New Algae Control Proving Effective

James Rada, Jr.

Emmitsburg Town Manager Cathy Willets told the mayor and commissioners that the town’s new algae-control system in Rainbow Lake is proving effective so far.

The new system, which cost the town $38,650 for setup and $13,000 a year for calibration, was installed in April of this year. The LG Sonic system uses ultrasound to destroy the algae, causing it to sink to the bottom of the lake. Willets presented the results of the first three months of operation of the system.

The first data looked at was the presences of chlorophyll in the water. Willets said that this is the biggest indicator that shows algae is not growing. The amount of chlorophyll has dropped from 20 ug/L to 5 ug/L.

The next item examined was phycocyanin, which causes taste and odor problems in the water. It has dropped from 4-5 ug/L to near 0.

Water turbidity, which affects how clear the water is, has dropped from 4.0 NTVs to <1 NTO. Willets pointed out that town staff have received multiple comments from fisherman using the lake that the water is noticeably clearer.

Coagulant usage and backwash water usage are both down.

“We are doing more backwashes, but the gallons used are less,” Willets said.

The water usage is down from 1,292,250 gallons to around 600,000 gallons. This is saving the town 85 water taps.

Willets also told the commissioners that since the system has been installed, there has been no unexpected filter-related overtime.

Two items that have not shown any noticeable difference is the usage of soda ash and chlorine. Usage of these items is expected to be reduced as the new system continues to operate.

Also, while the system has been operating as expected, the satellite uplink that will allow LG Sonic to monitor the system hasn’t been able to be established yet, which is something that is being worked on.

“Staff is very pleased with what they’ve seen so far,” Willets said.

Data from August and September will be examined with interest because this is the time when the lake has historically had its largest algae growth.