Electrolysis and permanganate (PM) oxidation are two commonly used technologies for water treatment. However, they are often handicapped by their slow reaction rates. To improve the removal efficiency of refractory contaminants, we combined electrolysis with PM using an activated carbon fiber (ACF) as cathode (E-ACF-PM) for the first time to treat diclofenac (DCF) in aqueous solution. Up to 90% DCF was removed in 5 min by E-ACF-PM process. In comparison, only 3.95 and 27.35% of DCF was removed by individual electrolysis and PM oxidation at the same time, respectively. Acidic condition was more conducive to DCF removal. Surprisingly, soluble Mn(III) _{( aq)} formed on the surface of ACF was demonstrated as the principal oxidizing agent in E-ACF-PM process. Further studies showed that all three components (electrolysis + ACF + PM) were necessary to facilitate the heterogeneous generation of reactive Mn(III) _{( aq)}. Moreover, SEM images and XPS spectra of ACF before and after treatment revealed that the morphologies and elemental compositions of reacted ACF were nearly unchanged during the E-ACF-PM process. ACF can be remained active and utilized to the rapid degradation of DCF in E-ACF-PM process even after reused for 20 times. Therefore, the E-ACF-PM process may provide a novel and effective alternative on the generation of reactive Mn(III) _{( aq)} in situ for water treatment by green electrochemical reactions.

High-silica zeolites have been found to be effective adsorbents for the removal of organic micro-pollutants (OMPs) from impaired water, including various pharmaceuticals, personal care products, industrial chemicals, etc. In this review, the properties and fundamentals of high-silica zeolites are summarised. Recent research on mechanisms and efficiencies of OMP adsorption by high-silica zeolites are reviewed to assess the potential opportunities and challenges for the application of high-silica zeolites for OMP adsorption in water treatment. It is concluded that the adsorption capacities are well-related to surface hydrophobicity/hydrophilicity and structural features, e.g. micropore volume and pore size of high-silica zeolites, as well as the properties of OMPs. By using high-silica zeolites, the undesired competitive adsorption of background organic matter (BOM) in natural water could potentially be prevented. In addition, oxidative regeneration could be applied on-site to restore the adsorption capacity of zeolites for OMPs and prevent the toxic residues from re-entering the environment.

A novel advanced oxidation process, combined zero-valent iron and sulfite (Fe⁰/sulfite) system containing oxygen, was firstly developed to efficiently degrade organic pollutants at weak acidic and neutral conditions by selecting X-3B as a target compound. The removal of X-3B was attributed to the formed reactive radicals, such as SO₄ ^-, SO₅ ^- and HO^[rad], in the Fe⁰/sulfite system, and SO₄ ^- was evidenced as the principal reactive species. The quite low removal efficiency of X-3B (less than 5%) after reaction for 90 min with purging nitrogen gas suggests oxygen to be an essential factor for producing SO₄ ^- in the system. Optimal dosages of Fe⁰ and sulfite were suggested to be 0.5 mM and 1.0 mM, respectively, in the system as both the two chemicals would scavenge the reactive radicals at overdosing. The presence of 2 mM bicarbonate significantly inhibited the removal of X-3B from 74.1% to 37.5% in the system. Halide ions inhibited the removal of X-3B following a trend that Cl⁻ <Br⁻ <I⁻. HSO₃ ⁻, being effective in complexion of Fe(II) and transferring Fe(III) to Fe(II), is the main species during pHs 4–6, which results in the good reuse of Fe⁰ and the highest removal efficiency of X-3B at weak acidic condition. Fe⁰/sulfite system was also evidenced to be effective in the treatment of actual textile effluents along with improving biodegradability, and the removal of nitrobenzene, methylparaben, bisphenol A, imipramine and amitriptyline. Overall, this study provided a cheap and easy operational advanced oxidation process in treatment of aqueous organic pollutants.

In order to improve the efficiency of anaerobic sludge digestion, alkaline and high pressure homogenization (HPH) were combined to pre-treat the excess activated sludge. The effect of HPH operating parameters, including homogenization pressure and cycle number, on the performances of anaerobic sludge digestion was studied. The results demonstrated that the performances of sludge disintegration and anaerobic digestion were markedly enhanced by increasing the homogenization pressure. After pretreatment at a homogenization pressure of 60 MPa with one homogenization cycle combined with an alkaline dosage of 0.04 mol/L, the sludge TCOD, VS removal and cumulative biogas production in a mesophilic anaerobic digestion system increased by 24.68%, 18.95% and 95.81%, respectively, in comparison with that with the alkaline pretreatment alone. But the sludge disintegration and biogas production only slightly increased with the increase of homogenization cycle. Considering biogas production and energy-saving, the suitable homogenization operation was selected as homogenization pressure of 60 MPa with once cycle. Relationships between methane yield and sludge disintegration showed that the improved methane production was mainly attributed to the sludge disintegration resulted from combined sludge pretreatment.

Cyanobacteria blooms in source waters have become a worldwide issue for drinking water production. UV-activated persulfate (UV/PS) technology was firstly applied to remove cultivated Microcystis aeruginosa (M. aeruginosa) in bench scale. The presence of persulfate significantly enhanced both cytoclasis and algal organic matter mineralization compared with UV-C inactivation alone. Around 98.2% of algal cells were removed after UV/PS process treatment for 2 h at a dosage of PS being 1500 mg/L (approximately 6 mM). Both sulfate and hydroxyl radicals were proven to contribute to the removal of algae and the loss of cell integrity. The cultivated M. aeruginosa in death growth phase were found to be more vulnerable to UV/PS treatment than those growing in log phase, thus a significant lower dosage of PS is needed to achieve the desired removal efficiency. This study suggested a novel application of UV/PS process in the removal of algae in source waters due to the high degradation efficiency of both algal cells and their derived organic matter.