Evaluation of Purification Efficiency of Activated Sludge Treatment Plants for Pulp and Paper Industry Wastewaters in Finland

1990 ◽  
Vol 22 (9) ◽  
pp. 199-206
Author(s):  
J. Junna ◽  
J. Rintala
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Pulp Mills ◽  
Sludge Treatment ◽  
Actual Performance ◽  
Loading Rates ◽  
Removal Efficiencies

Since 1984, when the first activated sludge treatment plant (ASTP) was built to treat pulp and paper industry wastewaters in Finland, twenty more plants have been introduced by 1989. An evaluation was undertaken to find out the actual performance of the ASTPs in BOD7, CODc r and phosphorus removal. The evaluation included all the 12 ASTPs in operation in the pulp and paper industry at the beginning of 1987. The highest average BOD7 removals were about 90 % at pulp mills as well as paper and board mills. CODc r removal was generally higher at paper and board mills (about 40-70 %) than at pulp mills (about 25-55 %). Phosphorus was added to wastewater in most plants. In some ASTPs, phosphorus concentrations were lowered by 20-40 % compared with wastewater from the mill. In some plants phosphorus load on the recipient was higher than the load coming from the mill. In treated wastewater, correlations between suspended solids and BOD7, CODc r, phosphorus and nitrogen were significant in most plants. This indicated that low removal efficiencies resulted from poor suspended solids removal in the secondary clarification. Volumetric and sludge CODc r loading rates could not explain removal efficiencies when all plants were included in the comparison. In plants treating chemical pulping effluents, higher removal efficiencies were normally achieved with lower loading rates. When the plants were studied separately, the influence of loading rate was generally significant.

Treatment of Different Wastewaters from Pulp and Paper Industry in Methane Reactors

1985 ◽  
Vol 17 (1) ◽  
pp. 223-230 ◽  
Author(s):  
P K Latola
Keyword(s):  
Power Plant ◽  
Paper Industry ◽  
Granular Sludge ◽  
Paper Mill ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Plastic Foam ◽  
Loading Rates ◽  
Multi Stage ◽  
Removal Efficiencies

A wastewater from an integrated paper mill with a COD of 1200 mg/dm3 was anaerobically treated in a multi-stage reactor. The BOD7 removal efficiencies of 60-75 % were achieved at maximal loading rates of 5-6 kg COD/m3d and HRT of 4-6 hours due to the granular sludge. Industrial sulphite evaporator condensates from Ca- and Na-processes were treated in anaerobic filters containing light gravel, plastic foam and power plant slag as filter media. The BOD7 removals of 78 % on average were achieved at loading rates of 1.8-3.3 kg COD/m3d with Ca-process evaporator condensates and 80 % BOD7 removals were achieved with Na-process condensates at loading rates of 3.5-4.1 kg COD/m3d.

Behaviour of Alkylphenol Polyethoxylate Surfactants and of Nitrilotriacetate in Sewage Treatment

1987 ◽  
Vol 19 (3-4) ◽  
pp. 449-460 ◽  
Author(s):  
W. Giger ◽  
M. Ahel ◽  
M. Koch ◽  
H. U. Laubscher ◽  
C. Schaffner ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Operating Conditions ◽  
Municipal Sewage ◽  
Sludge Treatment ◽  
Loading Rates ◽  
Treatment Conditions ◽  
Physico Chemical ◽  
Treated Sewage ◽  
Removal Efficiencies

Effluents and sludges from several municipal sewage treatment plants in Switzerland were analyzed for nonylphenol polyethoxylates (NPnEO, n=3-20), nonylphenol mono- and diethoxylate (NPlEO, NP2EO), corresponding nonylphenoxy carboxylic acids (NP1EC, NP2EC) and nonylphenol (NP). These chemicals derive from nonionic surfactants of the NPnEO-type, and specific analitical techniques were used to study their behaviour during mechanical-biological sewage and subsequent sludge treatment. The parent NPnEO-surfactants, with concentrations in raw and mechanically treated sewage from 400-2200 mg/m3, were relatively efficiently removed by the activated sludge treatment. The abundances of the different metabolites varied depending on treatment conditions. The refractory nature of NPl/2EO, NP and NPl/2EC was recognized. Both biotransformations and physico-chemical processes determine the behaviour and fate of nonylphenolic substances in sewage treatment. Nitrilotriacetate (NTA) was found in primary effluents at concentrations between 430 and 1390 mg/m3. The various treatment plants showed different removal efficiencies for NTA depending on the operating conditions. Activated sludge treatment with low sludge loading rates and nitrifying conditions removed NTA with efficiencies between 95 and 99%. High sludge loading caused a decrease in NTA removal efficiencies from 70% to 39%.

