Open Pond Design Overview:
There are 2 main pond types:
- Open
- Closed
Open ponds
Open Pond Systems have had marginal success and are inexpensive to build, but are prone to multiple failures from many uncontrolled environmental conditions, ranked in order:
- Temperature and light differences – day and night, summer versus winter,
- Contamination from local algae into open ponds contaminating the cultured algae causing pond crashes;
- Evaporation, wind blowing dust particles into ponds and rain causing changes in salinity and pH, which affect growth of algae.
For the most part, open pond design has been pioneered in the following shapes…
- Round
- Raceway
Round: 
This shape is used mostly aquaculture and for production of Spirulina has a health food supplement. Used extensively throughout Asia, as well as the US.
Raceway
Raceway ponds have been the mainstay of pond designs for biofuels. Tested extensively during the 1970’s for the Aquatic Species Program, it is the most common design.
Closed Ponds:
An alternative to open ponds built in order to address the negatives discussed above, are closed ponds where the control over the environment can be regulated better than open ponds.
As a variation of the open pond system, the idea behind the closed pond is to close it off, to cover a pond or pool with a greenhouse-like covers of plastic or other similar, clear, material.
