Student interview: “Biological water treatment in fish farms can be optimized”

Sharada Navada recently started her PhD, studying biofilters at NTNU and Nofima. Photo: Per Henning, NTNU.

Sharada Navada is a process engineer from India who, after working a couple of years in the USA and a year in Drammen, has just started her doctoral work at the CtrlAQUA center. She is an employee of Krüger Kaldnes and currently resides in Trondheim where she is doing her PhD at NTNU and Nofima, thus creating a good synergy between industry and academia, like the CtrlAQUA center.

“I have always wanted to work in environmental engineering, and I really enjoy working on water quality.”

Her topic is optimizing moving bed biofilters, mostly in land-based aquaculture systems. Biofilters are central in a closed-containment system where dirty water from the fish tanks runs through a cleaning process, carried out by bacterial degradation. The biofilter is the biological part of the water treatment system, with a delicate balance maintaining the bacteria which degrade organics and convert ammonia to nitrates. Navada is looking at the dynamics of starting up the biofilter in different salinities and at how efficiently the bacteria convert ammonia to nitrates.

After completing her PhD in four years’ time, Navada says she will continue working for the recirculating aquaculture system supplier Krüger Kaldnes.

“I hope that during my four years as a PhD student, I will be able to build a good knowledge base, forge social connections in the scientific community and develop myself, so that I can contribute a lot more when I return to industry.”

Navada is very optimistic about closed-containment aquaculture:

“I believe that once we have improved the biofilters, we should also be able to reduce fresh water consumption quite substantially. That could have an economic impact by reducing the energy required for pumping and temperature regulation.”

University: NTNU – Department of Chemistry

Student status: PhD 2017-2020

Supervisors: Øyvind Mikkelsen, Bendik Fyhn Terjesen, Frederic Gaumet, Bjørn Rydtun

CtrlAQUA project: EXPO