Project Proposal: The Living Wetland

A Biosphere x AquaSai Initiative to Transform Wastewater into a Thriving Botanical Garden at Bottle Beach

Client: PRIVATE, Bottle Beach, Koh Phangan | Date: July 2, 2025

Project Overview

This proposal outlines the design and construction of a nature-based AquaSai Botanical Wetland system. Engineered to treat 100% of the wastewater from 20 bungalows, this system transforms a critical pollution liability into a valuable asset. Our goals are to eliminate effluent discharge, protect the fragile coral reef, create a source of recycled water, and enhance the resort's ecological and aesthetic appeal.

Design & Sizing

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Design Load (Persons)
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Daily Wastewater (Liters)
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Wetland Area (m²)
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Substrate Volume (m³)

Estimated Project Costs

Item Description Cost (THB) Cost (USD)
Design & Engineering Site survey, hydraulic design, botanical plan, project oversight. ฿ 150,000 $ 4,100
Site Prep & Earthworks Land clearing and excavation for the 200 m² wetland cell. ฿ 100,000 $ 2,700
Primary Treatment Tank 15,000 L pre-cast concrete or polyethylene septic tank. ฿ 200,000 $ 5,500
Wetland Containment High-quality, durable impermeable liner (EPDM/HDPE). ฿ 300,000 $ 8,200
Substrate & Media 150 m³ of washed gravel and sand layers. ฿ 300,000 $ 8,200
Plumbing & Connections Piping, fittings, and labor to connect all bungalows. ฿ 150,000 $ 4,100
Botanical Layer Native wetland plants (Alocasia, bamboo, water lilies). ฿ 75,000 $ 2,000
Labor & Installation Skilled and unskilled labor for construction. ฿ 400,000 $ 11,000
Water Reuse System Pump, 2,000 L storage tank, and plumbing for reuse. ฿ 125,000 $ 3,400
Subtotal ฿ 1,800,000 $ 49,200
Contingency (15%) ฿ 270,000 $ 7,400
Total Estimated Cost ฿ 2,070,000 $ 56,600

Project Timeline

Phase 1: Design & Permitting

Weeks 1-2

Phase 2: Procurement & Logistics

Weeks 2-4

Phase 3: Earthworks & Construction

Weeks 5-8

Phase 4: Planting & System Seeding

Week 9

Phase 5: Commissioning & Monitoring

Weeks 10-12

Value & Return on Investment

Ecological Protection

Directly protects the coral reef by eliminating nutrient pollution, investing in the core asset of the business.

Water Security

Creates 3.65 million liters of recycled water per year, reducing reliance on fragile freshwater sources.

Enhanced Guest Experience

The system functions as a beautiful, lush botanical garden, improving the resort's ambiance and becoming a unique feature.

Premium Branding

Authentically market the resort as a leading eco-luxury destination, attracting environmentally conscious travelers.

Operational Resilience

Future-proofs the resort against stricter environmental regulations and potential water shortages.

Assumptions & Exclusions

  • The resort will provide the land area (~250 m²) for the system at no cost.
  • The estimate assumes reasonable soil conditions and access for light machinery.
  • Costs for long-term operational maintenance (e.g., occasional plant trimming) are not included.
  • Costs for major landscaping features (e.g., boardwalks, lighting) are not included but can be quoted separately.