium / high / very high risk levels facilitates regulatory authorities to quickly identify high-risk water samples (for example, extremely high-risk wastewater with a viability value ≤ 4% requires immediate disposal measures), thereby improving the efficiency of environmental emergency response; the setting of viability value thresholds is based on algal ecotoxicology research (for example, 73% corresponds to no significant metabolic inhibition, and 4% is close to the lethal threshold), ensuring that toxicity classification is directly linked to algal population dynamics and the health of aquatic ecosystems, in line with international environmental risk assessment standards, and through the direct mapping of quantitative toxic effects and risk levels, the scientific, practical, and operational nature of water quality risk assessment is achieved;

[0037] Specifically, based on the water quality risk levels divided by the above algal cell viability index values, the following specific application or management measures can be formulated to ensure environmental safety and the rational use of water resources: For low risk, no significant toxicity or very low toxicity, suitable for general industrial water, agricultural irrigation or landscape water replenishment and other non-direct drinking purposes; regular monitoring can be carried out to maintain water quality stability, but no emergency treatment measures are required. It can be included in the routine water quality monitoring plan as a reference indicator of environmental quality;

[0038] For medium-risk areas, although the toxicity is relatively low, it has a certain inhibitory effect on algae and should be used with caution in situations with high water quality requirements, such as fishery farming and certain sensitive industrial production. The mild pollution early warning mechanism can be activated to increase the frequency of monitoring of the water source, assess the pollution source, and take preliminary control measures, such as reducing surrounding pollution emissions and strengthening the operation and management of sewage treatment facilities.

[0039] For high-risk areas with obvious toxicity to algae, direct use in aquaculture, agricultural irrigation, or as a source of drinking water is strictly prohibited; alternative water sources or deep treatment must be considered; the pollution emergency response mechanism should be immediately activated to conduct emergency investigation and blockage of the pollution source to prevent the spread of pollution. At the same time, the water quality in the area should be continuously monitored to assess the scope and extent of the pollution impact and formulate a remediation plan;

[0040] For extremely high-risk water samples, these are extremely toxic and pose a serious threat to the ecological environment. They must be immediately cut off from the water body to prevent further contamination. The highest-level pollution emergency plan will be activated, which can include evacuating residents in the affected area, sealing off the contaminated water source, urgently deploying emergency treatment equipment for on-site treatment, and carrying out ecological restoration of the contaminated water body. At the same time, the legal liability of relevant parties will be investigated, and environmental supervision and law enforcement will be strengthened.

[0041] The beneficial effects of the present invention are:

[0042] The method of the present invention is based on measuring the cell viability of algal cells using a microplate and a multifunctional microplate reader. Compared with the method of measuring cell viability using flow cytometry, it retains the advantages of fast measurement speed and simple operation, and reduces the cost of testing instruments and data analysis. In addition, the water quality toxicity is assessed by algal cell viability. Compared with the algal cell growth inhibition method, it can detect wastewater toxicity with high throughput, short time and high speed, and greatly reduces the number of 96-well microplates used, thereby reducing costs. The method can be widely used in wastewater toxicity determination and risk assessment. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of a method flow of an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to further illustrate the approach and effects achieved by the present invention, the technical solution of the present invention will be clearly and completely described below in conjunction with experiments.

[0045] Example 1: This example is applied to the effluent sample from the regulating tank of an industrial wastewater treatment plant. The method of comprehensive wastewater toxicity detection and water quality risk assessment of the present invention comprises the following steps:

[0046] S1. Determine the ammonia nitrogen concentration of the wastewater to be tested, and determine whether the wastewater to be tested needs to be diluted based on the ammonia nitrogen concentration of the wastewater to be tested. If dilution is required, dilute the wastewater to be tested with pure water to obtain diluted wastewater to be tested. If dilution is not required, perform the next step of treatment on the wastewater to be tested. Specifically, when the ammonia nitrogen concentration is greater than 30 mg / L, dilute the water sample with pure water to a concentration of ≤30 mg / L; when the ammonia nitrogen concentration is ≤30 mg / L, no dilution is required.

