High suspended solids removal of Indian drain water with a down-scaled Dissolved Air Flotation (DAF) for water recovery. Assessing water-type dependence on process control variables

Piaggio, Antonella L.; Soares, Laís Américo; Balakrishnan, Malini; Guleria, Tavishi; Kreuk, Merle de; Lindeboom, Ralph E.F.

doi:10.1016/j.envc.2022.100567

Cited by 7 publications

(5 citation statements)

References 48 publications

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“…Due to its low retention time, high loading rate, limited space occupation, production of tiny bubbles, and increased interactions of gas bubbles with particles/droplets, this equipment is preferred to the others that rely solely on chemical purification 2 , 3 . A sudden decrease in the pressure of the air–water mixture stream exiting the air-saturator at a pressure up to 700 kPa results in the formation of microbubbles with sizes ranging from 10 to 100 μm 4 , 5 . The separation efficiency of equipment such as DAF and induced gas flotation (IGF) is affected by the oil droplet diameter, flow pattern, bubble size, surfactant substances, temperature, and operating pressure.…”

Section: Introductionmentioning

confidence: 99%

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A digital image analysis approach to understand the microscopic and macroscopic phenomena in dissolved air flotation

Taghizadeh Mohammadi,

Movahedirad

2024

Sci Rep

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Dissolved air flotation (DAF) is an effective method for separating suspended oil and solid particles from wastewater by utilizing small air bubbles. This study aims to investigate the impact of key factors, such as saturating pressure and water flow rate, on the separation of fine oil droplets from a water stream. The macroscopic flow patterns within the cell were analyzed using particle image velocimetry (PIV), while Digital Image Analysis (DIA) was employed to study microscopic phenomena, including oil droplet rising velocity and oil-bubble contact mechanisms. Our findings propose a safe operating window (specifically, water flow rate and saturation pressure) for the effective separation of oil droplets without any oil escaping into the clean water stream. It was found that the oil droplet rising velocity increases with the saturation pressure up to 200 kPa. However, a further increase in the pressure of the air saturating chamber leads to a decrease in oil droplet rising velocity. Additionally, we identified a peak in rising velocity at an oil droplet size of approximately 200 µm. Below this threshold, the rising velocity increases with droplet size, while for droplet sizes exceeding 200 µm, the rising velocity decreases with size. This behavior can be explained by the conflicting effects of droplet size increment according to the Stokes law for the rising velocity of oil droplets. As the droplet size increases, the average density of the bubbles/droplet aggregate rises, reducing the ∆ρ in the Stokes law and subsequently lowering the aggregate rising rate. However, as per the Stokes law, the oil droplet rising velocity increases proportionally to the square of its size.

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Section: Introductionmentioning

confidence: 99%

“…The hydrodynamic design of the DAF equipment, the occurrence of bubbles, and the methods by which oil droplets and gas bubbles are connected result in sufficiently large flocs. As oil/bubbles aggregate has a lower density compared to the water, the formed clots flow to the top more quickly 4 , 6 .…”

Section: Introductionmentioning

confidence: 99%

A digital image analysis approach to understand the microscopic and macroscopic phenomena in dissolved air flotation

Taghizadeh Mohammadi,

Movahedirad

2024

Sci Rep

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“…In a paradigm change, wastewater is being perceived as a resource with the focus shifting from treatment towards recovery of resources (e.g., water, energy, nutrients) (Coats and Wilson, 2017). Wastewater flowing in urban drains is often characterized by low organic load (in terms of chemical oxygen demand, COD) (Dalvi et al, 2021;Piaggio et al, 2022). Considering the low energy consumption in anaerobic treatment and the advantage of retaining the slow-growing anaerobic microorganisms in the reactor, anaerobic membrane bioreactors (AnM-BRs) have been tested for treating as-is and diluted municipal wastewater (Baek et al, 2010;Ji et al, 2020;Lin et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Performance of Anaerobic Membrane Bioreactor (AnMBR) with Sugarcane Bagasse Ash-based Ceramic Membrane treating Simulated Low-strength Municipal Wastewater: Effect of Operation Conditions

