One option that I have read about in the past for sewage treatment is the use of supercritical water. A mixture of sewage and water are put into an insulated pressure vessel. The water is heated to over 320°C. Oxygen is injected into the water, where it reacts with sewage, breaking it down into water, CO2 and soluble salts. After the batch has fully decomposed, pressure is reduced by bleeding water and gases off, before adding a new batch of sewage and topping up the water. What comes out is CO2, nitrogen and water containing dissolved salts.
The gas and water can be directly injected into hydroponic and algae based food production, as the supercritical water will completely break down any pathogenic contaminants.
]]>]]>vacuum desiccating toilet - Russia developed one for Mir2. The core module for Mir2 became the Zvezda, but NASA insisted that toilet be removed, that a copy of the old toilet from Mir be used instead. Their concern was plumbing was too complicated. But I'm sure NASA regretted that at various times, wishing they had more efficient water recycling. We will need one that operates in gravity, and has a built-in bidet. (no toilet paper)
urine processor that is reliable - the one on ISS got clogged by calcium. Decalcified astronaut bones. And the one for our ship won't extract as much water as the one on ISS.
urine electrolysis tank - this will extract sodium hydroxide and potassium hydroxide, producing hydrogen and chlorine gas. Then recombine the gas with sodium hydroxide to form salt water, and boil dry the salt water in partial vacuum so the salt doesn't burn. Resulting salt must be food safe, with no urine smell.
water recycling shower - This was an invention by a design student in the UK. 70% of the water that goes down the drain, comes right back out the shower head. Brilliant idea, greatly reduces water consumption, and reduces energy required to heat water.
liquid soap for hand washing and body wash in showers, shampoo, laundry soap, dishwasher soap - all made from vegetable oil and either sodium hydroxide or potassium hydroxide. Result must be compatible with hydroponics, that is concentrated dirty water can be used as fertilizer.
The use is going to be a big thing for reducing what we bring to mars.
]]>How can Sewage and food waste be used to power trucks?
https://www.pollutionsolutions-online.c … ucks/55488
Sizing: in India, for a family of 8 with a few animals (say 8-10 cows), a 10m³ digester is recommended, with 2m³ gas storage. But a typical small family digester will be around one cubic metre. For cooking and lighting, you don’t need much; every kg of biodegradable material will yield around 0.4 m³ (400l) of gas, and gas lights need around 100l per hour. 2 gas rings for a couple of hours a day will use between 1-2 m³, so if you have some livestock, plus kitchen and human waste, you can do this easily. When it comes to driving any kind of engine (e.g. a generator or a pump) it’s a different matter, and is way beyond the domestic-scale. How long you leave the material in a batch digester depends on temperature (2 weeks at 50°C up to 2 months at 15°C). The average is around 1 month, so gauge how much material you will add each day, and multiply it by 30 to calculate the size of the digester.
ISS Links
International Space Station Internal Environments (ISS Internal Environments) - 11.22.16
But, you WANT the biological critters in the waste! They're an integral part of the ecosystem/ecology you are trying to build! Do not treat it, do not sterilize it. Just filter out the tampons, etc. Which should never go down the toilet in the first place. Anybody with a septic tank knows THAT.
GW
]]>Yes turning poop, sun, algea into fuel and fertilizer we have talked about for reclaiming processes.
Sun, sewage and algae: a recipe for success?
If all goes to plan over the next five years, the plant will produce about three tonnes of algae a day from 10 hectares of ponds, enough to run about 200 vehicles. First, much of the organic matter will be anaerobically digested to produce methane, another fuel source. This is already done on in some tropical countries and for special waste waters, such as that from breweries. The reason for the pre-treatment is so the algae don't have to battle it out with bacteria for the organics. Instead, the carbon dioxide produced alongside the methane is pumped back into the waste water, to feed the algae. A key advantage of the proposal is that the waster water is already full of the nutrients - nitrogen and phosphorus - that the algae need to grow.
human urine makes up less than one percent of the domestic wastewater treated at a facility such as Blue Plains, but contains 80 percent of the nitrogen and 55 percent of the phosphorous. To sanitize urine before application, it is either stored for 30 days in a sealed tank in a room-temperature greenhouse (background) or heated for 30 minutes in a solar pasteurizer (foreground).
News: Algae Farming Technology Yields Renewable Fuel, Uses Waste as Fertilizer
Algae Basics - Benefits of Algae which talks about 10 reasons why algae are a promising new source of fuel and other products:
Known Unknowns, Etc.
SpaceNut wrote:Another topic suggestion area for soil type and conditioning for agriculture:
Soil Manufacture on Mars
Sewage treatment
Building Soil with Salt Marshes
Building soil
Mars regolith analogThere are some very creative ideas in those threads. Focusing on soil, I find that many of the creative ideas for soil manufacture seem to introduce more unknowns than they remove. For example, the idea of blending waste streams into the soil could introduce unpredictable fluctuations in toxins, microbes, pH and nutrient loads. On Earth, soil microbes are diverse and abundant, and their metabolisms help the soil manage fluctuations. But on Mars, most of the beneficial soil microbes would be absent unless explicitly cultivated. Perhaps fluctuations could be managed by the greenhouse crew, but it would seem to be a worrisome job. It's just more unknowns.
Hydroponics removes unknowns by simplifying the soil down to an inert substrate, such as pH-neutral rinsed sand. In a greenhouse with ISRU fertilizer, sterile nutrients are added in a controlled manner, again removing unknowns. A microbiome isn't required and can be suppressed, to remove even more unknowns. For example, a plasma nitrate plant makes hydrogen peroxide as a byproduct. That hydrogen peroxide is added to the liquid nitrate fertilizer to kill off soil pathogens without harming the plants. (Conceivably this treatment could remove a further unknown: hypothetical Mars pathogens. Microbes evolved under anoxic conditions really don't like sudden peroxide oxygen baths.)
To my mind the removal of unknowns is a main reason to aim for a hydroponic greenhouse, one having no more organic matter in the substrate than may be necessary for water retention. A little cellulose could be adequate.
But am I missing something? Is there good reason to convert sand substrate into a soil that's rich in organics, microbes, worms, etc., in this unique circumstance?
I don't know what you do with the goldfish.
Cat food?
But seriously, we wouldn't have pets on Mars. Not for a while. Besides, dead goldfish could decay along with solid human waste to become fertilizer.
But again, with a grey water system, just don't use TP. That eliminates the need for a large greenhouse for trees. The washlet is simpler. And no need to separate waste streams. They did try to build such a system at MDRS, but had difficulty. In the end they removed the sewage processing system, and replaced the greenhouse. Not sure of their current status. Website here: GreenHab