Dear Kevin and others

Calculation is perfect. In fact I did not calculate office space. But it is required.
In India, as on date, there is not a single project completed at town level for septage management. First project has just been sanctioned for some town in the Rajasthan State, funded by ADB and State Government. I’ll be involved in that project. One RFP for another project on septage management for a few towns in the same state, funded by the ADB, BMGF and State Government, has been issued recently. Last year a similar project for Warangal town in Telangana State was funded by BMGF to ASCI, Hyderabad. I prepared drawings etc. The project has not been implemented so far. In the absence of technical data based on local conditions, it is a bit difficult to prepare actual drawing. Load of sludge drying bed @200 kg/m2.year is taken in designing, as you also mentioned. BOD of filtrate- an important parameter, is not known. TS is also not known. However, we take higher values in designing.
In designing filtration beds and treatment chambers, one major challenge is that actual quantity of septage to reach at the site is expected to be much lower than the calculated quantity. The reason is simple- calculation is based on 2-3 years cleaning interval of septic tanks. However, in practice people get septic tanks cleaned only after it is completely filled and there is blockage in flow of water from toilet pan. Normally it takes 5 years or more, depending on the size of the tank, to get it cleaned. In such case there would be unnecessary requirement of land. However, quality of treated water would be much better due to higher HRT in different chambers.

Regards
pawan

Dear Pawan and others

Here are my assumptions and a summary of my calculations for my assessment of the area needed for a conventional 'low tech' septage treatment plant. The calculations are approximate and Pawan is right to say that the calculated area is probably on the high side - I was being quite generous with my calculations as I did not want to be seen to be slanting the calculations to favour this approach.

I have already briefly described how I arrived at the figure of 40m3/d of septage to be treated so will start with that figure. My calculations also showed that a high proportion of this septage would be supernatant water so I have assumed a 2% solids content by weight.

Other assumptions are as follows:

Sedimentation tank area calculated on a flow figure intermediate between instantaneous discharge from a single tanker and likely maximum hourly rate of discharge. (This could be refined but does not greatly affect the calculated area)
Anaerobic baffled reactor area assumed - this could also be refined but again does not make a big difference
BOD removal 30% in hopper bottomed sedimentation tanks and 70% in ABR
70% of influent suspended solids reaches sludge drying beds
Area of facultative pond calculated using Arthur's equation = Load (kg/ha) - 20T - 60 where T is the centigrade temperature - which I would normally assume is the average temperature over the coldest three months of the year. For this calculation, I assumed a design temperature of 20 degrees centigrade - it would be higher in Indonesia, the Philippines and West Africa and somewhat lower in northern India and other places where there is a relatively low winter temperature.
Loading on sludge drying beds - 200kg dry solids/m2.yr
I did not calculate the area of maturation ponds required but assumed that this would be the same as that of the facultative ponds - this is almost certainly an overestimate.

Based on these assumptions, I arrived at the following areas:

Inlet works, including screening and space for trucks to turn and back up 150m2
Hopper bottomed sedimentation tanks (2no 4m x 4m + civil works 50m2
Anaerobic baffled reactor 150m2
Facultative ponds 500m2
Maturation ponds 500m2
Sludge drying beds (560m2 + allowance for dividing walls 600m2
TOTAL AREA FOR UNITS 1950m2
In my original rough calculation, I assumed a further 50% for circulation, office building etc, bringing the total area up to just under 3000m2. This could probably be reduced to say 25%, reducing the total area required to just under 2500m2.

I would stress again that these are approximate calculations, intended only to get an idea of the order of magnitude of the area required I am intending to refine them, and will eventually hope to share the refined calculations on the forum.

Any feedback on this would be welcome.

Dear Kevin

Your detail description on septage is very informative and useful. You are requested to kindly elaborate the required land. You mentioned that for 40 cum sepatage daily, total land requirement would be of the order of 3000 m2. It appears too high. What would be number and size of filtration beds (planted and unplanted)? For filtrate of less than 40 cum daily, land requirement for anaerobic sedimentation tanks, facultative and maturation ponds should not be so high. Such filtrate has very high BOD. If there is any published results, you may like to share.
Regards

Pawan

Thanks to Elisabeth for the various links, giving further information on the Janucki omniprocessor. The links do provide information that helps to build up a better idea of what is happening and the objectives of the omniprocessor initiative.

