activated sludge system Articles

  • The Role of Activated Sludge Solids in an Actiflo® System

    ABSTRACTThis research was conducted using jar tests to investigate the impact of adding activated sludge solids to the Actiflo® process, a high-rate clarification (HRC) system, to increase BOD removal in HRC systems treating raw wastewater during periods of high wet-weather flows (WWF). A study of dosages and impacts of ferric sulfate, polymer, microsand and activated sludge on performance of the ...

  • Influence of microbial activity on polar xenobiotic degradation in activated sludge systems

    Publisher's note. We very much regret that in production certain errors were introduced into the above article. We wish to apologise to authors and readers for these errors and any confusion that may have been caused: the corrections are given ...


    By IWA Publishing

  • The Removal of Alkylphenol Ethoxylate Surfactants in Activated Sludge Systems

    US EPA has finalized federal Water Quality Criteria for nonylphenol, a biodegradation intermediate of nonylphenol ethoxylates, which are commonly used surfactants. To provide information in support of this initiative, an assessment was made of the ability of wastewater treatment plants to remove these and other alkylphenol ethoxylate (APEO) surfactants that are used widely in domestic and ...

  • Guidelines for using activated sludge models

    Mathematical modelling of activated sludge systems is used widely for plant design, optimisation, training, controller design and research. The quality of simulation studies varies depending on the project objectives, finances and expertise available. Consideration has to be given to the model accuracy and the amount of time required carrying out a simulation study to produce the desired ...


    By IWA Publishing

  • Investigating Steam Application for Reducing Foaming in Activated Sludge Systems

    Filamentous foam, the dispersion of gas bubbles that creates a dense brown scum layer on the surface of activated sludge basins and secondary clarifiers, is caused by the predominance of mycolic acid-containing actinomycetes, such as Gordonia amarae (formerly Nocardia amarae) and the filament Microthrix parvicella. The accumulation of foam causes a variety of operational, safety, and aesthetic ...

  • Proteomics reliability for micropollutants degradation insight into activated sludge systems

    Little information is available on pharmaceutical trace compounds degradation pathways in wastewater. The potential of the proteomics approach has been evaluated to extract information on activated sludge microbial metabolism in degrading a trace concentration of a pharmaceutical compound (ibuprofen). Ibuprofen is one of the most consumed pharmaceuticals, measured in wastewater at very high ...


    By IWA Publishing

  • A Redefinition of the Role of Microorganisms in Bioaggregation in Activated Sludge

    ABSTRACT Aggregation of microorganisms is considered an important trait crucial to their ecological success and has significant implications for biological wastewater treatment. It has been thought that floc formation in such systems is primarily mediated by floc-forming bacteria, whereas other organisms do not really contribute to flocculation. This hypothesis was tested here by a ...

  • Achieving and maintaining of short-cut nitrification in a cyclic activated sludge system

    A lab-scale Cyclic Activated Sludge Technology (CAST) system was operated more than 5 months to evaluate the effects of the operation mode on nitrogen removal performance and investigate a feasible method for achieving short-cut nitrification in the system. Results showed that nitrogen was removed by conventional biological nitrification and denitrification in traditional operation mode ...


    By IWA Publishing

  • CH#824 - Steel Production - Activated Sludge

    BackgroundThe treatment plant at this Steel Mill treats approximately 0.3mgd waste from the coke and steel operations. Over the past year the treatment works improved performance and consistently produced a good quality effluent with respect to phenol, suspended solids, ammonia and cyanide. An improvement in performance was required to meet future discharge limits. To achieve this level of ...

  • Addressing digester foaming by fixing activated sludge system and gaining capacity in both

    The City of Richland Wastewater Treatment Facility digesters have experienced Nocardiainduced digester foaming problems from the time they went into operation in 1985. Because of the persistent foam, most or all of the thickened waste activated sludge (TWAS) was often not sent to the digesters but directly to the belt filter press to be dewatered separately from the digested sludge. It was ...