Dhiman¹,

Balakrishnan

Naddeo

et al. 2023

Water Air Soil Pollut

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This study assesses the performance of waste sugarcane bagasse ash (SBA)-based ceramic membrane in anaerobic membrane bioreactor (AnMBR) treating low-strength wastewater. The AnMBR was operated in sequential batch reactor (SBR) mode at hydraulic retention time (HRT) of 24 h, 18 h, and 10 h to understand the effect on organics removal and membrane performance. Feast-famine conditions were also examined to evaluate system performance under variable influent loadings. An average removal of >90% chemical oxygen demand (COD) was obtained at each HRT and starvation periods up to 96 days did not significantly affect removal efficiency. However, feast-famine conditions affected extracellular polymeric substances (EPS) production and consequently the membrane fouling. EPS production was high (135 mg/g MLVSS) when the system was restarted at 18 h HRT after shutdown (96 days) with corresponding high transmembrane pressure (TMP) build-up; however, the EPS content stabilized at ~60-80 mg/g MLVSS after a week of operation. Similar phenomenon of high EPS and high TMP was experienced after other shutdowns (94 and 48 days) as well. Permeate flux was 8.8±0.3, 11.2±0.1 and 18.4±3.4 L/m 2 h at 24 h, 18 h and 10 h HRT, respectively. Filtration-relaxation (4 min -1 min) and backflush (up to 4 times operating flux) helped control fouling rate. Surface deposits (that significantly attributed to fouling) could be effectively removed by physical cleaning, resulting in nearly complete flux recovery. Overall, SBR-AnMBR system equipped with waste-based ceramic membrane appears promising for treatment of low-strength wastewater with disruptions in feeding.

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“…When located after a pilot-scale anaerobic digester treating domestic wastewater, DAF removal of suspended solids was reported to reach 96% . Moreover, previous research showed that a lab-scale DAF could remove up to 95% of the influent total suspended solids (TSS) in the range of 0.03–5.0 g L –1 , resembling the TSS content of municipal wastewater and the real wastewater from the project target area, the Barapullah drain in New Delhi, India . Hence, using a different physical separation unit may ensure a high TSS retention while overcoming the AnMBR limitations.…”

Section: Introductionmentioning

confidence: 99%

“… 8 Moreover, previous research showed that a lab-scale DAF could remove up to 95% of the influent total suspended solids (TSS) in the range of 0.03–5.0 g L –1 , resembling the TSS content of municipal wastewater and the real wastewater from the project target area, the Barapullah drain in New Delhi, India. 9 Hence, using a different physical separation unit may ensure a high TSS retention while overcoming the AnMBR limitations. Replacing the AnMBR with an AD-DAF system, in which the flotation layer is returned to the anaerobic digester for sewage and drain pretreatment, is proposed.…”

Section: Introductionmentioning

confidence: 99%

Effects of Low Oxygen Dosages on an Anaerobic Membrane Bioreactor, Simulating the Oxygen Load in an Anaerobic Digester-Dissolved Air Flotation (AD-DAF) System

Piaggio,

Sasidhar,

Khande

et al. 2023

ACS EST Water

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This study reports the effects of microaeration on a laboratory-scale AnMBR (MA-AnMBR) fed with synthetic concentrated domestic sewage. The imposed oxygen load mimics the oxygen load coming from a dissolved air flotation (DAF) unit, establishing an anaerobic digester-DAF (AD-DAF) combination with sludge recycling. Results showed a reduced COD concentration in the MA-AnMBR permeate compared with the AnMBR permeate, from 90 to 74 mgCOD L −1 , and a concomitant 27% decrease in biogas production. The MA-AnMBR permeate ammonium (NH 4 + ) concentration increased by 35%, to 740 mgNH 4 + -N L −1 , indicating a rise in the hydrolytic capacity. Furthermore, the MA-AnMBR biomass seemingly adapted to an increased oxygen load, which corresponded to 1% of the influent COD load (approximately 55 mLO 2 d −1 ). Concomitantly, an increase in the superoxide dismutase activity (SOD) of biomass was detected. Meanwhile, negligible changes were observed in the specific methanogenic activity (SMA) of the microaerated biomass that was subjected to an oxygen load equivalent to 3% of the influent COD load in batch tests. The obtained results showed that an AD-DAF system could be a promising technology for treating concentrated domestic wastewater, improving sewage sludge hydrolysis, and overall organic matter removal when compared to an AnMBR.

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High suspended solids removal of Indian drain water with a down-scaled Dissolved Air Flotation (DAF) for water recovery. Assessing water-type dependence on process control variables

Cited by 7 publications

References 48 publications

A digital image analysis approach to understand the microscopic and macroscopic phenomena in dissolved air flotation

A digital image analysis approach to understand the microscopic and macroscopic phenomena in dissolved air flotation

Performance of Anaerobic Membrane Bioreactor (AnMBR) with Sugarcane Bagasse Ash-based Ceramic Membrane treating Simulated Low-strength Municipal Wastewater: Effect of Operation Conditions

Effects of Low Oxygen Dosages on an Anaerobic Membrane Bioreactor, Simulating the Oxygen Load in an Anaerobic Digester-Dissolved Air Flotation (AD-DAF) System

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