Sludge pellets convert sewage to energy for urban consumers

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monteville

Feeling the Heat
Nov 23, 2019
435
Dallas
Sludge is the solid sediments precipitated from sewage.

Anaerobic digestion of sewage is the mainstream treatment method over the globe, in which bacteria convert the effluents in sewage into metabolic products such as CO2, which is released into air.
It also uses a lot of electricity for blowing air into sewage to reduce the effluents.

Alternatively, a German company invented a process to convert sludge to pellets for recovering energy and displace CO2 emission.

This process is especially proper for large pellet plants in urban areas, because larger pellet plants have higher costs transporting raw materials from fields to plant, while wet sludge can be harvested from a central location of urban sewer system.



"The pellets are germ free, abrasion resistant, and can be stored safely. "
 
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stoveliker

Minister of Fire
Nov 17, 2019
5,354
Long Island NY
Suggestion, this is the third (leaves, wood chips - maybe more) thread with the very same basic concept. The very same objections will be raised. No real experiment will be done (by you - and certainly not by others on here) - and hence it remains pie in the sky.

Therefore, why not make one general thread, and keep that alive with the new source material every other week...? In the end it's the same subject.

"Blue sky ideas for pellet stove fuel"
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
Turd burglar.....lol
 

stoveliker

Minister of Fire
Nov 17, 2019
5,354
Long Island NY
Well, any value we can get out of something that is the definition of waste has my vote if it can be done environmentally proper, and economically sensible (financially self-sustaining).

I don't think pellets of this for fuel is that though (the energy needed to dry what is incredibly wet will outweigh the heat production...)
 

mtnbiker727

Feeling the Heat
Mar 11, 2019
273
PA
There are people burning poultry manure, because in some fantasy land they think it reduces nutrient pollution. Unfortunately, phosphorus has no gas phase, so if you burn it, it's still in the ashes. But you can harvest energy from the burning, and all of the burnable portions are gone, so it does reduce the transportation costs of hauling the manure.

Everything has it's place to a certain point. For rural folks (the primary burners of wood and pellets), sludge pellets are not practical because of transportation costs. For a country like Germany, which is the size of the state of Pennsylvania, transportation is not as bad, and they are lightyears ahead of America in all things environment (and subsidizing those things).
 

monteville

Feeling the Heat
Nov 23, 2019
435
Dallas
Well, any value we can get out of something that is the definition of waste has my vote if it can be done environmentally proper, and economically sensible (financially self-sustaining).

I don't think pellets of this for fuel is that though (the energy needed to dry what is incredibly wet will outweigh the heat production...)
In the video, the heat of drying is from hot flue of a "block heating station" (maybe the German of "district heating station"), so it does not use any additional energy for drying.

Given the fact the plant can harvest sludge from anywhere along the deep sewage mains, it could also be collocated with power plant or cement plant to use low grade heat in flue.
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
I'd say I'm in a good position to make pellets from poop, remember I own an extruder... I just don't believe I could deal with the smell of extruding them or dealing with them in th house, especially if they got damp...lol
 

stoveliker

Minister of Fire
Nov 17, 2019
5,354
Long Island NY
I'd say I'm in a good position to make pellets from poop, remember I own an extruder... I just don't believe I could deal with the smell of extruding them or dealing with them in th house, especially if they got damp...lol

Requires a different kind of mask..
 
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peakbagger

Minister of Fire
Jul 11, 2008
7,494
Northern NH
I have done trials burning sludge, not much BTU content when you factor in the cost to dry it.
 
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monteville

Feeling the Heat
Nov 23, 2019
435
Dallas
Everything has it's place to a certain point. For rural folks (the primary burners of wood and pellets), sludge pellets are not practical because of transportation costs. For a country like Germany, which is the size of the state of Pennsylvania, transportation is not as bad, and they are lightyears ahead of America in all things environment (and subsidizing those things).
Yes, sludge pellets are more economical for urban areas, because sludge can be harvested in a central location, and possibly co-located with a source of low grade waste heat, such as thermal power plant.
I have done trials burning sludge, not much BTU content when you factor in the cost to dry it.
You need a source of low grade waste heat to dry it. The video used the flue of a district heating station.
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan

Ocelot

Burning Hunk
Dec 27, 2010
113
Hudson Valley, NY
I would suspect the cost for a bag of poo pellets would be just as expensive, if not more than wood due to the increased processing and come with additional problems of their own. Look, lots of wood pellets are made from scrap wood from trees already cut for other purposes. Wood, corn, etc are already considered sustainable because it can be regrown. there are types of trees that grow very quickly and while not as strong and useful for construction or fine furniture, would be perfectly fine burning for energy use.

Get a decent pellet mill and experiment all you want with your yard debris, but you won't find it very economical and if you consider time and labor as an expense, it's a costly endeavor. The problem is that we already know that even with plain old commercial wood pellets, there are some cheap brands that are just bad. Those bad pellets don't give as much heat, cause feed problems, excess ash that clogs stoves, cause clinkers, crumble too easy, etc.

I'm enjoying significant savings using wood pellets instead of my oil furnace, even though I'm using more expensive premium soft wood. That goes for last year as well when oil was a lot less than it is this year. I'd save more from cheaper pellets, but I prefer the better ones. My small house is warmer in the areas we spend the most time in with the stove that I would have it with the furnace and I enjoy the atmosphere of the fire.

