I have an idea that would solve both your waste issues and heating issues .
The good news is that it will be very cheap and the bad news that intitially it will take a lots of hard work and propably 5 to ten years to impliment . I suspect these folks are used to hard work

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My suggestion is to grow willow .
Willow comes in many different types so I am sure there is a type or even types that will be suitable . It can grow upto 5m per year under a coppice rotation system either via a pollarding regime
https://en.wikipedia.org/wiki/Pollarding or by stooling
http://www.coppice.co.uk/woodland-types/willow/willow-cultivation/ . It is very easy to propagate and loves marginal humid soil like bogs and will survive flooding.
Uses
1 Firewood
Its great in a rocket mass heater cut small one winter dry over summer use next winter
2 Forage
Donkeys goats sheep and even cattle will eat it given the chance . in drought could be useful for farmers
3 Sewage
As part of a system along with reeds and rushes could be used to treat water
http://www.wikiwater.fr/a25-treatment-by-willow-plantation.html
4 Handy Crafts
Traditionally used along with rushes to make furniture, baskets, fish traps, bee hives etc Winter work on the Farm in Europe it could be in effect a small winter cash crop for the farmers .
5 Construction material and Fence Posts
Not the best wood for these tasks but since its free ................... Also for Wattle and Daub construction .
https://en.wikipedia.org/wiki/Wattle_and_daub
plus bonus you can make cricket bats from it
Once you have established the willow wood it will provide these products for ever at no extra cost just harvest once every year or two , think of it like a pension plan
Also other plants are possibilities -bamboo , Hazel , Acacia , etc