Sciencemadness Discussion Board

Processing animal waste (manure) - any way to speed up the process?

RogueRose - 14-10-2018 at 02:15

In many states there are agricultural communities where there are massive farms that have open pits of manure of millions of gallons and these pits/ponds are susceptible to flooding problems which causes all kinds of problems with disease and ground water contamination afterwards. Local regulators seem unwilling to tackle the problems and time and again we see overflows into creeks/rivers not to mention when we have big storms.

From what I have seen the best current method of handling the manure is covering the entire pit with a "tarp" and drawing off the methane. This seems VERY inefficient when some of the pits are 300ft x 300ft x 4-10ft or larger.

I'm wondering if a similar setup could be used w/o the large area being covered but process the manure in daily batches and then pump the manure into the holding pond after processing.


I am wondering if it would be possible to first remove the solids by using either a centrifuge or a large filter/press that could make "cakes" of the solids - possibly centrifuge first and then press the solids left from the centrifuge.

I'm not sure what is in the liquids (as far as compounds/elements) I suspect they would be high in ammonia, urea, potassium and phosphorus (I wonder how much phosphorus is in 6 million gallons of pig manure??).

Would passing the centrifuge'd liquids through a layer of CaCO3, Ca(OH)2 or some other relatively inexpensive material be useful in treatement of the manure? Maybe the filter material and or liquid could later be used as a field additive for nutrient?

IDK if it is possible to speed up the breakdown of the manure into methane (in a batch process) as I think the natural anaerobic process is fairly slow. IDK if changing the pressure and or temp within the batch process or any other manipulation would speed the process?

Does anyone know what the contents would be of the solids from centrifuging or pressing? I've heard of things like this being used a fuel pellets (not domestically/residential) and burnt possibly with the help of the methane, and then the ash is used as "bio-char" as a field additive. I've also seen that the solids are composted with wood chips/leaves/grass/etc.

If any of you have knowledge of how manure is handled in your country (even if in the US) I'd be interested in hearing the process and if there any ways that this can be processed w/o all the infrastructure like municipal waste water treatment plants (check out London't new WW treatment plant - it's CRAZY big!)





Deathunter88 - 14-10-2018 at 04:31

None of your proposed ideas are economically viable.

Morgan - 14-10-2018 at 05:09

Not really on topic of animal manure but perhaps of interest since they can no longer dump human waste into the sea. There are some crazy big holding tanks that are strangely pretty for what they hold.

This documentary although seemingly flippant/coarse at first, you find the ending chock full of concerning fun facts. And there's some chemistry to ponder. Seems like there's some degree of secrecy. Interesting that a tobacco company warns against it's use while u-pick strawberries grown with it are fine. Probably some plants take up the things you don''t want in your food.
You don't know ...
https://youtube.com/watch?v=QV9x79_WYbk


[Edited on 14-10-2018 by Morgan]

RogueRose - 14-10-2018 at 08:11

Quote: Originally posted by Deathunter88  
None of your proposed ideas are economically viable.


yeah I hear that type of thing a lot. I've been told a lot of things were "too expensive" and it was only because they relied on either manufactured solutions or some professional to do it for them. How many times have we seen things in this subject (chemistry) done for a mere fraction of the cost it is done in industry.

I remember before Tesla cars came out people didn't think much of electric cars and someone took an old/original Audi Quattro and a very large motor from a big old electric forklift and used what amounted to old laptop batteries and made one of the fastest "production" cars to do 0-60 or 0-100mph for about $800 (they built it themselves and had the car body already) that was faster than all the porsche's, ferarri's, lamborghini's, Merc's, Audi's, BMW's, etc - but it wasn't exactly luxury inside - just built for speed.
e
My point is, if someone would have asked what's the fastest way to go 0-100mph for $10,000 and can it beat my brothers Porsche 911 Turbo S - no one would have said "build an electric car" because no one had done that (probably b/c no one took into consideration increase power density of Lithium batteries yet) - but with new technologies, things that were too expensive 10, 20, 25 years ago may be feasible with current tech.

unionised - 14-10-2018 at 08:50

Quote: Originally posted by RogueRose  


I am wondering if it would be possible to first remove the solids by using either a centrifuge or a large filter/press that could make "cakes" of the solids - possibly centrifuge first and then press the solids left from the centrifuge.



