Our Phase I final report is available for reading if anyone is interested. You can find it here .

The earlier pictures and short video clip were experiments to determine vortex shapes and to determine the feasibility of sustaining an "air bearing". This was done without a housing. Some of our earliest experiments and concepts were carved out of wax. This proved to be a bit tedious, and we quickly migrated to 3D printed prototypes.

The video below is of our first successful proof of concept "liquid ring type compressor" utilizing an air bearing and wear compensating features. This worked well.



However when we scaled the unit up in size by a factor of four we experienced unusual frictional challenges. For convenience we spun the drive shaft of the compressor with a cordless drill. The 3D rapid prototypes had somewhat rough surfaces and when we experimentally operated the compressor we hoped the roughness would be smoothed out by self-machining of the wear surfaces. This sort of happened, but in a few minutes we started smelling ABS plastic,(the plastic used in the 3D printer),escaping out of the air bubbles generated from the compressor. Shortly after the smell became evident the distorting impeller caught one of the internal surfaces and the drive shaft twisted up like a garage spring, it spun the cordless drill backwards, and slung the drill's battery across the room.

This setback was caused by limitations in the prototyping method. We have since added some "idealized" bearings, and we have made a test model for the bearing assembly that seems to work well. The bearing design would be nearly immortal even in harsh wastewater conditions. The impeller now has low enough friction if can be spun by simply blowing on it. So the compressor's startup load is going to be very minimal.

While it is impossible to get around some of the physics of fluid flow, we have gone a long ways toward an increasingly efficient compressor with every incremental design improvement thus far.

We are currently in the process of making some other changes to the scaled up design and we will start printing the new design later this week.

Thanks for allowing us to share our journey!

Duvon McGuire
New Life International

For ATADs look for example here: forum.susana.org/forum/categories/105-pr...removal-final-report

But you will also find a lot of details on the web with a Google search.

Julius,
Thanks for the feedback. The points you are making regarding the horrendous energy inputs of conventional waste water treatment plants not necessarily passing a "sanity test" are quite valid. I have much the same criticism about simply "replicating" conventional stuff on a small scale. This was the problem with the first "miracle box" I inherited near the beginning of this journey. To operate it on a small scale was to create more than a $100 per month electric bill to simply drive the compressor.

One of the challenges of this research effort is how to talk about its current state of development and where it might ultimately lead. The story I shared was some personal background of where we came from, and not necessarily where we are going. The story is more about historic steps that lead us to where we are today and the realization that there is a significant need for affordable and sustainable compressed air. Thus the "idealized" part of the research is the quest for how to deliver air to a desired depth of fluid for whatever strategy where it might be needed. The original discussions about idealized sanitation with the international students put no restraints on the mechanisms and processes. As such I still do not wish to over restrict our future efforts between for example "wet" versus "dry" approaches to sanitation. The main part of the story and pictures come from our efforts to do something six years ago in the shadow of crippling regulations that overly restricted experimenting with "off-the-beaten-path" stuff.

Zooming up to a view from 40,000 feet: Ultimately the cycle of buying overpriced fertilizers laced with hazardous waste to try to grow food on depleted soil, and then dumping the mess into the environment in polluting and unrecoverable ways needs to stop.

As for the "liquid ring type compressor" which is the focus of this research, the name itself is a little bit of a misnomer. But, for lack of a better description, when I was applying for Phase I of the grant, "liquid ring type compressor" was the best I could do. In reality what we are working on is a "disruptive innovation" to both conventional liquid ring compressors as well as conventional compressors. The "disruptive innovation" description is one borrowed from Clayton M. Christensen from the Harvard School of Business. To view what we are doing through the lens of "disruption", the compressor innovation we are developing in some respects is "not-good-enough" or "worse" than established compressors. BUT, it is "good-enough" for the low end application for which it is designed. What we are developing will probably never compete with something that can air up a tire.

Energy costs money and there are limitations on its availability. As such what we are doing utilizes every bit of the energy available from a prime mover such as a windmill or even manual input; and it has as a goal of delivering ALL of that energy at the desired depth in a fluid in the form of compressed air along with all of its embodied frictional energy exactly where happy bugs need it. I am interested in hearing more about your comment regarding "auto thermophilic aerobic sludge desinfection". I was not familiar with this particular terminology, but the descriptive title does sound promising as a good first approximation where this technology might be field tested.

