Dear Kai,

In my role as moderator, I have just done a little regrouping exercise because I felt this topic of sewage sludge / toxic sludge deserved its own dedicated thread. So I have pulled out the main posts which were before buried in the thread on the wastewater reuse scheme in Braunschweig, Germany, into this new thread and have made cross-links in both directions at the beginning of the thread.

In my role as participant:
I agree with you that it is useful to distinguish fertiliser / soil conditioner made from sewage sludge (lovingly called biosolids in some countries but not in all countries) from fertiliser made from urine and faeces that are collected pure without any of the industrial pollutants that give us so many headaches and risks; like the Sanergy system which makes compost out of faeces, sawdust, urine (similar system being used by SOIL Haiti). I would much rather use their compost in my garden than compost made from sewage sludge originating from a large scale system with considerable industrial effluents having gone into the sewer.

But I am curious where you saw the term biosolids mentioned on the Sanergy website or in any of the posts in this thread ? I didn't find it.
As far as I know they call it Evergrow Organic Fertiliser.

(If you do find it then possibly the term "biosolids" was still "free" in Kenya and not associated with composted sewage sludge. Therefore, if they only speak to the Kenyan market it would be no problem - but not ideal, I agree)

About your point of sewage sludge = toxic sludge in the US: I don't know many sewage sludge experts in the US, so when I bumped into one at the FSM3 conference in Hanoi I was delighted and started a conversation with her. I said to her that I know from you that this topic is hotly debated in the US and that toxic sludge spreading on land is a big problem. She disagreed with this statement and said it is only a small, but very vocal group of people who are not listening to the scientic evidence. She said she gets a fair bit of hate mail from people (hopefully not from you ).

Her name is Sally Brown and she also had a presentation at this conference although it was not on biosolids but on compost from UDDTs (her husband is Chuck Henry from the Earth Auger toilets ). Nice combination of spouse's professions (it's similar for me, my husband works with centralised wastewater treatment plants in India at present )

Her presentation was:
*Benefits associated with local use of faecal compost from an innovative UDDT: Sally Brown, University of Washington, Seattle, WA, USA
www.susana.org/images/documents/07-cap-d...m-2/3-2-1-5Brown.pdf


Do you know Sally? She has probably published quite a bit on this topic. So I just wanted to provide a bit of balance and an opposing viewpoint to your point about the dangers of topix sludge spreading on land in the US.

Regards,
Elisabeth

P.S. Kai and I have discussed the Wikipedia page on sewage sludge by e-mail already (en.wikipedia.org/wiki/Sewage_sludge) - it would need a lot of work, as it's rather messy and a bit non-objective (i.e. non-encyclopedic), see also its talk page here:
en.wikipedia.org/wiki/Talk:Sewage_sludge
(in that regard it's the worst Wikipedia article I have ever come across in the sanitation sphere)

I shuttered when I came upon the term "biosolids" being used to describe the contents of the feces and urine bins (and, in turn, one of the components of the resulting compost).* These materials are absolutely NOT biosolids and great care should be taken to distance these materials from anything having to do with sewage sludge (the historic term for biosolids). Here's an excerpt from the book "Toxic Sludge is Good For You: Lies, Damn Lies and the Public Relations Industry" that gets to my point:

thewatchers.us/EPA/2/Rampton_NS.pdf


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*
Note by moderator:
This post was originally in this thread about the Sanergy urine-diverting dry toilets, so Kai was referring to their type of system.

joeturner - If it is as you say and there is an accounting, "...of these materials and the [associated] risk," then how do you explain the rapid rise of Class A sludge in the United States, a material that differs from Class B sludge only in that it has undergone a limited exothermic reaction? Existing regulations explicitly exempt Class A sludge from the restrictions that determine where and in what quantity sludge can be dumped. So, in other words, Class A sludge (and products containing it) can be applied anywhere and in any volume - the land-loading limits for heavy metals accumulation no longer apply. How is this an accounting of the dangers present in sludge? Again, I'm approaching this conversation from the point of view of North America.

