Nitrate versus Oxygen Utilization Rates in Wastewater and Activated Sludge Systems

1986 ◽  
Vol 18 (6) ◽  
pp. 115-122 ◽  
Author(s):  
Mogens Henze
Keyword(s):  
Activated Sludge ◽  
Oxygen Activity ◽  
Oxygen Utilization ◽  
Active Biomass ◽  
Respiration Rates ◽  
Activated Sludge Processes ◽  
Activated Sludge Systems ◽  
Raw Wastewater

Respiration rates for nitrate and oxygen are compared. Raw wastewaters vary much in these rates and the same holds for activated sludge systems. The denitrifying activity may range from 0-80 per cent of the oxygen activity. It is important to take these variations into consideration, when modelling complex activated sludge processes. Of similar importance are the amounts of active biomass in raw wastewater, as these amounts can exceed those produced in the activated sludge plant itself, and thus significantly can influence the overall composition of the active biomass.

The Influence of Raw Wastewater Biomass on Activated Sludge Oxygen Respiration Rates and Denitrification Rates

1989 ◽  
Vol 21 (6-7) ◽  
pp. 603-607 ◽  
Author(s):  
Mogens Henze
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Nitrate Respiration ◽  
Activated Sludge Process ◽  
Considerable Influence ◽  
Carbon And Nitrogen ◽  
Respiration Rates ◽  
Different Types ◽  
Activated Sludge Processes ◽  
Raw Wastewater

Experiments with 3 activated sludge processes have been made. They were fed with 3 different types of wastewater: raw wastewater, centrifuged wastewater and raw wastewater with extra suspended solids added. All 3 processes were operated at identical loadings of 0.06 kg COD/kg VVS·d. The experiments demonstrated that the raw wastewater solids had considerable influence upon the oxygen and nitrate respiration rates observed in the activated sludge biomass. In the present case the oxygen respiration rates were reduced by the introduction of raw wastewater solids into the activated sludge process. The nitrate respiration rates, however, were increased by the raw wastewater solids. These effects could have influence upon the design of activated sludge processes for carbon and nitrogen removal, with respect to the use of primary settling.

The effect of low sludge age on wastewater fractionation (SS, SI)

2003 ◽  
Vol 47 (11) ◽  
pp. 203-209 ◽  
Author(s):  
S. Haider ◽  
K. Svardal ◽  
P.A. Vanrolleghem ◽  
H. Kroiss
Keyword(s):  
Activated Sludge ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
The Other ◽  
Second Stage ◽  
Lower Maximum ◽  
The Difference ◽  
Selection Of ◽  
Activated Sludge Systems ◽  
Raw Wastewater

In lab-scale experiments at the 2-stage activated sludge pilot plant of Vienna's central WWTP it is shown that the wastewater soluble COD concentration, which is inert to a sludge with SRT < 1 d (SIA) is about double compared to the SI concentration in sludge with SRT > 10 d (SIB). Unexpectedly the ratio of SIA/SIB is independent of the sludge age between SRTs of 0.4 and 1.0 days. The difference between the two SI fractions is soluble COD that is readily biodegradable by the sludge with SRT > 10 d. However, it is degraded at a lower maximum growth rate. These results comply with earlier results gained with different methods and at different WWTPs. It is hypothesised that very low sludge ages result in a selection of fast growing bacteria, which can utilise only part of the SS in the raw wastewater. The other part of SS therefore remains in the wastewater and can thus be utilised for enhanced denitrification in the second stage. It is still unknown beyond which sludge age the soluble inert COD SIA starts to decrease, finally reaching the value SIB for low loaded systems (SRT > 5 days). From this point on SI and SS are assumed only to depend on the wastewater composition and not on the sludge age. The assumption of the Activated Sludge Model No.1 that the biodegradable fractions can be modelled as a single substrate and by a single removal kinetic (one Monod term) appears not to be applicable for low sludge ages. Some suggestions for mathematical modelling, design and operation of 2-stage activated sludge systems are given.

