Continuing in the world of Stormwater Quality systems, the next system we will look at is the stormwater filter.
There are several different types of proprietary stormwater filters. Designs range from systems that are intended to take out a single pollutant to those that are effective at removing a range of pollutants. Although the systems do differ in their intent, they often are fairly similar in their construction.
Stormwater filter systems are typically placed in a vault underground, often with steel lids that indicate the manufacturer. The filters have a way for stormwater to enter, either through the top or delivered in a pipe through the vault wall. Once inside, the stormwater is typically routed through some baffles and dead pools intended to settle out the large solids prior to the stormwater being directed through the filters themselves.
Here is where things start to get interesting (as interesting as stormwater ever gets). Depending on the pollutant the system is designed to remove, the filter media can be a single material or a combination of materials. One type of filter media, typically used to treat for suspended solids, is Chitosan. Chitosan is a naturally occurring substance made from crushed crustacean shells, such as shrimp and crabs. This type of filter is often used during construction to ensure that sediment is removed from construction water prior to discharge.
Other types of filter media exist that are just as interesting as Chitosan. Perlite, a volcanic rock, is used often due to its porosity which creates a very high surface area for a given volume of the material. This is very useful in the removal of suspended solids. Another is Zeolite, a mineral used when hydrocarbons need to be removed from the stormwater stream as well as suspended solids.
So how do these systems get maintained? Once you have determined that you have a filter system on your site, the best next move is to call the manufacturer of the system. Most manufacturers have maintenance departments that can help you to determine if the system needs maintenance and, if so, how to go about that.
Of course, you can always contact CatchAll Environmental as well. We are experienced in working with every type of stormwater filter system on the market and can diagnose not only the filter system but your entire stormwater system.
Next time, on to ponds
– See more at: http://www.catchallenvironmental.com/blog/water-quality-systems-stormwater-filter-systems#sthash.iuskhE1m.dpuf