De-inking Sludge Research Articles

06/01478 omposting of de-inking sludge from the recycled paper manufacturing industry: Gea, T. et al. Bioresource Technology 2005, 99, (10), 1161–1167

06/01478 omposting of de-inking sludge from the recycled paper manufacturing industry: Gea, T. et al. Bioresource Technology 2005, 99, (10), 1161–1167

Composting of de-inking sludge from the recycled paper manufacturing industry

Composting of two different types of sludge from the recycled paper manufacturing industry was carried out at laboratory scale. Physico-chemical sludge (PCS) from the de-inking process and biological sludge (BS) from the wastewater treatment plant were composted and co-composted with and without addition of a bulking material. Despite its poor initial characteristics (relatively high C/N ratio, low organic content and moisture), PCS showed excellent behaviour in the composting process, reaching and maintaining thermophilic temperatures for more than 7 days at laboratory scale, and therefore complete hygienization. Pilot scale composting of PCS was also studied, and a respiratory quotient of 1.19 was obtained, indicating a full aerobic biological process. Respiration tests showed a complete stabilization of the material, with final values of the static respiration index in the range of 1.1 mg O 2 g TOM −1 h −1. Composting is proposed as a suitable technology for the effective recycling of this type of sludge from the recycled paper manufacturing industry.

Heavy Metals Characterization of Sludge from a Philippine Recycling Paper Mill

Wastewater treatment sludge, which is the largest volume residual waste stream generated by the pulp and paper industry, is generally disposed of in a dedicated landfill. Composting the sludge is an alternative method proposed by the Asian Regional Research Program on Environmental Technology-De La Salle University (ARRPET-DLSU) Minor Issue Group. The Philippine Department of Agriculture's (DA) standards for an organic fertilizer's maximum allowable content of heavy metals provided the legislative regulation for the conversion of sludge to compost. The research was designed to characterize the sludge samples from TIPCO, a Philippine paper-recycling mill, and establish whether the sludge contained the heavy metals cadmium, chromium, lead, mercury, nickel, and zinc using atomic absorption spectrophotometer (MS). Sampling was done for four weeks during newsprint and white paper production. Three discharge terminals were established as sampling points. The samples showed that the metal content of the sludge vary from point to point and was highest throughout the manufacture of white paper. Chromium, mercury, and nickel, however, were nondetectable in all the samples, while cadmium was detectable only in very few samples. Lead and zinc were present at all three points and were highest at the de inking sludge. Comparing the results with Part 503 of the United States EPA and the DA's guidelines for organic fertilizers yield significantly lower parameter values. Composting the sludge was, therefore, found to be a feasible option for recycling paper-mill sludge since the metal content were very low compared to local and international standards.

Combined de-inking paper sludge and poultry manure application on corn yield and soil nutrients

Application of combined de-inking paper sludge and poultry manure may be an appropriate way to dispose of these residues and restore fertility of highly degraded soils. An experiment was initiated to determine the effects of a single application of this material, using two different application techniques, on corn yield and soil properties of two 12-ha fields of contrasting textures located in the Nicolet watershed in the province of Québec, Canada. De-inking paper sludge was mixed with poultry manure (PP) at a ratio of 25:1 and strip-applied before corn seeding. The study included three treatments: untreated control, a constant application rate, and variable application rates according to initial soil organic C content. The variable application rates were 10, 20 and 30 Mg dry weight ha-1. The strips were randomized within blocks, and the strips ran lengthwise in the blocks. Soil N immobilization and P release occurred on both sites at least 2 mo after PP incorporation, as measured at the corn eight-leaf and silk apparition stages by the anion-exchange membranes. Despite early N immobilization, grain yield was not affected whereas plant P uptake was increased by PP. At both sites, a single application of PP increased soil pH and major nutrient levels at harvest but had no significant effect on soil organic C. The application of PP also increased P saturation indices but the measured values were well below critical thresholds above which environmental risks would be high. The variable application rate treatment did not differ from the equivalent constant rate treatment for improving soil status and crop growth. This study indicates that mixing de-inking paper sludge and poultry manure may provide a cost-effective and environmentally friendly approach to land disposal of these wastes. Key words: Corn, paper sludge, poultry manure, precision farming, soil nutrients

Use of Paper-mill Wastes on Agricultural Soils: Is This a Way to Reduce Nitrate Leaching?

