HJ 91.1-2019Technical specifications for wastewater monitoring (English PDF)

3.5 Automatic sampling

The process of automatic continuous or intermittent collection of water samples according to a pre-programmed procedure by instruments and equipment.

3.6 Whole program blank sample

Replace the actual sample with experimental water and place it in the sample container and determine according to the program consistent with the actual sample. Consistent program includes transport to the sampling site, exposure to the on-site environment, loading into sampling bottles, preservation, transportation, and all analytical procedures, etc.

3.7 Laboratory blank sample

Replace the actual sample with experimental water and determine according to the analytical procedures consistent with the actual sample.

5.1 Requirements for discharge outlet setting

5.1.1 The discharge outlet shall meet the requirements of on-site sampling and flow measurement. In principle, it shall be located within the plant boundary, or within a range of not more than 10 m outside the plant boundary.

5.1.2 The monitoring section of wastewater discharge pipeline or channel shall be regular shapes such as rectangular, circular, trapezoidal. The flow in the measurement section shall be straight and stable and have a certain water level.

In the case of pollution discharge by closed pipe or channel, an open channel capable of satisfying the sampling conditions and flow measurement shall be provided.

When monitoring the overall treatment efficiency of wastewater treatment facilities, at the inlets of wastewater into the wastewater treatment facilities and the outlets of the wastewater treatment facilities, set monitoring points. When monitoring the treatment efficiency of each wastewater treatment unit, at the inlets of wastewater entering the wastewater treatment unit and the outlets of the wastewater treatment unit, set monitoring points.

5.2.3 Monitoring points for rainwater discharge

Pollutant discharging organizations shall divert rainwater and wastewater.

Rainwater, after collection, is discharged by rainwater pipelines. The monitoring point shall be set at the rainwater discharge outlet. If environmental management requires rainwater to be discharged after treatment, the monitoring points shall be set in accordance with 5.2.1.

6.1 Monitoring preparation

6.1.1 Preparation of sampling equipment and on-site test instruments

6.1.1.1 Sampling equipment are mainly sampling apparatus and sample containers. In accordance with the requirements of the analytical methods used in the monitoring items, it shall prepare appropriate sampling equipment. If the requirements are not clear, it may be implemented in accordance with Appendix

A.

6.1.1.2 The material of the sampling equipment shall have good chemical stability. During the sample collection and sample preservation period, no physical and chemical reaction with the water sample will occur, which will cause the concentration of water sample components to change. The sampling apparatus may be made of polyethylene, stainless steel, polytetrafluoroethylene, etc. The sample container may be made of hard glass and polyethylene.

6.1.1.3 The surface of the inner wall of the sampling apparatus shall be smooth and easy to clean and handle. The sampling apparatus shall have sufficient strength, be flexible, convenient, and reliable in use, have no bends to interfere with the flow velocity. It shall minimize the number of cocks and valves. The sample container shall have appropriate mechanical strength and good sealability. The sample container used for microbiological inspection shall be able to withstand high temperature sterilization; at sterilization temperatures, shall not release or produce any chemicals which can inhibit biological activity or cause biological death or promote biological growth.

intermittent discharge;

c) It is necessary to investigate the possible pollutants or the pollutant concentration at a specific time;

d) It is necessary to obtain data on the highest value, lowest value, or changes in pollutants;

e) It is necessary to get short-term (generally no more than 15 min) data, to determine change rule of water quality;

f) It is necessary to determine the change characteristics of the pollutants in the water body space, such as the changes of the pollutants in different sections and (or) depths of the water flow;

g) Situations for which pollutant discharge (control) standards and other related environmental management work stipulate that instantaneous samples can be collected.

When the production process of the pollutant discharging organization is continuous and stable, there are wastewater treatment facilities and they are operating normally, and the wastewater can be discharged stably (the concentration change does not exceed 10%), the instantaneous sample is better representative. The concentration of instantaneous sample may be used to represent the sampling concentration during the sampling period.

6.3.1.3 Composite sampling

The following conditions apply to composite sampling:

a) Calculate the average pollutant concentration for a certain period of time;

b) Calculate the mass load of pollutants per unit time;

c) Large changes in wastewater characteristics;

d) Situations for which pollutant discharge (control) standards and other related environmental management work stipulate that composite samples can be collected.

Composite sampling includes equal time composite samples and equal proportional composite samples.

When the change of wastewater flow is less than 20% of the average flow and the concentration of pollutants is basically stable, equal time composite samples may be collected.

6.5 Sample collection

6.5.1 Before sampling, it shall carefully check the sampling apparatus, sample container and its stopper (cap), and timely repair and replace the broken and unstable parts of the sampling tool. The sample container is ensured to be closed, reducing the chance of contamination and preserving it safely. Note that sample containers used for testing of microorganisms and other components shall be completely packaged before sampling, to avoid contamination of the container before sampling.