[0047] For example, after the wastewater sample to be tested is filtered through a 0.22 μm water filter membrane, the ammonia nitrogen concentration of the water sample is measured to be 23.20 mg / L < 30 mg / L, and the water sample does not need to be diluted;

[0048] S2. adding the wastewater to be tested that does not require dilution or the diluted wastewater to be tested to the algal cell culture system and exposing it to the poison for 24 hours, and then measuring and calculating the algal cell viability index value of the wastewater to be tested that does not require dilution or the diluted wastewater to be tested;

[0049] Specifically, the algae cells are Capricornis sphenanthera in the logarithmic growth phase, and the cell concentration in the algae cell culture system is 10 5 ~10 6 / mL;

[0050] The cell viability staining assay was used for the assay, and the assay steps included:

[0051] Fluorescein diacetate was added to the wastewater to be tested / the diluted wastewater to be tested to a concentration of 25 μM; the cells were then incubated at room temperature in the dark for 45 minutes to obtain fluorescently stained algal cells;

[0052] The fluorescence intensity of the algal cells after fluorescence staining was obtained using a multifunctional microplate reader, and the algal cell viability index value f0 was obtained by calculating the fluorescence intensity of the algal cells after exposure to the poison and the fluorescence intensity of the algal cells without exposure to the poison.

[0053] According to the algae cell activity index measurement value f0, the algae cell activity index value f1 of the wastewater to be tested is determined.

[0054] The algae cell viability index value f0 is calculated by the following formula (1):

[0055]

[0056] Where f0 is the measured value of algae cell viability index, that is, f0 is the measured value of algae cell viability index of the wastewater to be tested without dilution F1 is the average fluorescence intensity of algal cells after exposure to the poison, and F0 is the average fluorescence intensity of algal cells after no exposure to the poison.

[0057] The method for determining the algae cell activity index value f1 of the wastewater to be tested according to the algae cell activity index measurement value f0 is as follows: when the wastewater to be tested does not need to be diluted, the algae cell activity index value of the wastewater to be tested is

[0058] For example, after exposure to the poison, fluorescein diacetate (FDA) was added to a solution concentration of 25 μM, incubated for 45 min at room temperature in the dark, and then transferred to a black opaque 96-well microplate. The fluorescence intensity of the algae cells was measured using a multifunctional microplate reader at an excitation wavelength of 488 nm and an emission wavelength of 533 nm. The algae cell viability index value of the water sample was calculated using formula (1) to be 41.70%;

[0059] S3. Classify wastewater according to its water quality risk level: When the algal cell viability index value of the wastewater to be tested is greater than 73.00%, the toxicity level of the water sample is non-toxic or slightly toxic, and the risk level is low risk; when 73.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 48.00%, the toxicity level of the water sample is low toxicity, and the risk level is medium risk; when 48.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 4.00%, the toxicity level of the water sample is moderate toxicity, and the risk level is high risk; when 4.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 0.00%, the toxicity level of the water sample is highly toxic, and the risk level is extremely high risk. The algal cell viability index value of the effluent sample from the regulating pond is 41.70%, so the toxicity level of the effluent sample from the regulating pond is moderate toxicity, and the risk level is high risk.

[0060] Example 2

[0061] Based on the method of Example 1, this embodiment is applied to a sample of water effluent from an inclined plate dissolved air flotation system of an industrial wastewater treatment plant. A method for comprehensive wastewater toxicity detection and water quality risk assessment of the present invention comprises the following steps:

[0062] S1. After the wastewater sample was filtered through a 0.22μm water filter membrane, the ammonia nitrogen concentration of the water sample was determined to be 23.50mg / L<30mg / L. The water sample did not need to be diluted;

[0063] S2. Use the water sample to expose the cells of the ceratosporin-containing algae for 24 hours. After exposure, add fluorescein diacetate (FDA) to a solution concentration of 25 μM, incubate for 45 minutes at room temperature in the dark, and then transfer to a black opaque 96-well microplate. Use a multifunctional microplate reader to measure the fluorescence intensity of the algae cells under the channel of excitation wavelength 488 nm and emission wavelength 533 nm. Use formula (1) to calculate the algae cell viability index value of the water sample to be 21.57%;

[0064] S3. Classify the wastewater according to its water quality risk level: when the algal cell viability index value of the wastewater to be tested is greater than 73.00%, the toxicity level of the water sample is non-toxic or slightly toxic, and the risk level is low risk; when 73.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 48.00%, the toxicity level of the water sample is low toxic, and the risk level is medium risk; when 48.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 4.00%, the toxicity level of the water sample is moderately toxic, and the risk level is high risk; when 4.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 0.00%, the toxicity level of the water sample is highly toxic, and the risk level is extremely high risk; the cell viability index of the water sample effluent from the inclined plate dissolved air flotation is 21.57%, so the toxicity level of the water sample effluent from the inclined plate dissolved air flotation is moderately toxic, and the risk level is high risk.

