Improvement of the intersection method for the quantification of filamentous organisms: basis and practice for bulking and foaming bioindication purposes

2016 ◽  
Vol 74 (6) ◽  
pp. 1274-1282 ◽  
Author(s):  
Humbert Salvadó
Keyword(s):  
Wastewater Treatment Plants ◽  
Two Dimensions ◽  
Volume Index ◽  
Filament Length ◽  
Improved Method ◽  
Sludge Volume Index ◽  
Filamentous Microorganisms ◽  
Different Types ◽  
Intersection Method ◽  
The Impact

Bulking and foaming phenomena in activated sludge wastewater treatment plants are in most cases related to the abundance of filamentous microorganisms. Quantifying these microorganisms should be a preliminary stage in their control. In this paper, the simplicity of quantifying them based on the intersection method is demonstrated, by redescribing the theory and applying a new improved protocol; new data of interest are also provided. The improved method allows us to use it with stained smears, including epifluorescence techniques. The error that could be made, when considering the distribution of filamentous bacteria in fresh microscope preparations in two dimensions rather than three is negligible. The effect of the different types of filamentous microorganisms on the settleability was also studied. The effect of the total extended filament length on the sludge settleability was shown to depend on the type of filamentous organism and how it aggregates. When these groups of filamentous organisms are found in small aggregations and there is an increase in the number of filamentous organisms, the sludge volume index (SVI) increases proportionally to the filament length. However, when aggregation increases, the impact on the SVI is significantly lower.

Settling Characteristics of Activated Sludge in Danish Treatment Plants with Biological Nutrient Removal

1994 ◽  
Vol 29 (7) ◽  
pp. 157-165 ◽  
Author(s):  
Gert Holm Kristensen ◽  
Per Elberg Jørgensen ◽  
Per Halkjær Nielsen
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Volume Index ◽  
Biological Nutrient Removal ◽  
Sludge Volume Index ◽  
Filamentous Microorganisms ◽  
Best Parameter ◽  
One Year ◽  
Sludge Settling ◽  
Settling Characteristics

In 1989-91, a study was performed to investigate the settling characteristics of activated sludge in Danish treatment plants with biological nutrient removal. The study included three screening series on 38 treatment plants. Furthermore, the study included investigations during one year on seasonal variations in sludge settling characteristics at three treatment plants. The screening investigations were performed in November 1989 and May and September, 1990. Results showed that in the May-screening, 35-45% of the plants had a filament index of 2-2.5 or above, corresponding to a sludge volume index above 150 ml/g. When comparing data for diluted and non-diluted sludge volume indices, a SVI value of 150 ml/g seemed parallel to a DSVI of 110 ml/g. In the November- and September-screenings, some 30% of the plants had activated sludge showing a filament index in or above the critical area. Dominating filamentous microorganisms were found to be (in decreasing order): Microthrix parvicella, Type 0041, Type 021N, Type 0092, Type 0914, and Type 1851. A distinct variation over the year in sludge settling characteristics was found for the three plants. Sludge settling characteristics improved during summer, and deteriorated during winter. For activated sludge with a high content of filamentous microorganisms, the best parameter to follow the variations in sludge settling properties was the filament number. If the activated sludge concentration, the MLSS, varied significantly, the specific filament number was to be applied.

Effect of Lattice Anisotropy on Simulations of Grain Boundary Movement in Two-Dimensions

2004 ◽  
Vol 467-470 ◽  
pp. 1069-1074 ◽  
Author(s):  
Jiří Kroc
Keyword(s):  
Grain Boundary ◽  
Boundary Migration ◽  
Two Dimensions ◽  
Grain Boundary Migration ◽  
Main Task ◽  
Different Types ◽  
Simulated Material ◽  
The Impact ◽  
Lattice Anisotropy ◽  
Grain Boundary Movement

This paper try to elucidate some aspects of the impact of using two different types of computational lattices on the solution of simple models like, for example, grain boundary migration and/or dynamic recrystallization.Not surprisingly, the final solution is obviously affected by anisotropy of used lattices but as we know, they are computational lattices.Ho wever, a material itself has its own anisotropy of its lattice probably different from those lattices used in model.Therefore, the main task in nowadays simulations is to get rid of the influence of computational lattice and to achieve the properties of the lattice of the simulated material.

Forecasting the Long-Term Impact of Washington's Sentencing Guidelines: A Roller Coaster Ride

1992 ◽  
Vol 38 (3) ◽  
pp. 330-356 ◽  
Author(s):  
Glenn Olson
Keyword(s):  
Two Dimensions ◽  
Sentencing Guidelines ◽  
Roller Coaster ◽  
Forecast Horizon ◽  
Sentencing Guideline ◽  
Different Types ◽  
Long Term Impact ◽  
The Impact ◽  
Three Phases

In the early 1980s Washington State developed a simulation forecast for inmate populations that was used to estimate the impact of the state's pioneering sentencing guideline initiative. This process presented forecasting challenges that occurred in three phases over a 10-year period. Different types of forecasting challenges were specific to each of the three phases. These challenges are described along two dimensions: forecast horizon and level of detail. Various combinations of horizon and detail sometimes required mutually exclusive assumptions that yielded much different results.