scholarly journals Corrosion damage and in-service inspection of retractable sootblower lances in recovery boilers

TAPPI Journal ◽  
2021 ◽  
Vol 20 (10) ◽  
pp. 655-662
Author(s):  
FLAVIO PAOLIELLO
Keyword(s):  
Paper Industry ◽  
Effective Means ◽  
Corrosion Damage ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Near Miss ◽  
Chemical Recovery ◽  
Pulp Mills ◽  
Recovery Boilers ◽  
Component Failures

Several reports of accidents involving serious mechanical failures of sootblower lances in chemical recovery boilers are known in the pulp and paper industry. These accidents mainly consisted of detachment and ejection of the lance tip, or even of the entire lance, to the inside of the furnace, towards the opposite wall. At least one of these cases known to the author resulted in a smelt-water explosion in the boiler. In other events, appreciable damage or near-miss conditions have already been experienced. The risk of catastrophic consequences of the eventual detachment of the lance tip or the complete lance of a recovery boiler soot-blower has caught the attention of manufacturers, who have adjusted their quality procedures, but this risk also needs to be carefully considered by the technical staff at pulp mills and in industry committees. This paper briefly describes the failure mechanisms that prevailed in past accidents, while recommending inspection and quality control policies to be applied in order to prevent further occurrences of these dangerous and costly component failures. Digital radiography, in conjunction with other well known inspection techniques, appears to be an effective means to ensure the integrity of sootblower lances in chemical recovery boilers used in the pulp and paper industry.

Correlation of wood-based components and dewatering properties of waste activated sludge from pulp and paper industry

2010 ◽  
Vol 62 (2) ◽  
pp. 387-393 ◽  
Author(s):  
H. Kyllönen ◽  
J. Lehto ◽  
P. Pirkonen ◽  
A. Grönroos ◽  
H. Pakkanen ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Paper Industry ◽  
Bound Water ◽  
Calorific Value ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Waste Activated Sludge ◽  
Paper Mills ◽  
Elementary Analysis ◽  
Solids Content

Large amounts of wet sludge are produced annually in municipal and industrial wastewater treatment. Already in pulp and paper industry, more than ten million tons of primary sludge, waste activated sludge, and de-inking sludge is generated. Waste activated sludge contains large quantities of bound water, which is difficult to dewater. Low water content would be a matter of high calorific value in incineration but it also has effects on the volume and the quality of the matter to be handled in sludge disposal. In this research waste activated sludges from different pulp and paper mills were chemically characterised and dewatered. Correlations of chemical composition and dewatering properties were determined using multivariate analysis. Chemical characterisation included basic sludge analysis, elementary analysis and analysis of wood-based components, such as hemicelluloses and lignin-derived material. Dewatering properties were determined using measurements of dry solids content, flux and flocculant dosage. The effects of different variables varied according to the response concerned. The variables which were significant regarding cake DS increase in filtration or centrifugation and flocculant dosage needed in filtration were different from those which were significant regarding flux.

The Development of Waste Water Treatment in the Finnish Pulp and Paper Industry

1988 ◽  
Vol 20 (1) ◽  
pp. 25-36 ◽  
Author(s):  
A. Luonsi ◽  
J. Junna ◽  
I. Nevalainen
Keyword(s):  
Activated Sludge ◽  
Pollution Control ◽  
Biological Treatment ◽  
Paper Industry ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Quality Criteria ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Target Values