Moreover, there's a growing body of evidence that suggests that sludge is anything but free from human pathogens (recall that we only test and control for a few indicator pathogens) and that it (and the infrastructure that produces it) is serving as a very effective breeding ground for antibiotic resistance bacteria.

I echo your echoing of my concern regarding toxics in sludge. Amazingly, at least here in the US, the jury's still out regarding the extent of the threat that's posed by the plethora of the industrial toxins present in sludge. But like the above, there's a growing body of evidence that suggests that these synthetic pollutants - the vast majority of which no one tests for and which are subject to bioaccumulation and biomagnification - are taken up by food crops and feed crops and that they also migrate down into the soil, enter the water table and/or flow into surface waters (thanks to erosion) likely ending up on our plates and in our glasses. In general, thanks to the corrupting influence of industry which has acted effectively to limit the amount of independent research that's been done to date (or discredited same), we're only just beginning to scratch the surface regarding what we're up against when it comes to toxics in sludge (or,for that matter, toxics in water). So, given this, I think its disingenuous at best to state that sludge is safe. We simply don't know for sure, but things aren't looking good.

I think the facts do show that there exists only a very limited accounting of what's in sludge and that this is a deliberate action by regulators (which is curiously highly favorable to industry) in order to permit the continued dumping of this highly toxic material onto agricultural land and other land. Landfills and incinerators are expensive so government is catering to the lowest common denominator by essentially expanding the boundaries of our landfills to include (in the case of Class A sludge) basically everywhere. This is obviously moving us in the direction opposite from where we need to be going which is towards truly sustainable alternatives. And knowing what I know about the highly suspect industry funded studies that you allude to (that show all is well) and other independent third party studies which show quite the opposite, I am moved to err on the side of caution and to push for what by all logical reasoning are safer and far more lasting options.

Its important to note the following:

-- Dry toilets don't waste precious water like flush toilets do;
-- Dry toilets, assuming they are managed appropriately, do not directly pollute water - exactly the opposite of flush toilets.
-- The byproduct(s) of dry toilets, assuming that the pharmaceutical angle is properly addressed and certain precautions are taken to reduce pathogens, represents a free source of vital plant nutrients whereas the byproducts of WWTPs are basically a "toxic soup";
-- Onsite greywater systems mimic the natural water cycle, the opposite of what sewers do; and
-- Reliance on onsite rainwater harvesting and storage absolutely demands conservation which is exactly opposite from the effect that's produced by being hooked up to a pressurized (and seemingly endless) municipal supply.

Said another way, it seems to me that a person who not connected to municipal water and sewer but is the recipient of a targeted education campaign, is provided with secure options when it comes to the disposal of toxic substances and who is also outfitted with and reliant on a dry toilet, onsite rainwater harvesting and storage (or deliveries of finite supplies of water) and onsite greywater generally won't make excessive use of water nor will they tend to irrevocably pollute water or their immediate surroundings. This is in marked contrast to a person who is connected to a seemingly endless municipal water supply and a bottomless sewer. We still have the resources in the West that would allow us to dramatically reinvent the way we manage water, washwater and human excreta. We only lack the will.

And that's my point. These legacy systems will not stand the test of time (be it thanks to bankrupt municipalities, our looming low-energy future and/or climate change, etc.) so why continue to pour scarce public money into them when we could instead be using these resources to redesign the system instead? Sort of along the lines of "let's put our own house in order".

And no, burning this material is hardly safe as one still ends up with highly toxic fly ash. Plus, the huge investments that incinerators represent and the fact that they create an unending demand for sludge together makes it very hard to argue for alternatives (they become self-fulfilling prophesies). Just like garbage incinerators which beget more garbage (which begets more consumption, which begets more garbage, etc.) and which even require incinerator operators having to travel further and further afield to source feedstock. And in this day and age isn't resorting to the ancient technology of burning something a sure sign of laziness and/or lack of imagination? We can and must do better and not producing sludge in the first place seems to me the most logical place to start. Plus, just because we've been doing it one way for the last thirty or forty years doesn't mean that we have to continue doing so, particularly when there are inexpensive alternatives.

