SuSanA - Forum Kunena Site Syndication http://forum.susana.org/ Tue, 23 Sep 2014 04:20:04 +0000 Kunena 1.6 http://forum.susana.org/components/com_kunena/template/default/images/icons/rss.png SuSanA - Forum http://forum.susana.org/ en-gb Re: Nitrification reactor set up - by: winniek http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9953 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9953 [Start of Page 4 of the discussion]


I will start with suspended biomass and ensure the biomass isn't washed out and recycling just incase.
Thanks a lot.]]>
Resource recovery from excreta or faecal sludge Sun, 31 Aug 2014 15:39:31 +0000
Re: Nitrification reactor set up - by: kudert http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9952 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9952 Resource recovery from excreta or faecal sludge Sun, 31 Aug 2014 15:13:12 +0000 Re: Nitrification reactor set up - by: winniek http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9951 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9951 Thanks for the attached and I have already read through the paper.
I was thinking of using this "hybrid membrane-aerated biofilm reactor (MABR) was
used for the nitrification experiment" as i believe i wont have easy access to the Kaldnes rings.
I have seen the reactor but if you have more pictures of it. I would be grateful as i will get a better understanding on the set-up]]>
Resource recovery from excreta or faecal sludge Sun, 31 Aug 2014 15:08:42 +0000
Re: Nitrification reactor set up - by: kudert http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9950 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9950 4+. Since nitrification lowers the pH value, this amount of ammonium is not lost during distillation (except for a very small fraction). I attach a paper, in which we describe the fate of ammonia during distillation in more detail.]]> Resource recovery from excreta or faecal sludge Sun, 31 Aug 2014 14:50:42 +0000 Re: Nitrification reactor set up - by: winniek http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9949 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9949 did you anaylse the effluent N- concentrations, i.e. NH4+, NO2- and NO3- ? is so what was were there.
If the urine was partially nitrified does it mean only 50% of ammonium was converted to N03- . In that case what happened to the rest of the NH4+ when the effluent proceeded to the vacuum distiller]]>
Resource recovery from excreta or faecal sludge Sun, 31 Aug 2014 14:44:08 +0000
Re: Nitrification reactor set up - by: kudert http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9947 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9947
In our current system we use biofilm carriers. The fill rate is about 60%. The biofilm carriers are mixed by aeration and the oxygen concentration is therefore close to saturation. The maximum ammonia oxidation rate is about 400 gN/m3/d. The minimum hydraulic retention time can be calculated based on the ammonia concentration in the influent and the ammonia oxidation rate. For example, if the ammonia concentration in the influent is 4000 gN/m3/d, the hydraulic retention time will be 5 days, because half of the ammonia is oxidized.
The pH has to be kept in a narrow range by adjusting the influent rate. If the influent concentration and the temperature are constant, this can done by hand otherwise you might want to use a process controller, which keeps the pH in a narrow range of 0.1 units by switching the influent on and off. An optimal pH value is 6.
A detailed description of our pilot reactor can be downloaded at:
www.eawag.ch/forschung/eng/gruppen/vuna/...Udert_2013_Vancouver

Let me know, if you need any additional information.
Kai]]>
Resource recovery from excreta or faecal sludge Sun, 31 Aug 2014 13:16:48 +0000
Re: Nitrification reactor set up - by: winniek http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9895 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/3285-vuna-valorisation-of-urine-nutrients-in-africa-eawag-switzerland-and-south-africa?limit=12&start=36#9895 I am interested in carrying out a similar lab experiment and i would want to know more about the reactor set up that you used. What type of reactor, what was the flow rate the Hydraulic retention time , the volumes the concentration of the Dissolved oxygen. Basically the methodology and reactor set up. Thank you very much]]> Resource recovery from excreta or faecal sludge Wed, 27 Aug 2014 10:43:01 +0000 Re: Pivot Plant: Converting human waste to fuel to finance complete sanitation (Waste Enterprisers Holding and Pivot Ltd, Kenya) - by: kevintayler http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9836 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9836
Thanks for your earlier answer. This topic has stimulated my interest. I have been working on other aspects of FSM over the last 3 years but have not really looked at re-use options.

