Page 9 - PDZA Sustainable Aquarium Brochure

THE PROS AND CONS OF FILTRATION SYSTEMS

SAND FILTERS Yet concerns have arisen over sand filters in terms
For aquatic animal life support systems, the old of sustainability. The main concerns are the energy
stand-by for filtration is the pressure sand filter. they require to drive water through the sand bed
There are thousands of these filters installed in life and the large volume of water they require to lift and
support systems all over the world. They generally backwash the sand bed. Also, from a water quality
perform well and have many good attributes. point of view, there is concern about retention of
For instance, they capture pressure energy which organic material on the filter bed and leaching out
allows them to adapt to different building layouts of dissolved organic carbon into the system.
without necessarily wasting energy. Table 1 lists the advantages and disadvantages.

Table 1—Pros and Cons of Sand Media Filters

PROS CONS

• No moving parts and they are well • Pressure energy required to drive water
understood by operators through the sand bed

• Requires large water volumes for backwashing
• Captures pressure energy
and large backwash recovery systems

• Organics from “Tea Bag” effect creates higher
• Biological filtration
TOC in the water column

CASE STUDY: THE PACIFIC SEAS AQUARIUM AT POINT DEFIANCE ZOO & AQUARIUM 9