Apparatus, systems and methods are provided for the improved use of waste heat recovery systems which utilize the organic Rankine cycle (ORC) to generate mechanical and/or electric power from heat sources generating power from byproducts of water purification process(es). Waste heat energy obtained from heat source(s) is provided to one or more ORC system(s) which may be operatively coupled to electric generator(s). A heat coupling subsystem provides the requisite condensation of ORC working fluid by transferring heat from ORC working fluid to one or more other process(es) or system(s), such as anaerobic digester tank(s), to provide heat energy that enhances the production of fuel for the prime mover(s) without requiring the consumption of additional energy for that purpose.