  • Activated sludge bulking problem solved by AIRE-O2® system - Case Study

    ' Oxygen profiles on the AIRE-O2® system show good dissolved oxygen levels at both bottom and top levels,' reports the mill Problem In 1987, filamentous bacteria outbreaks in this northern pulp mill’s activated sludge basins were a problem. Anoxic conditions in sludge deposits between its diffuser heads, caused by a lack of mixing, encouraged the growth of Thiothrix . ...

  • Energy reduction in activated sludge - Case study

    Owner: Available by request. Contact Medora Corporation 866-437-8076 or info@medoraco.com System Overview: This is an activated sludge wastewater system that serves a city of approximately 16,000 residents. The North basin (see above photo) is the main reactor basin where aeration is supplied for mixing. The North basin covers 1.74 surface acres with an operating depth of 13.5 ft. The system ...


    By Medora Corporation

  • Virus elimination in activated sludge systems: from batch tests to mathematical modeling

    A virus tool based on Activated Sludge Model No. 3 for modeling virus elimination in activated sludge systems was developed and calibrated with the results from laboratory-scale batch tests and from measurements in a municipal wastewater treatment plant (WWTP). The somatic coliphages were used as an indicator for human pathogenic enteric viruses. The extended model was used to simulate the virus ...


    By IWA Publishing

  • Effect of sludge age on heavy metal biosorption by selector activated sludge

    The influence of sludge age on the metal biosorption characteristics of an aerobic selector-activated sludge was investigated. Two bench-scale aerobic-activated sludge systems were operated at sludge ages of 5 days and 15 days for studying biosorption of Cu and Cr(VI). In-vitro batch experiments were performed to compare biosorption characteristics of the sludge samples harvested from the ...


    By Inderscience Publishers

  • Rethinking wastewater characterisation methods for activated sludge systems – a position paper

    Increasingly stringent effluent limits and an expanding scope of model system boundaries beyond activated sludge has led to new modelling objectives and consequently to new and often more detailed modelling concepts. Nearly three decades after the publication of Activated Sludge Model No1 (ASM1), the authors believe it is time to re-evaluate wastewater characterisation procedures and targets. ...


    By IWA Publishing

  • Simultaneous nitrification and denitrification in activated sludge system under low oxygen concentration

    Simultaneous nitrification and denitrification (SND), which is more economical compared with the traditional method for nitrogen removal, is studied in this paper. In order to find the suitable conditions of this process, a mixed flow activated sludge system under low oxygen concentration is investigated, and some key control parameters are examined for nitrogen removal from synthetic wastewater. ...


    By Springer

  • Multicomponent activated sludge model for reactors in series with recycling

    Multicomponent models containing both substrate and biomass have an advantage over conventional models in seeking better understanding of activated sludge systems. Such models are also useful in the characterisation of wastewater. Studies in recent years have shown that most of the soluble organic matter in the effluent of treatment systems consists of soluble microbial products that arise during ...


    By Inderscience Publishers

  • Enrichment and application of nitrifying activated sludge in membrane bioreactors

    In this study, nitrifying bacteria were enriched in a membrane bioreactor (MBR, R1) and their bioaugmentation effectiveness was evaluated in another two MBRs (R2 and R3). Nitrifying activated sludge (NAS) with high nitrification activity of up to 3,000 mg-N/(L·d)−1 was successfully enriched in R1. The results showed that chemical oxygen demand concentration of 100–200 mg/L had no negative ...


    By IWA Publishing

  • Abattoir, commissioning of activated sludge plant case study

    This abattoir’s ancient activated sludge system needed complete refurbishment requiring the aeration tank to be drained. A characteristic of the waste water is its consistently very high ammonia concentration. The activated sludge system has to achieve a final effluent of 20 mg/l BOD, 10 mg/l ammonia and 30 mg/l suspended solids. The authorities required that this standard be ...


    By Bio Systems Europe

  • The impact of slowly biodegradable organic compounds on the oxygen uptake rate in activated sludge systems

    The hydrolysis process of slowly biodegradable substrate (XS) has an impact on the efficiencies of nutrient removal in activated sludge systems. Measurement of oxygen utilization rates (OURs) and corresponding chemical oxygen demand (COD) is accepted as a very useful tool to reflect the consumption of biodegradable substrates. The influence of the SS ...


    By IWA Publishing

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