Organic Waste Recycling

206 Organic waste recycling: technology and management

Methanol, a liquid fuel, has a calorific value of 5.34 kcal/g or 171
kcal/gmole. It is a poisonous liquid, but has wide applications as fuels, solvents
and anti-freeze agents. The use of methanol as an automotive fuel has the
following advantages such as: reduced emission of hydrocarbons, particulate
matters and toxic compounds, increased fire safety (because methanol is less
flammable than gasoline) and reduced dependence on imported oils. More than
10,000 methanol passenger cars and buses are currently in use and the number is
expected to increase in the years to come.

Figure 4.21 Model of dry gas scrubber for H 2 S removal

4.6.3 Digested Slurry

Although there is a considerable degree of reductions of organic, solid and
nitrogenous matters in anaerobic digesters, digester slurry still contains high
concentrations of the above matters (see Table 4.9) which should be treated
further prior to disposal. The digester slurry also contains various types of
pathogens (as stated in section 4.1), requiring great care in the handling and
disposal. On the other hand, high nutrient contents in the slurry make it suitable
to be reused such as compost fertilizer (Chapter 3) and in application to fish
ponds (Chapter 6) or on land (Chapter 9).

Biogas in

Wire net support

Ferric oxide or iron

filings