Environmental regulation in Thailand is primarily governed by the Enhancement and Conservation of National Environmental Quality Act B.E. 2535 (NEQA 1992). This comprehensive legal framework aims to control pollution through established standards, mandatory compliance for pollution sources, and routine inspections conducted by government officials. The enforcement process relies heavily on the authority of Pollution Control Officials (PCOs) who ensure that pollution sources adhere to the specified legal requirements under NEQA 1992.

 

The Necessity and Scope of Pollution Source Inspection

Role and Authority of Pollution Control Officials (PCOs)

The core responsibility for enforcement lies with PCOs, who are appointed by the relevant Minister to execute pollution control mandates under the Act. PCOs are crucial for maintaining environmental quality by checking and verifying the pollution control measures implemented by various entities.

A “pollution source” is broadly defined as communities, industrial factories, buildings, constructions, vehicles, places operating certain activities, or any other entity that constitutes a source of pollution.

PCOs are vested with significant powers under the Act, particularly Section 82. Under Section 82(1), PCOs have the authority to enter premises (including buildings, factories, or areas housing wastewater/waste treatment systems) during daylight hours or working hours to check the operating condition of pollution control systems, equipment, and instruments. They also review detailed records, statistics, or data related to the system’s operation, especially when there is reasonable suspicion of non-compliance with the Act.

Determining Sources Subject to Control

Not all pollution sources are subject to the same level of control. Under Section 69 of the Act, the Minister, upon recommendation from the Pollution Control Committee, announces the specific types of pollution sources that must control their discharge of wastewater or waste into public water bodies or the environment.These sources designated for control span various sectors, categorized primarily into Industry, Agriculture, and Community sources. Examples of Pollution Sources Subject to Wastewater Discharge Control:

  1. Industrial Sector (General and Specific Industries):
    Includes general industry and specific operations such as tanning, desalination, pulp/paper mills, and power generation plants.
  2. Agricultural Sector:
    Includes the rearing of swine (pig farming) and various types of aquaculture (coastal, brackish, and freshwater).
  3. Community Sector:
    Includes fuel service stations, land subdivision projects, and various types and sizes of buildings.

Building Categories Subject to Control (Based on Size/Type)

Buildings are classified into residential, commercial, and hospital types, and further stratified into Categories A, B, C, and D based on metrics such as number of rooms/units or total floor area. For example:

  • Residential Buildings:
    Condominiums: Type A: (≥ 500$ units); Type B (100 to <500 units). Dormitories or rented rooms: Type B: (≥ 250 rooms).
  • Commercial Buildings:
    Hotels: Type A (≥ 200 rooms); Type B (60 to <200 rooms). Shopping centers/department stores: Type A (≥ 25,000 sqm); Type B (5,000 to <25,000 sqm). Restaurants/Eateries: Type A (≥ 2,500 sqm); Type B (500 to <2,500 sqm).
  • Hospital Buildings:
    Classified by the number of overnight patient beds: Type A (≥ 30 beds); Type B (10 to < 30 beds).

Other Key Source Classifications

  • Land Subdivision Projects (Housing Projects):
    Type A (≥ 500 plots or >100 rai); Type B (100 to 499 plots or 19-100 rai).
  • Pig Farming Facilities:
    Classified by livestock unit weight: Type A (> 600 units); Type B (60 to 600 units). One livestock unit equals 500 kg total net weight of pigs.

 

Essential Environmental Legislation and Inspection Requirements

The enforcement structure mandates specific legal duties for owners/occupiers of pollution sources and establishes criteria, or standards, against which PCOs conduct inspections.

Legal Duties for Owners/Occupiers of Pollution Sources

  1. Duty to Install Treatment Systems (Section 70):
    Owners or occupiers are legally obligated to construct, install, or arrange for a wastewater treatment system as determined by the PCO, to ensure effluent meets control standards before discharge into public waters or the environment. If a source already had a system before being designated for control (under Section 69), they must notify the PCO for inspection and subsequent orders for adjustments or improvements.
  2. Duty to Maintain Records and Report (Section 80):
    Owners or occupiers of controlled pollution sources who possess their own treatment systems must maintain daily statistical data and detailed records (using Form ThS. 1) that reflect the system’s performance. They must also prepare a monthly summary report (using Form ThS. 2) and submit it to the local official (such as the Mayor or Governor of Bangkok) by the 15th day of the following month. This reporting can be done in person, by registered mail, or electronically via systems like http://www.ereportmatra80.com.