You could probably separate them.
Then you would have two waste streams to deal with.
What would be the point?

As far as I can tell, the most practical solution it to use the waste to generate methane.
The major advantage of that process is that it strips a fair bit of the energy into a second stream of material that contains a small fraction of the mass, but a large fraction of the value. (and separation of gas is easy- you just need a tank with a vet pipe on the top).

It might be interesting to let the material settle, draw of the most liquid portion of it, circulate that through limestone cobbles and then return the liquid to the tank.
That way, any soluble phosphates that are set free would be trapped as calcium phosphate from which they might be recovered.

On the other hand, you could take what's left when the methane generation slows down and spread it on the fields- like people have done for centuries.
No need for further processing.

Ubya - 14-10-2018 at 09:55

maybe the problem could be solved by using a concrete roof for the manure pits, not just a tarp, the equivalent of a gigantic tank.

unionised - 14-10-2018 at 11:42

Quote: Originally posted by Ubya  
maybe the problem could be solved by using a concrete roof for the manure pits, not just a tarp, the equivalent of a gigantic tank.

People pretty much do that
https://www.motherearthnews.com/renewable-energy/methane-gas...

RogueRose - 14-10-2018 at 13:58

Both of those ideas are good and somewhat what is done already in a few places. Most just have massive open air holding ponds. The problem that I see is that when you have a multi-million gallon pond and you are adding 2-10,000 gallons a day there is massive dilution of the manure when it gets into the pond and this is why I thought doing batch processing, even something like 3-4 tanks where each tank is 2 days worth (if it takes 6-8 days to process), then once finished digesting it is then either run through a centrifuge and/or filter bed then pumped into the pond. This way I would guess much of the smell is removed and probably much of the bacteria/contaminates (killed in aneorobic digestion) and some of the nutrients may be caught up in the calcium filter.. From there the liquid would be spread on fields.

The way it is now isn't a problem as far as how the manure is used for fertilizer but it is a problem when it comes to contamination during rain/floods as well as smell problems for up to 10+ miles. Those last two factors are the major issues which may seem small to some people but when you have 4-10 massive hog farms in one area hot summer days down wind can be unbearable (some people get sick) and storms cause major problems for everyone downstream (local water supplies).

I would think that if it was process like described above, much of the stuff that contaminates the water supply might be destroyed or contained but I'm not very familiar with the contents/compounds in waste like that.

Gearhead_Shem_Tov - 14-10-2018 at 16:11

Aerobic composting would probably be better all round from an ecological point of view (less fugitive methane emission, less smell, and production of high quality fertiliser).

The issue would be cost. Feedlots just can't sustain windrow composting the way they are currently set up. But feedlots aren't ecologically or economically sustainable in the long run if the externalities are properly accounted for: runoff pollution, breeding bacteria with antibiotic resistance, greenhouse gas emissions from the manure (and from cow farts too because of their feed), energy requirements, and land and water use for feed.

-Bobby

[Edited on 15-10-2018 by Gearhead_Shem_Tov]

RogueRose - 14-10-2018 at 16:45

Quote: Originally posted by Gearhead_Shem_Tov  
Aerobic composting would probably be better all round from an ecological point of view (less fugitive methane emission, less smell, and production of high quality fertiliser).

The issue would be cost. Feedlots just can't sustain windrow composting the way they are currently set up. But feedlots aren't ecologically or economically sustainable in the long run if the externalities are properly accounted for: runoff pollution, breeding bacteria with antibiotic resistance, greenhouse gas emissions from the manure (and from cow farts too because of their feed), energy requirements, and land and water use for feed.

-Bobby

[Edited on 15-10-2018 by Gearhead_Shem_Tov]


Thanks for mentioning aerobic composting I thought it was actually slower for some reason or maybe it isn't as complete. I think there is an advantage to anaerobic decomp, maybe it is that it produces more methane overall - so if it was used for energy production, anaerobic produces more but is slower..

The times that I stated, 6-8 days , is because there is a large composting facility near me that uses municipal waste (the solids) and mixes them with organic stuff, mainly wood chips in a huge, hot warehouse with very large piles and gigantic front end loaders to turn/mix it.