Just to clarify: in Europe sewage sludge is risk assessed for pathogens but also for metals and other pollutants. There are lots of studies about the potential risk from industrial effluents in land-spread faecal waste. I even saw a presentation the other week about the potential impacts on the (very new) risk from nanomaterials in faecal sludges spread to land. It isn't accurate to suggest that no account is taken of these materials and the risks when they're in sewage sludge spread to land.

PCBs, for example, are an obvious worry because the concentrations needed in the environment to be a problem are in the Parts Per Trillion.

I found it interesting to hear the different perspectives, in particular to hear from Kai from Vermont, USA about strong concerns regarding land application (or landfilling?) of sewage sludge from treatment plants.

It is interesting that Joe Turner (with his focus on pathogen removal) says:

Well faecal sludge applied to land in Europe is a) tested and b) risk assessed. So yes, in general, treated sludge is safe to apply to land.

Whereas Kai is more concerned here about the micropullants, e.g. pharmaceutical residues, and other "nasties", such as PCBs.

In Germany, the situation is not as clear cut as it seems to be in Switzerland from where Florian reported: some states of Germany allow land application (reuse of sludge on farm land) and others prescribe incineration. By the way, work conducted to remove phosphorus from sludge ash after incineration has shown that this is possible but currently still too expensive.

Coming back to the Braunschweig case, as it is such an interesting example:

Arno, do you or anyone else know exactly what measures the municipality of Braunschweig has put in place to control the discharge of industrial effluent into their sewer system?
I guess there is not so much industry in Braunschweig (250,556 people according to Wikipedia) but still, have they managed to ensure that each factory has its own on-site treatment system? Do they have a large team of trade waste inspectors that monitor the operations of factories and small-scale industries? Is it tightly controlled and fines imposed if necessary?

Also what about hospitals, have the operators of the sewer system also managed to keep the hospital effluent out of the municipal sewer system? That would be great (perhaps the same would apply for old age homes where perhaps lots of medical drugs are used as well)?

I think if you keep industrial wastewater and hospital wastewater (or let's say "non domestic sources") separate from the purely domestic wastewater, then the effluent and sludge from the wastewater treatment plant could be relatively free of toxins and heavy metals, and therefore application to land less of a concern. (source separation is one of the things that many ecosan systems employ, but it is not a "must have" to qualify as ecosan)

Personally, the word "ecosan" doesn't come to mind for me when looking at the Braunschweig case (but I also don't mind if someone wants to call it ecosan on the basis of its reuse aspects). Whether a sanitation system uses dry toilets or not does not define ecosan. We used to call ecosan also "closing the loop" (between sanitation and agriculture with regards to nutrient cycling) and in this case, such a wastewater reuse scheme would be a rather "large loop", compared to the "small loop" which would exist at a household scale system.

For me it is an example of a seemingly successful wastewater reuse scheme. And perhaps an example of a sustainable sanitation system specifically for this case in Germany (no shortage of water, skilled staff available etc.), although I don't really know enough about it (e.g. financial sustainability? Social acceptance seems to be there as it's never mentioned in the news in Germany as a controversial scheme.)

Oh and Kai, I agree with you that we should not blindly try to "export" such sewer-based schemes to developing countries. I don't think anyone would argue with you on that one. Each situation needs to be looked at as a case by case basis. In some cases, a DEWATS system might be most sustainable. In some cases it's dry toilets (UDDTs) or simple composting toilets like Arborloos. And in even other cases it could be sewer systems and centralised treatment plants (e.g. with biogas production from anaerobic sludge digesters). And so forth. One should never generalise and assume that one solution will fit all kinds of cases.
Or would you prescribe dry toilets for everyone everywhere at all times?

