Phosphorus removal from ethanol condensed thin stillage to produce a profitable, recycled fertilizer, while improving surface water quality.

The expansion of the ethanol industry has led to the wide spread availability and economic pricing of distillers grains (DGS), resulting in significant amounts of DGS being commonly included in animal diets. DGS typically replaces corn and protein supplements in the ration, but is has a much higher phosphorus concentration than corn. Therefore, the inclusion of DGS in livestock rations can significantly increase the phosphorus content in the excreted manure. Reducing the concentration of phosphorus in DGS would reduce the amount of excess phosphorus being fed to livestock, thereby decreasing any risk of surface water pollution from manure phosphorus.This project aims build upon the success of the Phase I project by conducting further research and development aimed at recovering excess phosphorus from ethanol condensed thin stillage (CTS). The system will remove soluble phosphorus from CTS, by converting it to the insoluble magnesium phosphate compound. The removed phosphorus would be a useful fertilizer for field crops or horticultural use. Similar technology has already been successfully used to remove phosphorus from liquid manure at confined animal feeding operations. Removing phosphorus at the ethanol plant would be more efficient, and impact a larger number of livestock operations at minimal (if any) cost to the livestock producer. Phase I results indicate that a reduction of soluble phosphorus in the CTS by 72% could decrease the excreted phosphorus at a beef feedlot by 36% when fed at 40% dry matter inclusion rate in common feedlot rations. There is no other beef feedlot management practice or technology available to reduce the excreted phosphorus so substantially while maintaining the same ration.This project will determine the reactor configuration, equipment needs, and operating conditions required for successful operation at an ethanol plant, as well as determine the fertilizer production at those optimal settings and normal conditions. The project will also test the fertilizer efficacy relative to common commercial fertilizers. Successful completion of the project would put KEMA in a position to license the technology for full-scale, commercial production.