I don't think there is much that can be done about cow/pig farts and burps but if both are lighter than normal air, if housed in a large barn/shack then maybe the gas could be trapped at the apex of the roof (like inverted funnel) and drawn out through duct work - then use that air/gas mix as the air to burn with the methane produced from the digestion pits - so if there is whatever % methane in the air (.5-3%??) it is burnt along with the pure methane from digestion.

I want to thank everyone who has participated in this thread. I know it isn't the most enjoyable topic but it is a major problem in many communities and in most countries (though maybe in small areas).

AJKOER - 14-10-2018 at 19:18

A faster process?

Perhaps some redox chemistry and sunlight (basically a photo-Fenton like reaction) may assist.

Try adding to the waste iron powder (from scrap iron with or without the addition of copper metal powder from copper pipes), lemon/citrus juice, a bit of sea salt and pump in air. Sunlight would augment the process as would adding heat treated carbon (from wood) or aluminum powder (from scrap aluminum).

For details on some of the possible chemistry, see my comments at http://www.sciencemadness.org/talk/viewthread.php?tid=96347#... .

[Edited on 15-10-2018 by AJKOER]

Ubya - 15-10-2018 at 04:10

Quote: Originally posted by AJKOER  
A faster process?

Perhaps some redox chemistry and sunlight (basically a photo-Fenton like reaction) may assist.

Try adding to the waste iron powder (from scrap iron with or without the addition of copper metal powder from copper pipes), lemon/citrus juice, a bit of sea salt and pump in air. Sunlight would augment the process as would adding heat treated carbon (from wood) or aluminum powder (from scrap aluminum).

For details on some of the possible chemistry, see my comments at http://www.sciencemadness.org/talk/viewthread.php?tid=96347#... .

[Edited on 15-10-2018 by AJKOER]


not feasible at all for metric tons of organic waste

AJKOER - 15-10-2018 at 04:43

One could use whole pieces of scrap iron, local organic produce of poor quality (for example, crap apples which is usually rich in citric/ascorbic acid), oxygen from air and carbon from a burned tree, which could serve as the reagents.

The current process is also chemical in nature dependent on the action of bacteria.

[Edited on 15-10-2018 by AJKOER]

Sulaiman - 15-10-2018 at 05:29

Quote: Originally posted by RogueRose  
Local regulators seem unwilling to tackle the problems and time and again we see overflows into creeks/rivers not to mention when we have big storms.


If regulations are not enforced then there is little prospect of improvement
as the cheapest waste processing method is already in use.

macckone - 15-10-2018 at 07:38

There are better ways to process this type of waste. They are used in sewage treatment plants. But there is no incentive to do so for farm waste. Regulations aren't enforced and they aren't held accountable for releases.

Given that the vast majority of the sewage stream is water, dividing into two streams is actually done to decrease processing time and cost. the liquid stream is settled and treated to clear it and various chemicals may be added to break down specific components. Oxygenation is a key process for the liquid stream. Special bacterial mats process out nitrates and urea. They are now using special bacteria to remove drug residues as well.

For the solid stream, it is treated as compost. Composting is a combination of aerobic and anaerobic processes.
Leachate from the solids is added back to the initial stream.

There are many volumes of literature on human waste processing. It is interesting to note that the final step of sludge processing is cooking it to kill off bacteria.

unionised - 15-10-2018 at 13:17

Quote: Originally posted by AJKOER  
A faster process?

Perhaps some redox chemistry and sunlight (basically a photo-Fenton like reaction) may assist.

Try adding to the waste iron powder (from scrap iron with or without the addition of copper metal powder from copper pipes), lemon/citrus juice, a bit of sea salt and pump in air. Sunlight would augment the process as would adding heat treated carbon (from wood) or aluminum powder (from scrap aluminum).

For details on some of the possible chemistry, see my comments at http://www.sciencemadness.org/talk/viewthread.php?tid=96347#... .

[Edited on 15-10-2018 by AJKOER]


That idea is workable to roughly the same degree that sunlight penetrate a few metres of manure.

There are better things to do with scrap metal.
Adding salt pretty much rules out any prospect of recovering value as fertiliser.
Adding charcoal or metals will increase the bulk (and ecotoxicity) of the material.


clearly_not_atara - 15-10-2018 at 13:47

Quote: Originally posted by Deathunter88  
None of your proposed ideas are economically viable.


