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.
Distance between tubes (b)=0.013-0.089 m
Length of plate (L)=0.88 m
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.
Durability and Warranty
The quoted warrenty is 12 months from instillation or 18 months from shippment, whichever comes first. They claim that typical life of the tube settlers is 20 plus years as long as they are not walked on or exposed to sunlight for extended periods of time while located out of water.