Dewatering of activated sludge by forward osmosis (FO) with ultrasound for fouling control

Lee, Sangsuk; Shon, Ho Kyong; Hong, Seungkwan

doi:10.1016/j.desal.2017.02.010

Cited by 35 publications

(11 citation statements)

References 42 publications

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“…Some reports revealed that a combination technique is necessary to improve the cleaning efficiency further. For instance, a combination of ultrasound and flushing has been reported in regenerating the membrane after dewatering activated sludge [64]; air sourcing combined with hydraulic flushing to remove the silica scale layer [4].…”

Section: Membrane Cleaningmentioning

confidence: 99%

Membrane Fouling – The Enemy of Forward Osmosis

Chang

Teow

Yeap

et al. 2021

AMST

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Forward osmosis (FO) is an osmotically driven membrane separation process. It is potentially applied in various industries for nutrient recovery and water reclamation. Although FO showed a lesser fouling tendency than other pressure-driven membrane processes, the solutes in the feed solution would still deposit on the membrane surface, forming a fouling layer that resists water permeation. For that reason, fouling mitigation is a trending issue in the FO process. A better understanding of the fouling mechanism is required before opting for the appropriate strategy to mitigate it. This article describes the fouling mechanism based on different foulant presented in the feed, followed by a method in relieving fouling in the FO process.

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Section: Membrane Cleaningmentioning

confidence: 99%

Membrane Fouling – The Enemy of Forward Osmosis

Chang

Teow

Yeap

et al. 2021

AMST

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“…Still, antifouling strategies should be envisioned especially in the case of sludge dewatering where cake formation is inherent to the process. The application of ultrasounds for fouling mitigation proved to impact sludge flocs; mitigation of fouling deposition was observed only under mild/controlled conditions—continuous ultrasound radiation applications may cause high organic release from sludge flocs, thus leading to higher fouling rate [ 165 , 166 ]. Module scale testing considering adapted module design to tackle clogging, and high solid concentration issues and anti-fouling strategies are still to be evaluated to further assess the potential of FO for sludge concentration.…”

Section: Applications Of Fo As Concentrating Processmentioning

confidence: 99%

Forward Osmosis as Concentration Process: Review of Opportunities and Challenges

et al. 2020

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In the past few years, osmotic membrane systems, such as forward osmosis (FO), have gained popularity as “soft” concentration processes. FO has unique properties by combining high rejection rate and low fouling propensity and can be operated without significant pressure or temperature gradient, and therefore can be considered as a potential candidate for a broad range of concentration applications where current technologies still suffer from critical limitations. This review extensively compiles and critically assesses recent considerations of FO as a concentration process for applications, including food and beverages, organics value added compounds, water reuse and nutrients recovery, treatment of waste streams and brine management. Specific requirements for the concentration process regarding the evaluation of concentration factor, modules and design and process operation, draw selection and fouling aspects are also described. Encouraging potential is demonstrated to concentrate streams more than 20-fold with high rejection rate of most compounds and preservation of added value products. For applications dealing with highly concentrated or complex streams, FO still features lower propensity to fouling compared to other membranes technologies along with good versatility and robustness. However, further assessments on lab and pilot scales are expected to better define the achievable concentration factor, rejection and effective concentration of valuable compounds and to clearly demonstrate process limitations (such as fouling or clogging) when reaching high concentration rate. Another important consideration is the draw solution selection and its recovery that should be in line with application needs (i.e., food compatible draw for food and beverage applications, high osmotic pressure for brine management, etc.) and be economically competitive.

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“…The driving force for FO is the osmotic pressure gradient across the semi-permeable membrane, and no external driving force is required [23]. FO is currently applied to biosolid separation in wastewater treatment and food processing [24]. Buckwatter et al reported that FO is considered as a partial dewatering method for microalgae growing on wastewater in a marine environment, using artificial seawater as the draw solution; average dewatering rates of 2 L/m 2 membrane/h were observed [21].…”

Section: Introductionmentioning

confidence: 99%

Optimisation of Tray Drier Microalgae Dewatering Techniques Using Response Surface Methodology

et al. 2018

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The feasibility of the application of a tray drier in dewatering microalgae was investigated. Response surface methodology (RSM) based on Central Composite Design (CCD) was used to evaluate and optimise the effect of air temperature and air velocity as independent variables on the dewatering efficiency as a response function. The significance of independent variables and their interactions was tested by means of analysis of variance (ANOVA) with a 95% confidence level. Results indicate that the air supply temperature was the main parameter affecting dewatering efficiency, while air velocity had a slight effect on the process. The optimum operating conditions to achieve maximum dewatering were determined: air velocities and temperatures ranged between 4 to 10 m/s and 40 to 56 °C respectively. An optimised dewatering efficiency of 92.83% was achieved at air an velocity of 4 m/s and air temperature of 48 °C. Energy used per 1 kg of dry algae was 0.34 kWh.

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Dewatering of activated sludge by forward osmosis (FO) with ultrasound for fouling control

Cited by 35 publications

References 42 publications

Membrane Fouling – The Enemy of Forward Osmosis

Membrane Fouling – The Enemy of Forward Osmosis

Forward Osmosis as Concentration Process: Review of Opportunities and Challenges

Optimisation of Tray Drier Microalgae Dewatering Techniques Using Response Surface Methodology

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