Thonburi, Thailand and made from cement ring,
demonstrated 65 , 72 , 79 and 83 % of oil and grease
removals at 1, 2, 3 and 6 hrs of HRT, respectively.
Moreover, BOD removal for 1-3 hrs of HRT was in
range of 40 – 50 % and SS removal for 3 hrs of HRT
was 50 % [15].