AUTOMATIC AND CONTINUOUS WASTEWATER MONITORING SYSTEM

1. What is an Automatic Observation Station?

Automatic and continuous monitoring refers to a continuous measurement and analysis process by automatic measurement or analysis instruments.

Fixed observation station/system refers to an observation station/system to be installed in a fixed and permanent manner at the identified position which may automatically observe the environment parameters.

2. Subjects required to continuously automatic wastewater observation under the Law on Environmental Protection 2020, including:

a) Concentrated production, business and service area, industrial cluster to discharge water into the environment;  

b) Investment project and facilities subject to risk of environmental pollution with average wastewater flow rate or higher;

c) Investment project and facilities not subject to risk of environmental pollution with high wastewater flow rate.

3. Automatic and continuous wastewater observation parameters

Monitoring parameters and position: According to specific nature of waste sources, wastewater treatment system and management requirements, the State competent authority may request the facilities to conduct automatic observation of pollution parameters and identify the installation position of automatic and continuous wastewater monitoring system as prescribed by the laws.

The Decree No. 40/2019 provides specific provisions on wastewater observation parameters as follows:

• Automatic and continuous wastewater observation parameters: Flow rate (input and output), temperature, pH, TSS, COD and Ammonia.
• For the projects/facilities subject to industrial production model with environmental pollution scale to be specially provided, industry's specific environment parameters shall be decided by the agency in-charge of approving EIA report or confirming the environmental protection plan;
• For cooling water using chlorine or chlorine-based antiseptic agent, following parameters shall be applied, including flow rate, temperature and chlorine.
• The automatic and continuous wastewater monitoring results are used to declare and pay for environmental protection fee for wastewater.

4. Basic requirements for automatic and continuous wastewater monitoring system:

Automatic and continuous wastewater monitoring must be complied with the technical regulations on environmental monitoring. Monitoring system data is directly sent to the provincial authority in-charge of environmental protection.

a) Automatic and continuous monitoring equipment: The monitoring parameters, measurement and analysis principle of the monitoring equipment are based to determine the proper installation method for monitoring equipment, concretely:

- Direct method: monitoring equipment (pH probe, temperature, etc.) is directly installed at the monitoring position behind the wastewater treatment system, the probe shall be located at least 10 cm from the wastewater surface and at least 15 cm from the bottom;

- Indirect method: Post-treatment wastewater is pumped into the station, flowing into sample tank to directly measure by probes which are directly merged into the tank or moved to the automatic analysis equipment assembly (if any);

b) Data receipt, transmission and management system: is used to collect, maintain and transmit the system’s automatic and continuous monitoring data to the State management authorities in-charge of environment. The data receipt, transmission and management system is detailed at Article 39 herein;

c) Reagent: is used to test and calibrate the system’s monitoring equipment;

d) Automatic sampling opacimeter: is used to take and maintain water sample when one of parameters exceeds the limit allowed by the code or required by the State competent authorities;

dd) Camera: is used to provide the online image located at position of monitoring equipment and discharge outlet of the wastewater treatment system before discharging into the receiving source, concretely:

dd1) In case of direct installation method for equipment: 01 camera is installed at discharge outlet of wastewater treatment system;

dd2) In case of indirect installation method for equipment: 01 camera is installed inside the station and 01 camera is installed outside the station at the discharge position of the wastewater treatment system;

dd3) Camera must be able to rotate (horizontal, vertical), view at night, ensuring visibility of objects to be monitored; record images by time and schedule the video recording;

e) Technical requirements for other auxiliary equipment for the automatic and continuous wastewater monitoring system specified at Appendix 10 issued under the Circular No. 10/2021, concretely:

1. Station house: is used to contain the System’s monitoring equipment to ensure a safe and stable environment for the equipment inside the station. The station house position must be qualified with at least requirements as follows:

a) Less vibration, shake;

b) Few impacts of dust and corrosive gases;

c) Stable power source. The power source and UPSs must ensure to maintain the continuous and stable operation of the System and the electrical equipment must be provided with switch, overcurrent protection, surge protection devices and voltage regulator with proper capacity to ensure the System’s stable operation, provided with UPSs to ensure the minimum 30-minute operation since power failure;

d) Convenient for installation, maintenance and safety for persons and equipment;

dd) Near the monitoring position.