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

2010 ◽  
Vol 62 (3) ◽  
pp. 701-707 ◽  
Author(s):  
M. Majewsky ◽  
T. Gallé ◽  
L. Zwank ◽  
K. Fischer
Keyword(s):  
Activated Sludge ◽  
Microbial Activity ◽  
Suspended Solids ◽  
Sewage Treatment ◽  
Total Suspended Solids ◽  
Active Biomass ◽  
Sewage Treatment Plants ◽  
Degradation Rates ◽  
Xenobiotic Degradation ◽  
Activated Sludge Systems

The influence of activated sludge quality on the co-metabolic biodegradation of three aminopolycarboxyl acids was investigated for a variety of Luxembourg sewage treatment plants. A combination of biodegradation experiments and respirometric techniques are presented as a reliable approach for the estimation of biokinetics and biological xenobiotic degradation rates that allow for identification of governing parameters such as microbial activity and active biomass. Results showed that biokinetics and degradation rates vary greatly between different plants. The fraction of active biomass on the total suspended solids ranged between 16.9 and 53.7%. Xenobiotic biodegradation rates correlated with microbial activity suggesting a relationship with WWTP performance for carbon and nutrient removal. The biokinetic information can be used to increase the prediction accuracy of xenobiotics removal by individual WWTPs.

Inhibitory effect of triclosan and nonylphenol on respiration rates and ammonia removal in activated sludge systems

2008 ◽  
Vol 70 (2) ◽  
pp. 199-206 ◽  
Author(s):  
Athanasios S. Stasinakis ◽  
Daniel Mamais ◽  
Nikolaos S. Thomaidis ◽  
Elena Danika ◽  
Georgia Gatidou ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Inhibitory Effect ◽  
Ammonia Removal ◽  
Respiration Rates ◽  
Activated Sludge Systems

scholarly journals Twenty-five years of ASM1: past, present and future of wastewater treatment modelling

2015 ◽  
Vol 17 (5) ◽  
pp. 697-718 ◽  
Author(s):  
M. C. M. Van Loosdrecht ◽  
C. M. Lopez-Vazquez ◽  
S. C. F. Meijer ◽  
C. M. Hooijmans ◽  
D. Brdjanovic
Keyword(s):  
Activated Sludge ◽  
Urban System ◽  
System Level ◽  
Nitrogen And Phosphorus ◽  
New Developments ◽  
Theoretical Concepts ◽  
Historical Developments ◽  
Activated Sludge Processes ◽  
Activated Sludge Systems ◽  
The Ideal

Activated sludge systems have been applied for 100 years now. Over the course of the years, researchers have developed various models to describe activated sludge processes. The main aim has been to gain a better understanding of the conditions that favour the conversions of carbon, nitrogen and phosphorus present in wastewater, and associated oxygen consumption and sludge production. The current paper presents a reflection on the historical developments, state-of-the-art of activated sludge modelling and future trends. Over the years, many wastewater research groups have benefitted greatly from the development of activated sludge models (ASMs). On one hand, modelling has been expanded through the development of novel theoretical concepts and their application in new fields. On the other hand, models have been used for practical projects. Although, scientists are still searching for the ideal model, one can say that ASMs are developed to the extent that they can be applied in practice with confidence. New developments are expected to be seen regarding plant-wide modelling, integration with other models at the (urban) system level, organizational and computational infrastructure, and interface and communication with various stakeholders and users.

Characterization of Wastewater for Modelling of Activated Sludge Processes

1992 ◽  
Vol 25 (6) ◽  
pp. 1-15 ◽  
Author(s):  
Mogens Henze
Keyword(s):  
Organic Matter ◽  
Mathematical Modelling ◽  
Activated Sludge ◽  
Transport System ◽  
Organic Nitrogen ◽  
Suspended Material ◽  
Nitrogen Fractions ◽  
Activated Sludge Processes ◽  
Raw Wastewater

The fractionation of organic matter in the various parts which are used for mathematical modelling is discussed. The fractions include inert soluble, readily biodegradable, rapidly hydrolysable, slowly hydrolysable, biomass and inert suspended material. Methods for measuring are also discussed. Fractionation of biomass in wastewater and in activated sludge is difficult at present, as methods are only partly developed. Nitrogen fractions in wastewater are mainly inorganic. The organic nitrogen fractions are coupled to the organic COD fractions. The fractions of COD, biomass and nitrogen found in a specific wastewater seem to be constant even when concentrations vary. Wastewater input to sewers and the sewer transport system significantly influences the raw wastewater composition at treatment plants.

