In Canada today, over 80 % of communities have lagoons that provide either primary, or with the addition of chemicals, secondary treatment to community wastewater. Westport, Ontario utilized a lagoon system that discharged into the Upper Rideau Lake twice annually. This release contained phosphorous which virtually destroyed the lake over a twenty-year period.

Westport Ontario's 1000 gpm (US) Snowfluent plant.

The solution proposed by Delta Engineering was one that allowed "zero direct discharge" into the Upper Rideau Lake. Westport is utilizing Snowfluent® as the sole wastewater treatment method.

Snowfluent combines advanced snowmaking techniques with the natural freezing process of water. The process of Snowfluent or Atomizing Freeze Crystallization was developed by Delta Engineering in cooperation with the Ontario Ministry of the Environment and Energy. Delta received the world-wide patents on this process in 1997.

Where other processes rely mostly on biological activity, Snowfluent utilizes the natural purifying properties of freezing water. As water freezes, individual molecules organize themselves into highly ordered hexagonal structures. The crystalline structures have impurities, and reject them to the crystal extremities. This natural rejection is the separation of "water from the wastes".

The only wastewater pre-treatment required is a few hours of retention in order to allow the settling of larger solids. (Other technologies such as filtration, require pretreatment. In combination then, pretreatment would be required for the summer process.) No dosing of the influent with coagulants such as alum is necessary, further reducing both operating costs and long-term sludge build-up. As Snowfluent is a physical treatment process, the system handles raw effluent as well as highly treated wastewater with similar results.

Research on traditional freeze-crystallization technology for wastewater treatment was shown to be highly effective but too costly due to the energy required for mechanical refrigeration and freezing. Also, practical aspects of applying the lab-scale methods to commercial sized installations proved to be too difficult, reducing the effectiveness of treatment overall.

The problems were solved by utilizing Delta's specialized snowmaking technology, automated process control software, high efficiency nozzles and cold winter temperatures, to provide effective freeze-crystallization and an environmentally friendly result.

The main advantage of this approach is the efficiency with which the heat of crystallization is removed from the wastewater. As the fluid becomes dispersed into the atmosphere, the droplets freeze into fine ice crystals. Snowfluent requires energy for atomization only, as refrigeration is supplied free of charge by Mother Nature!

Snowfluent has been specifically designed to work in cold, freezing climates where biological systems slow down or even stop working during the winter. The process is particularly suited to communities that have an existing lagoon or lagoons that require an upgrade to the quality of their existing treatment.

This "design-build" project for Westport provided the solution they required with innovative and effective technology, and the benefits of lower costs. The Westport facility, in its first season of operation, has already achieved cost savings of over 50% compared to the operational costs for the previous secondary treatment, using chemicals in the lagoon.

The project won the 1997 Association of Consulting Engineers of Canada top honour ­ the Schreyer Award.