A by-product from thermochemical processes, such as combustion
and gasification, is ash. The resulting ash contains high phosphorus
and potassium concentration that makes it a feasible
fertiliser for agricultural crops. Poultry litter ash was evaluated
as a potential phosphorus source for wheat and other crops, and
showed similar effectiveness as potassium phosphate when the
soils were limed [16]. This ash could be potentially sold at a price
comparable to fertilisers with phosphorus and potassium of different
ratios such as 0:7:30 and 0:10:20, at €11.45 per 50 kg bag.
However, the ash might require formulation and granulation
which might incur in additional costs. But at least the ash could
be used in its original state and save the farmer the expenditure
on agricultural fertiliser.