Client

A premier coastal development featuring residential communities, a golf course, and an interconnected lagoon system fed by desalinated water.

Challenge

Over several years, the resort experienced severe sediment accumulation, turbidity, and seasonal foul odours across its golf-course lakes and main lagoon. Testing revealed that all waterbodies had shifted toward brackish to hypersaline conditions, driven by:

• Continuous evaporation

• Nutrient-rich wastewater inflow

• Algal growth and die-off

• Anaerobic sediment decomposition

This combination led to:

• Persistent brown, turbid water

• Organic sludge buildup

• Sulphide-related odours during warm seasons

• Elevated COD, phosphate, chloride, sulphate, calcium, and magnesium — far above clean seawater levels

• Water chemistry exceeding limits for legal discharge to the sea (a requirement if dredging were to be considered)

Traditional dredging wasn’t possible: the lagoon water first needed to meet discharge standards, but pollutant levels made this unfeasible.

The resort needed a sustainable, non-disruptive solution to:

1. Remove foul odours

2. Reduce organic sediment

3. Improve water clarity

4. Lower COD and phosphate

5. Restore ecological stability

OASE Approach

 

OASE proposed a biogeochemical restoration strategy using:

• PeriDox® – fast-release oxygen to eliminate odours and clear turbidity

• SchlixX® – long-term oxygen delivery to digest organic sediment and bind phosphorus

This approach avoided the need for dredging while restoring water quality from within.
Three pilot tests were implemented: two lakes and a controlled treatment of the main lagoon.

Pilot Treatments

 

1. Small Golf-Course Lake (10,000 m²)

 

• 225 kg PeriDox® applied

• 750 kg SchlixX® applied

• Water clarity improved within 9 hours

• Sediment organic matter reduced by 48–62% over 3 months

• Sediment became more compact and stable

  “A clear sign of improvement was visible within hours of PeriDox treatment.” — Pilot Report

 

2. Large Golf-Course Lake (13,000 m²)

 

• 250 kg PeriDox®

• 1,000 kg SchlixX®

• Organic sediment reduced by 34–37%

• Noticeable decline in filamentous algae

• Sustained oxygen improvement in upper sediment layers

Both lakes showed hypersaline conditions:

• Conductivity: 65–86 mS/cm

• Chloride levels: 26,000–36,000 mg/L
  Higher than the Mediterranean Sea, confirming the challenging treatment environment.

3. Main Lagoon Water-Quality Improvement Test

 

A controlled on-site flow-through system was used to test SchlixX® at different dosages (100, 200, and 800 g/m³):

Key Outcomes

 

• COD reduction at all dosages

• PO₄ and total phosphate reduced to below discharge limits, especially at 800 g/m³

• Dissolved oxygen increased even when water was already near saturation

• Magnesium reduction due to pH-driven precipitation

• Phosphate <0.005 mg/L achieved at highest dose

• External laboratory analysis confirmed COD results matched pilot findings

These results demonstrated that OASE chemistry is effective even in high-salinity water where traditional biological treatments fail.

Results Summary

 

Water Clarity

 

• Brown, turbid water became visibly clear within 9 hours of PeriDox® application.

Odour Elimination

 

• Foul odours ceased following oxygenation and sediment stabilisation.

Sediment Reduction

 

Across both lakes:

• Average organic matter reduction: ~45%

• Equivalent to 93 m³ of organic sludge removed biologically in the small lake alone.

Nutrient Reduction

 

• Significant reduction in phosphate

• Sediments stabilised, reducing internal nutrient release

COD Reduction

 

• Up to 34% reduction in the main lagoon test

• Values confirmed by external laboratory

System-Wide Ecological Benefit

 

• Improved light penetration

• Better oxygen balance

• Reduced risk of algal blooms

• Foundations established for long-term recovery

Client Impact

 

The treatments successfully demonstrated that:

• Dredging was avoidable

• Water quality could be rapidly restored

• Hypersaline, nutrient-loaded systems can be rehabilitated without mechanical disruption

The results enabled the resort to pursue a sustainable long-term restoration plan without operational downtime or guest disturbance.

OASE Recommendations (Post-Pilot)

 

Based on the successful pilot, OASE issued a structured remediation plan including:

1. Stop discharge of untreated wastewater into the lagoon

2. Systemwide PeriDox® treatment (45 g/m²)

3. Two rounds of SchlixX® treatment (100 g/m²)

4. Aeration upgrades (19 aerators recommended)

5. Monthly monitoring at 10 lagoon points + all lakes

6. Stepwise dilution plan if discharge to the sea becomes required

7. Long-term system flow improvements through pumps and circulation

Conclusion

 

The pilot demonstrated that OASE’s Lake Therapy® approach can:

• Restore clarity

• Reduce sediment

• Suppress odours

• Improve ecological function

• Treat hypersaline and brackish systems

• Support regulatory compliance for discharge

All without dredging, draining, or disrupting resort operations.

OASE delivered measurable improvements in just hours, with sediment reductions observed over weeks to months, establishing a scalable strategy for full-site restoration.