The one thing I could see as an interesting point with pellet improvement is that maybe someone someday could come up with some sort of safe cheap additive that when added to the sawdust prior to pelletizing could increase BTU output by say 20% allowing a lower feed rate and thus less pellets per hour. However the increased cost would have to be less than the use savings.
 

stoveliker

Minister of Fire
Nov 17, 2019
5,354
Long Island NY
I would suspect the cost for a bag of poo pellets would be just as expensive, if not more than wood due to the increased processing and come with additional problems of their own. Look, lots of wood pellets are made from scrap wood from trees already cut for other purposes. Wood, corn, etc are already considered sustainable because it can be regrown. there are types of trees that grow very quickly and while not as strong and useful for construction or fine furniture, would be perfectly fine burning for energy use.

Get a decent pellet mill and experiment all you want with your yard debris, but you won't find it very economical and if you consider time and labor as an expense, it's a costly endeavor. The problem is that we already know that even with plain old commercial wood pellets, there are some cheap brands that are just bad. Those bad pellets don't give as much heat, cause feed problems, excess ash that clogs stoves, cause clinkers, crumble too easy, etc.

I'm enjoying significant savings using wood pellets instead of my oil furnace, even though I'm using more expensive premium soft wood. That goes for last year as well when oil was a lot less than it is this year. I'd save more from cheaper pellets, but I prefer the better ones. My small house is warmer in the areas we spend the most time in with the stove that I would have it with the furnace and I enjoy the atmosphere of the fire.

The one thing I could see as an interesting point with pellet improvement is that maybe someone someday could come up with some sort of safe cheap additive that when added to the sawdust prior to pelletizing could increase BTU output by say 20% allowing a lower feed rate and thus less pellets per hour. However the increased cost would have to be less than the use savings.
additive: unlikely to be found (for a large increase as 20%). I mean, it exists already; soak the pellets in diesel (oil). But that negates the whole concept of using wood to heat...
 
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SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
I told him he could buy my extruded a while ago. he never replied. Like I said, he's all about 'WE' when it should be 'HIM' as in me.
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
additive: unlikely to be found (for a large increase as 20%). I mean, it exists already; soak the pellets in diesel (oil). But that negates the whole concept of using wood to heat...
You have to be careful with that. I actually start my unit with wood pellets soaked in diesel but only for starting. Burning any oilseed (like soybeans) or using a diesel additive will destroy a stove from overheating. The HX is incapable of transferring the inherent heat from any petroleum based additive or oil seed like soybeans.
 

stoveliker

Minister of Fire
Nov 17, 2019
5,354
Long Island NY
You have to be careful with that. I actually start my unit with wood pellets soaked in diesel but only for starting. Burning any oilseed (like soybeans) or using a diesel additive will destroy a stove from overheating. The HX is incapable of transferring the inherent heat from any petroleum based additive or oil seed like soybeans.
Yes, sure.
In fact, it's a mode of usage the stove was not meant/designed for. I guess this would even affect any insurance pay out if things go south...

I meant not to suggest doing this, but to indicate that I think any additive (that adds a whopping 20% in btus!) is likely to be 1. highly processed and 2. likely fossil based (which includes 1). There is no real natural ("green") additive to my knowledge with a significant higher btu content. And once factories (and dino pee) get involved, it goes against the idea.

Sorry if I was not clear: I advise against doing stuff like this (unless you truly know what you are doing and are willing to accept the physical and financial risks).
 

tlc1976

Minister of Fire
Oct 7, 2012
1,097
Northwest Lower Michigan
additive: unlikely to be found (for a large increase as 20%). I mean, it exists already; soak the pellets in diesel (oil). But that negates the whole concept of using wood to heat...
Also kinda defeats the purpose of clean heat, a selling point with pellets. I wouldn’t want the smells of diesel fuel or dried poo in my living room.
 
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Ocelot

Burning Hunk
Dec 27, 2010
113
Hudson Valley, NY
additive: unlikely to be found (for a large increase as 20%). I mean, it exists already; soak the pellets in diesel (oil). But that negates the whole concept of using wood to heat...
Oh, I agree it's not only highly unlikely, but not worth it anyway. If there was something it would be more like a small amount of an oxidizer, but even then, that's what the combustion blower does anyway so again probably not worth it.
 

stoveliker

Minister of Fire
Nov 17, 2019
5,354
Long Island NY
I'd be even more hesitant to add an oxidizer to a fuel - in a metal box in my home.
Recipe for disaster (see explosives and rocket fuel)
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
Also kinda defeats the purpose of clean heat, a selling point with pellets. I wouldn’t want the smells of diesel fuel or dried poo in my living room.
Neither do I. I only use soaked pellets to start mine and I've used liquid charcoal fire starter as well. Maybe a small handfull of pellets and I'd never recommend that with a self ignition unit anyway. Mine is manual start.

No cal rod ignition when mine was built, about 20 years ago.
 

SidecarFlip

Minister of Fire
Feb 7, 2010
5,273
S.E. Michigan
Look, lots of wood pellets are made from scrap wood from trees already cut for other purposes
Exactly what Somerset Hardwood flooring does in Somerset, Kentucky. Their pellets are made from forestry slash and underiseable trees from their logging operations on their own leased forest lands. For them, the pellet mill they have on site is a value added part of the entire operation. Before they installed a grinder and extruder, they had to dispose of their waste via a landfill. Now, they turn their waste into a marketable product.

I believe they use some of the once landfilled wood to heat their pellet drying as well.
With their pellets, all you get is hardwood. No recycled pallets, no change in feedstock quality either.

I've roasted Somerset pellets before, very consistent quality bag to bag. Problem is, availability around here is spotty at best.
 

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