I would like to return to my initial question concerning the amount of dried sludge available. Based on a population of 1.2 million, the 50 tonnes of dried solids per day requires around 15kg of dried solids per person per year. I assume that the 50 tonnes per year applies to total solids (TS). I gave some rough calculations in my earlier email, based on figures from South Africa but I have done some further research, using information from both the FAME report on Accra, Dakar and Kampala and older studies of septic tanks from Europe and North America. (See www.tremolet.com/publications/report-fin...ar-kampala-and-accra for the FAME report).

All these studies give per-capita TS production figures of the order of 2 - 4kg/yr.The only exception is Accra where the figure for public latrine sludge comes out at 13.8kg/c.yr but this is assuming that sludge production is 730 litres per capita per year, which is very high and presumably reflects the fact that almost fresh faeces is regularly removed from public toilets.

Based on these figures, I think that the 50 tonnes per day figure is optimistic, if it refers to total solids. It may be that it refers to partially dried solids but this would have implications for the calorific value. A study conducted for the work in Accra, Kampala and Dakar arrived at a figure of 17.3 MJ/kg total solids (TS). (See www.iwaponline.com/washdev/004/0223/0040223.pdf) and clearly the TS figure is the relevant one.

The calculation in my earlier email, based on information from South Africa, gives a higher per-capita TS figure. Interestingly, the South African figures are taken from pit latrines with very low water contents - typically around 65 - 75% depending on depth. At these moisture contents, sludge will not be liquid and will have to be dug out.

One last point about the FAME calculations is that they assume high per-capita sludge volumes, 573 litres per person per year in the case of Dakar and around 290 litres per person per year in Kampala. These figures are much higher than those generally quoted in the literature (20 - 70 litres per person per year for pit latrines and leach-pits and 70 - 100 litres per person per year for septic tanks (mainly based on research in Europe and North America).

Overall, it seems to me that there are quite a lot of uncertainties here. Perhaps the next step after determining the technical viability of the approach should be to carry out more detailed assessment of the total amount of dried sludge that will actually be available. One point to note here is that there is a need to accurately assess both the TS content of septage and the amount of septage produced, neither of which is easy. The FAME reports do try to cross-check, using different approaches but I would still be worried about their assumptions on per-capita production.

I hope that this is helpful

Kevin]]>
Resource recovery from excreta or faecal sludge Thu, 21 Aug 2014 09:37:02 +0000
Re: Pivot Plant: Converting human waste to fuel to finance complete sanitation (Waste Enterprisers Holding and Pivot Ltd, Kenya) - by: timwikoff http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9683 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9683
Great questions and thanks for your interest in our work! We are currently under construction in Mombasa as well as working on some parallel projects for the sourcing of FS from the poorer areas of the city. Therefore, I'll have to ask for patience from the audience on answers to some of these questions - we would like to have specifics from the plant in full operation before spouting off.

Kevin to address your specific questions on volumes available we did a similar calculation and based that on the total population living in and very near Mombasa of 1.2 million people. Our estimate came to 50 tons per day. I don't have our formula or source off the top of my head but can get it for you. I believe we used WHO for our per person per day estimates but I'll have to check.

In terms of collection rate, we are estimating 80% collection at full scale - we are anticipating a minimum of a 2-3 year ramp up time to get there.