The recent development of Finnish pulp and paper industry external wastewater treatment has created positive results by reducing the oxygen consuming load (BOD7) of the recipients. This is due to the thirteen activated sludge plants and one anaerobic reactor which have been constructed during the last four years. The target values set in the form of suspended solids (SS) and BOD7 for 1985 (400 t BOD7/d) are expected to be achieved during 1987. Activated sludge plants have also created negative effects in the form of large amounts of surplus biological sludge and increased nutrient discharges, especially phosphorus which with reduced acute toxicity will increase the eutrophication of discharge areas. The share of activated sludge plants for the increased phosphorus discharges remains to be studied. The rapid increase started before the activated sludge plants started operation. In well operated activated sludge plant nutrient discharge is not increased. Although the specific water consumption and specific organic loads continuously decrease in pulp and paper production the increased production and more stringent requirements for pollution control prerequisite investments for external treatment. Therefore it is the time for efficient biological treatment plant construction and before 1995 a good number of mainly activated sludge plants will be constructed, for which time target values and some alternative guidelines to pollution control have been planned but not yet officially issued. Also requirements for CODCr, and total organic chlorine (TOCl) will be among the effluent quality criteria in the near future. When further requirements are issued the basis must be in the requirements of the biota which it is desired to live in the discharge areas. Much research is needed to find out how many of these requirements can be satisfied by modifications of present treatment processes. Thereafter the possibility of removing specific pollutants from the low volume fractions must be identified. The results of these studies must then be compared with the tertiary processes which can be added after the biological treatment plants which process the combined mill effluent. The problem must be regarded as a complex one because any substance removed from the wastewater will be found either in the sludge or in the air. The harmful compounds should be returned to normal ecological circulation or to the least harmful form and location in the most suitable waste stream.

Characterization and Dewatering of Activated Sludge from the Pulp and Paper Industry

1993 ◽  
Vol 28 (1) ◽  
pp. 193-201 ◽  
Author(s):  
J. Pere ◽  
R. Alen ◽  
L. Viikari ◽  
L. Eriksson
Keyword(s):  
Activated Sludge ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Contact Angles ◽  
Low Ph ◽  
Pulp And Paper ◽  
Hydroxyl Groups ◽  
Ftir Analysis ◽  
Floc Properties ◽  
Filter Cakes

Floc properties and dewatering of activated sludge from the pulp and paper industry were studied prior to and after an oxidative conditioning using Fenton's reagent Sludge samples were taken from four treatment plants, which differed with respect to organic loadings and wastewater source. Poor dewaterability was typical of heavily loaded sludges and a positive correlation between filtrability and the concentration of exopolysaccharides was observed. Oxidative conditioning improved the dewaterability of all the sludges tested, but especially that of heavily loaded sludges. Lab-scale piston press results were also comparable with those of controls conditioned with polyelectrolytes. As a result of the conditioning, the surface charge density of the flocs decreased and the contact angles of filter cakes were increased, which enhanced flocculation and settleability. It is possible that hydroxyl groups are oxidized during the oxidative treatment to carboxyl groups, which are more hydrophobic at low pH. This hypothesis was partly supported by FTIR-analysis, but obviously other mechanisms were also involved.

Clarifier Performance in Activated Sludge Process Treating Pulp and Paper Mill Effluents

1994 ◽  
Vol 29 (5-6) ◽  
pp. 313-328 ◽  
Author(s):  
Sakari Halttunen
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Paper Industry ◽  
Paper Mill ◽  
Field Studies ◽  
Pulp And Paper ◽  
Pulp And Paper Mill ◽  
Paper Mill Effluents ◽  
Sludge Settling ◽  
Activated Sludge Processes

High suspended solids concentrations are typical for pulp and paper industry treated effluents. A new clarifier model was developed to find the reasons for this problem. The model clarifier is divided into four different zones: inlet, settling, thickening and separation. In the inlet zone sludge is transported by water flow and neither thickening nor settling will happen. When water velocity decreases the main part of the sludge will settle until it reaches the thickening zone. Thickening will continue until the sludge is pumped away from the clarifier. Concentration increase depends on sludge concentration, time and specific thickening coefficient. The minor part, which is specific to the sludge, enters the separation zone and will either settle in the thickening zone or stay in the effluent. In intensive field studies on 12 different activated sludge processes sludge volume in the clarifier, effluent suspended solids concentrations and sludge settling qualities were examined. Modelled sludge blanket volumes were verified with blanket measurements. Modelled effluent suspended solids were also verified by concentration measurements. Sludge thickening characteristics can be estimated by DSVI. From the data collected two empirical relationships were noticed between sludge settling properties and process operation. Solids concentration in clarified water depends on settling number, which is the mean number of sludge settling during its residence time in the process (sludge age). Sludge settling properties seem to depend on collision load, which is defined as COD-load divided by return sludge biomass flow.

