A New Activated Sludge Model with Membrane Separation–Implications for Sewage and Textile Effluent

Self Cite

Background This study evaluated the essential role of the experimental support as an integral component of process design for the nitrogen removal activated sludge process. This role was demonstrated in prescribing and implementing a relevant design procedure; a similar treatment plant at Ambarlı in Istanbul was selected to provide the necessary experimental support, which was derived from the sewage, lab‐scale experiments, and from the plant itself. Each step of the design included the relevant scientific and conceptual basis and was implemented using the necessary experimental data specifically generated from a selected wastewater source. Results The target was to compile experimental data that would be necessary for the study and be equally applicable to similar design or research activities elsewhere. This data included major wastewater characteristics, chemical oxygen demand (COD) fractionation, process kinetics for COD removal and nitrification, applicable sewage temperature, and details for the impact of primary settling on system performance. Conclusion This study developed a new design approach involving solely COD for both the substrate and biomass but expressing the related component per unit flow rate. This approach offered a template that is adjustable to any similar design by only requiring specific information on the sewage flow and sludge age. The entire design procedure was presented as supported by original experimental data and in a summarized algorithm format. The study also emphasized the selection of an appropriate anoxic volume. A revised empirical expression was suggested for the computation of the corresponding denitrification potential, which was also supported by process modelling; they both indicated that the current empirical approach generally defined an excessively large anoxic volume. © 2022 Society of Chemical Industry (SCI).

N_{DP} goodbreak= \frac{(1 - Y_{NHE})}{2.86} ([], S_{normalS 0} goodbreak+ S_{normalH 0} goodbreak+ f_{BX} ((), \frac{V_{D}}{V_{T}}) X_{normalS 0})

Section: Experimental Evaluationmentioning

confidence: 76%

Section: Denitrification Potentialmentioning

confidence: 97%

Role of experimental support as an essential component of sustainable design of the activated sludge process for nitrogen removal

Orhon

Hallaç²,

Kurt³

et al. 2022

Self Cite

“…However, the hydrolysis half-saturation constants were found to be lower than the values in the literature. 37,38…”

Section: Wileyonlinelibrarycom/jctbmentioning

confidence: 99%

Anatomy of chemically enhanced sewage settling by particle size distribution analysis

Duba

Sözen

Doğruel

et al. 2022

Self Cite

BACKGROUND: This study investigated the anatomy of organic carbon (as chemical oxygen demand, COD) removal from sewage through chemically assisted settling, by means of particle size distribution (PSD) analysis: it showed which size fractions were affected, aside from the particulate COD. The experiments were conducted on the effluent of the existing preliminary treatment plant before deep-sea discharge into the Bosphorus. FeCl 3 , alum and polyaluminum chloride (PAC) were used as coagulants at different doses. The performance of the coagulants on the effluent COD was interpreted with PSD.RESULTS: PAC at 25 mg L −1 , selected as the optimum coagulant, reduced COD below soluble COD level, to around 145 mg L −1 , with an overall efficiency of more than 70%. Although chemical settling was most effective on particulate COD at >450 nm, it also provided a COD removal of 28% in 220-450 nm of the colloidal range and 40% in 13-220 nm of the range, representing soluble hydrolysable COD. The lowest removal rate was observed in the soluble range, consisting of readily biodegradable (only 5%) and a part of the inert COD (<2 nm) identified as 12%twice as high as ordinary domestic wastewaters, with only 1%.CONCLUSION: PSD and COD fractionation analyses were instrumental in depicting the potential of chemically enhanced settling to reduce COD in the soluble range, identifying the distribution of remaining COD fractions in different size intervals. The results also suggested a novel treatment process with additional membrane filtration, namely membrane chemical reactor, (MCR), reflecting a potential for replacing the conventional activated sludge process.

“…23,47 Later, relevant microbial mechanisms of super-fast MAS systems for organic carbon removal could be assessed by means of model analysis for domestic sewage and selected industrial wastewaters. 48,49 A review, after evaluating all existing information, argued that in the near future, the activated sludge process will be reshaped and 'the novel AS configuration shall not include gravity settling and it will be operated at extremely low ⊔ X levels of <2.0 d'. 50 The evaluation focused on the energy conservation aspect mainly because it constituted the rate-limiting step of the energy recovery mechanism.…”

Section: Effective Energy Conservationmentioning

confidence: 99%

Efficient energy recovery from wastewater with high rate activated sludge process: oversights and misguidances

Orhon

Çokgör

Sözen

2022

Self Cite

Background The major aim of the study was to define a scientific framework to evaluate energy recovery from domestic wastewater, based on model assessment of process stoichiometry and kinetics using relevant experimental data. The evaluation was tailored to reveal and explain all the oversights and misconceptions on the subject. A new approach was adopted to focus specifically on a paper by Liang et al. (2022) to better visualize and indicate scientific ways to remedy the key misguidances. The alternative appraisal utilized the latest available support in terms of the database for chemical oxygen demand (COD) fractionation and process kinetics. Results The evaluation first demonstrated the inherent deficiencies of high rate activated sludge (HRAS) configurations such as the sequencing batch reactor and contact stabilization; then, it presented a new way to define excess sludge components in terms of fractions of the influent COD, indicating the major handicap for energy recovery and biomass loss in the effluent due to gravity settling. Effective energy conservation was computed to remain between 17% and 37% when the sludge age was reduced from 2.0 d down to 0.5 d. Conclusions The study offered conclusive proof that the contact stabilization process with gravity settling was, in fact, inherently unsuitable for energy conservation. Instead, the emerging scientific approach proposed a single‐volume HRAS system with membrane filtration replacing gravity settling. An equally valid suggestion was to replace anaerobic technology for energy recovery with thermochemical technologies, such as high‐rate pyrolysis, with a much higher energy recovery potential. © 2022 Society of Chemical Industry (SCI).