Here are some points that may help the analysis. First, the population of Dakar in 2011 was 2.574 million From Tremolet Consulting report - tremolet.com/sites/default/files/downloa...FinalReport_WP4_.pdf. About 60% of the population was served by septic tanks or pits so the total potential population served by on-site sanitation facilities was just over 1.5 million. The total estimated septage production from this population was 1,017,842m3 per year, which works out at about 660 litres per person per year. (To put this into perspective, per-capita sludge accumulation rates in pit latrines in Africa are generally in the range 25 – 75 litres per person per year and the corresponding figure for Indonesia is less than 25 litres per person per year). The explanation for the high figure in Dakar appears to lie in the fact that much of the 'septage' removed from tanks is in fact water. (Presumably because of the high water table) The images in the video contained in the Gates blogspot referenced by Elizabeth confirm that the septage is indeed very watery. I would expect the moisture content of this septage to be up around 98% or even 99%.

According to the Janucki website (janickibioenergy.com/s100.html), the omniprocessor used in Dakar is of the S100 type. The website states that this has a capacity of 12.3 cubic metres per day and requires a moisture content not exceeding 84%. The larger and more recent S200 has a capacity of 92.3 cubic metres per day and the Janucki claim that it works with sludge water contents up to 100%. However, it requires a minimum dry solids weight of 9 – 11 tonnes per day. Assuming a generous 2% solids content in the Dakar sludge, 92 cubic metres of sludge would contain about 1.84 tonnes of dry solids per day and this will be the constraining factor unless another fuel such as solid waste is added to the omniprocessor. In theory, the S100 should not work with the moisture contents found in Dakar so it would be interesting to know (a) whether this was in fact a problem and (b) if so, how it was overcome.

To further complicate things, ONAS, the agency responsible for faecal sludge management in Dakar gives different information on its website (www.pseau.org/outils/ouvrages/onas_boues_mag_n_3_en_2014.pdf) This states that the omniprocessor deployed in Dakar can handle up to 450 cubic metres of raw sludge per day, with an average solids content of 1.5%. The ONAS site gives a similar figure for power output to that quoted by Janucki, which tends to confirm that it is indeed and S100 type, However, the information on the throughput of sludge is very different. This has important implications for planning - I would assume that the manufacturer's figure is correct.

This brief review of some key design parameters shows that there are some inconsistencies in the information that is available on the Janucki omniprocessor. It would be good if someone from Janucki, Gates or ONAS could provide some further information to clarify the situation, clearly set out the design parameters and say something about how experience in the field has either confirmed or led to modification in these design parameters.

One last point. I said in an earlier post that I would provide some information on the land requirements for a more conventional approach to septage treatment. I have made some rough calculations, based on an assumed 100,000 population, 80% with on-site sanitation, of which 50% are availing of regular (once every 4 years) pit/tank emptying services. These assumptions suggest that the amount of septage to be dealt with would be of the order of 40 cubic metres per day. This would include a large volume of supernatant water and so would be fairly weak and watery. I have assumed septage reception and screening, followed by hopper bottomed sedimentation tanks, an anaerobic baffled reactor and facultative and maturation ponds, with sludge drying beds for solids removed from the sedimentation tanks and baffled reactor. My calculations suggest that the land requirement would be of the order of 3000 square metres (0.3hectare), something over 10 times the footprint of the omniprocessor but still not very large. This arrangement is not electricity dependent. Most of the land is required for the ponds and drying beds and it would be possible to look at alternatives to both – perhaps high-rate filters to further reduce the liquid strength and planted drying beds, which require less area than unplanted drying beds.