[0065] Example 3

[0066] Based on the method of Example 1, the application object of this embodiment is the effluent sample of the secondary sedimentation tank of a certain industrial wastewater treatment plant. A method for comprehensive toxicity detection and water quality risk assessment of wastewater of the present invention comprises the following steps:

[0067] S1. After the wastewater sample is filtered through a 0.22μm water filter membrane, the ammonia nitrogen concentration of the water sample is measured to be 4.00mg / L<30mg / L. The water sample does not need to be diluted;

[0068] S2. Use the water sample to expose the cells of the ceratosporin-containing algae for 24 hours. After exposure, add fluorescein diacetate (FDA) to a solution concentration of 25 μM, incubate for 45 minutes in the dark at room temperature, and then transfer to a black opaque 96-well microplate. Use a multifunctional microplate reader to measure the fluorescence intensity of the algae cells under the channel of excitation wavelength 488 nm and emission wavelength 533 nm. Use formula (1) to calculate the algae cell viability index value of the water sample to be 74.35%;

[0069] S3. Classify wastewater according to its water quality risk level: When the algal cell viability index value of the wastewater to be tested is greater than 73.00%, the toxicity level of the water sample is non-toxic or slightly toxic, and the risk level is low risk; when 73.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 48.00%, the toxicity level of the water sample is low toxicity, and the risk level is medium risk; when 48.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 4.00%, the toxicity level of the water sample is moderate toxicity, and the risk level is high risk; when 4.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 0.00%, the toxicity level of the water sample is highly toxic, and the risk level is extremely high risk. The cell viability index value of the secondary sedimentation tank effluent sample is 74.35%, so the toxicity level of the secondary sedimentation tank effluent sample is non-toxic or slightly toxic, and the risk level is low risk.

[0070] Example 4

[0071] The difference from Example 1 is that in S2, the wastewater to be tested / diluted wastewater to be tested is added to the algal cell culture system and exposed for 20 hours; fluorescein diacetate is added to the wastewater to be tested / diluted wastewater to be tested to a concentration of 25 μM; and then incubated at room temperature in a dark environment for 30 minutes.

[0072] Example 5

[0073] The difference from Example 1 is that in S2, the wastewater to be tested / diluted wastewater to be tested is added to the algal cell culture system and exposed for 48 hours; fluorescein diacetate is added to the wastewater to be tested / diluted wastewater to be tested to a concentration of 25 μM; and then incubated at room temperature in a dark environment for 60 minutes.

[0074] Example 6

[0075] The difference from Example 1 is that the application object of this embodiment is the pre-treated effluent sample of a certain industrial wastewater treatment plant, the ammonia nitrogen concentration is 107.80 mg / L>30 mg / L, the wastewater to be tested needs to be diluted 4 times, and the algal cell activity index measurement value of the diluted wastewater to be tested is calculated by formula (1): is 36.59%; the algae cell activity index value of the wastewater to be tested is f1, which is calculated by the following formula (2):

[0076]

[0077] Where f1 is the algae cell viability index value of the wastewater to be tested, S is the dilution multiple; the calculated algae cell viability index value f1 is 12.93%;

[0078] S3. Classify wastewater according to its water quality risk level: When the algal cell viability index value of the wastewater to be tested is greater than 73.00%, the toxicity level of the water sample is non-toxic or slightly toxic, and the risk level is low risk; when 73.00% or greater than the algal cell viability index value of the wastewater to be tested is greater than 48.00%, the toxicity level of the water sample is low toxicity, and the risk level is medium risk; when 48.00% or greater than the algal cell viability index value of the wastewater to be tested is greater than 4.00%, the toxicity level of the water sample is moderate toxicity, and the risk level is high risk; when 4.00% or greater than the algal cell viability index value of the wastewater to be tested is greater than 0.00%, the toxicity level of the water sample is highly toxic, and the risk level is extremely high risk. The cell viability index of the pretreatment effluent sample is 12.93%, so the toxicity level of the pretreatment effluent sample is moderate toxicity, and the risk level is high risk.