This is basically the status quo. Nothing is cheaper than literally doing nothing. Until and unless manure producers are held accountable for the pollution they generate, none of this will change.

But assuming we want to do something about it, ozonolysis seems like a particularly good choice here. Ozone will attack many components of manure at under ambient conditions, including amines, thiols and N-heterocycles -- completely deodorizing and disinfecting it -- but it won't/shouldn't completely oxidize the contents to CO2/N2/H2O unless it catches fire (bad). Whatever remains might be profitable to extract and convert to polymers or other value-added products. Ozone also doesn't require any precursors but water (and a PbO2 cathode), which supports on-site manure processing, a big advantage when you don't want to carry around tons of shit.

Composting by contrast is the approach that is being attempted currently, and it isn't working. It's too slow and the fecal backlog keeps growing.

[Edited on 15-10-2018 by clearly_not_atara]

RogueRose - 15-10-2018 at 23:03

Quote: Originally posted by Sulaiman  
Quote: Originally posted by RogueRose  
Local regulators seem unwilling to tackle the problems and time and again we see overflows into creeks/rivers not to mention when we have big storms.


If regulations are not enforced then there is little prospect of improvement
as the cheapest waste processing method is already in use.


You have highlighted the EXACT point. The local regulators AREN'T willing to enact more strict guidelines for processing waste but would if the people voted someone in who supported it. It's a BIG issue in some areas.

Also they are using the cheapest method to deal with waste, which is exactly the problem, only a few places (farms) actually do a better job of management of the waste.

There is PLENTY of room to improve on on processing the waste but people need to demand these processes be used.

symboom - 16-10-2018 at 20:35

Agreed I also find interesting how it is used to generate electricity for people very far from the grid system
Of course sulfur and water must be removed
Even can provide natural gas source for a gas stove in developing areas of the world which can boil and clean dirty water
Take care of waste and have clean water and electricity sounds good to me


[Edited on 17-10-2018 by symboom]

AJKOER - 4-12-2018 at 08:50

Actually, putting aside the cost issue with my photo fenton-like process, there may be a very bad chemical consequence of incomplete breakdown.

I am thinking about the first stage in the breakdown of nitrates by hydroxyl radicals to nitrites:

NO3- + .OH = .NO2 + OH-

.NO2 + .NO2 = N2O4

N2O4 + H2O = HNO2 + HNO3

and now we have a more toxic nitrite presence. Per Wikipedia on nitrite in general (link: https://en.wikipedia.org/wiki/Nitrite):

"Nitrate or nitrite (ingested) under conditions that result in endogenous nitrosation has been classified as "Probably carcinogenic to humans" (Group 2A) by International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO) of the United Nations.[2][3]"

And, in the case of particular nitrites, like KNO2, even more concerns to quote from Wiki (https://en.wikipedia.org/wiki/Potassium_nitrite ):

"Like other nitrite salts such as sodium nitrite, potassium nitrite is toxic if swallowed, and laboratory tests suggest that it may be mutagenic or teratogenic. Gloves and safety glasses are usually used when handling potassium nitrite."

[EDIT] And, apparently depending on temperature, KNO2 is between 2 to 20 times more soluble than KNO3, which makes it more likely to get into the water table.

[Edited on 4-12-2018 by AJKOER]

Ubya - 4-12-2018 at 10:13

Quote: Originally posted by AJKOER  
Actually, putting aside the cost issue with my photo fenton-like process, there may be a very bad chemical consequence of incomplete breakdown.

I am thinking about the first stage in the breakdown of nitrates by hydroxyl radicals to nitrites:

NO3- + .OH = .NO2 + OH-

.NO2 + .NO2 = N2O4

N2O4 + H2O = HNO2 + HNO3

and now we have a more toxic nitrite presence. Per Wikipedia on nitrite in general (link: https://en.wikipedia.org/wiki/Nitrite):

"Nitrate or nitrite (ingested) under conditions that result in endogenous nitrosation has been classified as "Probably carcinogenic to humans" (Group 2A) by International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO) of the United Nations.[2][3]"

And, in the case of particular nitrites, like KNO2, even more concerns to quote from Wiki (https://en.wikipedia.org/wiki/Potassium_nitrite ):

"Like other nitrite salts such as sodium nitrite, potassium nitrite is toxic if swallowed, and laboratory tests suggest that it may be mutagenic or teratogenic. Gloves and safety glasses are usually used when handling potassium nitrite."



good to know that in the soil we have Nitrobacter that oxidizes nitrite to nitrate. now just remains the "everything must be radical" reaction you proposed

AJKOER - 8-12-2018 at 04:56

Quote: Originally posted by AJKOER  
A faster process?