Finally, it would be interesting to know what arrangements are in place for an independent assessment of the Dakar initiative. This is presumably fairly high on the list of priorities for the BMFG. If so, would it be possible to have an idea of when a detailed assessment will be generally available. This should, of course, include assessment of running costs, income from the sale of electricity and water and a discussion of problems encountered and the extent to which it was possible to overcome those problems.

Dear Andrew, Kevin and all,

I am following your questions and answers about the Janicki Omniprocessor with interest, please keep the discussion going.

I saw this image in the Guardian today - so a prototype of this machine is now in Dakar, Senegal:



Source:
www.theguardian.com/global-development-p...s-senegal-sanitation

(I have just mentioned this article also in another thread about use of mobile phone ICT for sanitation: forum.susana.org/forum/categories/197-mo...nitation-esani-msani)

Section from the article (nothing new to what we discussed above, I think):

Designed by Janicki Bioenergy under the backing of the Bill and Melinda Gates Foundation, the $1.5m omniprocessor dries faecal waste and burns it, to drive steam through turbines to produce electricity. Meanwhile, the steam produced when drying the sludge is filtered, condensed and treated to produce drinkable water.

The omniprocessor can produce a net power of 250KW of electricity – which could run 25,000 households – and around 80,000 litres of drinking water per day (enough for about 35,000 people) – which could be sold to the national grid or bottled like mineral water.

While Curtis welcomes this innovation in the much-neglected field of sanitation, she remains cautious about the complexity of safely collecting and transporting human waste from pit latrines to the plant.

Many of these pits are down very narrow alleys, inaccessible to emptying trucks,” says Curtis. “The waste processing plants are far away as nobody wants to live anywhere them – so you need a solid business model for waste collection.”

It will be interesting to know what comes out of the trials in Dakar!

Oh wait, I just discovered that the man himself who has done so much to raise public interest in the sanitation crisis already, Bill Gates, wrote about the omni processor on his blog. This is exciting! (OK, yes, he probably has staff members who wrote the article, but still).

See blog post here:
www.gatesnotes.com/Development/Omni-Processor-Update

Note the first paragraph:

You may recall that the JOP takes human waste and turns it into drinking water, electricity, and ash. (It is actually one of several Omni Processors being developed that treat human waste and produce something of value.)* It’s tempting to focus on the drinking water, for obvious reasons. But the goal is not to provide water. The goal is to dramatically improve sanitation for all the cities in poor countries.

This short video linked from the Bill Gates blog is good and worth watching ("Omni Processor in Senegal"):



You may or may not agree with the omni processor being a signification piece of the puzzle. But just because the name of Bill Gates is connected to this R&D work, the video already got 40,000 hits within 2 days of being uploaded! Our "normal" videos are lucky to get 2000 hits within six months... Whatever increases public interest in sanitation around the world, has got to be a good thing (only danger might be that unrealistic expectations could be created that the solution is really simple and that you only need the right technology to fix everything...)

Regards,
Elisabeth

* I used to think that this machine is "the omni processor" but I have since learnt that it is only one example of "an omni processor". There are other examples, too. See this Wikipedia page which explains it:
en.wikipedia.org/wiki/Omni_Processor

As expected, check out the spike in click rates of this Wikipedia article now that it's in the news again: stats.grok.se/en/latest/Omni_Processor
I didn't create the page but I made substantial improvements to it, see history page here:
en.wikipedia.org/w/index.php?title=Omni_...essor&action=history

Apologies for my delayed response to latest posts on this topic.

The reasons why septage treatment plants fail are complex and vary from country to country. However, based on field studies in Indonesia and review of secondary information from the Philippines and other countries, I would say that the following are important:

1. Overestimation of demand, resulting in plants that are grossly oversized. This is a common problem in Asia and I suspect may also be an issue in Africa.
2. Poor design details, which make it difficult for operators to carry out routine operational tasks. The biggest problem here is usually desludging. This is a task that requires large effort at infrequent intervals and often gets delayed or neglected, with the consequence that facilities fail or underperform.
3. Selection of inappropriate technologies - in particular those that require regular inputs of chemicals, highly trained operators and, most crucially, a regular electricity supply.
4. Inadequate funding - septage treatment plants do not recover their operating costs and need to be subsidized from charges for septage collection and transport.
5. Inappropriate management systems - perhaps the most serious constraint on good operation and maintenance. This relates to the low priority that most municipal decision-makers give to wastewater and septage management. This, in turn impacts on the availability of funds and the ability to attract and retain appropriately trained operators. (Most operators are paid at the lowest rates and have no capacity to operate anything other than the most simple plants).