Claims

1. A method for comprehensive wastewater toxicity detection and water quality risk assessment, characterized in that: The following steps are involved: S1. Determine the ammonia nitrogen concentration of the wastewater to be tested, and determine whether the wastewater to be tested needs to be diluted according to the ammonia nitrogen concentration of the wastewater to be tested. If dilution is required, dilute the wastewater to be tested with pure water to obtain diluted wastewater to be tested. If dilution is not required, perform the next step of treatment on the wastewater to be tested; S2. Adding the wastewater to be tested that does not require dilution or the diluted wastewater to be tested into the algae cell culture system and exposing it to the poison for 20 to 48 hours, and then measuring and calculating the algae cell activity index value of the wastewater to be tested; S3. Determine the water quality risk level of the wastewater to be tested based on the algae cell activity index value of the wastewater to be tested.

2. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 1, characterized in that: Before determining the ammonia nitrogen index of the wastewater to be tested in S1, the wastewater to be tested is filtered through a 0.22 μm water filter membrane.

3. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 1, characterized in that: The method for determining whether the wastewater to be tested needs to be diluted based on the ammonia nitrogen concentration value in S1 includes: when the ammonia nitrogen concentration is >30 mg / L, using pure water to dilute the ammonia nitrogen concentration of the water sample to ≤30 mg / L; when the ammonia nitrogen concentration is ≤30 mg / L, no dilution is required.

4. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 1, characterized in that: In S2, the algae cells are Capricornis horned algae in the logarithmic growth phase.

5. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 1, characterized in that: The cell concentration in the algae cell culture system is 10 5 ~10 6 pieces / mL.

6. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 1, characterized in that: In said S2, the method for determining the algae cell viability index value of the wastewater to be tested is any one of a cell density determination method, a fluorescence parameter determination method and a cell viability staining determination method.

7. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 6, characterized in that: In S2, the cell viability staining assay is used for determination, and the determination steps include: Fluorescein diacetate is added to the wastewater to be tested that does not require dilution or the diluted wastewater to be tested to a concentration of 25 μM; the mixture is then incubated at room temperature in a dark environment for 30 to 60 minutes to obtain fluorescently stained algal cells; The fluorescence intensity of the algal cells after fluorescence staining was obtained using a multifunctional microplate reader, and the algal cell viability index value f0 was obtained by calculating the fluorescence intensity of the algal cells after exposure to the poison and the fluorescence intensity of the algal cells without exposure to the poison. According to the algae cell activity index measurement value f0, the algae cell activity index value f1 of the wastewater to be tested is determined.

8. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 7, characterized in that: The algae cell viability index value f0 is calculated by the following formula (1): Where f0 is the measured value of algal cell viability index, f0 includes the measured value of algal cell viability index of the wastewater to be tested without dilution The algae cell activity index of the diluted wastewater to be tested is measured Two values: F1 is the average fluorescence intensity of algal cells after exposure to poisons, and F0 is the average fluorescence intensity of algal cells after no exposure to poisons.

9. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 8, characterized in that: The method for determining the algae cell viability index value f1 of the wastewater to be tested based on the algae cell viability index measurement value f0 is: When the wastewater to be tested does not need to be diluted, the algae cell activity index value of the wastewater to be tested When the wastewater to be tested needs to be diluted, the algal cell activity index value of the wastewater to be tested is calculated as f1 by the following formula (2): Where f1 is the algal cell activity index value of the wastewater to be tested, and S is the dilution multiple.

10. A method for comprehensive wastewater toxicity detection and water quality risk assessment according to claim 1, characterized in that: The method for determining the water quality risk level of the wastewater to be tested according to the algal cell viability index value of the wastewater to be tested in S3 is: when the algal cell viability index value of the wastewater to be tested is greater than 73.00%, the toxicity level of the water sample is non-toxic or slightly toxic, and the risk level is low risk; when 73.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 48.00%, the toxicity level of the water sample is low toxicity, and the risk level is medium risk; when 48.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 4.00%, the toxicity level of the water sample is moderately toxic, and the risk level is high risk; when 4.00% ≥ the algal cell viability index value of the wastewater to be tested is greater than 0.00%, the toxicity level of the water sample is highly toxic, and the risk level is extremely high risk.

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