Environmental Engineering Reference
In-Depth Information
On an industrial scale, water use is likely one of the most wasteful practices, and some
strategies can be adopted to reduce consumption. The main actions include adjusting processes,
replacing processes with alternatives that consume less water or no water, reuse, recycle, and
mitigate the impact.
Proportional to water consumption is the generation of wastewater, which needs treatments
to preserve aquatic ecosystems before discharging back to bodies of water. These days, aerobic
systems are the most widespread methods to treat wastewater. These systems use large amounts
of energy and generate solids in the form of sludge that needs further treatment. Alternatives to
aerobic systems are the anaerobic ones that use less energy, produce less solids, and generate
methane gas that can be used as a source of energy. Effluents after anaerobic treatment need
further polishing before being discharged to surface waters. This polishing step can be com-
pleted with traditional aerobic systems, the use of membranes, or engineered natural systems.
The use of engineered natural systems is not common, but enough science exists to develop
and use them as a supplement of anaerobic wastewater treatment. Engineered natural systems
consist of a series of steps that use microorganisms, protozoa, snails, and plants to carry out
each step of the process.
Finally, the preservation of aquatic ecosystems is not complete without a good storm man-
agement system. Precipitation in the form of rain and snow that cannot infiltrate the ground
flows to the surroundings as a runoff, which promotes erosion, downstream flooding, reduces
groundwater recharge, and loads surface water with pollutants.
Runoff can be controlled by promoting natural water infiltration in the vicinity of the rain-
fall area and delaying the residual runoff to avoid peak discharges. This can be achieved by
minimizing impervious surfaces, using filter strips around impervious areas, creating swales
and check dams, and redirecting the excess to retention ponds, detention ponds, bioretention
cells, or constructed wetlands.
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