T The dissolved air flutation is a process of separating the solidity or suspended particle by means of floating. The suspended solidity is floated on to the water susrface by the the aid of air bubbles. The air soluted under the atmosphere pressure that released to the atmosphere pressure. The suspended particles will form the formation where the spesific weight of particles is lower than that of water such that the particles will absorb the air bubbles. The particles will tend to rise up the surface and separated by sweeping out. In this reseacrh it has been conducted some variations, those are 2, 75,: 3, 2: 3,5 bars, living time: 20, 24, 30 minutes, as well as the suspended solidity concentrations: 800, 1000, 1200, 1400, 1600, 1800 mg/hr. The parameter observed is in the forms of the suspended solidity and COD that each obtained from the result of analysis by using the gravimetry method and colorimetry method with wavelenght of 600 nm. The efficiency of removing the suspended solidity and COD is influenced by the parameter of living time. The increase of the living time in the soluted air flotation tank will decease the removing efficiency. The optimum living time for the suspended solidity and COD is 20 minutes. The parameter of air ratio (A/S) process the suspended solidity is highly influenceds by the intirely removing effiency. If the ratio A?Ss enlarged, then it will decrease the removing efficiency of suspended solidity and COD. The result of research shows that the optimal ratio A/S for the suspended and COD is 0, 0158 with the removing efficiency of COD is by 98 %. The parameter of air ratio (A/S) process tothe effluent of the suspended solidity shows that if the ratio A/S is enlarged, the it will decrease the effluent value of the suspended solidity. The range of removing efficiency of suspended solidity in living time 20 minutes is 53-68 mg/ltr, in living time 24 minutes is 70-81 mg/ltr, in living time 30 minutes is 65-90 mg/ltr.