Recirculating Aquaculture System and Nitrification: A Review

Aquaculture or aquatic farming is an important source of food, nutrition, and livelihood globally. Conventional farming techniques are limited by low yields, are water intensive and cause nutrient pollution. Recirculating aquaculture system (RAS), wherein water is treated and reused (recirculated), provides up to 100 times higher yields and is well-known to be a sustainable farming technique. This paper discusses the merits and challenges of RAS and reviews the different processes applied for the treatment of water—including solids removal, ammonia removal and disinfection—in RAS. Since, ammonia generally assumes foremost concern in RAS, this work focuses on nitrification in RAS. Parameters affecting nitrification process and the different types of commonly used reactors have been reviewed.