2. Sampling pump and water pipe (if any)

- Sampling pump: Automatic monitoring system under direct method shall be provided with at least 02 pumps and control system to alternatively operate to ensure that water is continuously pumped into the holding tank or measuring and analytical equipment. Air bubbles must not be created in the pipe and holding tank. Pump body and chamber shall be made of stainless steel or materials that that does not alter water sample quality;

- Water pipe: pipes must be made of durable material that does not affect the water sample quality and is resistant to microbiological contamination. There must be two pipes laid in parallel to facilitate the pipe cleaning and periodic maintenance;

- In the cases where indirect method is used to install measuring equipment, piping between the monitoring location and the holding tank must be as short as possible and the diameter (at least ø27) must be large enough for the pipe not to be blocked.

3. Fire alarm system, smoke detector, direct lightning and surge protection devices.

4. Other auxiliary equipment: depending on methods of measurement and analysis, and physical condition at the monitoring location, the auxiliary equipment may (but is not required to) include the following:

- Sewer grates: sewer grates shall be used to prevent rubbish and dirt from sticking to the probes, affecting the results. Sewer grates shall be made of stainless steel and resistant to corrosion;

- Sample container: sample container shall be used to contain the surface water samples to be monitored and probes. The container shall be made of stainless steel or material that does not affect water to be monitored and facilitates maintenance. Its volume must be compliant with the requirements for installation of monitoring equipment (at least 15 liters). It must be designed to ensure continuous flow of water and minimize the deposition of water samples in the holding tank, thereby ensuring the accuracy and integrity of water samples;

- Wastewater container: wastewater container shall be used to contain analyzed wastewater and standard solutions after use. The wastewater container must be made of chemical-resistant materials to prevent leaks. The waste must be stored in a separate area and warning sign must be put up therein. The waste shall be managed and treated according to applicable regulations on management of waste.

5. Temperature and humidity meters must be installed inside the station.

5. Technical requirements for automatic and continuous wastewater monitoring system:

The Circular No. 10/2021 specifies the technical requirements for automatic and continuous wastewater monitoring system, concretely:

5.1. Automatic and continuous monitoring equipment

Technical specifications of the system’s automatic and continuous wastewater monitoring equipment must be qualified with following requirements at least:

No.	Monitoring parameters	Unit	Accuracy		Resolution	Response time
			(% reading)	(% measuring interval)
1	Flow rate	m3/h	± 5%	± 5%	-	≤ 5 minutes
2	Temperature	oC	± 5%	± 5%	0,1	≤ 5 seconds
3	Color	Pt-Co	± 5%	± 5%	-	≤ 5 minutes
4	pH	-	± 0,2 pH	± 0,2 pH	0,1	≤ 5 seconds
5	TSS	mg/L	± 5%	± 3%	0,1	≤ 10 seconds
6	COD	mg/L	± 5%	± 3%	0,5	≤ 15 minutes
7	NH4+	mg/L	± 5 %	± 5 %	0,2	≤ 30 minutes
8	Total Phosphorus	mg/L	± 5 %	± 3 %	0,1	≤ 30 minutes
9	Total nitrogen	mg/L	± 5 %	± 3%	0,1	≤ 30 minutes
10	TOC	mg/L	± 5%	± 5%	0,1	≤ 30 minutes
11	Residual chlorine	mg/L	± 5 %	± 2%	0,1	≤ 30 minutes

Regarding accuracy of the monitoring equipment in Table 3: the reading or measuring interval-based accuracy may be applied;

b) The automatic monitoring equipment must have at least 01 measuring interval capable of measuring a value ≥ 3 times the limit value specified in the National Technical Regulation on Environment applicable to the facility (except for temperature and pH);

c) It is recommended to use synchronous monitoring equipment certified by international organizations, including United States Environmental Protection Agency (US EPA), Environment Agency's Monitoring Certification Scheme (mCERTs) and German Technical Inspection Association (Technischer Überwachungsverein, TÜV);

d) The monitoring equipment can automatically store and export monitoring data and status of the measuring equipment (including at least the following status: measuring, calibrating and error). Regarding velocity and temperature, “calibration” status is not required.