Selector Volume in Pulp and Paper Activated Sludge Wastewater Treatment Plants – Bench Scale and Pilot Plant Studies

1994 ◽  
Vol 29 (5-6) ◽  
pp. 303-311
Author(s):  
J. Wessberg ◽  
T. Welander ◽  
M. Jönsson
Keyword(s):  
Activated Sludge ◽  
Pilot Plant ◽  
Wastewater Treatment Plants ◽  
Pulp And Paper ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Bench Scale ◽  
Reference Process ◽  
Kraft Mill

Laboratory activated sludge reactors were operated on effluent wastewater from a kraft mill. Two of the three reactors were initially preceded with a “normal” size aerated selector, 2% of the total aerated volume, with unsatisfactory sludge volume index development. When the selectors were replaced by larger ones, 13% of the aerated volume, the sludge volume index could be kept below 50 ml/g for the selector processes while continuing to be higher and more unstable in the reference process. A pilot plant, operated in situ on the same wastewater, showed a comparable improvement in sludge volume index when its selector, 7% of the total volume, was replaced by one that constituted 13% of the total volume, corresponding to a selector load of 3 g BOD / g VSS * d. According to studies of the COD balance around one bench scale selector, the COD removal mechanism in the selector was respiration/assimilation rather than uptake/storage.

Carbonate addition - an effective remedy against poor activated sludge settling properties and alkalinity conditions in small wastewater treatment plants

2004 ◽  
Vol 48 (11-12) ◽  
pp. 411-417 ◽  
Author(s):  
B. Wett ◽  
A. Eladawy ◽  
W. Becker
Keyword(s):  
Wastewater Treatment Plants ◽  
Ph Value ◽  
Solid Phase ◽  
Monitoring Program ◽  
Volume Index ◽  
Nitrification Rate ◽  
Marble Powder ◽  
Effective Remedy ◽  
Sludge Settling ◽  
The Impact

The impact of marble powder on the performance of small seasonal treatment plants dealing with high ammonia concentrated wastewater has been investigated. The carbonate has been added to one of two parallel lab-scale SBR-systems as an alkalinity depot and a bio-carrier. The focus of the monitoring program was put on the measurement of carbon fractions in the liquid and the solid phase and on the alkalinity conditions. Monitoring results show a significant correlation between carbonate dosage (and corresponding inorganic carbon concentration and pH-value) and sludge volume index and nitrification rate.

Monitoring activated sludge settling properties using image analysis

2004 ◽  
Vol 50 (7) ◽  
pp. 281-285 ◽  
Author(s):  
R. Jenné ◽  
E.N. Banadda ◽  
I.Y. Smets ◽  
J.F. Van Impe
Keyword(s):  
Image Analysis ◽  
Activated Sludge ◽  
Volume Index ◽  
Filament Length ◽  
Sludge Volume Index ◽  
Filamentous Bulking ◽  
Sludge Properties ◽  
Fully Automatic ◽  
The One ◽  
Sludge Settling

The goal of this study is to develop a monitoring system for activated sludge properties, as this is an essential tool in the battle against filamentous bulking. A fully automatic image analysis procedure for recognising and characterising flocs and filaments in activated sludge images has been optimised and subsequently used to monitor activated sludge properties in a lab-scale installation. The results of two experiments indicate that the image information correlates well with the Sludge Volume Index. It is shown that, at the onset of filamentous bulking, there is an increase in total filament length on the one hand, and a change in floc shape on the other hand.

Contact Zone: French Practice with Low F/M Bulking Control

1994 ◽  
Vol 29 (7) ◽  
pp. 221-228 ◽  
Author(s):  
R. Pujol ◽  
J. P. Canler
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Contact Zone ◽  
Wastewater Treatment Plants ◽  
Volume Index ◽  
Treatment Facility ◽  
Sludge Volume Index ◽  
Simple Rules ◽  
Rational Operation ◽  
Effective Use

A study of twelve wastewater treatment plants in France confirms the effectiveness of the contact zone technique in controlling sludge bulking (with a reduction in the Sludge Volume Index in 91% of cases) and foaming (improvement of the situation in 75% of the cases). The study focused on low-F/M activated sludge units in which organisms such as Microthrix p. or type 0041 (characteristic of these plants) were identified. Contact zones do not entail any major limitations, a fact which advocates their use in this type of treatment facility. Rational operation of the plant (in terms of aeration and sludge production) and compliance with a few simple rules will ensure effective use of this technology.