6.5.2 REACH the monitoring point; before sampling, arrange the sampling

container and related tools neatly.

6.5.3 Samples are collected against the monitoring scheme. When sampling, it shall remove the floating matters such as sundries and garbage on the water surface; it shall not stir the sediment at the bottom of the water.

6.5.4 Before sampling, use water sample to rinse the sampling container and

sample container 2~3 times.

6.5.5 The container materials selected, the preservatives added and their

amount, the preservation period, and the volume of water samples collected, etc. for different monitoring items must be implemented in accordance with the analytical method requirements of the monitoring item. If not explicitly required, it may be performed in accordance with attached Table A.

6.5.6 After the sampling is completed, a label shall be attached to each sample container. The label content includes the sample number or name, the sampling date and time, the name of monitoring item, etc. At the same time, fill in the on- site record.

6.5.7 After the sampling is completed, check the monitoring scheme, on-site records, and actual sample numbers. If there are errors or omissions, it shall conduct supplementary sampling or re-sampling immediately. If samples are not collected at the sampling site according to the monitoring scheme, the actual situation shall be recorded in detail.

6.5.8 Other requirements

a) For some monitoring items, before sampling, sampling apparatus and sample containers cannot be washed, such as animal and vegetable oils, petroleum, volatile organic compounds, microorganisms, etc.;

b) For some monitoring items, water samples collected at different times cannot be mixed for determination, such as water temperature, pH value, chroma, animal and vegetable oils, petroleum, biochemical oxygen

6.7 On-site record

The on-site record shall include the following: monitoring purpose, name of pollutant discharging organization, meteorological conditions, sampling dates, sampling time, model and number of on-site test instruments, sampling points, production conditions, treatment process of wastewater treatment facilities, operation of wastewater treatment facilities, wastewater discharge amount/flow, on-site test items and monitoring methods, descriptions of sensory index of water samples, sampling items, sampling methods, sample numbers, preservation methods, samplers, reviewers, personnel of pollutant discharging organization, and other related matters which need to be explained. The specific format may be developed on its own.

6.8 Sampling safety

On-site monitoring personnel must consider corresponding safety precautions and take necessary protective measures during sampling.

The monitoring personnel shall be in good health and adapted to the requirements of the work. When sampling on site, at least two persons shall be present at the same time.

During monitoring, it shall be equipped with necessary protective equipment and first-aid supplies. When sampling on site, if there are corrosive, high temperature, toxic, volatile, and flammable substances near the sampling location, wear protective equipment. On-site monitoring personnel shall pay special attention to safety, avoid slipping and falling into the water, and wear life jackets if necessary.

7.1 Sample preservation and transportation

7.1.1 The samples, after collection, shall be sent to the laboratory for analysis as soon as possible. According to the requirements of the analytical methods used in the monitoring items, the preservation method of the samples shall be determined, to ensure that the samples are analyzed and tested within the specified preservation period. If the requirements are not clear, it may be implemented according to Appendix A.

7.1.2 According to the geographical location of sampling points and the

preservation period of monitoring items, select an appropriate mode of transport.

Before the sample is transported, the outer (inner) lid of the container shall be tightly closed. Packing shall be separated and fixed with shock-absorbing materials such as foam plastic to prevent damage. In addition to being lower than the pollutant discharge limit of the pollutant discharging organization.

8.2.3 Unless otherwise specified in the analytical method, wastewater, before

analysis, shall be shaken evenly for sampling, and shall not be filtered or clarified.

9.1 Original record

9.1.1 Record content

9.1.1.1 On-site record

The on-site record shall be performed in accordance with the relevant contents of 6.2 and 6.7.

9.1.1.2 Handover record

Handover record is performed in accordance with the relevant content of 7.2.

9.1.1.3 Original record of laboratory analysis

The original record of laboratory analysis includes standard solution preparation and calibration records, instrument working parameters, calibration curve records, analysis and test original records for each monitoring item, and internal quality control records, etc. Each laboratory may, according to needs, design various original analysis record forms on its own.

The original record of analysis shall contain sufficient information to identify, where possible, the factors which affect the uncertainty, and to enable laboratory analysis to be reproduced at the conditions closest to the original.

9.1.2 Record requirements

9.1.2.1 The original records of on-site monitoring and sampling of wastewater, sample preservation, sample handover, sample processing, and laboratory analysis shall be carefully filled in each column of the record form according to the prescribed format and recorded in a timely manner.

9.1.2.2 The original record form shall be uniformly numbered. Individuals shall not destroy or damage it without authorization. When it is used up, it shall be archived and stored on schedule.

9.1.2.3 The original record shall be recorded in time and must not be filled in or transcribed in a way of recollection.

9.2.6 In numerical calculations, after the number of significant digits is determined, the remaining figures shall be rounded off according to the rounding-off rules.

