Most of Thailand's municipal and industrial wastewater treatment systems are conventional, consisting of chemical treatment (coagulation, flocculation), physical treatment (sedimentation, sand filtration), biological treatment (activated sludge (AS), stabilization pond (SP), constructed wetland (CW)) and chlorine disinfection (Industrial Estate Authority of Thailand; Pollution Control Department 2017b). However, conventional treatments are often ineffective in treating the wide variety of emerging pollutants, such as persistent organic pollutants (POPs), per- and polyfluoroalkyl substances (PFAS), pharmaceutical residues, and antibiotics (Schultz et al. 2006; Kunacheva et al. 2011; Wang et al. 2021). Most treated wastewater meets the national effluent quality criteria for discharge to the public as shown in Table 2, covering six parameters – pH, biological oxygen demand (BOD), suspended solids (SS), oil and grease (O&G), total nitrogen (TN), and total phosphorus (TP) (Ministry of Natural Resources and Environment 2010). However, this wastewater is not suitable for reuse in human or food contact applications because new groups of emerging pollutants that may affect human health and the environment are not included.
Type of wastewater treatment system and quality control standard in Thailand
| . | Law and regulation . | ||||||
|---|---|---|---|---|---|---|---|
| Domestic wastewater system . | Act . | Quality control standard . | |||||
| Type . | Scope . | Systems . | Issue . | Name . | First issue . | Name (No. of Parameters) . | Parameter list . |
| On-site | Individual household and buildings | O&G trap, cesspool, septic tank, commercial package system On-site WWTP | 1979 | Building Control Act | 1994 | 1. Building effluent std. (8) (Ministry of Natural Resources and Environment 1994) | -pH, BOD, SS, Fat O&G (common) -TDS, settable solids, TKN, sulfide (only topics 1 and 2) -TN, TP (only topic 3) |
| Real estate, housing estate | 1992 | NEQA | 1996 | 2. Real estate effluent std. (8) (Ministry of Natural Resources and Environment 2021) | |||
| Cluster | Small community | Combined sewer, pumping station and small WWTP (50–500 m3/day) | 1992 | NEQA | 2010 | 3. Central WWTP effluent std. (6) (Ministry of Natural Resources and Environment 2010) | |
| Central | Large community | Combined sewer, pumping station and central WWTP | |||||
| Industrial wastewater system | |||||||
| On-site | Individual factory | On-site WWTP | 1979 | Industrial Estate Authority Act | 1987 | 4. Effluent control std. into central WWTP for factory (30) (Industrial Estate Authority of Thailand 2017) | -pH, BOD, COD, SS, TDS, TKN, O&G, temperature, color, odor, Hg, Se, Cd, Pb, As, Cr+3, Cr+6, Ba, Ni, Cu, Zn, Mn, H2S, HCN, formaldehyde, phenols, free chlorine, pesticides (common) -Surfactants (only topic 4) |
| 1992 | Factory ACT | 1996 | 5. Effluent control std. for factory (28) (Ministry of Industry 2017) | ||||
| 1992 | NEQA | 1996 | 6. Factory, industrial estate and industrial zone effluent control std. (28) (Ministry of Natural Resources and Environment 2016) | ||||
| Central | Industrial estate | Separated sewer, pumping station and WWTP | |||||
| . | Law and regulation . | ||||||
|---|---|---|---|---|---|---|---|
| Domestic wastewater system . | Act . | Quality control standard . | |||||
| Type . | Scope . | Systems . | Issue . | Name . | First issue . | Name (No. of Parameters) . | Parameter list . |
| On-site | Individual household and buildings | O&G trap, cesspool, septic tank, commercial package system On-site WWTP | 1979 | Building Control Act | 1994 | 1. Building effluent std. (8) (Ministry of Natural Resources and Environment 1994) | -pH, BOD, SS, Fat O&G (common) -TDS, settable solids, TKN, sulfide (only topics 1 and 2) -TN, TP (only topic 3) |
| Real estate, housing estate | 1992 | NEQA | 1996 | 2. Real estate effluent std. (8) (Ministry of Natural Resources and Environment 2021) | |||
| Cluster | Small community | Combined sewer, pumping station and small WWTP (50–500 m3/day) | 1992 | NEQA | 2010 | 3. Central WWTP effluent std. (6) (Ministry of Natural Resources and Environment 2010) | |
| Central | Large community | Combined sewer, pumping station and central WWTP | |||||
| Industrial wastewater system | |||||||
| On-site | Individual factory | On-site WWTP | 1979 | Industrial Estate Authority Act | 1987 | 4. Effluent control std. into central WWTP for factory (30) (Industrial Estate Authority of Thailand 2017) | -pH, BOD, COD, SS, TDS, TKN, O&G, temperature, color, odor, Hg, Se, Cd, Pb, As, Cr+3, Cr+6, Ba, Ni, Cu, Zn, Mn, H2S, HCN, formaldehyde, phenols, free chlorine, pesticides (common) -Surfactants (only topic 4) |
| 1992 | Factory ACT | 1996 | 5. Effluent control std. for factory (28) (Ministry of Industry 2017) | ||||
| 1992 | NEQA | 1996 | 6. Factory, industrial estate and industrial zone effluent control std. (28) (Ministry of Natural Resources and Environment 2016) | ||||
| Central | Industrial estate | Separated sewer, pumping station and WWTP | |||||
NEQA, Enhancement and Conservation of National Environmental Quality Act; SS, suspended solids; TDS, total dissolved solids; TP, total phosphorus; TN, total nitrogen; TKN, total Kjeldahl nitrogen; HCN, hydrogen cyanide; Std., standard.