If energy comes from windmills, or other readily renewable energy, and we can concentrate all of that energy and air more than a meter below a fluid's surface, might this find interesting utility?

Blessings,

Duvon McGuire

Nice story, however I fail to see how you want to create an "ideal" sanitation solution by replicating a traditional WWTP on a smaller scale.

Those are in my opinion a technological dead end and will always be hampered by the aeration energy requirements (today they use highly efficient turbine compressors, with high oxygen transfer membrane aerators and even recover energy from sewage bio-digestion, and the energy requirements are still driving operators mad).

More promising is probably the Anammox process ( en.wikipedia.org/wiki/Anammox ) but in the end it is quite insane to spend a lot of energy trying to get rid of all the organic carbon and the nitrogen compounds, which where produced using a lot of energy in the first place (photosynthesis and fertilizer production).
And I am not even mentioning the madness that is diluting all that perfectly fine drinking-water with feces to flush them down the drain.

Waterless (or at least conserving) source separation and heat disinfection of the potential contagious solids is a working and simple solution, and retains the valuable fertilizer as a side effect. The problem is just finding a way to make it work similar to "flush and forget" or as you put it "maintenance free" in a sufficiently cheap way to accommodate to the human nature of not wanting to deal with one's own remains.
It's as simple as that, no black box needed

The compressor you are trying to develop might be a nice solution to run a "auto thermophilic aerobic sludge desinfection" unit though, which uses the air only to supply the thermophilic bacteria in a liquid composting type of setup to heat up the sludge to a sufficiently high temperature to kill all pathogens and not to remove all those valuable nutrients from the sludge.

In order to more fully understand the “Overcoming a Strategic Roadblock to Idealized Sanitation” effort, I’d like to first pause and connect a few dots.

Several years ago my wife and I had the privilege of teaching a water purification class for international students. The students were actively involved in community development work, and they came from a wide variety of developing world countries. The training practicum was directed specifically to water purification, but the discussion quickly expanded in all sorts of related directions. The emerging discussions started addressing the challenges of water scarcity, water pollution, irrigation, water quality, water ownership, hygiene, food security, and when we got to the subject of appropriate sanitation, the conversations began to stall. We were tripping over the subject of sanitation; there were too many complex and varied needs, too little money to adequately address the challenges, and no clear direction as to how to resolve the overwhelming issues.

It was during these discussions I was first exposed to the degree to which the developing world’s subterranean water resources were being trashed by pit latrines. Under the flag of “sustainability” some pit latrines were being dug down as deep as 80 feet! In most cases the latrines were dug during the driest part of the dry season and people simply dug until they hit water and could dig no further. In order to prolong the investment in the above ground structure the hole below got bigger and much deeper. I have spent much of my life interacting with the developing world, but this was a startling revelation. I knew latrines had problems but suddenly I started to realize why some drinking water wells had high nitrates when there was no indication of commercial fertilizers being used in the surrounding countryside. I recalled a situation in Asia where people gave up trying to disinfect water in a well because it smelled like sewage from a public latrine hundreds of feet away. I quickly realized that if pit latrines were the state of the art in “safe and sustainable sanitation”, we were NOT going to join the parade.

During break my wife and I took some large flip chart poster paper and began sketching out an idealized community development dream. There were many interconnecting lines and dots everywhere and when the international students returned from their break, we resumed the discussions. One after another the students each commented that this was the answer, this is what is needed, and this is truly sustainable. Without getting too caught up in all of the details, the summary went something like this:

We start our community around securing an adequate source of water. We take this water and we disinfect it so that not only is drinking water in abundance, but it can be safely used for other applications such as cooking, bathing, food preparation, etc. When the people are finished with the water, we take the waste water and we “appropriately treat it”; and I drew a large square that I called “the black box” - something yet to be determined. I then drew a line out of the “black box” and I added another step: safe disinfection of waste and waste water. We then directed the flow to safe disinfected water to produce safe food for the people, and so on. For those of you from overseas who are not familiar with the “black box” colloquialism, it is a reference to a system or process that does something, but you cannot readily see into it or intuitively understand how it is going to work. Often something that is proprietary whose functionality is hidden or disguised can be referred to as being a “black box”. In this case the “black box” was technology and processes that could safely treat waste in a sustainable manner and at the same time generate value without doing any secondary harm.

