Removal of iron ore slimes from a highly turbid water by DAF

Abstract

This paper addresses Dissolved Air Flotation (DAF) process variables, such as the flocculation parameters and the recycle water addition, as well as the pretreatment chemical variables (coagulation conditions), to determine the optimal values for the flotation of iron ore slimes found in a highly turbid water sample from the Gualaxo do Norte River, a tributary of the Doce River Basin in Minas Gerais, Brazil. This work was conducted using a flotatest batch laboratory-scale device to evaluate the effectiveness of DAF for cleaning the water polluted by the Samarco tailings dam leakage and determine the ability of DAF to reduce the water turbidity from 358 NTU to values below 100 NTU, aiming to comply with current legislation. The results showed that the four types of tested coagulants (PAC, ferric chloride, Tanfloc SG and Tanfloc SL) provided adequate conditions for coagulation, flocculation and flotation (in the range of 90-99.6% turbidity reduction). Although the process variables were optimized and low residual turbidity vales were achieved, results revealed that a portion of the flocs settled at the bottom of the flotatest columns, which indicated that the turbidity results represented removal caused by a combination of flotation and sedimentation processes simultaneously.

Detection of intestinal parasites in human faecal samples using dissolved air flotation

“…The inconsistency in the performance of parasite recovery when using 20% water volume may be related to the higher coalescence of bubbles, which can increase the internal hydrodynamic forces (turbulence) inside the flotation column, which may increase shear between particles and microbubbles [25]. This is similar to results reported by Faustino et al [26]: excellent turbidity removal in wastewater samples with a high content of Fe(OH) 3 using saturated water volumes from 10% to 12%. These authors also observed that an increase to 18% saturated volume did not result in higher removal of Fe(OH) 3 .…”

Evaluation conditions to treat slime water with coagulant-bioflocculant by orthogonal design

“…However, with rapid economic development, various industrial wastewater discharges increase, and water pollution is becoming increasingly severe (Chiban, 2011;Chiban, Soudani, Sinan, Tahrouch, & Persin, 2011). Among these, coal mine wastewater is one (Faustino et al, 2019).…”

Effect of Cone-Plate Clarifier Structure Parameters on Flocculation Efficiency

“…Because the sedimentation process mainly removes larger particles, the flocculation efficiency (the aggregation of smaller particles into larger flocs) is very important [16,17]. Therefore, it is very important to directly measure and monitor the particle size distribution (PSD) in the process of particle separation and sedimentation [18][19][20]. The on-line particle counter can measure the number of particles and the distribution of particles with different sizes.…”