Groundwater nanofiltration process efficiency improvement with additional concentrate membrane treatment

Nanofiltration (NF) of waste water originated from nanofiltration drinking water plant stationed in town of Kikinda (Northern Serbia) was investigated. Experiments on removal characteristics of nanofiltration membranes when exposed to influent rich in arsenic and natural organic matter under different flux and transmembrane pressure (TMP) conditions were conducted in order to obtain drinking water from waste water and reduce total amount of waste water. Applied NF membranes showed remarkable removal characteristic. Also, obtained result for concentrate yield, an indicator of reduced concentrate amount, of 8.89% under optimum flux value presents considerable amount of reclamated drinking water. Calculated empirical and theoretical concentration factors quotients were indicated to probable accumulation of some inlet water components at NF membrane surface. Based on the obtained results that nanofiltration membranes remove natural organic matter, arsenic, ammonia and sodium with high efficiencies of 98%, 96%, 80% and 93% respectively, conceptual design of drinking water plant for City of Kikinda was defined and presented.

Download Full-text

Coagulation/flocculation/ultrafiltration for natural organic matter removal in drinking water production

Water Science & Technology Water Supply ◽

10.2166/ws.2004.0111 ◽

2004 ◽

Vol 4 (5-6) ◽

pp. 215-222 ◽

Cited By ~ 2

Author(s):

A.R. Costa ◽

M.N. de Pinho

Keyword(s):

Drinking Water ◽

Organic Matter ◽

Natural Organic Matter ◽

Membrane Fouling ◽

Membrane Filtration ◽

Membrane Surface ◽

Water Production ◽

Cellulose Acetate Membranes ◽

Wide Range ◽

Drinking Water Production

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.

Download Full-text

Direct coagulation pretreatment in nanofiltration of waters rich in organic matter and calcium

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0063 ◽

2001 ◽

Vol 1 (4) ◽

pp. 25-33

Author(s):

A. I. Schäfer ◽

A.G. Fane ◽

T.D. Waite

Keyword(s):

Organic Matter ◽

Natural Organic Matter ◽

Surface Waters ◽

Process Efficiency ◽

Nanofiltration Membranes ◽

Multivalent Ions ◽

Flux Decline ◽

Calcium Complexes ◽

The Impact ◽

Significant Flux

Nanofiltration (NF) can remove natural organic matter (NOM) and multivalent ions from surface waters. Large hydrophobic organics and calcium ions are responsible for irreversible fouling of nanofiltration membranes and thus a decrease of process efficiency and increase in cleaning requirements. Fouling due to the precipitation of organic-calcium complexes and the impact of colloids and coagulant (FeCl3) on the precipitation of these species was investigated. Coagulation in solution (as opposed to in the boundary layer) did not cause significant flux decline and was able to prevent irreversible fouling under conditions which were previously determined as detrimental. The rejection was varied if a strongly charged solid was deposited on the membrane.

Download Full-text

Assessment of Coagulation–Flocculation Process Efficiency for the Natural Organic Matter Removal in Drinking Water Treatment

Water ◽

10.3390/w13213073 ◽

2021 ◽

Vol 13 (21) ◽

pp. 3073

Author(s):

Corina Petronela Mustereț ◽

Irina Morosanu ◽

Ramona Ciobanu ◽

Oana Plavan ◽

Andreea Gherghel ◽

...

Keyword(s):