As we left the water purification and disinfection training session, I could not stop thinking about that wonderful community development dream. And I kept grappling with that one major shortcoming: “the sanitation black box”. I had yet to be introduced to the concept of “reinventing the toilet”. My thoughts were directed more toward rethinking what happens downstream from the toilet.



We live in a rural area in Southern Indiana that is still, and probably forever will be, on septic tanks and drain field laterals; (the only possible exception may eventually be mine). During my lifetime we have had more than a few unfortunate displeasures: digging up septic disasters for replacement, upgrades, or simply pumped the sludge out of them. At no time did these exercises go quickly, or inexpensively. They always cost more than expected, and they were always at the worst possible time and more inconvenient than one could imagine. I vowed that if we ever built a house we were going to design a septic system that would never need to be pumped out! EVER!!

At the time the proclamation of owning a “no maintenance septic system” was based more on wishful thinking than solid technical inspiration. But some unexpected events seemingly from nowhere began to spark the missing technical inspiration. This begins a still unfolding story. We spend most of our waking hours trying to help the needy in the developing world with development ideas that typically start with safe water. As such we have not attempted thus far to commercialize our inventions or seek a lot of publicity. That being said, one of our volunteers, without our permission, published a bunch of information about what we were doing in a farm magazine with National distribution. We told him to NOT do it. He did it anyway. And just what we feared happened. We began receiving distracting inquiries from all over the country. People wanting us to do nonprofit pro-bono disinfection of chicken water, livestock water, contaminated wells, rotten egg water, etc. However, one inquiry from a startup, landed almost squarely in the middle of the flip chart from our discussions with the international students. The inquiry wanted us to disinfect the waste water that came out of their wastewater treatment “black box” which was designed to replace conventional septic tanks.

We sent one of our disinfection units to them to experiment with wastewater disinfection and it worked perfectly. But, they wanted the system more automated. In the meantime they sent down a large three compartment tank for us to experiment with. (The magical sanitation “black box” we had only dreamed about.) We were excited about how revolutionary this whole effort was going to become.



The death of the “black box” occurred on several levels all at once. The first blow to the effort was the disintegration of the startup that provided the “black box” alternative to the septic system. To this day I do not know what happened, but the infrastructure of the startup dissolved. The second part of the demise came with the realization that the “black box” was anything but maintenance free. If someone bought one of these things it required a monthly maintenance fee and monthly inspections. If the system was not adequately maintained: backed up toilets with no easy remedy was soon to follow. Worse from our standpoint, the design did not lend itself very well to reliably being disinfected downstream.

But the final technical discouragement, which connects us to this current research project on liquid ring type compressors, was the realization there was a huge energy input to operate the unit. If nothing broke down, the electric bill alone was going to run somewhere between $100 and $150 PER MONTH!! No way! We were putting all sorts of energy saving ideas into our new house and I was not about to use significantly more electricity to run the waste treatment component of the house than the entire rest of the house combined (even if we left every single light in the house burning). As you have perhaps guessed by now, the number one energy killer of the system was the air blower/compressor that operated the aerobic chambers of the “black box”.

I finally resigned myself to purchase a smaller blower/compressor with less energy demand which would cost about $50 per month to operate full time. But in the back of my mind I thought I might be able to get away from full time operation and succeed with intermittent use. The technical challenges were on their way to being solved, but my personal home project was doomed to die in an unanticipated way.

Armed with a new set of exciting design ideas I headed into town to get a septic permit as a prerequisite for a building permit for our proposed new house. At this point we could almost summarize the exercise as “the end of the story”. The inspectors and those responsible for permits were NOT going to allow me to install something that was experimental without certification. Arguments that we needed to experiment in order to know what to certify went nowhere. Certification for a one of a kind system like I was proposing was going to cost somewhere between $100,000 to maybe over $250,000. I had zero ability to even think about spending this sort of money, the certification was much more than I had set aside for the bulk of the construction of the entire house. Out of curiosity I looked at the proposed certification test methods and I discovered the methods were fundamentally flawed and did nothing to answer the larger questions regarding functionality and appropriateness. I soon realized no one was going to sign off on anything different from the minimal code. I tried different approaches and I saw my exciting design dismantled one feature at a time until there was virtually nothing innovative left.

