mass balace of biodigestor eco city technology process
Pagandai V Pannir Selvam
Clone pannirbrof Biogas to Energy | Insight Maker https://insightmaker.com/insight/114792/Clone-pannirbrof-Biogas-to-Energy 
Simple mass balance model for lakes, based on the Vollenweider equation:

dMw/dt = Min - sMw - Mout

The model was first used in the 1960s to determine the phosphorus concentration in lakes and reservoirs, for eutrophication assessment.


Ecocity model , Joanna 

http://www.divaportal.se/smash/get/diva2:631144/FULLTEXT01.pdf