Logan Utah, Environmental Department operated regional wastewater treatment plant - 460 acres of lagoons, and 240 acres of wetlands. Image credit:Logan UT Environment Department.
For years I've been reading press releases about impractical-sounding inventions for growing algae in arrays of plastic tubes, genetically modifying algae to optimize biofuel yield, and so on. Pretty much all of it is decades from even pilot scale proof of concept, and most of it missing the cost saving potential of finding industrial and public works synergies.
All the more reason to be impressed by the elegant thinking displayed by USU Energy Dynamics Laboratory researchers and Logan UT officials who propose converting a series of presently polluting wastewater lagoons into an algal bio-fuel (methane) and fertilizer (phosphorus) production facility. If the project succeeds - and I see no reason why it shouldn't - an existing waste facility is made to double as a productive industrial process, discharge permit limits for phosphorus will be met more cost-effectively, and downstream drinking water reservoirs will be better protected.Salt Lake City Tribune covered the story in detail (see Logan to turn sewage lagoons into algae farm: Energy-rich plant feeds off pollutants):
Just a few excerpts to give you a flavor.
For the past several years, detergents and agricultural runoff have turned Logan's five wastewater lagoons into a phosphate-filled soup, posing a menace to sensitive wildlife habitat downstream and racking up costly clean-up bills....A collaborative project between the city and the Utah State University Research Foundation will use the ponds to grow algae, which might not only fix the phosphate problem for little money but produce energy. The city has won a $500,000 state grant to begin converting the 460-acre lagoon complex into an algae farm as a small-scale pilot project..Here's the money quote:
The algae cultivated in the lagoons is to be converted to methane and used as fuel for electrical generation and the phosphorus would be extracted to sell to fertilizer manufacturers and other industries.Now...let's look at this on a much larger scale.
Issa Hamud, Logan's environmental director, said the city was spending at least $250,000 every year to aerate the lagoons to prevent algae growth and was facing the prospect of building a $180 million treatment facility as a permanent solution to the phosphorus problem.
There are numerous rural and suburban waste treatment lagoon systems that could do the same thing, using existing infrastructure, already paid for by local, state, and Federal taxpayers. Hence. this idea is ripe for scale up all over the USA and beyond.
In cold climates,waste heat from power plant secondary cooling water discharges could be used to enhance biofuel and coproduct yields. What else could be brainstormed for still greater synergies? See list of possibilities below.
Add your ideas to the comments, please. Maybe others will be pick them up and develop viable proposals.
Brainstorm list for algal biofuel production synergies.
Extract industrial and electrical utility generating plant waste heat to maintain ponds at optimum temperature.
Use nurtient-laden runnoff (flood waters of Mississippi River or agricultural storm drainage for example) as growth medium. It's good for flood storage as well -- ideal in the Mississippi Delta.
Harvesting done with micro-filtration tech (off the shelf technology).
Located near existing natural gas fired generation facilities, if methane producing.
Located near existing refineries if bio-oil producing.
Contiguous or near to existing gas/oil distribution and refining infrastructure.
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