Co-cooking moso bamboo with hardwoods

TAPPI Journal ◽  
2014 ◽  
Vol 13 (6) ◽  
pp. 9-15 ◽  
Author(s):  
TROY RUNGE ◽  
JACKIE HEINRICHER ◽  
DAN MEIER
Keyword(s):  
Paper Industry ◽  
Pulp Mill ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Pulp Mills ◽  
Fiber Properties ◽  
Kraft Process ◽  
Native Forests ◽  
Hardwood Species ◽  
Gradual Introduction

Bamboo is one of the world’s fastest growing feedstocks and represents a promising nonwood resource that can be utilized in the pulp and paper industry. The timber varieties offer low feedstock costs, can be processed similarly to trees from a logistics standpoint, and have useful fiber properties for papermaking. Plantations have not yet been established due to propagation costs, limiting adoption of bamboo as a pulp feedstock to smaller pulp mills primarily in China, where there are native forests. Recent advances in micropropagation may allow lower establishment costs, but gradual introduction into the supply chain will be required. One concept is to gradually include bamboo feedstock into an established pulp mill as plantations are established, using co-cooking with a wood species. Previous work has shown that bamboo cooks fairly easily using the kraft process with conditions similar to hardwood species.

Nutrient minimisation in the pulp and paper industry: an overview

2004 ◽  
Vol 50 (3) ◽  
pp. 111-122 ◽  
Author(s):  
A.H. Slade ◽  
R.J. Ellis ◽  
M. van den Heuvel ◽  
T.R. Stuthridge
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Treated Wastewater ◽  
Nitrogen And Phosphorus ◽  
Treatment Technology ◽  
Solids Separation ◽  
The Impact

This paper reviews nutrient issues within the pulp and paper industry summarising: nitrogen and phosphorus cycles within treatment systems; sources of nutrients within pulping and papermaking processes; minimising nutrient discharge; new approaches to nutrient minimisation; and the impact of nutrients in the environment. Pulp and paper industry wastewaters generally contain insufficient nitrogen and phosphorus to satisfy bacterial growth requirements. Nutrient limitation has been linked to operational problems such as sludge bulking and poor solids separation. Nutrients have been added in conventional wastewater treatment processes to ensure optimum treatment performance. Minimising the discharge of total nitrogen and phosphorus from a nutrient limited wastewater requires both optimised nutrient supplementation and effective removal of suspended solids from the treated wastewater. In an efficiently operated wastewater treatment system, the majority of the discharged nutrients are contained within the biomass. Effective solids separation then becomes the controlling step, and optimisation of secondary clarification is crucial. Conventional practice is being challenged by the regulatory requirement to reduce nitrogen and phosphorus discharge. Two recent developments in pulp and paper wastewater treatment technologies can produce discharges low in nitrogen and phosphorus whilst operating under conventionally nutrient limited conditions: i) the nutrient limited BAS process (Biofilm-Activated Sludge) which combines biofilm and activated sludge technologies under nutrient limited conditions and ii) an activated sludge process based on the use of nitrogen-fixing bacteria. Aerated stabilisation basins often operate without nutrient addition, relying on settled biomass in the benthal zone feeding back soluble nutrients, or the fixation of atmospheric nitrogen. Thus effective nutrient minimisation strategies require a more detailed understanding of nutrient cycling and utilisation. Where it is not possible to meet discharge constraints with biological treatment alone, a tertiary treatment step may be required. In setting nutrient control guidelines, consideration should be given to the nutrient limitations of the receiving environment, including other cumulative nutrient impacts on that environment. Whether an ecosystem is N or P limited should be integrated with wastewater treatment considerations in the further design and development of treatment technology and regulatory guidelines. End-of-pipe legislation alone cannot predict environmental effects related to nutrients and must be supplemented by an effects-based approach.

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