Perhaps some redox chemistry and sunlight (basically a photo-Fenton like reaction) may assist.

Try adding to the waste iron powder (from scrap iron with or without the addition of copper metal powder from copper pipes), lemon/citrus juice, a bit of sea salt and pump in air. Sunlight would augment the process as would adding heat treated carbon (from wood) or aluminum powder (from scrap aluminum).

For details on some of the possible chemistry, see my comments at http://www.sciencemadness.org/talk/viewthread.php?tid=96347#... .

[Edited on 15-10-2018 by AJKOER]


Here a direct reference (see https://pubs.acs.org/doi/abs/10.1021/es00026a011?journalCode... , but H2O2 can be formed in situ by pumping in air/O2 into acidic ferrous, see "Generation of Hydroxyl Radicals from Dissolved Transition Metals in Surrogate Lung Fluid Solutions" by Edgar Vidrio, et al at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2626252/) with respect to the photo-fenton reaction with citrate in the range pH 3 to 8.

I would void employing any copper with the iron, not because it will certainly assist the fenton process with a very favorable redox couple reaction:

Cu(l)L + Fe(lll)L' = Cu(ll) + Fe(ll) where L, L' are citrates

but because of environmental toxicity concerns with copper.

To keep recycling the ferric to ferrous, solar light and solution agitation from possibly a wind driven device may help. I still think attempting to active carbon (see https://www.researchgate.net/publication/276120744_Enhanced_... ) from heated charcoal (also removes complex organics) may also assist. Also, application of electricity with stainless steel electrodes from solar cells is a possibility (see 'Trends in electro-Fenton process for water and wastewater treatment: An overview' at https://www.sciencedirect.com/science/article/pii/S001191641... ).

Another option is employing nano iron embedded in an appropriate medium like clays (see 'Clays and oxide minerals as catalysts and nanocatalysts in Fenton-like reactions — A review' at https://www.sciencedirect.com/science/article/pii/S016913170...), zeolites (see 'Removal of Nitrate from Water using Supported Zero-Valent Nano Iron on Zeolite' at http://ijhe.tums.ac.ir/browse.php?a_id=16&sid=1&slc_... ,...).

[Edited on 8-12-2018 by AJKOER]

pneumatician - 11-2-2019 at 18:55

Reduce the farm?

I want to do the same with my organic trash. first I need to reduce the food to little bits. After this many juices/water is separated, good for plants, else compact it and last expose to Sun or burn with mirrors or passive heat from the Sun. Also is possible to use worms to recycle trash to compost. So you need to find some organism happy eating pig shit :)

Ubya - 12-2-2019 at 04:39

Quote: Originally posted by pneumatician  
Reduce the farm?

I want to do the same with my organic trash. first I need to reduce the food to little bits. After this many juices/water is separated, good for plants, else compact it and last expose to Sun or burn with mirrors or passive heat from the Sun. Also is possible to use worms to recycle trash to compost. So you need to find some organism happy eating pig shit :)

small scale is much easier, you could turn your trash in compost, or you could feed it to a digester and make methane for your house, or you could feed it to red wigglers or black soldier fly larvae to produce some protein feed for poultry

pneumatician - 12-2-2019 at 08:43

well, I watch some years ago a doc where say Pentagon have a modified organism that can eat a well of oil in hours? days?, so if you live in usa call the Pentagon and ask if have one to eat shit, who known? :D or contact with European commission and co. asking or search about the problem of methane from cows, permafrost... The last or provisional option is EQUILIBRIUM, so use the purines for something else and do not produce more than your system can "digest" / process. Maybe some aquatic plant live happy in this environment and produce something you can sell.