5.2. Reference materials

a) The reference material used for periodic inspection must be within its shelf life, have a minimum accuracy of ± 5% (± 0.1 pH for pH) and traceable to standards in accordance with regulations of the law on measurement;

b) Reference materials must meet at least 01 concentration in the equipment’s measurement range equivalent to each parameter specified in Table 3, except for temperature and flow.

5.3. Automatic sampling and sample storage equipment

The automatic sampling and sample storage equipment must be featured by following functions:.

a) Automatically take samples (periodic, unscheduled or over time) and store samples in the storage cabinet at 4 ± 2°C for a period of time suitable for parameter analysis;

b) Receive control signals from competent authorities to serve automatic remote sampling;

c) Automatic sampling cabinets must be sealed and managed by the Department of Natural Resources and Environment.

6. Requirements for management and operation of automatic and continuous wastewater monitoring systems:

6.1. Installation of the system’s measuring interval: upon operating an automatic and continuous monitoring system to transmit data to the receiving unit, equipment must have a measuring interval capable of measuring a value ≥ 3 times the limit value specified in the National Technical Regulation on Environment applicable to the facility;

6.2. Assurance of the system quality

a) Management and operation personnel: there must be sufficient personnel knowledgeable about the system in order to manage, maintain and operate it;

b) The system management dossier must be retained by the system operator and presented at the request of a competent authority. The dossier includes:

b1) List of monitoring parameters;

b2) List and technical specifications of monitoring equipment of the equipment manufacturer;

b3) User guide;

b4) Design drawing and description of the system;

b5) Standard operating procedure (SOP): A SOP must include contents relating to system start-up and operating procedures; daily system check procedures; frequency and procedures for checking accuracy of equipment with standard solutions; procedures for mixing chemicals, reference materials and creating calibration curve of the analytical equipment (if any); frequency and procedures for maintaining monitoring equipment; equipment inspection and calibration frequency; frequency of replacement of accessories and consumables according to the manufacturer’s recommendations; procedures for rectifying errors; data back-up procedures; data examination and reporting procedures; regulations on safety during system operation and procedures for storage, management and treatment of generated waste;

b6) Standby equipment, parts and accessories;

b7) Operational logbook and equipment maintenance, inspection and calibration logbook;

b8) User manual for some common errors and how to troubleshoot the problems during the system management and operation;

b9) Logbook for monitoring and inspection of daily operations of the system;

b10) Certificate enclosed with report on inspection and calibration of the system’s monitoring equipment;

b11) Record on checking of the system with standard solutions.

6.3. Before the system is officially put into operation, the system operator shall submit relevant documents to the Department of Natural Resources and Environment, including:

a) Information about the system investor and operator: name and address;

b) Installation time (starting and ending time), and time and result of system quality control in accordance with the regulations specified in Clause 6 of this Article;

c) Design drawing and description of the system; list of monitoring parameters and methods of installing monitoring equipment (direct or indirect method); descriptive information and images, diagram and map of the monitoring locations;

d) List and technical specifications of measuring and analytical equipment; manufacturers and equipment models; certificate enclosed with an inspection and calibration result report; monitoring data gathering and storage system; static IP address (data transfer protocol) attached to the system.

