Effect of Starch on the Flocculation and Settling Behaviour of Titanium Dioxide Suspensions

1974 ◽  
Vol 9 (1) ◽  
pp. 154-171
Author(s):  
S.N. Ray ◽  
C. Hsi ◽  
B.C. -Y. Lu
Keyword(s):  
Titanium Dioxide ◽  
Suspended Solids ◽  
Settling Velocity ◽  
Pollution Abatement ◽  
Paper Mills ◽  
Paper Making ◽  
Jar Test ◽  
Settling Behaviour ◽  
Dimensionless Function ◽  
Flocculation Rate

Abstract This study concerns the problem of removal of suspended solids from the effluent streams of paper mills by chemical treatment. As titanium dioxide is one of the ingredients used in paper mills and present in the effluent streams, its flocculation and settling behaviour were investigated. Jar test experiments were conducted using alum and organic polyelectrolyte as the flocculants. As starch is also used in the paper making process, its influence on the flocculation and settling behaviour of titanium dioxide was conducted with the concentration of starch varying between 0–3% of the dry solids. The experimental results on flocculation are expressed in terms of dimensionless function Gθϕ and flocculation rate constants. The fraction of solids settled is presented in terms of the settling velocity. Concentration of starch was found to have a significant influence. The amount of alum required could be reduced by 75% by using starch 0.6% of the amount of titanium dioxide in the suspension and at the same time improving the settling velocity two folds. A possible application of this finding in pollution abatement is discussed.

Water Pollution Abatement in Small Paper Mills in India

1988 ◽  
Vol 20 (1) ◽  
pp. 37-48 ◽  
Author(s):  
L. Panneerselvam
Keyword(s):  
Water Pollution ◽  
Wastewater Treatment ◽  
Raw Materials ◽  
Pollution Abatement ◽  
Pulp And Paper ◽  
Operating Costs ◽  
Small Scale ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Recovery System

In order to reduce the demand for the forest based raw materials by the organised industrial sectors like the large integrated pulp and paper mills, the Government of India started promoting several small-scale pulp and paper mills based on non-wood agricultural residue raw materials. However promotion of these small mills has created another environmental problem i.e. severe water pollution due to non-recovery of chemicals. Because of the typical characteristics like high silica content etc. of the black liquor produced and the subsequent high capital investment needed for a recovery system, it is not economically feasible for the small Indian mills to recover the chemicals. While the quantity of wastewater generated per tonne of paper produced by a small mill is same as from a large integrated pulp and paper mill with a chemical recovery system, their BOD load is four times higher, due to non recovery of chemicals. However the existing wastewater disposal standards are uniform for large and small mills for e.g. 30 mg BOD/l. To meet these standards, the small mills have to install a capital intensive wastewater treatment plant with heavy recurring operating costs. Therefore the feasible alternative is to implement various pollution abatement measures, with the objective of not only reducing the fibre/chemical loss but also to reduce the investment and operating costs of the final wastewater treatment system. To illustrate this approach, a case study on water pollution abatement and control in a 10 TPD mill, will be discussed.

Methods for determining the settling velocity profiles of solids in storm sewage

1996 ◽  
Vol 33 (9) ◽  
pp. 117-125 ◽  
Author(s):  
Emmanuelle Aiguier ◽  
Ghassan Chebbo ◽  
Jean-Luc Bertrand-Krajewski ◽  
Peter Hedges ◽  
Naomi Tyack
Keyword(s):  
Suspended Solids ◽  
Settling Velocity ◽  
Test Procedure ◽  
Velocity Profiles ◽  
Test Methods ◽  
Efficient Treatment ◽  
Experimental Procedure ◽  
Comparative Tests ◽  
Settling Process ◽  
Settling Characteristics

Recently, research has shown that a settling process is an efficient treatment for the removal of suspended solids from storm sewage. In order to design settling tanks, there is a need to determine the settling velocity characteristics of these solids. Devices and test methods for measuring settling velocities of solids in storm sewage have been developed by researchers. A literature review has revealed that the settling velocity profiles obtained with some methods (Chebbo, 1992), (Michelbach and Wohrle, 1993) and (Tyack et al., 1993) are very different. In order to explain why the results are different and to quantify the influence of the experimental procedure on the settling velocity grading curves, we have compared the selected methods when tested with the same sample and we have studied the effects of the conservation of the sample before the test, of the concentration of solids in the device and of the nature of the water on the settling velocity profiles. The results of the comparative tests indicate that the settling velocities are significantly lower with both the Cergrene and Aston methods than with the UFT test procedure. Moreover, the study has shown that the settling characteristics of solids change with time, that the use of sewage liquor rather than demineralised water or drinking water can change the results of the measurement and that the higher the concentration of solids, the greater the velocity of settled particles.

