Impact of Chlorinated-Assisted Backwash and Air Backwash on Ultrafiltration Fouling Management for Urban Wastewater Tertiary Treatment

To improve membrane fouling management, the NaClO-assisted backwash has been developed to improve permeability maintenance and reduce the need for intensive chemical cleanings. This study is aimed to focus on the efficiency of NaClO-assisted backwash in real UF pilot scale and with periodic classic backwash (CB) and air backwash (AB). The impacts on hydraulic filtration performance, physicochemical properties of membrane material under different addition frequencies of NaClO, and the performance of chlorinated CB and AB will be discussed. In result, 10 mg Cl2 L−1 NaClO addition in backwash water is confirmed to greatly improve the overall filtration performance and backwash cleaning efficiency. One condition stands out from the other due to better control of irreversible fouling, less NaClO consumption in 10 years prediction, sustainable and adaptable filtration performance, and less potential damage on the physicochemical properties of the membrane. Additionally, it can be inferred from this experiment that frequent contact with NaClO induced some degradation on the PES-made UF membrane surface properties. To retain the best state of UF membrane on anti-fouling and qualified production, the optimized condition with more frequent NaClO contact was not suggested for long-term filtration.

Magnetic Photocatalyst for Wastewater Tertiary Treatment at Pilot Plant Scale: Disinfection and Enrofloxacin Abatement

In this work, we have tested a photocatalytic material consisting of a core of SiO2/Fe3O4 coated with TiO2 (Magnox) for plausible tertiary wastewater treatment. For this, a pilot plant of 45 L equipped with an Ultraviolet light (UVC) lamp was employed to study the degradation of a model contaminant, enrofloxacin (ENR), as well as water disinfection (elimination of Escherichia coli and Clostridium perfringens). The influence of different operational conditions was explored by means of dye (rhodamine-B) decolorization rates, analyzing the effects of photocatalyst quantity, pH and recirculation flow rates. The magnox/UVC process was also compared with other four Advanced Oxidation Processes (AOPs): (i) UVC irradiation alone, (ii) hydrogen peroxide with UVC (H2O2/UVC), (iii) Fenton, and (iv) photo-Fenton. Although UVC irradiation was efficient enough to produce total water disinfection, only when employing the AOPs, significant degradations of ENR were observed, with photo-Fenton being the most efficient process (total enrofloxacin removal in 5 min and c.a. 80% mineralization in 120 min, at pH0 2.8). However, Magnox/UVC has shown great pollutant abatement effectiveness under neutral conditions, with the additional advantage of no acid or H2O2 addition, as well as its plausible reuse and simple separation due to its magnetic properties.

EXPERIMENTAL STUDY OF TERTIARY TREATMENT OF WASTEWATER USING ZEOLITE

Small individual household wastewater treatment plants not always operate well. Consequently, the concentrations of ammonium nitrogen and phosphate phosphorus are exceeded. The aim of the work was to examine the zeolite as a wastewater tertiary treatment material and propose environmentally friendly ways to solve fresh water problem. During experiment zeolite filter material was tested. In the article is analyzed zeolite filtering efficiency of nutrient removal from wastewater. Zeolite filler most effective was against ammonium nitrogen (99.9–10.1%) and relatively less effective against phosphate phosphorus (51.2–4.9%).

RESEARCH OF WASTEWATER TERTIARY TREATMENT / TRETINIO NUOTEKŲ VALYMO TYRIMAI

Small individual household wastewater treatment plants not always operate well. Consequently, the concentrations of ammonium nitrogen and phosphate phosphorus are exceeded. The aim of the work was to found the most effective material for wastewater tertiary treatment and propose environmentally friendly ways to solve fresh water problem. Three filter fillings (foam-glass, zeolite and biochar) were tested. As a result, we have got a following conclusion, foam-glass removed phosphate phosphorus most effectively (efficacy – 14−91%) and against ammonium nitrogen, comparatively effective was zeolite (efficacy – 29−100%). Santrauka Individualaus buitinių nuotekų valymo įrenginiai ne visada dirba efektyviai. Dėl to fiksuojami nitratų azoto, amonio azoto, bendrojo azoto, bendrojo fosforo ir fosfatų fosforo koncentracijų išvalytose nuotekose viršijimai. Darbo tikslas surasti efektyvias medžiagas tretiniam nuotekų valymui ir pasiūlyti šiai problemai spręsti aplinkai draugiškas technologijas, kad išvalytos nuotekos nepakenktų aplinkos kokybei. Buvo tirti trys filtro užpildai (pustiklis, ceolitas, bioanglis). Gauti rezultatai ir išvados, kad pustiklis efektyviau (efektyvumas – 14−91%) šalina iš nuotekų fosfatų fosforą, o ceolitas – amonio azotą (efektyvumas – 29−100 %).

Research of Wastewater Tertiary Treatment

The tertiary wastewater treatment experiment was performed on the experimental stand which was installed in a wastewater treatment plant and which consisted of three filters of the diameter of 380 mm with a non-submerged media. Biologically treated wastewater was constantly supplied to these filters. Tertiary wastewater treatment process was aggravated due to low temperature of wastewater (6 °C) and high fluctuations of load according to individual pollutants – the difference between the minimum and maximum values ranged from 3 to 10 times. The productivity of removal of pollutants according to individual contamination rates reached 8 to 43%.