MC & UM Algae/Biodiesel Project

• Background Review

• Status as of May 12, 2009

MCES Interest in Algae

CO2 + P + N + light

GHG 1.0 -> 0.3 Hypoxia

Concept

1) Extract oil from algal cell mass – some species => 50% oil by weight

2) Use catalytic hydrothermal gasification on wet material to generate usable synthetic gas, heavy oil, and char

Project Goal

Determine the technical and economic

feasibility of using algae to reduce

nutrient and carbon dioxide emissions

and subsequently recover oil and other

energy products from the algal cell mass.

MC Focus

• Phosphorus removal

– MPCA proposing substantial reduction in effluent limits

– Any value from cell mass reduces net cost of P removal

• CO2 removal and value of credits

• Nitrogen removal

Metro Plant Schematic

ScrnGrit

PrimarySettling

ActivatedSludgeAeration

Final Settling

Disinfect

Sludge ThickeningDewatering

Sludge Incineration

centrate

Application at Metro

Concentration Mass Total N

centrate

125 mg/l 1,040 lb/day

Soluble P

centrate

190 mg/l 1,580 lb/day

CO2 incineration

1.7 – lb/lb dry sludge burned

430 ton/day

Oil Production Potential

centrate P - mg/l 200 measure

P removal - % 50 assume

centrate flow - mgd 1 known

algal cell mass - % P 1 literature

P removal - lb/day 833 calculate

algal cell mass produced - lb/day 83,300 calculate

algal cell oil content - % 20 assume

oil recovery efficiency - % 80 assume

oil production - lb/day 13,328 calculate

oil production – gal/day 1,780 calculate

UM Screening Algal Species

UM Bioreactor Design

UM/MC Harvesting Experiments

Metro Pilot Plant

Located in SMB

Door closed to protect intellectual property – reactor design

Experimental Reactors

Reactor A Reactor B

Tanks 4 4

Type Plug Flow Mixed

Light intensity

1.5 X X

Simplified Growth Model

CO2 + N + P + light O2 +

Corganic + O2 + N + P CO2 +

Pilot Plant Performance*

Reactor A Reactor B

TSS Produced 497 gm/day 415 gm/day

STP removed 47 gm/day 43 gm/day

STP removed 67% 60%

* Varying wasting schedule during startup – not steady state operation

Project Funding

Phase 1 Phase 2

MC $40k $250k

UM – IREE $40k $250k

Xcel Energy $150k

State of Minn ______ $500k__

Totals $230k $1,000k