6.4. Automatic and continuous monitoring equipment must undergo inspection, calibration, testing and periodic check

a) Equipment must be inspected and calibrated in accordance with prevailing legal regulations on measurement;

b) Equipment must be periodically checked using reference materials according to the manufacturer’s recommendations at least once a month by the system operator; must be re-inspected or re-calibrated if value given by the measuring equipment deviates by ≥ 10% from the reference material concentration value. It is recommended that measuring equipment be re-inspected or re-calibrated if the value given by the measuring equipment deviates by < 10% from the reference material concentration value. The process of checking equipment with reference materials and inspecting and calibrating equipment must be specified in the operational logbook;

c) It is recommended that equipment be checked periodically by making a comparison with results of monitoring of parameters in the facility’s periodic environmental monitoring program (if any);

d) The maintenance, repair and replacement of components and accessories must be included in a plan by the system operator and specified in the SOP.

6.5. If it is necessary to carry out maintenance, inspection, calibration and replacement of components and accessories, repair and replacement of measuring and analytical equipment, the facility owner shall comply with the following requirements:

a) Submit the Department of Natural Resources and Environment a written notification, specifying the plan for and ending time of maintenance, inspection, calibration and replacement of components and accessories or repair and replacement of measuring and analytical equipment;

b) If the operation of automatic monitoring equipment is suspended for 48 hours or more, the facility owner shall carry out monitoring at least once a day for the parameters not measured using automatic and continuous monitoring equipment until its operation is resumed. Monitoring results must be retained and sent to the Department of Natural Resources and Environment.

6.6. Before being officially put into operation, the quality of the system must be controlled once a year by a licensed independent unit according to the procedures below:

a) Inspect monitoring locations as prescribed;

b) Check the system’s functions of gathering, storing and transmitting automatic and continuous monitoring data;

c) Check components, technical specifications and other functions of the system;

d) Evaluate the system’s relative accuracy, including: 

d1) Carrying out reference monitoring:

d.1.1) Reference monitoring is the use of periodic monitoring methods specified in Appendix 4.1 enclosed with this Circular or methods accepted by US EPA as the equivalent methods to make a comparison between the obtained results and monitoring results of the system;

d1.2) Reference monitoring of each parameter shall be carried out;

d1.3) At least 06 samples shall be used as reference for every parameter to be monitored.

d2) Calculating and evaluating reference monitoring data using relative accuracy (RA, concretely:

d2.1) Calculation shall be made as prescribed in the Appendix 12 enclosed with the Circular No. 10/2021;

d2.2) RA result shall be evaluated as follows:

- The system's monitoring data will be accepted if RA is within the allowable limit specified in Table 4 below:

Table 4. Allowable limits of parameters used to make RA-based evaluation

No.	Parameter	Allowable limit of RA (%)
1	pH	≤ 20
2	TSS	≤ 30
3	Color	≤ 20
3	COD	≤ 20
5	N-NH4+	≤ 20
6	Total P	≤ 20
7	Total N	≤ 20
8	TOC	≤ 20
9	Residual chlorine	≤ 30

- For the parameters not mentioned in Table 4, RA results for such parameters must be sent to the automatic data receiving authority for consideration and decision on data receipt and management;

đ) QC information shall be made into a record on checking of technical specifications, functions and RA of the system, which is specified in the Appendix 13 enclosed with the Circular No. 10/2021.

7. Requirements for data logger at automatic and continuous environmental monitoring stations and systems

A data logger at stations and systems where automatic and continuous environmental monitoring (water quality, ambient air quality, wastewater and exhaust gases) equipment must satisfy at least the following requirements:

7.1. Receipt, storage and management of data in the data logger

a) The system must be directly connected to measuring and analytical equipment, data controller, and automatic sampling system (if any) and must not be connected through other equipment;

b) The output signal of the system must be digital;

c) Data must be stored for at least 60 consecutive days. At least, stored data must include: measurement parameters, results, unit, time and status of the measuring equipment (measuring, calibrating and error);

d) For the automatic and continuous wastewater and exhaust gas monitoring systems, the connection ports not used to transmit or receive data to managing authorities must be sealed by the local regulatory bodies;

đ) Information including measurement parameters, results and units (prescribed by the corresponding National Technical Regulation), measuring time and status of the measuring equipment must be displayed and data must be extracted using the data logger.