At some point the voice of reason sort of prevailed on one key person as they realized that I was not attempting to circumvent the codes or take an inferior shortcut. I was shocked, I thought this was intuitively obvious, but someone on the regulatory side actually had this realization. But, there were two things that were nonnegotiable: the wastewater system had to have at least a minimum number of feet of laterals to absorb the liquid effluent, (no creative secondary usages) and coming out of the house the waste water had to enter a conventional septic tank that was at least 500 gallons. They sort of conceded (off the record) that whatever I put in between the septic tank and the laterals was my problem, but in the end, whatever entered the septic tank had to eventually enter the laterals.

This arrangement was not what I wanted, but it was a huge concession and I was relieved to leave the “certification roadblock” and move forward any way I could. I was going to go above and beyond the spirit of the law, but I was not thrilled with the limiting prospects of having a conventional septic tank that might require pumping. I was seriously in search of a septic solution that would not require pumping or other hassles.



We purchase a conventional septic tank that was not exactly “conventional”. My plan was to follow as closely as possible the dream my wife and I had outlined years earlier with the international students. But the lack of freedom was crippling. We started to look at our personal wastewater system as something that might theoretically handle all of the wastewater needs of a fairly large cluster of families or small village. But first something had to be done about that conventional septic system. I went shopping for tanks. I wanted to have a series of anaerobic zones followed by a large tank that would be aerobic, and then I was going to modify the original “black box” that had been given to us and turn it into a disinfection and retention zone before discharging into the distribution box and off into the laterals. In the back of my mind if the disinfection process worked as I envisioned it, I might one day convince the zoning people I knew enough about what I was doing to perhaps bypass the laterals and use the water directly for surface irrigation. But, to help keep the primary tank from filling up with sludge I wanted to recycle so called “activated sludge” captured from the aerobic section and inject it all the way back to where the waste first entered the anaerobic tank.

I discovered the local manufacturer of tanks occasionally made large 2000 gallon three compartment tanks. We modified the baffles in the tank by drilling a hole above the water line through each baffle to accommodate a 1 inch diameter PEX tube to transport the captured activated sludge back to the raw sewage entry point.

We then purchased a 2000 gallon “pump tank” which we modified to serve as an aerobic tank. It also housed the plastic media to foster enhanced bacterial growth. The tank also contained a homemade “burp pump” that could operate simultaneously off the aerator compressor. This effort gave rise to part of our vision for our current research compressor: aeration to create aerobic biological microenvironments and then using then using the air in a “burp pump” to transfer liquids. This strategy extracts or reclaims all of the energy input into the wastewater system. All friction or heat goes into the system as well to help stimulate microbial growth and benefits.

“Let the games begin!” I am still somewhat surprised my wife was game for all of this. We had very little time to install everything while the tanks were still new and before someone might start using the toilets in the house. My wife put on her “let the games begin” shirt and I actually had her help install the components inside the aerobic tank.
The aerator assembly was weighted down with pieces of steel rebar which would also serve as a slow release of iron ions to aid the growth of bacteria. Eventually the 1 inch diameter by 20 foot long PEX tube was threaded through the baffles of the primary anaerobic tank and into the aeration tank where it was attached to the homemade “burp pump” which has no moving parts and operates off, you guessed it, compressed air.

For those who have waded through all sorts of tedious academic toilet data, I would like to share a humorous side story, which was NOT funny at the time. One of the unintended consequences of installing “off the beaten path” innovations in our wastewater system was “delay” in filling the tanks with water. Delay in this context was not getting the wastewater tanks filled up with water before a huge drenching storm poured water on the construction site all night long. The next morning the fiberglass tank (the original tank given to us) floated out of the ground. It looked like some sort of underground ship escaping from a voyage to the center of the earth. The inlet area was still partially buried in what was by then mud, but the other end was sticking out of the ground at about a 45 degree angle.

Fortunately the escaping tank created a path for the flood waters and thus preventing the concrete tanks from also floating. The bad thing was this possibility was anticipated and it still happened. I told the man running the excavator to dig a trench along the tanks to a depth below their bottoms to prevent water from collecting around the tanks and causing them to float. He assured me the trench was overkill and it did not need to be that deep … and that the tanks could not possibly float. He spent the next day shoving gooey mud around and resetting the elevation of the tank such that it would drain. I wish I had taken a picture of the escaping tank, it was surreal.

