Reoxygenation

The table shows that at start-up, Dissolved Oxygen levels are 0.4mg/l at the bottom depth of 30 feet and just 0.2mg/l at 15 feet, so the deoxygenated zone extends at least 15 feet above the bottom.

After 10 weeks, not only have Dissolved Oxygen levels been raised to 5.9mg/l at the bottom, at the surface it has increased from 5.15mg/l at start-up to 9.6mg/l.

This verifies reoxygenation of the whole water column.

The graph shows data from a drinking water reservoir where inadequate Dissolved oxygen levels were causing a variety of problems in treating the water and achieving compliance for potable water produced. Within a month of start-up the target level was achieved and maintained thereafter.

The next graph shows data obtained by placing a probe 8 inches into the sediment before start-up and 24 months later.

The sediment was severely anaerobic at start-up. Significant reduction of sediment, increase in depth and reduction in rooted invasive weeds had been noted. When sediment DO was measured again aerobic conditions were confirmed to prevail 8 inches into the sediment. This establishes conditions that facilitate sediment digestion and elimination.