Regards,
Elisabeth

KaiMikkel wrote:
Might I suggest a friendly amendment? If so, how about, "So yes, in theory, treated sludge is safe to apply to land". I offer this because, after all, the federal regulations surrounding sludge (as least in North America) only require the testing and control of a few heavy metals (maybe PCB's in some cases) and a few indicator human pathogens. I would argue that the testing regime that you refer to is woefully inadequate given that it totally overlooks the scourge of antibiotic resistant bacteria and so-called "contaminants of emerging concern" (what I prefer to call "industrial toxics").

There are not endemic faecal pathogens and people rarely die from faecal infections in Europe or North America. So you can call it whatever you like, the facts are the facts: water treatment systems in developed countries are, in the vast majority of cases, safe.

As you are no doubt aware, oversight of sludge in the US is based upon at least two outdated concepts; namely, the "dilution solution" and "the dose makes the poison". I refer to these concepts as "outdated" for two important reasons. One, the extent of the human population (7 billion and climbing) makes them inappropriate, and two, the nature of many of the thousands of toxics currently in circulation which can negatively affect life in quantities measured at parts per billion or even parts per trillion.

Yes, but this is irrelevant because you've now moved from talking about water treatment services in countries where there are resources to ensure that sewage treatment is safe and the other x billion who do not have safe sewerage. I have never ever heard anyone argue that non-functioning sewage is desirable, and in fact in many situations can be worse than no sanitation at all, but that does not change the fact that functioning water-based sewerage, water treatment and land application of sludge is safe.

As far as your pointing out that the Minority World is not suffering from water borne diseases while the Majority World is literally swimming in them, I don't think this is necessarily a result of the former having a relative plethora in legacy wastewater infrastructure and the the latter not having same but instead a result of the former having something and the latter, at least relatively speaking, having nothing.

I take it you are aware of the history and what the same developed countries faced before they had functioning sewerage? Developed countries do not have endemic faecal pathogens because there is a functioning, risk-assessed faecal treatment system and robust healthcare.

We'd be in the same boat (but even better off as far as toxic pollution and availability of drinkable water is concerned) if the "west" had opted instead for (what I guess I now need to refer to as) sustainable sanitation. The trick is for places currently lacking any effective sanitation to skip over the "step" manifested by legacy systems and, like many have done with landline versus cellular technology, go right to sustainable solutions. In this way, the last thing I think we should be dong is importing legacy sanitation technology to the rest of the world.

I don't think there is any evidence for this.

Sewered sanitation already serves basically all persons in Europe and North America, and the majority of the urban population of the rest of the world. We may think about this system what we want, call it outdated or legacy or other things, but there is little doubt that this system is going to stay with us for quite some time. So simply damning this system and the sludge it produces is not enough, we've to make this system work as good as possible, which also includes dealing with sludge.

I live in a country where the agricultural use of sewage sludge is forbidden. All sewage sludge is burned in waste incineration plants or other facilities like cement factories.

Now, if that is the more "sustainable" way to deal with it, rather than the reuse of nutrients aimed for in other countries, I am not so sure.

Joe Turner - You wrote, "Well faecal sludge applied to land in Europe is a) tested and b) risk assessed. So yes, in general, treated sludge is safe to apply to land."

Might I suggest a friendly amendment? If so, how about, "So yes, in theory, treated sludge is safe to apply to land". I offer this because, after all, the federal regulations surrounding sludge (as least in North America) only require the testing and control of a few heavy metals (maybe PCB's in some cases) and a few indicator human pathogens. I would argue that the testing regime that you refer to is woefully inadequate given that it totally overlooks the scourge of antibiotic resistant bacteria and so-called "contaminants of emerging concern" (what I prefer to call "industrial toxics").

As you are no doubt aware, oversight of sludge in the US is based upon at least two outdated concepts; namely, the "dilution solution" and "the dose makes the poison". I refer to these concepts as "outdated" for two important reasons. One, the extent of the human population (7 billion and climbing) makes them inappropriate, and two, the nature of many of the thousands of toxics currently in circulation which can negatively affect life in quantities measured at parts per billion or even parts per trillion.