Water Quality ◽

Drinking Water ◽

Organic Matter ◽

Natural Organic Matter ◽

Oxygen Demand ◽

Principal Component ◽

Drinking Water Treatment ◽

Water Source ◽

Process Efficiency ◽

Aluminum Concentration

Natural organic matter (NOM) represents a range of heterogeneous hydrophobic and hydrophilic components naturally occurring in the water source and, due to the fact that they can act as precursors for the disinfection, by-products may have a considerable impact on drinking water quality. Coagulation–flocculation (C/F) is among the most applied processes for NOM removal from water sources (especially rivers). In this study, C/F efficiency for a river water supply was investigated in cold and warm conditions, by varying the coagulant dose and mixing conditions. In this study, polyhydroxy aluminum chloride PAX XL 60, and polyacrylamide FloPam AN 910 SEP were used as coagulant and flocculant, respectively. Multiple water quality indicators were determined, such as turbidity, chemical oxygen demand (COD), dissolved organic carbon (DOC), and residual aluminum concentration. Some unconventional parameters relevant for NOM removal were also considered, like absorbance at 254 nm (A254), at 280 nm (A280), and at 365 nm (A365), as well as the ratios A254/DOC, A254/280, and A254/A365. After coagulation–flocculation, turbidity was completely removed in all the studied conditions. The DOC content was reduced by up to 22.65% at a low temperature and by up to 31.81% at a high temperature. After the addition of polyelectrolyte in cold conditions, the efficiency in terms of A254 increased by up to 37.4%, while the specific absorbance decreased. The high molecular weight NOM increased after C/F, based on the A254/A365 ratio. Chemometric analysis was employed in order to determine the effect of the coagulant dose on the process efficiency. The optimum coagulation–flocculation conditions were corroborated by means of the principal component analysis.

Download Full-text

Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽

10.3390/membranes11070461 ◽

2021 ◽

Vol 11 (7) ◽

pp. 461

Author(s):

Fu Yang ◽

Zhengkun Huang ◽

Jun Huang ◽

Chongde Wu ◽

Rongqing Zhou ◽

...

Keyword(s):

Wastewater Treatment ◽

Shear Rate ◽

Membrane Surface ◽

Filtration Efficiency ◽

Operating Conditions ◽

Process Efficiency ◽

Transmembrane Pressure ◽

Leather Industry ◽

Pore Blocking ◽

The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

Download Full-text

Natural organic matter removal in a full-scale drinking water treatment plant using ClO2 oxidation: Performance of two virgin granular activated carbons

Journal of Water Process Engineering ◽

10.1016/j.jwpe.2021.102001 ◽

2021 ◽

Vol 41 ◽

pp. 102001

Author(s):

Outi Kaarela ◽

Markus Koppanen ◽

Tero Kesti ◽

Riitta Kettunen ◽

Marja Palmroth ◽

...

Keyword(s):

Drinking Water ◽

Organic Matter ◽

Water Treatment ◽

Natural Organic Matter ◽

Activated Carbons ◽

Treatment Plant ◽

Drinking Water Treatment ◽

Water Treatment Plant ◽

Full Scale ◽

Oxidation Performance

Download Full-text

Pilot Study on the Combination of Different Pre-Treatments with Nanofiltration for Efficiently Restraining Membrane Fouling While Providing High-Quality Drinking Water

Membranes ◽

10.3390/membranes11060380 ◽

2021 ◽

Vol 11 (6) ◽

pp. 380

Author(s):

Yan Chen ◽

Huiping Li ◽

Weihai Pang ◽

Baiqin Zhou ◽

Tian Li ◽

...

Keyword(s):

Drinking Water ◽

Activated Carbon ◽

Membrane Fouling ◽

Membrane Surface ◽

Post Treatment ◽

Size Exclusion ◽

Transmembrane Pressure ◽

Feed Water ◽

High Quality ◽

Treated Water

Nanofiltration (NF) is a promising post-treatment technology for providing high-quality drinking water. However, membrane fouling remains a challenge to long-term NF in providing high-quality drinking water. Herein, we found that coupling pre-treatments (sand filtration (SF) and ozone–biological activated carbon (O3-BAC)) and NF is a potent tactic against membrane fouling while achieving high-quality drinking water. The pilot results showed that using SF+O3-BAC pre-treated water as the feed water resulted in a lower but a slowly rising transmembrane pressure (TMP) in NF post-treatment, whereas an opposite observation was found when using SF pre-treated water as the feed water. High-performance size-exclusion chromatography (HPSEC) and three-dimensional excitation–emission matrix (3D-EEM) fluorescence spectroscopy determined that the O3-BAC process changed the characteristic of dissolved organic matter (DOM), probably by removing the DOM of lower apparent molecular weight (LMW) and decreasing the biodegradability of water. Moreover, amino acids and tyrosine-like substances which were significantly related to medium and small molecule organics were found as the key foulants to membrane fouling. In addition, the accumulation of powdered activated carbon in O3-BAC pre-treated water on the membrane surface could be the key reason protecting the NF membrane from fouling.

Download Full-text