Upgrading of wastewater treatment plants equipped with rotating biological contactors to nitrification and P removal

2000 ◽  
Vol 41 (1) ◽  
pp. 145-153 ◽  
Author(s):  
O. Nowak
Keyword(s):  
Wastewater Treatment ◽  
Oxygen Concentration ◽  
Phosphorus Removal ◽  
Wastewater Treatment Plants ◽  
Research Work ◽  
Design Parameters ◽  
Different Types ◽  
Rotating Biological Contactors ◽  
The Impact ◽  
P Removal

In the course of a research project on the further use of treatment plants with rotating biological contactors for nitrification and phosphorus removal, full-scale investigations were carried out. From the results design parameters for phosphorus pre-precipitation as well as for secondary and tertiary nitrifying RBCs were derived. Regarding the impact of the oxygen concentration, the alkalinity and the pH, respectively, on nitrifying biofilms, former research work could mostly be confirmed. Concepts for the upgrading of different types of RBC plants are discussed - including cost estimations.

A Comparative Study of Floc and Sludge of Leachate under Different Types of Coagulants

2015 ◽  
Vol 802 ◽  
pp. 406-411 ◽  
Author(s):  
Nur Shaylinda Mohd Zin ◽  
Hamidi Abdul Aziz ◽  
Mohd Nordin Adlan ◽  
Azlan Ariffin ◽  
Mohd Suffian Yusoff ◽  
...  
Keyword(s):  
Ferric Chloride ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Sludge Formation ◽  
Sludge Characteristics ◽  
Floc Size ◽  
Different Types ◽  
Tapioca Flour ◽  
Sludge Settling ◽  
Composite Coagulant

This study compared the floc and sludge formed during the coagulation of leachate by different types of coagulants. The coagulants tested in this study were Ferric chloride (FC), pre-hydrolyzed iron (PHI), dual coagulant (PHI+TF(tapioca flour)), and composite coagulant (pre mix of PHI and TF (PHITF)). The floc and sludge were characterized by measuring the sludge volume index (SVI), sludge velocity (SV), and floc size. Results showed that the hierarchy for SVI, SV, and floc size were FC>PHI>PHI+TF>PHITF, PHITF>PHI+TF>PHI>FC, and PHI+TF>PHITF>PHI>FC, respectively. PHITF demonstrated the lowest SVI and the shortest sludge settling time among the tested coagulants. PHI+TF produced the largest floc size. The addition of TF in PHI as a composite and dual coagulant significantly improved the floc and sludge characteristics. PHITF improved the floc and sludge formation of partially stabilized leachate.This study compared the floc and sludge formed during the coagulation of leachate by different types of coagulants. The coagulants tested in this study were Ferric chloride (FC), pre-hydrolyzed iron (PHI), dual coagulant (PHI+TF(tapioca flour)), and composite coagulant (pre mix of PHI and TF (PHITF)). The floc and sludge were characterized by measuring the sludge volume index (SVI), sludge velocity (SV), and floc size. Results showed that the hierarchy for SVI, SV, and floc size were FC>PHI>PHI+TF>PHITF, PHITF>PHI+TF>PHI>FC, and PHI+TF>PHITF>PHI>FC, respectively. PHITF demonstrated the lowest SVI and the shortest sludge settling time among the tested coagulants. PHI+TF produced the largest floc size. The addition of TF in PHI as a composite and dual coagulant significantly improved the floc and sludge characteristics. PHITF improved the floc and sludge formation of partially stabilized leachate.

scholarly journals Microwave Supported Treatment of Sewage Sludge

2016 ◽  
Vol 67 (4) ◽  
pp. 286-291 ◽  
Author(s):  
František Janíček ◽  
Milan Perný ◽  
Vladimír Šály ◽  
Markus Giemza ◽  
Peter Hofmann
Keyword(s):  
Energy Efficiency ◽  
Sewage Sludge ◽  
Microwave Irradiation ◽  
Oxygen Demand ◽  
Microwave Treatment ◽  
Biological Properties ◽  
Volume Index ◽  
Microscopic Structure ◽  
Sludge Volume Index ◽  
The Impact

Abstract This work is focused on microwave treatment of sewage sludge. The aim of our experiments was to investigate the impact of microwave radiation upon different sewage sludge parameters such as concentration of nitrates and nitrites, phosphates, COD (Chemical Oxygen Demand), SVI (Sludge Volume Index) and the microscopic structure of sludge. The experiments with microwave irradiation of sewage sludge indicate that moderate microwave power causes visible effects on the chemical, physical and biological properties of the sludge. The calculation of profitability and energy efficiency is also presented.

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