As far as your pointing out that the Minority World is not suffering from water borne diseases while the Majority World is literally swimming in them, I don't think this is necessarily a result of the former having a relative plethora in legacy wastewater infrastructure and the the latter not having same but instead a result of the former having something and the latter, at least relatively speaking, having nothing. We'd be in the same boat (but even better off as far as toxic pollution and availability of drinkable water is concerned) if the "west" had opted instead for (what I guess I now need to refer to as) sustainable sanitation. The trick is for places currently lacking any effective sanitation to skip over the "step" manifested by legacy systems and, like many have done with landline versus cellular technology, go right to sustainable solutions. In this way, the last thing I think we should be dong is importing legacy sanitation technology to the rest of the world.

KaiMikkel wrote: Well this is thoroughly depressing.

I'm therefore glad to hear from you that Sweden and the rest of the EU does't experience these realities and that your sludge is so pristine that its perfectly safe to apply it to farmland. You and your fellow residents are quite lucky in this regard, no?

Finally, how tragic that so many of the world's economically disadvantaged find themselves eating food grown in wastewater. Again, more proof that the last thing we should be doing is continuing the build-out of legacy wastewater systems. They are ineffective and not sustainable so why again are we promoting them in a forum titled "Sustainable Sanitation"?

Well faecal sludge applied to land in Europe is a) tested and b) risk assessed. So yes, in general, treated sludge is safe to apply to land.

I share your worries about the mixing of industrial wastes with faecal wastes and the huge amount of water that the system required. There are also potential environmental problems due to losses from agricultural fields - although these are obviously not only related to human faecal wastes but animal and inorganic fertilisers as well.

But to say that dry toilets are somehow safer than functioning sewage treatment works is to make this argument a tautology. Monitored and functioning sewage and treatment systems in Europe (and I assume North America) work very well and produce faecal waste which is measurably safe from pathogens. This is one of the reasons we do not have endemic faecal pathogens and why we do not have high levels of faecal infections in Europe. It happens, but nowhere near as often as those infections in other parts of the world.

Of course there are problems with trying to import these ideas to other parts of the world. A non-functioning sewage treatment works is less than useless. Sewers with infrequent water flushing can make problems considerably worse. But that is nothing to do with a fundamental problem with the system of sewage treatment and everything to do with a lack of funds, knowledge and infrastructure to keep them working.

And, of course, in many developing country situations discussed here there is not so much mixing of human faeces with other industrial pollutants which can cause problems anyway.

Note by moderator: the posts in this thread prior to 12 Feb 2015 were originally in this other thread which was discussing whether the wastewater reuse scheme in Braunschweig, Germany could be called ecosan or not.

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Well this is thoroughly depressing.

OK, while I'm in full agreement that we need to clean up what currently ends up in sewers, in the United States (where we absolutely do not operate on the precautionary principle and instead cling to both the "dilution solution" and the concept that "the dose makes the poison") this will never happen, at least not until the chemical industrial complex succumbs to the realities of living on a finite planet.

In the United States, industry is permitted to dump almost anything it wants into public sewer systems and this won't change (because we won't give up what industry produces) until, again, the current system collapses under the weight of climate change and/or peak fossil fuels.

www.sludgefacts.org/Ref125.pdf

Amidst the relentless drive in the U.S.A. to land apply sludge (even though we know full well what it likely contains thanks to the results of EPA's 2009 Targeted Sludge Survey) there are countless local examples of grassroots groups hard at work attempting to ban the practice. Most troubling, however, is the associated push to retrofit existing WWTPs or open new privately-owned facilities that are able to meet the requirements to produce Class A sludge (the later coming in response to the fact that municipalities are struggling to maintain public systems). This dewatered and pathogen stabilized form of sludge is able to entirely circumvent the regulations that limit where and and what quantity it can be dumped. As a result, this material is quietly ending up more and more in consumer fertilizer and soil amendment products which are increasingly being applied pretty much everywhere that we've historically applied "compost".

