Turning Toilet Sludge into Energy

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How can I use community toilets to collect and treat faecal sludge and convert it to energy? 

Which technologies are the best to use to gain energy from sludge? Are there any alternative methods - I have heard of tiger worms which make fertilizer out of faecal sludge, is there anything similar for energy?

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18 Answers

  1. Rajesh....we have a system that uses our proprietary CONRAD...continuous anaerobic digestion units. These units are housed inside 40ft. ISO Containers....we make either gas that is bottled and used or electricity, as you desire.

    Because these units also use our SOLUTEK solution the incidence of malodor is negligible.

    The by product - water - is of agricultural use grade and can be further treated for use in showers, toilets or as drinking water.

    www.soleco-technology.com

    Hugh.

  2. In our proprietary process, we convert any kind of sludge into energy : power, drinking water and fuel with no residues or emissions. advise us the quantity of sludge available and will confirm how much energy will be generated.

    regards

  3. Dear Mr Rajesh, the main problem is to HANDLE the human faecal waste & bring up to the processing point, whether biogas or pyrolysis. Smell & the very psychological reluctance of operating people hinders it. Suction pumps may better be used. 

    However, anaerobic digestion tends to produce another secondary liquid waste,( after biodigestion of waste).

    Making fuel blobs out of dried waste may still be smelly. It is ok for fuel scarcity areas. ( People are known to use cow or buffalo dung for the same.)

    Thus pyrolysis seems a better option. 

    Any specific ideas on handling the faecal waste without human touch? In one of the videos, hoses & pumps are seen being used. 

    Regards,

    Dr. Modak

    1 Comment

    1. Dear Dr Modal,

      I'm working on similar research "stabilization of fecal waste for composting and pyrolysis" I will be happy happy, if anyone can help me to edit the language of my recent manuscript for publication. Thanks 

  4. One more thing, the great thing about gasification is the heat kills all pathogens, oils and grease are not a problem, and all pharmaceutical or chemical residues are broken down into elemental form. Heavy metals and volatiles get filtered from the scrubbing system and emissions are very low.  The remaining char could also be used safely as a fertilizer (being 100% pathogen-free).  Contact me judi@krzyzanowski.ca if you would like more info. 

  5. I would suggest gasification. Many systems, including one made by a company I do work for, can handle up to 50% moisture. They produce a high energy syngas that can then be used to power a turbine. Please let me know if you would like more info. It would maybe need some drying, or in the alternative could be mixed with a dry biomass such as straw or flax shive. 

  6. BioKube has installed a system in Accra, Ghana treating wastewater from public toilets in the city and from private holding tanks. The sludge is dewatered and turned into charcoal used for domestic cooking. The water is treated and can be used for irrigation. 100 % circular economy.
    For more info, contact me at pt@biokube.dk

    See also document below with video of the operational system.
    https://drive.google.com/file/d/0B2es7H4aLFiaRllfVlY3bl8xWm8/view?usp=sharing

     

  7. Hi Rajesh, It's largely a matter of scale. Gates' foundation has been pioneering research and would be worth contacting for small scale community related solutions. Digestion followed by generation is high-technology compared to other options and will require significant skills to operate and maintain.

     

  8. Mr.Rajesh Taneja,

    You can consider bio digester.It processes energy (bio gas ) which is a clean green energy and sustainable.You need to consider the necessary modifications to suit your needs.For instance the number of toilets that outputs the faecal sludge,the size of space to construct the bio digester,environmental impact of your project and of course budget.

    The beauty part of it is that you will have continuous flow of bio gas energy for as long as people are using the toilets.Good luck.

    Thank you.

  9. While the sludge is a great fertilizer energy source, our sewer systems are rich with FOG.  I built an 8000 sf plant to distill the brown grease out of wastewater. The process itself used the grease product  to fuel the boiler for steam.  Brown grease is rated about 2K less in BTU's as #2 diesel fuel and if managed properly, can easily be fired in a wetback boiler. The FOG's are particularly a nuisance waste in urban areas where restaurants and grease -laden cooking / dish washing occur frequently. Many folks were after the spent yellow grease from fryers but few venture into the brown grease (high fatty acid) model. Google search "Jim Mathis, Klines" for a video we produced to overview the process or copy the url address below into your search bar:

    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjX4szC_a3TAhWD24MKHSszAesQtwIIJDAA&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3D_v-NJ8qOYNM&usg=AFQjCNEMnhbXcmMkO5HQ7VkLsl6zrMIwrA

  10. I'm looking for suppliers for a small scale systems, suitable for small size community houses.

     

    Contact me at akhafagy@ymail.com

     

    2 Comments

  11. Generally, in a well-functioning and designed biogas digester, the pathogen removal in the slurry is sufficient so the  treated sludge  can be reused for soil fertilisation. To increase the safety, it may be aerobically composted (or processed in a  sludge  drying or humification bed) before reuse .

    A small-scale  biogas reactor  or  anaerobic digester  is an  anaerobic treatment technology that produces (a) a digested slurry ( digestate ) that can be used as a  fertilizer and (b)  biogas  that can be used for  energy Biogas is a mix of  methane , carbon dioxide and other trace gases which can be converted to heat, electricity or light. Small-scale biogas  reactors  are typically designed to produce  biogas  at the household or community level in rural areas. The airtight  reactors  are filled with animal manure from the farm. Kitchen and garden wastes can also be added and  toilets  can directly be linked to the  reactor  for co-treatment of  excreta .

    biogas reactor  is an airtight chamber that facilitates the  anaerobic  degradation of black water sludge , and/or  biodegradable  waste (e.g. animal manure, kitchen and garden wastes). It also facilitates the collection of the  biogas , a mixture of  methane  (CH4) and carbon dioxide (CO2) produced in the  fermentation  processes in the  reactor . The gas forms in the slurry and collects at the top of the chamber, mixing the slurry as it rises.The pressure exerted by the rising gas can be used to transport the gas to the collection vessel or directly to where it is going to be used. The  digestate is rich in  organics  and  nutrients , almost odourless and pathogens  are partly inactivated.

     

     

    1 Comment

    1. Thanks for the information, please can you proofread my manuscript on a similar topic? Thanks