In my opinion, land availability is not a huge issue and land requirements can be reduced by careful design. There is something on this in my recent WEDC Conference paper but I will try to put together some notes for this forum.

When assessing the suitability of a technology such as the Omniprocessor, it will be important to consider (a) the likely loading and its relationship to the service area (b) the reliability of the electricity supply and (c) the ability to recruit, train and retain appropriately skilled workers and (d)ongoing operational costs in relation to likely income. I think that the onus is on those proposing new technologies to show how its use will be compatible with the likely loading, the availability of a reliable electricity supply, the finances available for operation and maintenance and the systems to recruit and retain effectively skilled workers. It is always good to remember Eric Dudley's two principles - 'how does this technology solve the problem?' and'what might go wrong?'

Even though mechanically it is possible to make drinking water out of feces it is illogical to utilize copious amounts of water to flush organic resources from the toilet and garbage disposal to some far away separation facility when utilizing a fraction of the amount of water and separating the blackwater from the remaining greywater onsite with proven decentralized technologies with .2 of a gallon of water per flush and a small amount of water for the separated garbage disposal, 100 percent of those resources can be converted into carbon dioxide and water vapor and reusable liquid and solid soil compost with the greywater treated, filtered, ozoned, carboned and reverse osmosis recycled into drinking quality with a 95 percent recovery is possible without the yuck factor.

Therefore, separation reduces the need for water, separation mentally is acceptable and separation makes it easier doing it onsite.

The immediate initial assumption that human excrement and organic kitchen scraps are WASTES needs to be re-evaluated utilizing separation wastewater plumbing and treatment systems and Mother Nature's natural methods of aerobic decomposition and vermiculture.

Once we understand that the WASTES we are trying to dispose/get rid of are actually liquid and solid gold for total recycling into food production instead of oil will we be able to comprehend that the remaining greywater can be recycled by getting the majority of the problem out of the water with separation, not to mention reducing the need for water immediately by at least 40 percent.

Please Google Equaris Corporation, AlasCan, WCCO TV NEWS PROJECT ENERGY, Don Shelby, Afton, MN.

As Bucky proclaimed, we need to design PRODUCTIVE not CONSUMPTIVE dwellings to be sustainable with technologies logically treating entities separately as they were and are created.

Clint

HI Kevin,

Agreed, it is important to look at the entire sanitation chain and I think the foundation is doing that. Besides the Omni-Ingestor project (collection and delivery) and the Omni-Processor (solids processing) they are investing in technology and testing of new service models, improving policy and regulatory conditions, looking at ways of increasing demand for sanitation services, and engaging manufacturing partners with sufficient capacity.

The foundation’s initial approach for the RT, OP, and OI was to cast a wide net and try to identify novel technologies that might someday become viable means of improving sanitation in urban settings. They are gradually focusing on fewer technologies that they consider viable.

Regarding the OP: I’m not at liberty to disclose the Omni-Processor RFP but the idea was to develop means of processing combined fecal sludge and solid waste in a small facility serving 1000 to 100k people in dense urban settlements. The processed waste could result in energy, fertilizer, or soil amendments that would generate revenue and offset the waste collection costs. The Janicki OP, which isn’t the only OP project, may not adhere to the original RFP but that isn’t shocking as this is an R&D effort. As you suggest, the problem may have been adjusted to suit the technology. Again, not shocking, as there is a learning curve associated with new projects, new players, new objectives, etc.

In response to your second question: does the OP offer a better response to the problem than other technologies? I don’t know. There will undoubtedly be cases where the answer is no. But there may be cases where the answer is yes. If the foundation and Janicki think they are on a path to a solution, it is their prerogative to follow it. The S100 and the S200 won’t be the only solutions or the final solutions. Ultimately, the goal is to have commercially viable, sustainable products and product development doesn’t just end…it’s a process and the Janicki OP is a step in that process.

