Algae Farms for Carbon Capture

Submitted by Thunder_Burt t3_1253tn7 in Futurology

How practical would it be to reroute some of the waste water, which has nitrogen and phosphorous, into big man made lakes and using it to grow algae to capture carbon and treat the waste water? After the algae is grown it can be filtered out and the water can be sent back to the waste water system. The algae can then be pyrolyzed in a low oxygen environment and turned into charcoal. To me this feels like a cheap and an easy to integrate approach to pulling CO2 out of the atmosphere than traditional CCUS tech. Would there be any drawbacks to this?

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Surur t1_je2cepy wrote

I cant read the full article, but if a giant algae farm can only offset 8000 cars, the process cant be that efficient.

https://fortune.com/2022/07/05/brilliant-planet-startup-marine-algae-carbon-capture-climate-change/

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AtomGalaxy t1_je2ga3j wrote

You know what else would offset 8,000 cars? Short-range, low speed, autonomous minibuses that move people on demand from their homes to multi-mobility nodes. These nodes would then be connected together by premium mass transit, whether Bus Rapid Transit, Light Rail, heavy rail, or MAGLEV. That, and 15 minute cities where most people don’t have to travel that far for daily needs. We need the mesh network of new innovative mobility to bridge the gap to hub-and-spoke traditional mass transit.

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Thunder_Burt OP t1_je2hyfp wrote

True that, but afterwards we will need to remove the existing CO2 in the air to return the climate back to normal. Mass transit is definitely the most effective way to prevent cars from impacting the environment, I was just using cars as a unit of measurement for CO2.

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AtomGalaxy t1_je2twxb wrote

Sure, but if we don’t need all the land we’re currently using for parking, we can build a lot of new infill mixed-use housing that’s built of fast growth biomass materials (compressed laminated timber, bamboo, pine, hemp) that are all sequestering carbon while lowering the average person’s carbon footprint. Figure out mass adoption of plant, fermented, or lab-grown protein, and we’re well on our way to tackling climate change.

I figure this buys us enough time to get to orbital solar-based energy with panels made largely from materials mined on the moon.

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Thunder_Burt OP t1_je31v7h wrote

I dont think wood biomass sequestration can reach the scale we need to remove significant amounts of CO2 compared to algae. Wood also releases carbon dioxide as it decomposes over time, it would need to be pyrolyzed for a more long term form of sequestration.

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Thunder_Burt OP t1_je2fbwa wrote

That sounds about right, the numbers I've read shows an acre of algae offsets about 225 cars worth. But I actually think this is a pretty big number though when considering how much area we have available to us, including what's covered in ocean water. And in comparison it takes 240 trees to offset the CO2 of one car.

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Surur t1_je2ldsp wrote

GPT4 raises the following issues:

  1. Infrastructure and land requirements: Constructing large man-made lakes and the necessary infrastructure to reroute wastewater, filter out the algae, and perform pyrolysis is a complex and costly undertaking. Additionally, acquiring the land to build these lakes can be challenging, especially in densely populated areas.
  2. Water treatment efficacy: While algae can help remove some nutrients from wastewater, they may not be effective in treating all types of contaminants, such as heavy metals, pathogens, or pharmaceuticals. Depending on the composition of the wastewater, additional treatment processes may still be needed to meet water quality standards.
  3. Algae bloom control: Providing optimal conditions for algae growth can be challenging, and if not managed properly, can lead to harmful algal blooms (HABs). HABs can produce toxins and create hypoxic or anoxic conditions that harm aquatic life and negatively impact water quality.
  4. Greenhouse gas emissions: The process of pyrolyzing algae into charcoal requires energy, which may contribute to greenhouse gas emissions depending on the source of energy used. Additionally, there is the risk of methane and nitrous oxide emissions during the algae growth and decomposition process, which are potent greenhouse gases themselves.
  5. Climate conditions: The efficiency of algae growth for carbon capture and wastewater treatment is dependent on local climate conditions, such as sunlight, temperature, and precipitation. The performance of this approach may vary significantly across different locations, limiting its global applicability.
  6. Charcoal disposal and utilization: Once the algae is converted to charcoal, it needs to be disposed of or utilized in a way that prevents the re-release of captured carbon. This could include using it as a soil amendment, for carbon sequestration, or as a fuel source. However, each of these applications has its own set of challenges and limitations.
  7. Economic viability: The cost-effectiveness of this approach compared to traditional CCUS technologies or other carbon capture and wastewater treatment methods remains uncertain. A thorough assessment of the costs and benefits, as well as comparisons to alternative solutions, would be needed to determine its economic viability.
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Thunder_Burt OP t1_je30uj3 wrote

I'm gonna have to start using GPT more lol. I'd say the first point of being expensive and complex applies to any climate change solution so its more a matter of relative complexity and cost. Number 2 makes sense, the used water from the algal bloom would still have to go back to the water treatment system, but it might be easier to clean since it no longer contains nitrates and phosphates. I'm not sure if 3 would matter since we wouldn't have any other aquatic life existing in the bloom. 4 was surprising to me, I didnt know algae could release methane and nitrous oxide, that would definitely have to be avoided.

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cgnops t1_je3pgyj wrote

Need energy to convert the algae into anything, need good yields, and then if you burn it’s just back into the air as co2. There is a reason that all the big investors in algae to biofuels have given up, they don’t produce enough fatty oils per gram to make it cost effective. It could be work and be useful but it’s still really far from being productive enough to continue developing the technology. It’s just tough to engineer really old organisms to do things they don’t do naturally at the levels we need to be productive. Modern efforts are moving to electric vehicles and away from combustion. The future is boats and planes burning fuel and cars and trucks running electric.

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mi2h_N0t-r34l_ t1_je6vxws wrote

Can I put shrimp in the tanks and place the concept on my roof, that I may enjoy sushi on a monthly basis?

Would go great with my quail-egg sandwiches...

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