Enviropax
Enviropax is a company located in Salt Lake City, Utah. They produce clarification and mixing systems. They construct trapezoidal plastic tube settlers.
Product
The hyperlink located bellow links to a page that describes the tube settlers. The quoted price for tube settlers was for trapezoidal shaped tubes which are not pictured on the website.
http://www.enviropax.com/tubedetail.htm
The picture located above is a rendering of a tube located in a tube settler module.
Quoted Price
The quoted price for 86.21 square meters of 0.762 vertical meters high of tube settler is $31,500 for the Gracias plant. That is $365.39 per square meter.