hello @hardaeborla,
this type of system is very used in the Venezuelan fields and in the Colombian fields, due to the benefits that generates these systems, the pig excrement produces methane gas that is used for kitchens and also to fertilize the fields, I did not know that already there are companies that sell these systems, in the field it does it of artisan way and it is quite effective, I believe that this type of information must be but diffused in African countries where they have enough cattle and have difficulties with the domestic gas, as for the smell in Venezuela they make them totally closed thus the smell does not affect to the people.