In the past most stormwater runoff was allowed to pour directly into steams and rivers causing erosion, pollution, fish kills, and then drought in some places. Since the EPA has placed a strong emphasis on stormwater management, far more of the rainfall is now absorbed into the local soil where it is naturally handled by nature. This allows the soil to filter the water for months and years before it enters streams and rivers. In addition to that, when it is absorbed into the soil it doesn’t create the massive erosion problems which washes away large amounts of precious topsoil into the rivers. Plus, replenishing the aquifers is also a top priority for drinking water. One of the important parts of stormwater management are the hydrodynamic separators that are the first step in cleaning the water from the streets and parking lots.
The Hydrodynamic Separator’s Value When Managing Stormwater
These separators play a valuable role by being a first step in filtering stormwater runoff. The first thing they do is allow some of the heavier sediments to settle out at the bottom of the chamber. They still allow the cleaner water to continue on down the stormwater drainage system.
They are also quite good at removing plastics, like bags, plates, wrappers, and packaging which can clog up a stormwater system quickly. These waste materials are usually a result of litter, but also fall out of garbage cans and off of trucks on the way to the dump.
They Work By Creating A Natural Swirling Vortex
One of the natural qualities of flowing water is its ability to swirl. This motion has a tendency to throw certain pollutants out, especially floatables like oil and trash. At the same time sediments settle to the bottom and cleaner water is allowed to travel on. By having these separators spread out in the system, a lot of the trash, oil, and sediments are captured in a pre-treatment system. Then large trucks move through and vacuum out the garbage on a scheduled basis.
Selecting The Right HDS For Your Needs
In most municipalities the local engineers have pre-selected the best hydrodynamic separators based on the average amount of rainwater, peak water flows, types of garbage, and amounts of sediment. Then the amount of space, which is dictated by bedrock, water tables, and above ground footprint is also taken into consideration. If the local stormwater engineers have done the hard work, it’s best to follow their advice.
On the other hand, if you have to do the entire selection process on your own, you’ll need to know a lot of facts like the amount of yearly rainfall and the peak rainfall amounts too. Then, knowing the amounts and sizes of the litter is also important. After that, the average particle size of the sediments that are likely to be caught in the water flow on your street should be enough for you to choose your size, shape, and type of hydrodynamic separator.
Taking care of the environment, starting at every level, is an important factor in saving the earth. Failure to do so will result in polluted rivers, dead fish, muddy oceans, and extinct coral reefs. It all ads up to a ruined earth. But it can be saved just one step at a time by taking care of stormwater near its source rather than at its destination.