Here’s a question for you: If there are simpler and cheaper technologies available, why are they not being utilized? Can they fit in one or two 40’ shipping containers or do they require large plots of land? Can they be located in urban areas to reduce transportation costs? Do they generate revenue? If not, what compels their adoption and motivates a private enterprise to make the investment and maintain the equipment. Is the expectation that a government agency will operate the facility? That seems to have a poor record of success.

Regards

A couple of further points.

Andrew says that the omniprocessor is not meant to deal with faecal sludge collection and transport. OK, but it is important to look at the whole sanitation chain - there is ample evidence from Asia that most faecal sludge treatment plants are underloaded and it is important to at least have an idea of how the sludge is going to get to the plant at the design stage.

Andrew - you say that the solution must address the problem statement. The obvious follow up question is 'what is the problem statement for the omniprocessor?'. The website focuses on electricity generation but Pawan has suggested that the financing and operational costs are likely to exceed the income generated from selling electricity.

The capacity of the S200 is said to be about 92 cubic metres per day. This is quite a large volume - few septage treatment plants in medium-sized towns receive this volume although the volume would be increased if scheduled emptying could be introduced. There have been attempts to do this but there is still a long way to go before such attempts can be deemed successful. Regardless of this, the minimum dry solids required 10 - 11 tonnes per day, is much higher than the amount reaching most septage treatment plants. The website does say that additional dry combustible matter can be used to augment the dry matter produced from sludge and so bring the weight up to the minimum required by the plant. To me, this sounds like adjusting the problem to suit the technology and it would be better to start from the problem and explore technologies to solve the problem. Simpler and cheaper technologies are available so why go for something that is expensive and relatively complex?

So, I come back to my question above - 'what is the problem statement?' and add a second 'in what ways does the omniprocessor offer a better response to the problem than other technologies?'

Dear All
Omni Ingestor (OI) and Omni Processor (OP) by Janicki were also demonstrated during the last exhibition on RTTC organized by BIRAC/ BMGF in Delhi in 2014.
Cost of one unit was much more. It was higher than the annual budget of Sanitation Head of most of the Local bodies of small towns. Cost of electricity produced per day from such unit was calculated to be much lower than the cost of interest (as per standard Bank interest rate) on the cost of the unit. Further, costs of maintenance and collection / transportation and manpower are extra. Therefore, income generated from the system can’t meet even the interest amount of the bank, if the project is funded by any Bank. The cost is calculated when the system runs into its full capacity, i.e., loading of 35 cum of septage per day. Such volume is quite large.
The technology does not appear economically sustainable.

Cheers

Pawan

Hi Kevin,

I'd like to point out that the Janicki OP is not intended to solve the problem of fecal waste collection and transport. The technology being developed in the Omni-Ingestor project is intended to deal with those issues.

While I'm a fan of solving problems using the simplest technology possible, the solution must address the problem statement. The foundation is attempting to develop technology for specific applications, namely sludge management in densely populated urban settlements. For a wide range of reasons, traditional means of waste management are not working or are not implemented in this market.

Cheers,

Andrew

Dear all,
As Kevin points out, am really looking for the gap that the omniprocessors will fill in my setting- Uganda (a developing country).
Most of the solid waste is collected and treated on site using septic tanks and soak pits if lucky and few people are connected to the central sewer system. Majority of the population uses pit latrines which are not even lined so there is no option of emptying them but excavating a new pit.

How do they plan to get the resource i.e sludge they need for there processor? Except from the treatment plant were volumes are low how do they plan to roll it out into the communities?

How do they plan to distribute the energy they plan to produce during the burning of the waste if any is left?

Like Kevin pointed out, how will you distribute the water collected?
A heads up here: consider the acceptability of this water in the community!!!! You may produce water that no one wants to come near!!!

And what are the final implications of the processors as compared to what the community currently have?