Failure to comply with PCO orders (e.g., to install a system under Section 70) can result in administrative fines of up to 7,000 Baht per day until compliance is achieved. Failure to collect statistics or report (Section 80) carries criminal penalties, including imprisonment of up to one month or a fine of up to 10,000 Baht, or both (Section 106).

Mandatory Inspection Parameters (Wastewater Discharge Standards):

Wastewater discharge standards (Section 55) are crucial benchmarks used during inspections to ensure environmental quality. These standards vary depending on the type and size of the pollution source. PCOs collect wastewater samples to compare parameters against these legally defined standards.

Table: Examples of Wastewater Control Parameters for Buildings (P.S. 2567, Section 5):

Parameter Type A Type B Type C Type D
pH (Acidity/Alkalinity) 5.5 – 9.0 5.5 – 9.0 5.5 – 9.0 5.5 – 9.0
BOD (Biochemical Oxygen Demand) ≤20 mg/L ≤30 mg/L ≤40 mg/L Residential: ≤50 mg/L Commercial/Hospital: ≤100 mg/L
TSS (Total Suspended Solids) ≤30 mg/L ≤40 mg/L ≤50 mg/L ≤60 mg/L
Oil and Grease ≤20 mg/L ≤30 mg/L ≤40 mg/L Residential: ≤20 mg/L Commercial/Hospital: ≤50 mg/L
TKN (Total Kjeldahl Nitrogen) ≤35 mg/L ≤35 mg/L ≤40 mg/L –
Sulfide ≤1.0 mg/L ≤1.0 mg/L ≤1.0 mg/L –
TDS (Total Dissolved Solids) Residential/Commercial: ≤1,000 mg/L Residential/Commercial: ≤1,000 mg/L Residential/Commercial: ≤1,300 mg/L –
TDS (Hospital) Increase ≤1,000 mg/L from normal water use Increase ≤1,000 mg/L from normal water use – –

Note: For hospital buildings, specific parameters such as Total Coliform Bacteria (≤ 5,000 MPN/100 ml), Fecal Coliform Bacteria (≤1,000 MPN/100 ml), and Free Chlorine (≤1.0 mg/L) are also mandated for Type A and B buildings.

General Parameters for Industrial Wastewater (P.S. B.E. 2539, Section 3):

Industrial sources are typically controlled against a broader range of pollutants, including temperature, heavy metals (like zinc, copper, mercury, cadmium, lead, nickel, manganese), cyanide, phenols, formaldehyde, chlorine, and often higher limits for BOD and COD. For instance, industrial wastewater standards often cap BOD at ≤20 mg/L and suspended solids at ≤50 mg/L, but may permit different values depending on the receiving water body and source characteristics.

 

Future Operations: Section 73 and the Role of Licensed Controllers

A major ongoing challenge in pollution management is the frequent lack of technical skills and knowledge among pollution source owners/occupiers, leading to inefficient operation of wastewater treatment systems and subsequent non-compliance. To address this pain point and enhance enforcement effectiveness, the government is implementing a new mechanism focused on professionalized oversight, leveraging Section 73 of the Act.

Introducing the Licensed Controller

Section 73 mandates that any person contracting to serve as a Wastewater Treatment System Controller or a Service Provider for wastewater treatment or waste disposal must obtain a license from the local official. This licensing requirement took effect with the publication of the relevant Ministerial Regulation B.E. 2567 (2024) on November 26th, 2024, with full force starting 240 days later, on July 24th, 2025.

The core objective of this new structure is to employ a third-party auditing system, similar to certified public accountants or private vehicle inspection centers. Licensed Controllers and Service Providers, possessing valid professional licenses (e.g., Environmental Engineering or Environmental Science/Technology), will assume responsibility for certifying operational reports submitted to the government, reducing the direct inspection burden on government PCOs.