There are two main prongs to our wastewater system. After we installed the aeration system and the “burp pump” we tested it to assure proof of concept and functionality. We paused on our personal wastewater project for two primary reasons. The first reason we paused is forward looking: in the back of my mind I would like to see biological baseline data collected from the various tanks BEFORE the aerobic system is turned on. And as the system comes on line, I would like to see ongoing data collection that would be predictive and give insights into more advanced and effective designs.

Right now the system has been operating for six years in a passive mode whereby it is in some sort of biological equilibrium. It would be good to know what this equilibrium is, and then to be able to measures biological and compositional shifts with time as the microenvironment changes by intermittent aeration and possibly continuous aeration. I believe intermittent aeration has the potential to alter the aerobic and anaerobic environment in useful ways. As such windmill power for liquid ring type compressors in the developing world context, or even in our own advanced systems such as we have installed is a viable option. And, no, none of my tanks have been pumped out in six years.

The second reason we paused on our personal wastewater systems was we were dissatisfied with the air compressor state of the art and how expensive it would be to operate. This gave rise to our desire to develop a solution that would not only satisfy our own needs for affordable wastewater treatment, but that the solution would be viewed through the empathetic lens of: “if we lived in the developing world, what would we want for ourselves and our family?” We are still working to answer this question. We still remember the exciting discussions with the international students regarding idealized development. And we are still pressing on to demystify the sanitation “black box” that creates truly safe and sustainable systems that fit into a wider panorama of development.

Our efforts in “Overcoming a Strategic Roadblock to Idealized Sanitation” is an important piece to this panorama. The unfolding opportunities from the Bill and Melinda Gates Foundation and the Grant Challenge Programs have been a tremendous catalyst in turning this dream into an ongoing reality. Thank You!! from: Duvon McGuire, Staff, and those we serve!

It's not entirely clear what you want to use this optimized compressor/vacuum-pump for. Is it for aerating waste-water lagoons?

An disadvantage of a liquid-ring type compressor would be clearly that is needs a relatively high and continuous speed engine (best would be probably an electric one) which rules out many application like running it directly on windpower etc.

Interesting project from the point of reducing costs and maintenance though... I looked into liquid ring type vacuum-pumps for running low cost vacuum sewer systems before... maybe that would be an interesting field for you to look into too.

Hello,

This is the grant we are working on here at New Life International in Underwood, Indiana.

Title of grant: Overcoming a Strategic Roadblock to Idealized Sanitation

Subtitle (more descriptive title): Creating Sustainable and Appropriate Technologies with Global Access for Sanitation in Developing Countries with Injection Molding Techniques

Name of lead organization: New Life International, Inc.

Primary contact at lead organization: Duvon McGuire

Grantee location: Underwood, Indiana, USA

Developing country where the research is being or will be tested (if known): Currently testing in the United states. Proposed country for developing country tests will be Haiti.

Short description of the project: The project is to create an inherently low friction "liquid ring type compressor" for waste water treatment in the developing world context.

Goal(s): The goal of this project is to strategically tackle the critical technological roadblock of needed compressed air for “idealized sanitation solutions”.

Objectives:

1. Determine the feasibility of creating a developing world appropriate “liquid ring type compressor/aerator”.
2. Determine whether a liquid ring type compressor can be created such that it can operate in the horizontal plain instead of the conventional vertical plain.
3. Design the resulting compressor/aerator such that it is “designed for manufacturing” and “tool-able” using low cost injection molding techniques to help insure global access.
4. Redefine “appropriate technology” and “sustainability” as something that not only works, but lasts.

Start and end date: November 1st, 2011 to May 1st, 2013

Grant type: GCE Round 7

Funding for this research currently ongoing (yes/no): Yes

Research or implementation partners: None

Links, further readings – results to date: www.waterfortheworld.com/System_Resource...dealized_Sanitation/

Some pictures:
[img size=450x338]cms.icglink.net/files/2341/Image/project1.jpg[/img]

[img size=450x338]cms.icglink.net/files/2341/Image/project2.jpg[/img]

Video about the experiment:



Thank you for taking the time to look at this.

Duvon McGuire