Effect of feed mode and Food Microorganisms ratio on efficiency of Plug-Flow activated sludge systems with plug-flow in removal of organic matter, phosphor PO4 and nitrat NO3

Laboratory and pilot plant experiments on anoxic selector activated sludge systems were conducted on two wastewaters in some cases supplemented with nitrate, acetate or glucose. To prevent bulking sufficient anoxic selector detention time and nitrate levels must be available to reduce selector effluent soluble COD to below 100 mg/l and to reduce readily metabolizable organic matter to virtually zero (< 1 mg/l). Soluble COD/NO3-N removal stoichiometry is in the range 6.0-6.7. Selector systems have elevated soluble substrate removal and denitrification rates compared to CSTR systems. These rates are not affected greatly by temperature (20-25°C) for CSTR sludges but are for selector sludges. Upon exhaustion of nitrate in a selector soluble COD leaks out of the activated sludge in significant amounts. Thiothrix sp. and type 021N denitrify only to NO2 and at much slower rates than Zoogloearamigera does to N2. A sequencing batch system provides an optimistic estimate of the SVI that can be obtained by an anoxic selector system.

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Dynamic Modeling of Diffused Aeration Requirements for High-Rate Plug-Flow and Step-Feed Activated Sludge Systems

Proceedings of the Water Environment Federation ◽

10.2175/193864710798207260 ◽

2010 ◽

Vol 2010 (9) ◽

pp. 7226-7245

Author(s):

Peter Schauer ◽

S. Murthy ◽

S. Kharkhar ◽

A. Shaw ◽

C. deBarbadillo ◽

...

Keyword(s):

Activated Sludge ◽

Dynamic Modeling ◽

Plug Flow ◽

High Rate ◽

Activated Sludge Systems

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Coke oven wastewater treatment by two activated sludge systems

Global NEST Journal ◽

10.30955/gnj.000346 ◽

2013 ◽

Vol 8 (1) ◽

pp. 16-22

Keyword(s):

Organic Matter ◽

Wastewater Treatment ◽

Activated Sludge ◽

Nutrient Removal ◽

Municipal Wastewater ◽

Treatment Plant ◽

Coke Oven ◽

Synthetic Wastewater ◽

Removal Efficiencies ◽

Activated Sludge Systems

In this study two bench scale activated sludge systems were used, a CSTR and an SBR for the treatment of coke – oven wastewater. Both reactors were inoculated with activated sludge from a municipal wastewater treatment plant. At the first stages of operation, reactors were feed by a mixture of municipal wastewater and synthetic wastewater. Full acclimatization of the microorganisms to synthetic wastewater was achieved in 60 days. The operation of the reactors was divided into three distinct periods. The first period was characterized by the treatment of high organic but non-toxic synthetic wastewater. During this period COD and BOD5 removal efficiencies reached 95 and 98% respectively, in both reactors. Nutrient removal was better in the SBR reactor rather than in the CSTR. In the second period phenol was added in concentrations up to 300 mg l-1. Degradation of phenol started about the 20th day after its introduction to the reactors. In this period no effects of phenol to nutrient removal were observed, whereas the removal efficiency of organic matter in both reactors was slightly decreased. During the third period phenol concentrations of the influent were gradually increased to 1000 mg l-1, while cyanide and thiocyanite were added to the influent composition to concentrations reaching concentrations of 20 and 250 mg l-1 respectively. The composition of the influent of this period was a full assimilation of coke oven wastewater. Introduction of increased phenol concentrations along with cyanide compounds initiated irreversible effects on the activated sludge microfauna of the CSTR causing inherent problems to the treatment process, while SBR showed greater capacity to withstand and degrade toxic compounds. The beginning of this period was characterized by decreased settleability of the suspended solids as well as decrease of organic matter and nutrient removal efficiencies. Monitoring of the effluent characteristics during this period reported over 90% for organic load, 85% of nutrient removal and over 90% of phenol and cyanide removal in SBR, while the removal efficiencies for the CSTR were 75, 65 and 80% respectively.

