When an 18” water main broke in the Washington Arboretum and sent soil, road oil and debris into the Japanese Garden’s Koi pond, the lives of irreplaceable fish and the whole ecosystem were in danger.

Within a critical 24 hour time window treatment with chitosan and sand filtration was initiated to reduce the turbidity levels and improve the overall aesthetics of the Koi Pond. After two days of treatment approximately one million liters had been treated and the high turbidity of the water had been reduced from 155 NTU to below 5 NTU after treatment.

The treatment project ensured the survival of the Koi fish and improved the overall ecosystem in the ponds. The reduction of suspended sediment also resulted in reduced problems with oxygen depletion of the water – something which had been a problem in the past. Finally, the park could be reopened to the public with visual improvements in water quality.

This was the first time Jakob Sjöberg and John Macpherson worked together with chitosan based technology. The project was the starting point for a close collaboration between Jakob and John in the U.S. It was key in the foundation of Swedish Hydro Solutions.