The other important aspect of collection that I should note is that we don't plan to do much of it ourselves. The parallel work we have running is to figure out the best incentives for local entrepreneurs to bring us sludge. We would love to pair technology coming from other Gates grantees with local business people in Mombasa and enable a thriving local market for sludge. The other avenue to pursue, again with Gates grantees is partnering with firms that are experts in collection but not "productizing" the FS. Firms like Sanergy or WSUP come to mind. But before we are able to do any of that, we need to get our demonstration plant built so that we fully understand our internal economics and operations and can go to potential partners with a solid proposal.]]>
Resource recovery from excreta or faecal sludge Fri, 08 Aug 2014 18:29:13 +0000
Re: Pivot Plant: Converting human waste to fuel to finance complete sanitation (Waste Enterprisers Holding and Pivot Ltd, Kenya) - by: kevintayler http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9679 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9679
I would like to follow up on Chris Canaday's question about the economic costs of the system. It would also be useful if you could provide some further information on how you plan to go to scale.

You say that the present plant can produce about 5 tonnes of fuel per day. You don't say what the ratio of fuel produced to feedstock of dried sludge is but I assume that it is not more than one.

Long-term sludge accumulation rates are typically of the order of 25 - 50 litres per person per year. According to the work done by Nwaneri et al in South Africa, the average water content of the top metre in a pit latrine, the part from which sludge is most likely to be removed is about 75%. Assuming that sludge removal equates to 40 litres per person per year, that equates to about 10kg of dry solids per year. The population of Mombasa is around 1 million so the amount of dry solids generated if every person in the city used a pit latrine and the sludge from all these pit latrines was collected, the amount of dry solids available would be about 10,000 tonnes per year or about 27 tonnes per day. My question here is whether there will be enough sludge to keep your proposed 40 tonnes per day plant going, bearing in mind that it will be hard to get 100% coverage of sludge collection services. Many people in peripheral areas are likely to build a new pit rather than empty their old one.

The economic question concerns the relationship of the cost of bringing all sludge to a single treatment site (as opposed to more localized solutions that involve less transport)and the sales potential from the fuel produced by the process. My impression is that the transport costs are going to be rather high. A related point is the balance between the fuel produced and the fuel used in bringing sludge to the treatment point.

I guess that you have looked at these points so it would be good if you can expand on them.

Thanks

Kevin Tayler]]>
Resource recovery from excreta or faecal sludge Fri, 08 Aug 2014 13:14:25 +0000
Re: Faecal sludge to biodiesel (Columbia University, USA and Kumasi, Ghana) - by: psewor http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/4796-faecal-sludge-to-biodiesel-columbia-university-usa-and-kumasi-ghana?limit=12&start=12#9647 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/4796-faecal-sludge-to-biodiesel-columbia-university-usa-and-kumasi-ghana?limit=12&start=12#9647 This results calls for critical rethinking to save our water bodies and also health of the people.
Your design if adopted would add value to human waste (that is from "waste to money").

I have carried out critical comparative case study analysis between Ghana and United Kingdom on treatment and disposal of liquid waste, its effect on water bodies. The book can be found at Amazon online library.

I wish you all the best.]]>
Resource recovery from excreta or faecal sludge Thu, 07 Aug 2014 08:32:02 +0000
Re: Faecal sludge to biodiesel (Columbia University, USA and Kumasi, Ghana) - by: SeptienS http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/4796-faecal-sludge-to-biodiesel-columbia-university-usa-and-kumasi-ghana?limit=12&start=12#9605 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/4796-faecal-sludge-to-biodiesel-columbia-university-usa-and-kumasi-ghana?limit=12&start=12#9605
First at all, I would like to introduce myself. I am a post-doctorate from the Pollution Research Center at the University of KwaZulu Natal, Durban, South Africa. I am supervising Master Students projects about the treatment of human waste in the context of 'Reinvent the Toilet Challenge'.

I would like to share with you a helpful information for your researches that I get from the South African Chemical Engineering Conference last week. In that conference, I assist to a conference untitled: 'Optimization of biodiesel production from waste vegetable oil and egg shell ash: application of response surface methodology' by Ngoya Tshizanga, from the Cape Peninsula University of Technology, South Africa.
On this research, a CaCO3 catalyst obtained from egg shields ash was tested for the production of biodiesel, and shows to improve the process. You can find several other work related to this subject in literature.
I think the use of egg shields ash as catalyst for biodiesel production can be interesting in our context, as this kind of material is very accessible (mainly in rural areas).

