I've attached a copy of a case study related to conversion of chicken manure to biogas and electricity useful fuel cells.

This case study is part of the following courses that I teach at Yale University:

Khalil, Y.F., (2016). Environmental Risk Assessment (ERA). Professor Khalil's Lecture Notes, Yale School of Forestry & Environmental Studies (F&ES).

Khalil, Y.F., (2016). Green Energy Systems (GES). Professor Khalil's Lecture Notes, online Course, School of Engineering & Applied Science (SCAS), Yale School of Forestry & Environmental Studies (F&ES).

You can easily dry farm manure (say chicken manure) by leaving it in ponds exposed to sun radiation for a few days to reduce the moisture content.

Hope this helps answer your question.

Professor Yehia Khalil

Yale University

USA

Prof. Khalil,

Thanks for your comment about drying poultry manure by leaving it exposed to the sun. Can you refer me to publications showing how this works, considering rainfall? 

Thanks also for sending Amy Bolten's slides. Part of our research is the augmentation of biochar with natural fertilizers such as vermicast and thermophilic compost, with and without prior Bokashi-fermentation to accelerate decomposition. (Time is an important resource for subsistence farmers.)

We also consider converting the anaerobic (and pathogen-containing) digestate from biogas plants to aerobic state for adding nutrients and beneficial (aerobic) microorganisms to the soil. And with biochar to retain those amendments in the soil season after season.

If the drying of chicken litter is considered on a domestic scale then I would propose that solar drying could be effectively and efficiently used.

There are a huge variety of solar dryers developed for fruit and vegetable drying.

You can choose any simple solar dryer looking into its cost and capacity of drying.

As per the available literature chicken litter has an initial moisture content of 75 % but by the time it is collected from the floor along with other constituents its moisture content will be approximately 20 to 40 %.

You want the final moisture content to be around 10 %.

So proper selection of a solar dryer will be able to reduce the moisture content of chicken litter collected from the floor which will be around  40 %  to 10 % in about 5 to 6 hours on a bright and sunny day.

There are many review papers published on solar dryers from which you will be able to select the best possible solar dryer for your application.

Good afternoon, Jairaj. Thanks for your comments.

Please refer me to websites showing the mechanical arrangements which you have in mind.

I speculate that poultry litter will show the same drawbacks as wood-chips from freshly-harvested timber: When left in a pile, only chips on the surface dry out. To dry the entire mass of wood-chips they need to be stirred. For that reason, I think the equipment shown at http://bit.ly/2cQ3ymz (for example) will not be efficient.

I was thinking of a manually-operated rotary dryer set at an angle so that hot air will pass through it by natural convection. Or a manual mechanical device to lift the litter and let it fall through passively-heated air. Or air which has been heated indirectly in the same way as shown in the image referred to above.

I hope it would not need continuous manual operation. Do you think that such a device may work if activated, say, every half an hour, when somebody passes by?  

Greetings John, I believe this paper (and in particular its references) describing small scale lemon drying process can be of some inspiration. I saw them present at the 2015 ASME conference.

Thanks,

-Steve

Thanks, Steve.

My idea was about thin layer drying of chicken litter.

Just fill the chicken litter in the morning and collect the dried material in the evening.

Your idea of rotary dryer will be complex and costlier which requires power supply.

I have attached two papers which were published by a researcher from our school. 

I had seen the performance of the solar dryer while drying chillies and tendu leaves.

The solar dryer had three trays and temperatures inside the drying compartment was appreciable.

I feel the papers will give you details regarding the solar dryer fabrication.

Thank you, Jairaj. 

I used a technique named biodrying. Biodrying technique was explored for three types of animal wastes including beef, swine, and poultry

manures in three 900-L batch reactors. Corn stover was mixed with each manure type prior to the experiments to reduce

the initial moisture content of the mixture to about 60% w.b. Three replicates of each type of manure-corn stover mixture

were investigated at a time. Blowers were connected to the reactors’ outlets to move air in a downdraft mode through the

mixtures.

Temperature values of all types of manure-corn stover mixtures increased with time. The highest recorded temperature

was 71°C in the poultry manure-corn stover mixture at day 5. Moisture content of the three types of manure-corn stover

mixtures reduced from 60% to less than 27% w.b. within 2 to 4 weeks. The study showed a noticeable reduction in

biodried manure weight, which, in turn, may reduce manure transportation cost. Small reductions of manure-corn stover

heating values were observed for the three manure types. A feedstock suitable for a thermochemical gasification process

could be produced via the investigated biodrying process.

Thanks Sammy. This will be useful for when we increase the operations to agri-industrial scale. 

Biodrying is a variation of aerobic decomposition, used within mechanical–biological treatment (MBT) plants to dry and partially stabilise residual municipal waste. Biodrying MBT plants can produce a high quality solid recovered fuel (SRF), high in biomass content. Here, process objectives, operating principles, reactor designs, parameters for process monitoring and control, and their effect on biodried output quality are critically examined. Within the biodrying reactors, waste is dried by air convection, the necessary heat provided by exothermic decomposition of the readily decomposable waste fraction. Biodrying is distinct from composting in attempting to dry and preserve most of biomass content of the waste matrix, rather than fully stabilise it. Commercial process cycles are completed within 7–15 days, with mostly H2O(g) and CO2 loses of ca. 25–30% w/w, leading to moisture contents of

Thanks, Abooali. Is this approach also used at small scale? (artisanal / domestic / small-community scale). If yes, please refer me to published work and outcomes.