> size="2" face="Verdana">The aim of this work was to evaluate the performance of coagulants combined with three polyelectrolytes (anionic, cationic and non ionic) using dissolved air flotation (DAF) in the treatment of effluents of the soybean oil refinery. This study was conducted at laboratory-scale to find, through the coagulation diagram, the best limits of pH and coagulant concentration. With those limits, the dosage of flocculants was varied to achieve the optimum dosage. For that, some parameters were fixed: time and rapid mix gradient (1 min and 150 s-1), time and slow mix gradient (10 min and 40 s-1 - 5 min and 20 s-1), pressure in saturation chamber (450 kPa) and ascension velocity (1.67 cm min-1) for two flotation tests. After the flotation tests, samples of treated effluent were collected for comparison with crude effluent. The removal percentage obtained of chemical oxygen demand (COD) was 93.7 and 95.1% and of oil and greases (O&G) was 94.2 and 99.8% for the test 1 and 2, respectively. Despite excellent efficiencies of removal, the treated effluent did not present characteristics for reuse in cooling towers, because the COD was above 75 mg L-1 O2.
展开▼
机译：> size =“ 2” face =“ Verdana”>这项工作的目的是使用溶解气浮法（DAF）评估结合三种聚电解质（阴离子，阳离子和非离子）的凝结剂的性能大豆炼油厂的废水。这项研究是在实验室规模进行的，目的是通过凝结图找到pH值和凝结剂浓度的最佳限值。在这些限制下，絮凝剂的剂量可以变化以达到最佳剂量。为此，固定了一些参数：时间和快速混合梯度（1分钟和150 s -1 ），时间和慢速混合梯度（10分钟和40 s -1 -两次浮选试验的5分钟和20 s -1 ），饱和室中的压力（450 kPa）和上升速度（1.67 cm min -1 ）。浮选试验后，收集处理过的废水样品与粗废水进行比较。在测试1和2中，化学需氧量（COD）的去除率分别为93.7％和95.1％，而油脂（O＆G）的去除率分别为94.2和99.8％。尽管去除效率很高，但处理后的废水并没有在冷却塔中重复使用的特性，因为COD高于75 mg L -1 O 2 。
展开▼
