OctoAir microbubble diffuser ends high manganese in drinking water for Alberta community
DATE POSTED: September 30, 2019
Low-energy system enables high oxygen transfer to quickly reduce manganese concentration
- Problem: High manganese causing taste, odour, and colour issues in municipal drinking water
- Location: MD Opportunity #17, AB
- Solution: Canadianpond OctoAir™ diffuser
- Results: Manganese levels reduced in raw water –> from 0.8 mg/L to ~0.27 – 0.4 mg/L.
The problem: High manganese was causing year-round taste and odour issues in tap water
High manganese is a common seasonal occurrence for the Municipal District of Opportunity #17 in northern Alberta, which draws its water from the South Wabasca Lake. For years operators at the Desmarais Water Treatment Plant, had been able to successfully control manganese in finished water using potassium permanganate and a blower-powered conventional aeration system.
But during the summer of 2014, the manganese level rose significantly. Chemical treatment along with microfiltration membrane treatment was unable to achieve the desired level of manganese in finished water. As a result, finished water during the summer months would be distributed with an average manganese concentration of 0.2 mg/L, which would react with the chlorine disinfection and cause the water to change to a muddy brown colour. Though the water was still safe to drink, residents began to notice unpleasant taste, odour and colour issues with the tap water, prompting many concerns and complaints to the water utility.
The solution: Micro bubbles from OctoAir solves the problem within a few days
In July 2018, plant operators installed the Canadian Pond OctoAir™ diffuser into the storage pond that supplies raw water to the treatment plant. The process was simple—operators just connected an air line from a compressor to the OctoAir and lowered the unit into the desired location. There was no impact to the plant operation and the installation was completed in about four hours.
Rather than using an energy-intensive blower, OctoAir relies on a small 120V, 3/4 HP compressor that uses a fraction of the electricity, but dramatically outperforms conventional aerators. Unlike conventional coarse-bubble aeration systems, OctoAir produces abundant micro bubbles that provide mixing and high oxygen transfer to the raw water. This high level of dissolved oxygen in raw water causes oxidation and precipitation of the dissolved manganese.
The results:
“We noticed a big drop in manganese within two or three days of starting the OctoAir diffuser,” said Earl Gullion, Utilities Manager for MD Opportunity #17. “We experience the highest manganese concentration in the summer, when it can reach 0.8mg/L in raw water. But once we started the OctoAir, manganese in raw water dropped significantly and consistently remains in a range of about 0.4 to 0.27 mg/L.”
The drop in manganese enabled operators to optimise potassium permanganate dosage and membrane filtration to reduce manganese concentration in finished water from an average of 0.2 mg/L to only 0.01 mg/L—eliminating taste, odour and colour problems for residents.
“The OctoAir diffuser requires no maintenance,” Gullion said. “We haven’t touched it since we installed it, but it continues to function well and helps provide a consistent reduction of manganese in our drinking water.”
The plant also experienced numerous other benefits that have improved water quality and helped reduce operating costs including:
- A 55% reduction in potassium permanganate use as the dose dropped from 1.8 mg/L to just 0.82 mg/L
- The cleaning interval for the membrane system was extended by two to three times
- Turbidity in finished water has dropped from about 0.03 NTU to 0.001 NTU
- Operational savings enabled the community to recover the cost of the OctoAir diffuser in less than a year
Contact us to learn more about the Canadian Pond OctoAir diffusers for aeration and manganese control.
In western Canada contact Don Burgess, DWG Process Supply
OctoAir™ is a trademark of Canadianpond.ca