You may already know about this, but we never know. If you are interested, I can contact the researchers from the presentation.

Best regards,
Dr. Santiago Septien Stringel
Santiago]]>
Resource recovery from excreta or faecal sludge Mon, 04 Aug 2014 15:13:11 +0000
Re: Pivot Plant: Converting human waste to fuel to finance complete sanitation (Waste Enterprisers Holding and Pivot Ltd, Kenya) - by: canaday http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9594 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9594
What is the dewatering process?
So the sludge is dried, but not pyrolized or anything?
What temperatures are achieved, for how long, in the Thermal Drying stage?
Do you have a break-down of the economic and environmental costs of the system?
What does the final solid fuel look like? Is it a briquette?

Thanks for sharing this info. Good luck with your project. Please keep us informed.

Best wishes,
Chris Canaday]]>
Resource recovery from excreta or faecal sludge Sat, 02 Aug 2014 11:21:56 +0000
Re: Pivot Plant: Converting human waste to fuel to finance complete sanitation (Waste Enterprisers Holding and Pivot Ltd, Kenya) - by: timwikoff http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9592 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9592
Thank you for your comments. And I totally agree that learning the limitations of a proposed solution is also important. Not every idea can succeed, so it is important to explore and document when something won't work.

For the FS to Biodiesel research in Ghana, there were a few challenges but the most vital resulted from the actual observed yields of lipids from FS. On average, our samples from exhauster trucks were recording about 9% lipid yield from 100% dried FS. However, as you know the trucks carry sludge that has a range of 1-5% TSS. The second negative twist that we observed was that only 50% of the lipids recovered were saponifiable (able to convert to diesel). Therefore for an average size truck of 8m3 carrying 3% TSS FS, we were only able to produce 13.5 liters of biodiesel. Due to the cost implications on both capex and opex to move that volume of liquid around, the production of biodiesel was untenable as a financially viable business.

Dr. Chandran of Columbia University (co-PI on the FS to BD grant) and several students are furthering the fermentation research to explore the possibility of raising yields by producing more FFA. However that work is ongoing and I'm not certain that it has the ability to raise the lipid level high enough to make biodiesel a viable business model. You would need to discuss with Dr. Chandran about that.

For the solid fuel - we agree that the stigma may be too great for individual buyers. Therefore we are targeting industrial users of biomass fuels. Any company with a large boiler or kiln. We have done this to avoid some of the stigma issues around the feedstock for the fuel. We have found that industrial users are concerned about safety but if those concerns can be satisfied by 3rd party lab results, they are willing to purchase the fuel.

Regarding the process - you can see our process train in the attached picture from my last post. Happy to answer any direct questions you may have about that.

All the best,
Tim]]>
Resource recovery from excreta or faecal sludge Fri, 01 Aug 2014 23:23:29 +0000
Re: Pivot Plant: Converting human waste to fuel to finance complete sanitation (Waste Enterprisers Holding and Pivot Ltd, Kenya) - by: pkjha http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9586 http://forum.susana.org/forum/categories/98-resource-recovery-from-excreta-or-faecal-sludge/9398-pivot-plant-converting-human-waste-to-fuel-to-finance-complete-sanitation-waste-enterprisers-holding-and-pivot-ltd-kenya#9586 To know something is not possible, is also an achievement. It will help save time and money of other researchers. But the point is what went wrong? Your process of biodiesel production appeared to be lucrative. Is there any problem with the process or technically not feasible to achieve the assumptions. I remember you had mentioned the production of 10% VFA from FSM.
Solid fuel should not be the problem. However, its social acceptability may have some problem in some communities. You may like to mention your process to make such fuels.
Regards

Pawan]]>
Resource recovery from excreta or faecal sludge Fri, 01 Aug 2014 08:59:55 +0000