scholarly journals Jagellonian Ledgers as Sources for Watermark Research and Paper History Studies: The First Papermills of East-Central Europe

2020 ◽  
Vol 12 ◽  
pp. 324-340
Author(s):  
Krisztina Rábai
Keyword(s):  
Central Europe ◽  
Detailed Examination ◽  
Paper Mills ◽  
East Central Europe ◽  
East Central ◽  
Paper Making ◽  
The Everyday ◽  
History Of ◽  
Shed Light ◽  
Different Parts

This study is based on the analysis of the paper and the text of royal and princely accounts in which scribes registered the everyday incomes and expenditures of four Jagiellonian courts, located in different parts of East-Central Europe around the turn of the 15th and 16th-century. The period covers the establishment and the very first years of paper mills in Silesia and the Polish Kingdom. Regarding the lack of archival sources preserving the foundation and running of these mills, the cradles of paper-making in East-Central Europe, one should use many different and quite laconic written sources to shed light upon these revolutionary years. Although accounts could preserve mentions of purchasing, trading and using paper, in most cases the textual information is not adequate to reconstruct a detailed and clear image of paper producing; researchers should examine the medium of writing - the paper - itself. Instead of the investigation of single sheets, folded papers, small notebooks and bound books such as accounts proved to be more useful. One can compare the sheets of the volumes and find those traces which lead to the paper mills, the places of their origin. Through the detailed examination of one especially complex and interesting ledger from the courts of Prince Sigismund, the author attempts to demonstrate the opportunities lay in watermark studies. Furthermore, the article purposes to reflect on the huge hiatus clearly perceptible on the field of watermark research and paper history in East-Central Europe and the necessity of developing a database of watermarks reflecting on the history of paper-making in this region. 

Wastewater Treatment for Effluent Reuse: Lime-Induced Removal of Excreted Pathogens

1989 ◽  
Vol 21 (3) ◽  
pp. 79-84 ◽  
Author(s):  
M. P. Gambrill ◽  
D. D. Mara ◽  
J. I. Oragui ◽  
S. A. Silva
Keyword(s):  
Wastewater Treatment ◽  
Suspended Solids ◽  
Domestic Wastewater ◽  
Faecal Coliforms ◽  
High Quality ◽  
Average Percentage ◽  
Effluent Reuse ◽  
Jar Test ◽  
Better Than ◽  
Crop Irrigation

High quality effluents suitable for crop irrigation can be produced by lime and Clarifloc treatment of raw domestic wastewater: in laboratory jar-test experiments the average percentage removals were 99.999 for faecal coliforms, 99 – 99.9 for salmonellae, 99.9 – 100 for total parasites and 99 – 99.9 percent for rotavirus. The average removals of COD and suspended solids were 79 – 87 and 97 percent respectively. Clarifloc treatment was marginally better than that achieved by lime.

Wastewater Characteristics

1985 ◽  
Vol 17 (1) ◽  
pp. 1-28 ◽  
Author(s):  
Nils-Erik Virkola ◽  
Kristiina Honkanen
Keyword(s):  
Suspended Solids ◽  
Raw Materials ◽  
Waste Water Treatment ◽  
Water Systems ◽  
Pulp And Paper Mills ◽  
Paper Mills ◽  
Environmental Laws ◽  
The Past ◽  
General Terms ◽  
Pollution Loads

Forceful measures have been taken in the past decade to reduce the pollution loads of pulp and paper mills. Besides more effective external waste water treatment, internal arrangements have been made to reduce pollution loads, e.g. by closing water systems. New processes and technically improved machines and equipment have made it possible to utilize raw materials and chemicals more efficiently. This has also reduced the pollution loads of the mills. In the 1970s, pollution loads were restricted by environmental laws and regulations in many countries, and the restrictions will become tighter during the 1980s. This will require much research and development. In this paper, characteristics of effluents (BOD, suspended solids, colour, TOC, COD, toxicity) discharged from chemical and mechanical pulping processes and from paper and board mills are presented in general terms and by mill department. Process developments and effects of these developments on pollution loads are described and future trends are discussed.

Patterns of gross deposition in reservoirs enriched in inorganic tripton

2001 ◽  
Vol 58 (11) ◽  
pp. 2177-2188 ◽  
Author(s):  
Steven W Effler ◽  
Carol M Matthews (Brooks) ◽  
David A Matthews
Keyword(s):  
New York ◽  
Suspended Solids ◽  
Inorganic Material ◽  
Settling Velocity ◽  
Particulate Phosphorus ◽  
Overlying Water ◽  
Longitudinal Gradients ◽  
The Individual ◽  
Carbon Particulate ◽  
Inorganic Components