9.2.7 In numerical calculations, as for the values of certain multiples, fractions, discontinuous physical quantities and values which are completely calculated or defined based on theory without measurement, the number of significant digits may be regarded as infinite. In calculations, determine the number of significant digits as needed.

9.3 Rules of rounding off for numerical values

The rules of rounding off for numerical values shall be in accordance with GB/T

8170.

9.4 Approximate calculation rules

9.4.1 Addition and subtraction

When the approximate values are added and subtracted, the number of significant digits of the sum or difference is the same as the least number of digits after the decimal point of each approximate value. During the calculation, one decimal place can be reserved. The calculation result is processed according to the rules of rounding off for numerical values.

9.4.2 Multiplication and division

When multiplying and dividing approximate values, the number of significant digits of the resulting product and quotient is the same as the least number of significant digits of each approximate value. During the calculation process, each approximate value may first be rounded down to one digit more than the least number of significant digits. Finally, the calculation result is processed according to the above rules.

9.4.3 Power and extraction of a root

When the approximate value is powered or extracted for a root, the calculation result has the same number of significant digits as the original approximate value.

9.4.4 Logarithm and anti-logarithm

In the logarithmic calculation of approximate value, the number of digits after the decimal point (excluding the first digit) of the result shall be the same as the number of significant digits of the original figure.

9.4.5 Average value

RB/T 214, HJ 630, HJ/T 373 and other related content.

10.2 Sampling quality control

10.2.1 Basic requirements

For different monitoring items, according to the requirements in the selected analytical method, collect quality control samples.

Before sampling, the preservative shall be subjected to a blank test. Its purity and grade must meet the requirements of analysis. The quality of sampling apparatus and sample containers shall be randomly checked. They can be used only after the spot check is qualified.

10.2.2 Whole program blank sample

According to the requirements of the analytical method, collect whole program blank samples. The blank measurement value shall meet the requirements of the analytical method and generally shall be lower than the method detection limit. If not specified in the analytical method, each batch of water samples shall be whole program blank samples and sent to the laboratory for analysis with the water samples, to determine the accuracy of the analysis results, and to grasp the impact of the entire process operation steps and environmental conditions on the samples.

10.2.3 On-site parallel samples

According to the requirements of the analytical method, collect on-site parallel samples. If not specified in the analytical method, for homogeneous samples, monitoring items which can do parallel double samples (except on-site monitoring items, suspended solids, petroleum, animal and vegetable oils, microorganisms, etc.) shall also collect on-site parallel samples. Each batch of water samples shall collect at least 10% of the on-site parallel samples (except for automatic sampling). When the number of samples is small, for each batch of water samples, make the on-site parallel sample for at least 1 sample. When there is a large difference in the measurement results of the on-site parallel samples, the water samples shall be reviewed, to check the impact of the sampling and analysis process on the results.

10.3 Quality control of laboratory analysis

10.3.1 Laboratory blank sample

When each batch of water samples is analyzed, if the blank sample has a response to the test item, make at least 2 laboratory blanks. The measurement results shall meet the requirements in the analytical method and generally shall

The precision of a set of measured values is expressed as standard deviation or relative standard deviation.

10.3.4 Accuracy control

10.3.4.1 Basic requirements

Accuracy can be controlled by methods such as analyzing standard samples and self-prepared standard solutions, or spiked recovery in the laboratory. The accuracy control index of monitoring item is determined in accordance with the requirements in the analytical method.

10.3.4.2 Determination of standard sample/certified reference material

USE standard samples/certified reference materials as control measures. Each batch of samples carries a quality control sample of a known concentration, which is determined simultaneously with the sample. The standard sample/certified reference material shall not be the same source as the standard solution used to draw the standard curve.

If the laboratory prepares quality control samples by itself, it shall pay attention to the comparison with the standard samples/certified reference materials. Do not use the same standard solution as drawing the calibration curve. It must be prepared separately.

10.3.4.3 Spiked recovery

The spiked recovery test includes matrix spiking and matrix spiking parallel, etc.

Matrix spiking and matrix spiking parallel are performed before sample pretreatment. Spiked samples and samples are analyzed under the same pretreatment and measurement conditions. In the actual application, attention shall be paid to the form of spiked substance, the spiked amount, and the spiked matrix. The spiked amount is generally 0.5~3 times the sample content, but the total concentration after spiking shall not exceed the linear range of calibration curve. When the concentration to be measured in the sample is near the method detection limit, the spiked amount shall be controlled in the low concentration range of calibration curve. There shall be no significant change in sample volume after spiking, otherwise, when calculating the recovery rate, this factor shall be considered. Each batch of samples of the same matrix type shall be randomly sampled at a certain proportion for spiking recovery and parallel sample determination.

10.3.5 Other

The relevant content of other quality control measures in the laboratory shall be

Chinese Standards

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