Influence of Source Characteristics, Chemicals, and Flocculation on Chemically Enhanced Primary Treatment

Neupane, Dilli; Riffat, Rumana; Murthy, Sudhir; Perić, Marija; Wilson, Thomas E.

doi:10.2175/106143007x221355

Cited by 13 publications

(9 citation statements)

References 9 publications

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“…[22] The velocity gradient was 174.8 and 45 s −1 during the mixing and reaction phase respectively, close to 150 and 14 s −1 by Haydar et al [20].…”

Section: Orthogonal Test Designsupporting

confidence: 81%

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Feasibility and optimization of wastewater treatment by chemically enhanced primary treatment (CEPT): a case study of Huangshi

Wang

et al. 2016

Chemical Speciation & Bioavailability

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Carbon and nutrients as well as suspended solids (SS) removal by chemically enhanced primary treatment (CEPT) were conducted in the Qingshan wastewater treatment plant in Huangshi, Hubei Province. Feasibility of this process for wastewater treatment were investigated in detail by comparing the removal performance of three inorganic chemical coagulants (polyaluminium chloride, polyaluminium ferric chloride [PAFC] and poly ferric sulfate) individual or couple with poly acrylamide, optimizing the conditions during CEPT by both single factor analysis and orthogonal test designs. The results of this study demonstrated that CEPT turned out to be an effective method for wastewater treatment, with PAFC as the optimal coagulant, which showed preeminent removal capacity for chemical oxygen demand, total phosphorus and SS. The optimal working condition could be at pH 7.0, settling time 15 min, and velocity gradient of 174.80 and 15.56 s −1 for mixing and reaction phase respectively. While the coagulant dosage depends on raw water attributes, which had a decisive effect on CEPT treatment performances. However, the three coagulants behaved poorly in nitrogen removal.

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“…[22] The velocity gradient was 174.8 and 45 s −1 during the mixing and reaction phase respectively, close to 150 and 14 s −1 by Haydar et al [20].…”

Section: Orthogonal Test Designsupporting

confidence: 81%

“…This was due to that metal ions in raw water precipitated in such environments, thus aid coagulation process by coagulant. [22] That's why flocs could be seen even without coagulants dosage in our study. Therefore, the original pH of raw water (6.82) was selected as the optimal pH.…”

Section: Orthogonal Test Designmentioning

confidence: 63%

Feasibility and optimization of wastewater treatment by chemically enhanced primary treatment (CEPT): a case study of Huangshi

Wang

et al. 2016

Chemical Speciation & Bioavailability

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“…Therefore, different regionally focused efforts have been undertaken to develop simple but higher‐rate processes targeting not only solid but also colloidal and soluble organic matter : Chemically enhanced primary treatment (CEPT) prior to the activated sludge has been successfully used in North America and Europe. In combination with phosphorus precipitation, CEPT has become an economically viable option and complementary dosing of flocculants and coagulants has improved efficiency further (Neupane, Riffat, Murthy, Peric, & Wilson, 2008; Wan, Gu, Zhao, & Liu, 2016) significantly reducing the organic loadings to downstream treatment processes. Contact‐Stabilization process (CS) has been implemented in North America already since the fifties (Ullrich & Smith, 1951). Biosorption was identified as the dominant mechanism of high‐rate carbon removal in the activated sludge process which can be enhanced by aerating return sludge in a separate stabilization tank before the biomass is exposed to raw sewage in the anaerobic contact zone (Van Winckel, 2014).…”