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

2013 ◽  
Vol 69 (6) ◽  
pp. 1136-1144 ◽  
Author(s):  
J. Drewnowski
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Oxygen Utilization ◽  
Batch Tests ◽  
Hydrolysis Process ◽  
Major Discrepancy ◽  
The Impact ◽  
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 fraction in biological wastewater treatment systems has been extensively investigated, but little information is known about the effects of XS on OUR. The aim of this study was to determine the immediate effects of particulate and colloidal (XS) biodegradable compounds on oxygen utilization for a full-scale process mixed liquor from a large wastewater treatment plant located in northern Poland. Since it is difficult to distinguish XS in a direct way, a novel procedure, based on the standard batch tests, was developed and run in parallel reactors with settled wastewater (SWW) and pretreated SWW samples. Two types of aerobic OUR experiments with low and high substrate/biomass (S0/X0 ratio) concentration, were carried out with the SWW without pretreatment, and pretreated with a coagulation–flocculation (C–F) method. The removal of colloidal and particulate fractions by C–F resulted in reduced process rates. The major discrepancy in the rate reductions (over 300% referred to the OURmax) was observed during the OUR batch test with high S0/X0 ratio.

Respirometry in control of the activated sludge process

1996 ◽  
Vol 34 (3-4) ◽  
pp. 117-126 ◽  
Author(s):  
Henri Spanjers ◽  
Peter Vanrolleghem ◽  
Gustaf Olsson ◽  
Peter Dold
Keyword(s):  
Activated Sludge ◽  
Respiration Rate ◽  
Control Strategies ◽  
Task Group ◽  
Activated Sludge Process ◽  
Respiration Rates ◽  
Technical Report ◽  
Activated Sludge Systems

This paper summarises progress of the IAWQ Task Group developing the Scientific and Technical Report (STR) on respirometry in control of the activated sludge process. The significance of respirometry in activated sludge systems is explained from a biochemical background. A classification is proposed which includes all respirometric measuring principles described in the literature. The different respiration rates that can be measured are reviewed and some variables that can be deduced from respiration rate are discussed. Some elementary control concepts will be provided that are necessary for the evaluation of respirometry-based control strategies. Finally, a number of respirometry-based control strategies will be classified and discussed.

scholarly journals Enhanced settling in activated sludge: design and operation considerations

2018 ◽  
Vol 78 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Glen T. Daigger ◽  
Eric Redmond ◽  
Leon Downing
Keyword(s):  
Activated Sludge ◽  
Quality Criteria ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Water Quality Criteria ◽  
Subsequent Removal ◽  
Solids Concentration ◽  
Activated Sludge Processes ◽  
Sludge Settleability ◽  
Activated Sludge Systems

Abstract Settling of activated sludge particles has long been the key to successfully achieving secondary treatment. While soluble products can be converted to particulate components via microbial reactions in the activated sludge process, it is the subsequent removal of these particulate components that is the key to achieving ultimate water quality criteria. An understanding of the operating parameters for selecting good settling activated sludge particles was first documented in the 1970s and 1980s. An understanding of the growth pressures that can be imposed on filamentous organisms, and the impacts of selector zones in general, allowed the design and operation of activated sludge processes to routinely achieve good sludge settleability. More recently, research has identified what could be the next evolution in flocculant growth, with the growing interest in aerobic granular sludge. Aerobic granular sludge is purported to provide superior settling properties, and many of the growth pressures identified for aerobic granular sludge are also present in activated sludge systems. These enhanced settling sludge systems are gaining significant interest, but the factors leading to enhanced sludge settleability could be present in historical and existing systems. Three facilities were evaluated that exhibited enhanced settleability (i.e. sludge volume indices of less than 70 mL/g the majority of the time) to determine how these enhanced settling sludges compare to typical settling curves from the literature. The enhanced settling sludge facilities exhibit key differences related to surface overflow rate, return activated sludge (RAS) pumping requirements, and sensitivity to solids concentration that are critical for developing effective settling designs for enhanced settling sludge facilities. As more facilities aim to achieve enhanced settling sludge for intensification of infrastructure, it will be important to carefully consider historic settling curves and to develop site-specific settling criteria when possible.

Sign in / Sign up

Export Citation Format

Share Document