Degree Type


Date of Award


Degree Name

Master of Science


Agricultural and Biosystems Engineering

First Advisor

Kurt A. Rosentrater


The fast-growing world population prompts researchers to evaluate both environmental and economic impacts during manufacture and service processing. Distillers dried grains with solubles (DDGS) fractionation and aquaponics are two bioprocesses aiming to make full use of materials and resources. This study conducted Life cycle assessment (LCA) and Techno-economic analysis (TEA) for DDGS fractionation and tilapia-basil aquaponics.

DDGS mainly contains protein, oil, fiber, and ash. DDGS could have more economic value and wider use if it could be separated into higher protein fraction and higher fiber fraction. In our work, the optimization of three parameters of a gravity separator (side slope, eccentric shaft vibration, and air flow rate), was conducted to separate DDGS. Based on the optimized results, LCA and TEA were conducted for DDGS fractionation for three scales.

Aquaponics is the system combining hydroponic and aquaculture, in which fish and plants are raised together and are beneficial from each other. LCA and TEA were conducted for a pilot scale of tilapia-basil aquaponics located on Iowa State University campus, and the results were scaled up to larger systems.

The results showed that when operation scale was large enough, both DDGS fractionation through a gravity separator and tilapia-basil aquaponics were profitable, and the environmental impacts decreased as the scale expanded. The results will provide useful data for optimizing DDGS fractionation and aquaponics.


Copyright Owner

Kun Xie



File Format


File Size

135 pages