Ancient civilizations like the Egyptians, Greeks, and Romans understood long ago the importance of sanitation and wastewater management, building elaborate sewage systems by using underground drainage channels to carry wastewater away from their cities. These systems relied on gravity to transport wastewater to nearby bodies of water, since water cannot flow upward without being pumped. Today, many sewage systems continue using gravity in a similar way, with a suitable slope that facilitates the... Читать дальше...