The term paper-mill waste is used for different products: de-inked fiber sludge, primary fiber sludge, secondary sludge and mixtures. The aim of this study was to find out if any of these materials can be safely used on agricultural soils to induce net N immobilization of N, and thereby decrease nitrate (NO 3 ) leaching. Chemical characterization showed that secondary sludge derived from biological waste water treatment was a nutrient-rich material low in fiber content, whereas primary and de-inked fiber sludge were high in fiber content and low in nutrient content. Cellulose-C and hemi-cellulose-C amounted to 46% and 36% of the organic C present, respectively, and C/N ratios were around 130 in primary and de-inked fiber sludge. Incubation studies at 8°C over 2 months showed that the decomposability of primary and de-inked fiber sludge in soil was not significantly different. Both showed lower decomposability than secondary sludge. Concentrations of inorganic N in soil declined to very low levels after application of primary and deinked fiber sludge and their capacity for net N immobilization was 4.8-7.2 kg N t - 1 C added at 5°C. However, contents of Cu, Cd and polycyclic aromatic hydrocarbons in de-inked fiber sludge limit its use on arable land. Only primary fiber sludge was found to be suitable as a introgen catch fiber material for use on agricultural soils.

Cyanide in paper de-inking sludge used as a soil amendment

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Effect of de-inking paper sludge compost application on soil chemical and biological properties

A 2-yr field study evaluated the effect of applying compost of de-inking paper residues and poultry manure (DSPC) on the chemical and biological properties of Tilly silt loam (Gleyed Humo-Ferric Podzol) in Sainte-Croix de Lotbinière, Qué bec, Canada. The experiment began in 1996 with snap bean ( Phaseolus vulgaris L. ‘Centralia’) and continued in 1997 on the same plots with potato ( Solanum tuberosum L. ‘Gold Rush’). In 1996, treatments included three rates of mineral fertilizer (MF) (60, 120 and 180 kg P2O5-K2O ha-1), three rates of DSPC (14, 28 and 42 Mg ha-1 on a dry matter basis) alone or in combination with MF, and an untreated control. In the spring of 1997, main plots were divided into four subplots and P fertilizer was applied at 0, 44, 88 and 132 kg ha-1. The DSPC increased soil pH and water content. Soil inorganic N increased just after DSPC application, but this effect lasted only 1 yr. Soil Mehlich-3 extractable P showed a significant increase due to DSPC application and the increase was much larger when DSPC was applied in combination with P fertilizer. Soil phosphatase and urease activities were also increased by DSPC. Application of DSPC increased soil Mehlich-3 extractable K and Mg contents. Except for Mn and Zn, soil Mehlich-3 extractable heavy metal contents were not influenced by DSPC. This experiment indicates that compost derived from a mixture of de-inking papermill sludges and poultry manure is a potential source of nutrients for crops and can effectively improve chemical and biological properties of low fertility or degraded soils. Key Words: De-inking sludge, paper biosolids, poultry manure, phosphorus, potassium, enzyme activity

Decomposition of paper de-inking sludge in a sandpit minesoil during its revegetation

