Use

http://www.google.com/search?sourceid=navclient&aq=hts&oq=&ie=UTF-8&rlz=1T4ADFA_enUS356US357&q=CPI+separators

and

http://www.google.com/search?sourceid=navclient&aq=0&oq=API+separator&ie=UTF-8&rlz=1T4ADFA_enUS356US357&q=api+separator&gs_upl=0l0l0l56734lllllllllll0&aqi=g4&pbx=1

These separators may or may not have problems based on the composition of the influent. I had to redesign my API seperators to eliminate a dead space behind the lower sludge scraper because asudden increase in flow rate would disturb an accumulation of settled sludge causing a very degraded discharge

grrun