Scope and Phased Implementation of Controller Requirements

The requirement to appoint a Controller (under Section 70, enforced via the new mechanism) is not universal; it targets specific pollution sources known for management challenges, particularly excluding industrial factories already covered by factory laws.

Source Categories Required to Appoint a Controller:

  • Buildings (Types A and B): Residential, Commercial, and Hospital types
  • Land Subdivision Projects (Types A and B)
  • Pig Farming Facilities (Types A and B)
  • Community Wastewater Treatment Systems (CWTS) (All Types)
  • Any pollution source (excluding factories) with a WWTS capacity ≥ 100 cubic meters per day.

The Pollution Control Department (PCD) has established a phased timeline for PCOs to issue orders requiring these sources to appoint a Controller as shown in table below:

Phase Start Date Source Categories Affected
Phase 1 October 24, 2025 Commercial Buildings (Type A), Hospital Buildings (Type A)
Phase 2 April 24, 2026 Residential Buildings (Type A), Commercial Buildings (Type B), Hospital Buildings (Type B), Land Subdivision (Type A), Pig Farming (Type A), Community WWTS (All types), and WWTS ≥100 m³/day
Phase 3 October 26, 2026 Residential Buildings (Type B), Land Subdivision (Type B), Pig Farming (Type B)

 

Duties of the Licensed Controller

The Ministerial Regulation B.E. 2567 (2024) explicitly defines the duties of the licensed Controller (Section 15):

  1. Operation and Maintenance: Controlling, inspecting, analyzing, operating, and maintaining the wastewater treatment system.
  2. Record Keeping (Section 80): Collecting daily statistical data and records demonstrating the system’s performance, to be kept at the pollution source premises.
  3. Reporting (Section 80): Preparing and submitting a monthly summary report on the system’s operation to the local official.
  4. Advising Owners: Providing written recommendations to the owner/occupier for managing, correcting, modifying, improving, or repairing the system to ensure effluent meets control standards.

By transferring these technical operational responsibilities to licensed third-party professionals, the PCD aims to significantly improve compliance rates and allow PCOs to focus on higher-level regulatory oversight and enforcement against serious infractions. The PCD also maintains a central electronic database (http://epc.pcd.go.th) to monitor registration, performance reports (Section 80 reports), and compliance of both Controllers and pollution sources.

 

Conclusion and Preparation for Operators

The implementation of the new Ministerial Regulation under Section 73 marks a structural shift in environmental regulation, moving towards mandated professional oversight for pollution sources demonstrating persistent compliance difficulties.

For owners or occupiers of pollution sources, particularly those designated in the phased schedule (Buildings A/B, Land Subdivision A/B, Pig Farming A/B, CWTS, and sources with wastewater  ≥ 100 m³/day), preparation is mandatory and time-sensitive as the phases roll out starting October 24 , 2025.

Recommended Key Actions for Operators:

  1. Ensure WWTS Compliance (Section 70): Operators must ensure that their wastewater treatment system is properly constructed, installed, and operating effectively, achieving the legally mandated discharge standards (Section 55/69).
  2. Appointment of Licensed Controller (Section 73/70): The primary new requirement is the appointment of a licensed Controller or Service Provider. This professional must be appointed in writing using the official form (ThS 73-03) and must possess a valid professional license.
  3. Support Controller Duties (Section 80): Once appointed, operators must cooperate to facilitate the Controller’s duties, especially the daily collection of data and submission of monthly performance reports (ThS. 1 and ThS. 2) to the local official via the electronic system.
  4. Adherence to PCO Orders: If a PCO inspection reveals non-compliance, they will issue administrative orders (under Section 70 or 82(2)) for construction, installation, alteration, improvement, or repair of the system. Failure to comply with these administrative orders can lead to heavy administrative fines calculated daily (up to 7,000 Baht/day under Section 70, or generally up to 10,000 Baht/day). Continued non-compliance may result in confiscation or auction of assets to cover outstanding fines.

By actively engaging a licensed Controller and ensuring robust system management, operators can mitigate the risk of administrative penalties and criminal charges associated with environmental non-compliance, thus aligning their operations with Thailand’s evolving environmental quality enforcement procedures.