The first thing you need to understand is that new water treatment plants are costly. Sewer plants treat unsanitary water and unable to return safely to the water cycle. For this to be operational, plants require large tracts of land and various equipment, excluding operational costs. Due to these costs, it is impractical to expand water districts and municipalities for adding new treatment plants for commercial developments and new housing. But the newly constructed buildings still need to be connected to a functional sewer system. This means moving sewage to the gravity system of an old treatment plant.
The next thing to consider why the wastewater lift station in Houston ( http://draneranger.com/services/ ) is required is the best land for development has probably been built on. This means as urban regions start expanding, new buildings are located far away from the central sewer infrastructure. We can say that today, the new construction cannot be tied into a gravity system. In some places, there are hills or other geographic features between gravity sewers and new construction. In some other places, the land is so flat that the only way for creating a gravity line is digging down deeper and deeper. This may sound simple, but to actually dig and install deep infrastructure is quite difficult.
Typically sewage needs to flow at about 2-feet per second for preventing the sewage from becoming septic. This is equal to a 2% slope for the sewer lines. This means every pipe of 100 feet needs to drop 2 feet. By the timeline touches 10-feet deep, the installation charges increase steadily. These gravity lines become more expensive when they are installed at deeper levels. This means the damaged or leaking pipes are more expensive to replace or repair in the future. At a certain level, cost ratios vs distance vs depth make it much affordable for pumping sewage up to a higher elevation where gravity can resume. Therefore, lift stations avoid the requirement for deep gravity lines by lifting sewage to elevated levels where gravity lines are less costly.
Typically, a customer can expect a life span of 15 to 20 years or more from steel lift stations. In most cases, this is more than adequate as the anticipated flow rates are designed for only ten years of expansions. Lift stations made of steel are coated with a high solid epoxy paint system and further safeguarded by anodes for deterring cathodic action.