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The Concept of Soluble Residual Product Formation in the Modelling of Activated Sludge

Water Science & Technology ◽

10.2166/wst.1989.0236 ◽

1989 ◽

Vol 21 (4-5) ◽

pp. 339-350 ◽

Cited By ~ 53

Author(s):

D. Orhon ◽

N. Artan ◽

Y. Cimşit

Keyword(s):

Organic Matter ◽

Activated Sludge ◽

Product Formation ◽

Cellular Materials ◽

Batch Reactors ◽

Sequencing Batch Reactors ◽

Soluble Organic Matter ◽

Residual Product ◽

Hydrolysis Of ◽

Activated Sludge Systems

The soluble effluent COD of a well operated activated sludge plant is likely to be composed almost entirely of organic matter generated by microbial activity. There is evidence to show that a significant portion of this soluble organic matter is non-degradable and may be due to similar microbial mechanisms. A model for the formation of these soluble residual products, (SRP), is propose'd, relating the SRP formation to the hydrolysis of non-viable cellular materials in the reactor. The set of equations describing the model are successfully calibrated and verified for a set of representative experimental data derived from Sequencing Batch Reactors. The model is found to explain and predict COD accumulation at the end of each cycle of these activated sludge systems.

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The effect of reactor configuration and operational mode on Microthrix parvicella bulking and foaming in nutrient removal activated sludge systems

Water Science & Technology ◽

10.2166/wst.2002.0457 ◽

2002 ◽

Vol 46 (1-2) ◽

pp. 61-64 ◽

Cited By ~ 7

Author(s):

C. Noutsopoulos ◽

D. Mamais ◽

A.D. Andreadakis

Keyword(s):

Activated Sludge ◽

Nutrient Removal ◽

Plug Flow ◽

Selective Advantage ◽

Operational Mode ◽

Intermittent Aeration ◽

Reactor Configuration ◽

Microthrix Parvicella ◽

Activated Sludge Systems ◽

Removal System

Three bench-scale nutrient removal activated sludge units were used to examine the effect of the reactor configuration and the intermittent aeration mode on the growth of Microthrix parvicella. According to the results, the plug flow configuration seems to achieve satisfactory Microthrix parvicella control. The imposed concentration gradient for both RBCOD and SBCOD creates a selective advantage for the floc forming bacteria throughout the system (both the anoxic and oxic zones) and limits Microthrix parvicella growth. In terms of the operational mode, the intermittent aeration CSTR nutrient removal system promotes the growth of M.parvicella and deteriorates the settling characteristics of the activated sludge.

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Causes of, and control strategies for, Microthrix parvicella bulking and foaming in nutrient removal activated sludge systems

Water Science & Technology ◽

10.2166/wst.1998.0569 ◽

1998 ◽

Vol 37 (4-5) ◽

pp. 9-17 ◽

Cited By ~ 13

Author(s):

D. Mamais ◽

A. Andreadakis ◽

C. Noutsopoulos ◽

C. Kalergis

Keyword(s):

Activated Sludge ◽

Nutrient Removal ◽

Control Strategies ◽

Plug Flow ◽

Pilot Scale ◽

Long Chain Fatty Acids ◽

Flow Reactors ◽

Microthrix Parvicella ◽

And Control ◽

Activated Sludge Systems

Bench and pilot scale nutrient removal activated sludge units were used to examine the effect of factors such as temperature, substrate type (easily biodegradable in the form of acetate and slowly biodegradable in the form of oleic acid) on Microthrix parvicella growth. The configurations examined include complete mix with and without selectors (anoxic and anaerobic) and plug flow reactors. The results indicate that low temperatures and substrates in the form of long chain fatty acids favour the growth of M. parvicella. With respect to reactor configuration, a plug flow configuration was shown to be quite effective in controlling the growth of M. parvicella and producing a sludge with good settling characteristics, while the presence of a selector, either anoxic or anaerobic, had no significant effect on the growth of M. parvicella.

