Water: septic system 2

Illustration of a house with an underground septic system draining to groundwater

Illustration of a septic system with a rectangular tank and incoming and outgoing pipes

Another illustration of a wastewater treatment plant, with pools, buildings and a drainage pipe

Illustration of a second type of house

Transmission of information as light pulses

Illustration of a rounded dam

Illustration of an upright water pipe

Illustration of a second type of cell phone tower