The Proliferation of Blue-Green Algae: Context, Challenges and Innovative Solutions (50m Lecture)

Phosphorous levels contained in discharged treated effluent from wastewater treatment systems directly impacts the eutrophication of lakes and the formation of blue algae blooms, which are toxic to animal and human life.  

Lack of sustainable and technically applicable solutions to an onsite wastewater treatment application for single dwellings has relegated this issue to a lower-priority level.

An approach based on a Self-Cleaning electro-coagulation process for phosphorus removal and disinfection has been tested at full scale on three different testing platforms in cold conditions for over one year. The system is now certified under the new CAN/BNQ 3680-600 Standard. The tested system of a 600 USGpd capacity is composed of a 1450 USG primary reactor followed by the 530 USG Self-Cleaning electro-coagulation unit (EC) followed by tree different combination of systems: a sand filter or an absorbent media-based filter combined or not with a UV disinfection unit.

The standalone Phosphorus Removal Unit removed by itself total phosphorus below 1.0 mg/L, which correspond to B-I and P-I classes (TSS ≤ 100 mg/L, BOD₅ ≤ 150 mg/L and Total P ≤ 1.0 mg/L) under the CAN/BNQ 3680-600 Standard.

When combined to a gravity fed sand filter 1.2 guspd/ft² area, the unit produced a high quality treated effluent with Total P concentration at 0.1 mg/L, BOD₅ and TSS below 5 mg/L and Fecal coliforms below 10 counts/100 mL.

Combination of the Phosphorus Removal Unit with the Ecoflo Biofilter, an organic media biofilter, produced treated effluent with a concentration of below 0.3 mg/L in total P, less than 3 500 fecal counts and < 10 mg/L of TSS and BOD₅  

Based on the CAN/BNQ 3680-600 Standard, the system is certified under B-IV and P-II and D-I classes (TSS and BOD₅ ≤ 10 mg/L, Total P ≤ 0.3 mg/L and Fecal coliforms or E.Coli ≤ 50 000 counts/100 mL). To reach high disinfection levels in fecal coliforms or E.Coli, an auto-cleaning UV unit has been added to the previous system. Results indicated a high level of disinfection reaching a “not detectable” level (D-III) according to the CAN/BNQ Standard (median value below 10 counts/100 mL).