Vancouver has a few district heating systems. One near Olympic village uses waste heat from sewage flow as the main heat source, only emitting carbon when sewage flow is slow/cool.
They use a heat pump to move heat from shower/dishwasher/laundry outflows into a high pressure steam system.
This is energy that would otherwise be lost warming the dirt around the sewers.
You can get home drain heat recovery systems too, and either pump the heat into the air or just passively pre-warm the water entering your house/watertank.
Vancouver has a few district heating systems. One near Olympic village uses waste heat from sewage flow as the main heat source, only emitting carbon when sewage flow is slow/cool.
They use a heat pump to move heat from shower/dishwasher/laundry outflows into a high pressure steam system.
This is energy that would otherwise be lost warming the dirt around the sewers.
You can get home drain heat recovery systems too, and either pump the heat into the air or just passively pre-warm the water entering your house/watertank.