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Good practice Imported

Laem Phak Bia Royally Initiated Project — Oxidation Ponds, Constructed Wetlands & Mangrove Filtration for Municipal Wastewater (Phetchaburi, Thailand)

Thailand · Phetchaburi · See the Thailand profile

Evidence: Observational / pre–post Top 58% 40/100 · Ask Evidence Copilot about this practice

Since 1990, Thailand's royally initiated Laem Phak Bia project has treated municipal wastewater via oxidation ponds, wetlands and a 181-hectare mangrove forest; monitoring shows the mangrove stage lifts dissolved oxygen 32% and cuts ammonia up to 74%.

32.4 %
Increase in dissolved oxygen after the mangrove treatment stage (long-term monitoring)
73.8 %
Ammonia reduction after the mangrove treatment stage (long-term monitoring)
64.3 %
Nitrate reduction after the mangrove treatment stage (long-term monitoring)
182 hectares
Area covered by the LERD treatment project (1990-present)
Laem Phak Bia Royally Initiated Project — Oxidation Ponds, Constructed Wetlands & Mangrove Filtration for Municipal Wastewater (Phetchaburi, Thailand)

Details

Maturity
Established
Promoter
Chaipattana Foundation / Laem Phak Bia Environmental Research and Development (LERD) Project
Period
1990-present
Keywords
wastewater treatment, mangrove restoration, environmental research

Context

Thailand's King Bhumibol Adulyadej initiated a research project in 1990 in Ban Laem District, Phetchaburi Province, to test whether natural systems could treat municipal wastewater while restoring a degraded coastal mangrove. The Laem Phak Bia Environmental Research and Development (LERD) project now covers roughly 182 hectares.

Activities

Wastewater passes through a four-stage treatment train: sedimentation and oxidation ponds, a grass filtration bed, free-water-surface constructed wetlands (with pilot systems comparing aquatic plant species), and a replanted mangrove forest before discharge to the coast.

Results

University-led monitoring of the mangrove stage found it raises dissolved oxygen by about 32.4%, reduces ammonia by about 73.8% and nitrate by about 64.3%, with final effluent meeting standards suitable for coastal aquaculture.

Conclusions

The project has operated continuously for more than three decades under Thailand's Chaipattana Foundation and remains a long-term research site for Thai universities studying nature-based municipal wastewater treatment; no independent replication of the full four-stage model at another site was found.

Implementation
Indicative cost
Medium (€50k–€500k) — No cost figures published in the sources reviewed.
Time to results
Long (> 3 years) — Continuous operation since 1990; no fixed end date.
Staffing & skills
Chaipattana Foundation (royally established development foundation) operates the project, Thai universities conduct ongoing water-quality monitoring and research

Conditions for success

  • Multi-stage natural treatment train combining oxidation ponds, wetlands and mangrove reforestation
  • Long-term institutional backing (Chaipattana Foundation) enabling more than 30 years of continuous operation
  • Use as an active university research site sustaining ongoing monitoring and technical refinement

Commonly funded by

Philanthropic / foundation funding

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Data sources

Where this practice's information was retrieved from, and when.

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