Section: Introductionmentioning

confidence: 99%

Operational and structural A‐stage improvements for high‐rate carbon removal

Wett¹,

Aichinger²,

Hell³

et al. 2020

Water Environment Research

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Biosorption of organics is investigated at two sites in order to optimize operation and infrastructure for carbon removal and redirection in upstream, high‐rate processes. Sufficient process temperature and stable mixed liquor solids concentration were established as the key impact parameters for the process performance. Improved COD removal was achieved by either substantially enhanced aeration (elevated metabolic state) or by enhanced flocculation capability (dosed chemicals). Separation and thickening of organics are typically operated as continuous‐flow processes. The optimization of performance parameters led to a new A‐stage process named alternating activated adsorption. The AAA process is presented as a novel configuration linking biosorption and thickening capabilities in an alternating scheme without mechanical equipment. The performance data from its first trial indicate benefits from process dynamics including high organics capture rates and thickening capabilities reaching solid concentrations higher than 40 g(TSS)/L. COD removal could be increased further by adding biologically generated polymer, that is waste sludge from B‐stage. © 2020 Water Environment Federation Practitioners Points Enhanced preliminary treatment helps to increase capacity and energy efficiency. Low RAS rates, SRT control, aeration, high temperatures, and metal dosing are key performance parameters for removal rates and energy efficiency. The Triple‐A process offers new possibilities for A‐stage in terms of performance increase and flexibility showing similar or better results compared with conventional A‐stage. Adding B‐sludge improved COD and nutrient removal rates. High preliminary removal rates of COD and N foster sidestream processes.

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“…One of the existing technologies being considered for carbon redirection is chemically enhanced primary treatment (CEPT) [1]. CEPT refers to the process whereby chemicals are added to primary influent to promote coagulation and/or flocculation in primary clarifiers, resulting in improved removals via precipitation of particulate/dissolved solids as well as the carbon and nutrients associated with those solids [2]. Historically, metal salts, such as ferric chloride and alum, were considered as coagulants to be added to primary influent to enhance the removal of phosphorus.…”

Section: Introductionmentioning

confidence: 99%

“…The other advantages of CEPT include a reduction of the footprint of primary settling processes, as it permits operation at high surface overflow rates, while also reducing the footprint and operating cost of subsequent biological treatment processes due to the decreased organic and nitrogen loadings contained in primary effluent. Despite these advantages, previous studies concerning CEPT have only focused on the selection of coagulants and flocculants for wet weather flow conditions and phosphorus removal [2,11,12]. Studies that holistically address the potential for optimization of CEPT technology for simultaneous carbon redirection, wet weather flow, and phosphorus removal are limited.…”

Section: Introductionmentioning

confidence: 99%

Optimizing Chemically Enhanced Primary Treatment Processes for Simultaneous Carbon Redirection and Phosphorus Removal

Tang

Shewa

Murray³

et al. 2019

Water

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There has been increased interest towards maximizing wastewater energy recovery by enhancing the carbon captured through the primary treatment process such as chemically enhanced primary treatment (CEPT). This research was conducted to optimize the CEPT performance in terms of redirection of carbon and nutrients in both bench- and full-scale operations. In order to improve the CEPT process, the performance of ferric chloride and seven types of polymers were evaluated through jar testing. The optimal coagulant (15 mg/L ferric chloride) and flocculant (0.5 mg/L poly aluminum chloride (PACl)) combination achieved total COD, soluble COD, total suspended solids (TSS), and total phosphorus (TP) removal efficiencies of 76, 58, 89, and 84, respectively, in a full-scale primary clarifier operation. In doing so the organic matter and phosphorus were concentrated in CEPT sludge, making them available for recovery. Furthermore, the relationship between influent characteristics and removal rates under varying operating conditions was investigated. It was found that soluble COD removal appeared to be season-dependent, and TSS removals were independent of influent TSS concentrations in all scenarios. The removal of tCOD, sCOD, and TP had a positive relationship with their corresponding concentrations when the polymer Alcomer® 120L was used, whereas no correlation between removal and concentration was observed with PACl.

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Influence of Source Characteristics, Chemicals, and Flocculation on Chemically Enhanced Primary Treatment

Cited by 13 publications

References 9 publications

Feasibility and optimization of wastewater treatment by chemically enhanced primary treatment (CEPT): a case study of Huangshi

Feasibility and optimization of wastewater treatment by chemically enhanced primary treatment (CEPT): a case study of Huangshi

Operational and structural A‐stage improvements for high‐rate carbon removal

Optimizing Chemically Enhanced Primary Treatment Processes for Simultaneous Carbon Redirection and Phosphorus Removal

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