Removal Of Hydrophobic Fractions Research Articles

Effect of Fe-based catalytic ozonation and sole ozonation on the characteristics and conversion of organic fractions in bio-treated industrial wastewater

The conversion of hydrophobic (HPO)/transphilic (TPI)/hydrophilic (HPI) fractions of dissolved effluent organic matter (EfOM) in water by sole ozonation process (SOP) and catalytic ozonation process (COP) were investigated in this study. The modified iron shavings were used as catalyst in COP. The difference in total organic carbon (TOC) removal rate between SOP and COP for two types of bio-treated industrial wastewater was mainly caused by the different HPI degradation degree. The accumulation of HPI in SOP was 28.8% (in bio-treated dyeing wastewater) and 88.8% (in bio-treated paper-making wastewater) higher than that in COP, while HPO was degraded by more than 90% in both processes. Part of HPO was converted to TPI in the early stage (0–15 min) and the original HPI in the raw water was degraded at the same time. In the middle stage (15–60 min), TPI was transformed into HPI. The remaining fluorescent substances in HPI fraction in SOP were higher than those in COP, indicating that more HPI was accumulated in SOP. Among the fluorescent substances, aromatic protein II and SMP-like substances were removed more completely, while humic acid-like substances were relatively more difficult to degrade. Furthermore, COP had higher removal for fulvic acid-like substances, SMP-like substances and humic acid-like substances than SOP, while the removals of aromatic protein by COP and SOP were almost the same. COP had better removal effect than SOP for TPI and HPI organic pollutants with molecular weight (MW) more than 2 kDa. SOP and COP had no significant difference in the removal of HPO fraction and small molecular organics with MW less than 2 kDa. The remaining organic pollutants in the effluent of COP was mainly hydrophilic small molecular substances, which would be benefit for secondary biochemical process.

Profiling Olive Oil Mill Wastewater by Resin Fractionation: Effect of Acid Cracking, Coagulation, Electrocoagulation, and Fenton's Reagent

The organic matter content in original and chemically treated olive oil mill wastewater obtained from a three phase extraction plant was profiled by a resin fractionation procedure to evaluate changes in its characteristics after acid cracking as well as chemical treatment by FeCl3 coagulation, electrocoagulation with stainless steel electrodes, and an advanced oxidation processes (Fenton's reagent). For this purpose, untreated, acid‐cracked, and chemically treated wastewater samples were fractionated into hydrophobic and hydrophilic (acid–base–neutral) structures using XAD‐8, XAD‐4, AG‐MP‐50, and Duolite A‐7 resins. Structural distribution analysis of the untreated samples indicated that hydrophobic structures were the major (75–95%) components of the wastewater's organic matter content. For the total phenols parameter, a significant fraction (56%) appeared to be hydrophobic neutral coinciding with the acute toxicity of the olive oil mill wastewater. A significant amount of oil and grease as well as particulate organic matter could be removed by subjecting the original wastewater sample to acid cracking. FeCl3 coagulation appeared to be effective in the removal of hydrophobic fractions whereas electrocoagulation and the Fenton's reagent were also effective in the removal of hydrophilic organic matter. After chemical treatment of the olive oil mill wastewater, a significant shift in its structural distribution pattern was observed from mainly hydrophobic to more hydrophilic fractions.

Profiles of dissolved organic matter and haloacetic acid formation potential in drinking water treatment by a comprehensive fractionation technique

A comprehensive fractionation technique was applied to a set of water samples obtained along a real drinking water treatment plant with ozonation and granular activated carbon (GAC) treatment to obtain detailed profiles of dissolved organic matter (DOM) and to evaluate the haloacetic acid (HAA) formation potentials of these DOM fractions. The results indicated that ozonation and GAC treatment showed limited ability to remove hydrophilic fractions (23%), while removal of hydrophobic fractions was 72%. The contribution of hydrophilic fractions to HAA formation increased from 30 to 61% along the treatment train because of better removal for hydrophobic fractions both in concentration and reactivity. Similar trends were also found for trihalomethanes.