How cellular wastes are removed from the human body and how wastes are removed from a city?

There are several systems in the body that get rid of cellular waste.
1. The urinary system removes urea from the body.
2. The spleen removes aged and damaged blood cells from the blood stream and breaks them down. The liver then removes the hemaglobin and breaks it down further. Some of the by products are excreted with the bile (ie heme) and some are released back to the blood stream to be removed by the kidneys (urea).
3. Some cellular waste is transported by the blood to the lungs where it is released through exhalation. (ie carbon dioxide)
4. Some cellular waste is removed from the body through perspiration.

Lysosomes have powerful enzymes and acids to digest and recycle cell materials. Proteins aren't the only type of cellular waste. Cells also have to recycle compartments called organelles when they become old and worn out. For this task, they rely on an organelle called the lysosome, which works like a cellularstomach.