In the United States, management of sludge is increasingly falling into the hands of a smaller and smaller number of growing for-profit corporations replete with shareholders who only care about the bottom line and skillful PR departments that live and breath greenwashing.

And to your point that, "...much of the toxins are already in [my] body," the fact that we are awash in a chemical soup hardly justifies adding to this burden through the indiscriminate dumping of toxic sludge (or effluent) on agricultural land and/or elsewhere. Following this logic its OK to contaminate everything everywhere because its already polluted. Where does that lead exactly?

I'm currently reading a terrifying expose written by a former EPA official (along with the help of a writing assistant) called "Poison Spring: The Secret History of Pollution and the EPA". If there was ever a call to action to upend the way we currently operate this is it and I encourage you to read it to understand what we're up against here in North America. But, again, until the overriding system crumbles, I have serious reservations about dumping sludge anywhere other than in a lined and monitored landfill. And regarding landfills (what I view as the best-worst option) NYC does not landfill all of its sludge as you seem to think. Some portion of it ends up undergoing lime stabilization in facilities located in Pennsylvania and Colorado (!) this portion then being applied to agricultural land (somewhere).

www.nyc.gov/html/dep/html/wastewater/biohome.shtml

www.nyc.gov/html/dep/html/wastewater/wwsystem-biosolids.shtml

So, while you view this process as "reuse" (deceptively termed "beneficial reuse" in my country) I and many others view it as nothing less than the export of a toxic legacy typically to low-income rural communities that lack the representation to effectively combat it. I am therefore truly baffled that anyone finds it acceptable to refer to dumping toxic sludge on land as "ecological sanitation". Again, there's nothing "ecological" about the systems that create sludge and there's nothing "ecological" about dumping sludge on land, no matter how we spin the concept. Moreover, in my view, its fiduciarily irresponsible given their utter lack of resiliency to spend public money in patching up these failed systems.

As I've written elsewhere before, sludge is a symptom of a disease and that disease is our using water to transport human excreta (and everything else that's poured down drains and flushed down toilets) to somewhere else for someone else to deal with. Rather than attacking the root of the problem (the systems that facilitate the production of sludge) we mask this disease by employing a host of "out-of-sight, out-of-mind" tactics that combine to effectively kick the can down the road for future generations to deal with our mess. These tactics include continuing to sewer communities, exporting sludge beyond state lines, refusing to admit on a regulatory level that sludge is toxic waste and should be managed accordingly, refusing to jettison our reliance on ineffective and outdated WWTps and/or refusing to deploy truly ecological alternatives (like waterless toilets, onsite greywater systems and onsite rainwater harvesting and storage).

On a personal level, I just looked out the window of the home I am currently house-sitting and observed a gardener spraying glyphosate on the cobblestone street not ten feet away. Close by there's an activated sludge WWTP (located a soccer field's width away from where I sit) that makes living in this property with the windows open during a westerly breeze impossible. It also discharges a constant stream of treated effluent right into a freshwater lake, the shore of which is located approximately two hundred feet from where I sit. Likewise, reliable studies show that the water table under this house has dropped 250 feet in the last decade and yet I don't know of the existence of even one dry toilet, one rainwater harvesting system, one low-flow showerhead or one low-flow aerator in this entire town. The river that supplies the aforementioned lake runs a gauntlet of industrial producers and agricultural land on its way here. People here prefer as a result to pull water from the ground (mistaking it as a cleaner supply) rather than take advantage of the surface source feet that exists feet from their homes. This is my experience (and the experience of many, many others). I'm therefore glad to hear from you that Sweden and the rest of the EU does't experience these realities and that your sludge is so pristine that its perfectly safe to apply it to farmland. You and your fellow residents are quite lucky in this regard, no?

Finally, how tragic that so many of the world's economically disadvantaged find themselves eating food grown in wastewater. Again, more proof that the last thing we should be doing is continuing the build-out of legacy wastewater systems. They are ineffective and not sustainable so why again are we promoting them in a forum titled "Sustainable Sanitation"?