7.2. Transmission of environmental monitoring data

a) Data must be transmitted using FTP or FTPs or sFTP to a server with the account and address provided by the Department of Natural Resources and Environment. Internet connection speed must be at least 30Mb/s; If the transmitting unit and receiving unit are capable of meeting the technical conditions, the use of a data transmission method which is more modern than the prescribed one is encouraged;

b) Every data file must be transmitted in real time but no later than 5 minutes after data is gathered from the data logger and such file shall be stored in a folder. For the automatic and continuous wastewater and exhaust gas monitoring systems, data must be transmitted to the Department of Natural Resources and Environment from the static IP address notified to the Department of Natural Resources and Environment;

c) Real time must be synchronized with Vietnam Time Zone (GMT+ 7);

d) In case the data transmission is interrupted, after the recovery, the system must automatically transmit the interrupted data. Where the data transmission is interrupted for more than 12 hours, the system operator must send a written response and email about causes and remedial measures for the interruption to the data receiving authority;

dd) Receipt of control signals for remote automatic sampling (if any) and gathering of data upon request are allowed.

7.3. File format and content

a) Data is formatted in a *.txt file;

b) A file must include 05 main pieces of information: measurement parameters, measurement results, measurement units, measurement time and status of the measuring equipment (measuring, calibrating and error). Structure, content and name of the file are specified in the Appendix 15 enclosed with this Circular;

c) Information from cameras shall be transmitted to the Department of Natural Resources and Environment using RTSP. Camera data must be stored for a period of 03 months.

7.4. Data security and integrity

a) After the automatic and continuous wastewater and exhaust gas monitoring system is officially put into operation, an account and password are required to control access to the data logger and connection ports must be sealed. Account and password (Admin, Host, Superhost, Master, Supervisor) of the data logger must be provided to the Department of Natural Resources and Environment to manage and control connection ports, configuration and firmware upgrade process;

b) The facility and system operators must ensure and take responsibility for data security and integrity, FTP server account and static IP address through which data is transmitted.

8. Management, disclosure and sharing of environmental monitoring data & information:

8.1. Environmental quality monitoring data includes: automatic and continuous environmental quality monitoring results of the environmental quality monitoring programs as prescribed.

8.2. Report on environmental quality monitoring results, including: Quarterly and annual report on environmental quality results (for automatic and continuous monitoring).

8.3. Format of environmental quality monitoring data and reports:

a) Format of environmental quality monitoring data: data specified in Clause 1 Article 42 hereof in a computer file in word format (.doc or .docx) for environmental quality monitoring reports; in excel format (.xls or .xlsx) for periodic monitoring results; text file for automatic and continuous monitoring results;

b) Forms of automatic and continuous monitoring result reports are specified in Tables A3 and A4 in the Appendix 16 of the Circular No. 10/2021.

9. Responsibilities of the local Department of Natural Resources and Environment:

a) To follow up the automatic and continuous wastewater monitoring data; to evaluate the automatic and continuous wastewater monitoring results in accordance with average daily value (24 hours) of the measuring results and comparing with the maximum allowable value of pollution parameters under the technical regulation on waste; to follow up and inspect the recovery in the following circumstances: interrupted monitoring data; finding the monitoring parameters exceeding the required environment-related technical regulations and recommend the settlement measures as prescribed;

b) To summarize and transmit the automatic and continuous wastewater monitoring data in the province to the Ministry of Natural Resources and Environment as prescribed and at the request.

10. Legal foundations:

The Law on Environmental Protection in 2020 (hereinafter referred to as Law on Environmental Protection 2020 ratified on 17 November 2020 by the 15th National Assembly at its 10th session);

The Decree No. 40/2019/NĐ-CP of the Government on amending and supplementing a number of Articles of the Decrees on providing details and guiding the implementation of the Law on Environmental Protection dated 13 May 2019;

The Circular No. 10/2021/TT-BTNMT of the Minister of Natural Resources and Environment dated 30 June 2021;

Appendix 13: Record on Checking Technical Specifications and Relative Accuracy of Automatic and Continuous Wastewater Monitoring System (the Circular No. 10/2021/TT-BTNMT)