SUSTAINABILITY THROUGH ADVANCED BIOLOGICAL TREATMENT OF RECIRCULATING AQUACULTURE SYSTEM EFFLUENT

There is a growing trend in the overall water market focused on the reusability of treated wastewater.  This trend is being driven by several factors, most notably:

∙βThe increasing quality of treated wastewater driven by the desire to reduce nutrient levels for environmental consideration, and

∙βThe growing recognition of the value of water, particularly in times of severe water shortages driven primarily by drought conditions.

At the same time, there is also recognition that in order to support the exponential growth in the global population, fish is viewed as a critical protein source.  This in turn, has put increased importance on the use of Recirculating Aquaculture System (RAS) to help meet this expanding need.  The question becomes, can these needs overlap each other?

Treated wastewater consists of a diverse microbiological community consisting of bacteria, algae and other residuals from the treatment process.  For instance, in order to reduce nutrient levels to meet environmental considerations, metal salts are commonly used to "precipitate out" dissolved nutrients, such as phosphorus.  However, there can also be residual chemical salts remaining in the discharged effluent depending on the filtration process used, if any.  Further, not all municipal facilities have a defined dissolved oxygen requirement in their discharge permit.  

This paper will discuss the use of an advanced biological nutrient recovery process that results in:

∙βBest in class discharged nutrient levels.  Typical results from multiple municipal and industrial wastewater facilities has resulted in:

o      Total phosphorus reductions of 90+%

o      Total nitrogen reduction of up to 60-75%

o      Ammonia reduction to near non-detect levels

o      Nitrate  reductions of nearly 50%

o      Dissolved oxygen increase of 30-40%

∙βIn addition to exceptional nutrient performance, a by-product of the process is the production of a biomass that has favorable nutritional characteristics

Results will be presented from multiple facilities demonstrating the ability to produce reuse quality water suitable for direct application in RAS operations.