Magnitudes and patterns in the deposition of chlorophyll (Chl), organic carbon, particulate phosphorus (PP), and suspended solids are documented for seven New York reservoirs based on analyses of metalimnetic and near-bottom sediment trap collections. Inorganic material dominated the trap collections and caused a decoupling of the downward fluxes of Chl and PP because of major contributions of inorganic components to P deposition. These contributions were manifested in the stoichiometry of trap collections, the much higher estimates of settling velocity (SV) for PP compared with Chl, and differences in patterns of Chl and PP deposition within individual reservoirs and among these systems. Most of the deposited phosphorus in these reservoirs (71–98%) was associated with nonphytoplankton particles. In contrast to the other constituents, the estimates of SV for Chl were lower and more uniform; nearly 50% of the individual estimates (n = 188) were between 0.15 and 0.25 m·day–1. Longitudinal gradients in sediment deposition occurred as a result of gradients in both overlying water concentrations and settling characteristics of the particles. Seasonal and vertical patterns in trap collections and budget calculations indicate that resuspension contributed to deposition, to varying extents, in all of the reservoir basins.

Preparation, Characterization and Photocatalytic Application of Carbonate Modified Titania

2013 ◽  
Vol 764 ◽  
pp. 219-235
Author(s):  
Rita Sandeep Dhodapkar ◽  
Nageswara Rao Neti
Keyword(s):  
Titanium Dioxide ◽  
Catalytic Activity ◽  
Pollution Abatement ◽  
Oxygen Demand ◽  
Binding Energies ◽  
Advanced Technology ◽  
Oh Radicals ◽  
Oh Groups ◽  
Adsorption Sites ◽  
Photocatalytic Application

Carbonate is a common pollutant in water and wastewater. A study to understand its influence on the photodegradation rates is necessary especially when TiO2/UV technique is emerging as an advanced technology for pollution abatement. In the present investigation, we report surface modification of titanium dioxide using carbonate ions, characterization of carbonate modified titanium dioxide (CMT) and photocatalytic application of carbonate modified TiO2. Titanium dioxide from two different sources namely BDH, Mumbai and Degussa AG, Germany was used as photocatalyst. The CMT catalysts were characterized using potentiometry, FT-IR and XPS. Approximately, 18.9 mg CO3/g CMT(BDH) and 8.13 mg CO3/g CMT(Degussa) was found loaded as determined by potentiometry. The C 1s and O 1s binding energies observed at 289.2 and 531.3 eV, respectively were attributed to surface carbonate species. The adsorption and photodegradation of Acid Blue I dye examined using neat TiO2 as well as CMT catalysts revealed that carbonate inhibits catalytic activity for color and Chemical Oxygen Demand (COD) removal. The photo degradation rate constant (k, s-1) decreases gradually with increasing concentration of carbonate. Thus, in the absence of carbonate kdye is 5.45 × 10-4 s-1 (R2 = 0.97) and kCOD is 3.50 × 10-5 s-1 (R2 = 0.97). At 100 mg/L CO32-, kdye is 0.16 × 10-4 s-1 (R2 = 0.96) and kCOD is 2.66 × 10-5 s-1 (R2 = 0.98). In addition, the carbonate spiking studies revealed the onset of inhibition soon after the addition of carbonate into reacting suspensions of TiO2. The results suggest that carbonate inhibits catalytic activity through formation of strong surface complex under suitable pH by displacing OH2+ and OH groups from TiO2 surface. This results not only in fewer (OH)surface groups available for h+ trapping for oxidation into OH radicals but also in non-availability of adsorption sites for the dye molecules. A pretreatment to remove carbonate from (waste) water appears necessary prior to application of TiO2/UV technique

Degradation of wine industry wastewaters by photocatalytic advanced oxidation

2005 ◽  
Vol 51 (1) ◽  
pp. 113-120 ◽  
Author(s):  
P. Navarro ◽  
J. Sarasa ◽  
D. Sierra ◽  
S. Esteban ◽  
J.L. Ovelleiro
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Heterogeneous Catalysts ◽  
Suspended Solids ◽  
Advanced Oxidation ◽  
Wine Industry ◽  
Biological Processes ◽  
H2o2 Concentration ◽  
High Concentration ◽  
Promising Technology

Wine industry wastewaters contain a high concentration of organic biodegradable compounds as well as a great amount of suspended solids. These waters are difficult to treat by conventional biological processes because they are seasonal and a great flow variation exists. Photocatalytic advanced oxidation is a promising technology for waters containing high amounts of organic matter. In this study we firstly investigated the application of H2O2 as oxidant combined with light (artificial or natural) in order to reduce the organic matter in samples from wine industry effluents. Secondly, we studied its combination with heterogeneous catalysts: titanium dioxide and clays containing iron minerals. The addition of photocatalysts to the system reduces the required H2O2 concentration. Although the H2O2/TiO2 system produces higher efficiencies, the H2O2/clays system requires a H2O2 dosage between three and six times lower.

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