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Biodegradation of selected organic nitrogen compounds in activated sludge systems

10.32469/10355/8128 ◽

2010 ◽

Author(s):

Jia Guo

Keyword(s):

Activated Sludge ◽

Organic Nitrogen ◽

Nitrogen Compounds ◽

Activated Sludge Systems

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The Effect of Metallic and Ionic Species on the Performance of a Biological Effluent Treatment System

Water Quality Research Journal ◽

10.2166/wqrj.1977.013 ◽

1977 ◽

Vol 12 (1) ◽

pp. 191-212

Author(s):

B. Volesky ◽

Q. Samak ◽

P. Waller

Keyword(s):

Activated Sludge ◽

Inorganic Ions ◽

Industrial Effluents ◽

Original Data ◽

Ionic Species ◽

Threshold Concentration ◽

Effluent Treatment ◽

Organic Load ◽

Metallic Ions ◽

Activated Sludge Systems

Abstract Review of the available results appearing in the recent literature is presented focusing particularly upon the effects of metallic ions such as Cr, Cu, Zn, Cd, Hg, V, Zn, Ni and Co. Some original data involving the effects of Na are presented and discussed. Development of parameters used in evaluating the influence of toxic or inhibitory species on the mixed microbial population of an activated sludge system is of crucial importance and different techniques employed such as BOD-COD-TOC-removal rates, Oxygen Uptake Rate, and others are discussed, showing relative inadequacy of currently applied assays. From the data available, certain trends can be discerned. There is a definite threshold concentration for each metallic ion, depending on the organic load of the feed. In the order of increasing toxicity to activated sludge systems reflected in lower BOD removals the following metals have been listed as inhibiting factors at concentrations starting from 1 ppm applied on a continuous basis: hexavalent chromium, cobalt, zinc, cadmium, trivalent chromium, copper and nickel. Metals in combination have not been reported to exhibit any significantly different effects as compared to those observed with individually introduced metallic ions. Tolerance of some activated sludge systems to shock loadings by various inorganic ions and metals is reviewed. The conclusions are of particular importance for estimating the performance of biox systems handling industrial effluents which are likely to contain toxic components of inorganic or metallic nature.

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On the Problem of “Two-Phase” Activated Sludge

Water Science & Technology ◽

10.2166/wst.1991.0185 ◽

1991 ◽

Vol 24 (7) ◽

pp. 59-64 ◽

Cited By ~ 1

Author(s):

R. W. Szetela

Keyword(s):

Activated Sludge ◽

Single Phase ◽

Phase System ◽

Two Phase ◽

Wastewater Treatment Process ◽

Sludge Stabilization ◽

Technological Advantage ◽

In Series ◽

State Models ◽

Activated Sludge Systems

Steady-state models are presented to describe the wastewater treatment process in two activated sludge systems. One of these makes use of a single complete-mix reactor; the other one involves two complete-mix reactors arranged in series. The in-series system is equivalent to what is known as the “two-phase” activated sludge, a concept which is now being launched throughout Poland in conjunction with the PROMLECZ technology under implementation. Analysis of the mathematical models has revealed the following: (1) treatment efficiency, excess sludge production, energy consumption, and the degree of sludge stabilization are identical in the two systems; (2) there exists a technological equivalence of “two-phase” sludge with “single-phase” sludge; (3) the “two-phase” system has no technological advantage over the “single-phase” system.

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Steady State Measurement of Oxygenation Capacity

Water Science & Technology ◽

10.2166/wst.1985.0139 ◽

1985 ◽

Vol 17 (2-3) ◽

pp. 303-311

Author(s):

Kees de Korte ◽

Peter Smits

Keyword(s):

Steady State ◽

Activated Sludge ◽

Plug Flow ◽

Usual Method ◽

Steady State Method ◽

State Measurement ◽

Flow Systems ◽

Air System ◽

State Method ◽

Steady State Measurement

The usual method for OC measurement is the non-steady state method (reaeration) in tapwater or, sometimes, in activated sludge. Both methods are more or less difficult and expensive. The steady state method with activated sludge is presented. Fundamentals are discussed. For complete mixed aeration tanks, plug flow systems with diffused air aeration and carousels the method is described more in detail and the results of measurements are presented. The results of the steady state measurements of the diffused air system are compared with those of the reaeration method in tapwater. The accuracy of the measurements in the 3 systems is discussed. Measurements in other aeration systems are described briefly. It is concluded that the steady state OC measurement offers advantages in comparison with the non-steady state method and is useful for most purposes.

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