Rethinking The Conversion Process Of Poultry Litter To Biogas

The poultry industry is generally comprised of broiler chicken production, egg production, day-old chick suppliers and other poultry. While micro-enterprise businesses are gaining prominence as a means to address the challenges of job creation, economic growth and equity, the industry has future challenges concerning poultry litter management.

- Dr. Idan Chiyanzu

Considering the emerging trends of increased growth in this subsector, the environmental impact of poultry litter requires some close monitoring. Our fundamental premise is that the industry focus needs to shift away from direct use of poultry litter as a fertiliser, due to the high quantities of nitrogen (N), phosphorus (P), and potassium (K) that would accumulate in agricultural soils.

Energy generation

Recently, environmentalists raised concerns over the impact of poultry litter dumping in terms of odour, emissions, stormwater release, as well as dust particles.

Waste is an unavoidable by-product of the poultry economy and it is the responsibility of individuals and entities such as co-operatives, to utilise litter for further economic value such as deploying renewable generation technologies for a more sustainable and efficient economy.

To date, biogas and electricity are the most common forms of energy generated from any of the waste-to-energy processes. Anaerobic digestion, thus far, is the technology of choice for the conversion of poultry litter and other waste into bioenergy and bioproducts such as bio-fertilisers.

A challenge for the digestion of poultry litter, has been the need to add a large amount of water to digesters as a means to adjust the litter to a total solid (TS) concentration of under 15%, as the TS concentration of poultry litter is approximately 70%.

Transitioning from the dumping of poultry litter to repurposing it, is unavoidable and will require careful selection of technology. All of the existing technologies require a certain amount of investment. Therefore, should a farmer choose anaerobic digestion or thermochemical conversion options, its feasibility and justification need to be very strong.