Langley, BC -- The City of Port Alberni operates a wastewater treatment lagoon treating average flows of ~45,000 m3/d of municipal and industrial effluent. The cities nine existing surface aerators are old and unreliable and spare parts are often no longer available. Whenever a unit breaks down, or is pulled for service, parts need to be manufactured adding significant maintenance costs and down time.

During the summer the towns fish processing and packaging plant ramps up production. The effluent from this fish processing operation effectively doubles the biological loading on the city’s wastewater treatment lagoon. The existing aeration equipment cannot keep up with the increased loading and effluent DO figures drop below permitted values. The City contacted Midan Industries Ltd to arrange an on-site trial of the Turborator to determine if the Turborator would provide an acceptable and cost effective alternative to traditional surface aerators.

Midan Industries Ltd supplied one, twenty horsepower unit, on a floating platform for a two month trial. The unit was customized to compensate for the shallow depth of the lagoon. The standard ten foot shaft was replaced with a six foot shaft. This customized shaft placed the impeller only three feet below the surface instead of the standard seven feet. The shallower installation of the shaft meant that the area of influence for mixing was reduced, and that air pulled down the hollow shaft would rise to the surface faster – reducing the amount of time for reactions to take place.

The unit was delivered and installed and the trial was conducted. Overall the installation of the trial unit had a positive effect with daily DO figures stabilizing and averaging 18% higher than the one month period prior to the trial.

• The average DO reading for the month prior to installation of the trial unit was 2.46 Mg/l. with 390 HP of installed aeration
• The average DO reading for the trial period was 2.89 Mg/l an overall increase of 18% with 410 HP of installed aeration an increase in energy demand of 5%
• In the one month prior to the installation of the trial unit 16 of 30 (56%) of the daily DO readings fell below 2.00 Mg/l and readings fluctuated wildly from day to day.
• In contrast, during the Turborator trial DO figures stabilized with only 7 of 56 (12.5%) of the daily DO readings falling below 2.00Mg/l

The Turborator is ideal for existing wastewater treatment plants that require a reliable and efficient source of additional oxygen and mixing. Our units are produced in a range of sizes from 5 – 25 horsepower and can be customized to suit the particular installation and application. Limited product trials and equipment leases are available.