For example, the cost a conventional Indian design fixed dome anaerobic
digester is estimated at approximately US$500 for a family scale unit (Preston,
1995). An investment of this scale is likely to be prohibitive for many small
and subsistence farmers, even if they recognise the potential benefits.
Changes in the design to exploit more affordable materials can dramatically
alter the cost and therefore the potential impact of such technologies,
with low cost digesters now being promoted at less than US$50 per family
unit (Ibid.). Understanding the benefits Any new technologies or practices must be seen
to benefit the livelihoods of the farmer in terms of improved performance of livestock or crops or the value of the energy produced. Different agricultural wastes have different potential benefits as animal feed, feedstock for anaerobic digester or other uses. It is important that meaningful information is available in a form that is accessible and relevant to the farmers, which illustrates the realistic potential of the actual waste available. Without such information farmers will not be able to
make informed decisions as to which approaches will be of most value to their own livelihoods. Pilot projects and demonstration programmes are frequently an essential part of promoting and proving new waste management technologies or practices
for a particular setting.