What is the best option for dealing with 5000kg of kitchen waste every day?
Alexander Rohan John, Environmental Engineer, Vellore, Tamil Nadu, India
“This is a big amount of waste to deal with. There are several options including cheaper and more capital intensive depending on the circumstances to be dealt with. The cheapest way is open air row composting. Smell, dust and flies will make this suitable only in far-from-houses and other human activity areas. The most expensive way is anaerobic digestion, creating gas for application in a gas engine and rich compost to be applied in agriculture. And, everything in between from tunnel composting to indoor controlled row composting. Or even to be processed in a municipal Waste to Energy plant, where the calorific value of the waste can be lowered with this kitchen waste (lower calorific value = higher capacity installation in tonnes/hour)
Melle B. van der Meulen, MD/Senior Consultant, MHV Consultancy Ltd and Member of the International Waste Management Consortium, Enschede, Netherlands
I agree with what Melle has said above. There are a number of options from the low-tech/ low-cost to high-tech/high-cost. In a situation like this in India, one has to ascertain
- How well separated is the waste?
- Is it pure food waste or does it include pieces of packaging and other materials?
- The moisture content – Is it fairly dry residue or is it a sloppy type of waste?
- Is there land available to operate a processing facility of some kind? How large is the plot of land?
- How much buffer distance is there to the nearest neighbours? What is the current land use of the neighbouring properties?
- Are there water sources nearby, which could become contaminated by runoff from the waste?
- Lakes, rivers/streams, wells/underground aquifers?
- What is the local climate like?
- Annual rainfall average temperatures?
- If you built a composting plant, is there a local market/need for compost to be used in agriculture?
- Would you get paid for the material you produce or would you have to give it away free?
- If you built an anaerobic digestor, is there a local market/need for the energy it would produce?
- Would you get paid for the energy or would you have to supply it at a discount (or free) to get a use for it?
The answers to the above questions will pretty much determine the solution.
Lee Smith, Principal Consultant at Mobius Environmental, Sydney, Australia