Paper de-inking sludge was used as an organic amendment for revegetating an abandoned sandpit in Québec, Canada. In situ patterns of sludge decomposition and of total nitrogen and phosphorus dynamics were characterized in a litter bag study. In a one-time operation, sludge was applied at a rate of 0 or 105 Mg dry matter ha −1, along with N at 3, 6 or 9 kg Mg −1 sludge and P at 0.5 or 1.0 kg Mg −1 sludge. Sludge and fertilizers were incorporated into the top 0.21 m of the minesoil and tall wheatgrass ( Agropyron elongatum (Host) Beauv.) was seeded. Mass loss was well described by a double exponential model when cumulative degree-days (sum of daily temperature above 0°C) were used as the independent variable. Fifty-one percent of the initial material decomposed with a half life of 0.4 yr, whereas the remaining material had a much slower rate of decay with a half life of 13 yr. The large size and slow decomposition rate of the recalcitrant pool of this material were attributed to the high lignin content and the presence of clay in the sludge. Both N and P in decomposing sludge presented a short accumulation phase followed by a long release phase which likely contributed to the successful revegetation of this disturbed sandpit site.

Dynamics of Physical Organic Matter Fractions During De‐inking Sludge Decomposition

Replenishment of soil C and N is essential for sustainable revegetation of minesoils. Our study investigated paper de‐inking sludge as the organic amendment for revegetating an abandoned sandpit in Québec, Canada. Sludge was incorporated at 0 (check) and 105 Mg dry matter ha−1 before seeding tall wheatgrass (Agropyron elongatum (Host) Beauv.). Nitrogen (at 315, 630 and 945 kg N ha−1) and P (at 52.5 and 105 kg P ha−1) were also applied to all plots. Distribution of C and N was determined periodically in two sizes (<53 μm and >53 μm) and two densities (<1.8 g cm−3 and >1.8 g cm−3) of soil fractions during 823 d. After 823 d, C concentrations were 43 and 69% of those of Day 5, for the low and high N rates, respectively. With time, the proportion of C in the heavy (>1.8 g cm−3) fraction increased from 20 to 55%, but remained near 20% in the fine (<53 μm) fraction. Increasing N rates increased C conservation mainly in the coarse (>53 μm) fraction. The amount of N recovered in all fractions decreased after Day 86, in accordance with a previous litter bag study. Although inorganic N was positively correlated with total N in all fractions, the fine fraction was the best indicator of the size of the mineral N pool. Addition of sludge to the sandpit favored the restoration of C and N pools, and high levels of mineral N increased this effect. Residues became denser but remained relatively coarse during their decomposition.

124 Evaluation of the Chemical Characteristics of Three Organic Residues and the Effect of Their Use on the Environmental Medium

The richness of the organic residues in certain fertilizing elements justifies their valorization in horticulture. However, their contents in pathogenic and toxic elements can restrict their use. In this context, this study was conducted in order to evaluate the effect of three organic residues on the environmental medium and the risks of water contamination by the release of heavy metals. Physocarpus opulifolius `Nanus' was transplanted into four substrates. The control substrate contained 4 peatmoss: 5 composted conifer bark: 1 fine crushed gravel (by volume). The three other substrates (25% of peatmoss was substituted by organic residue) contained 10% of fresh bio-filters (FBF), 10% of composted sewage sludges (CSS), or 10% of de-inking sludges (CDS). The pots (5l) were placed in plastic vats and the drainage water was recovered in vessels (17l). The experimental design was in complete blocks with six replications. Samples of the drainage water were collected every 2 weeks for analysis. The pots were fertilized every week (400 mg/Ll of N) and growth parameters were statistically analyzed by ANOVA. The chemical analysis of the residues proves that they contain weak concentrations in organic contaminants. There is an accumulation of \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{NO}_{3}^{-}\) \end{document} in drainage water following the fertilization; the same applies to sulfates and potassium. On the other hand, heavy metals are not released in important concentrations and so the lead, zinc, manganese, and copper contents do not exceed the desirable limits. Moreover, the Physocarpus plants produced in CSS substrates had a growth significantly larger than those plants produced in FBF or CDS substrates. The three organic residues do not constitute a risk of pollution for the environment.

Use of De-inked Paper Sludge in Potting Mixes for Geranium and Zinnia Production

De-inked paper sludge from newsprint recycling was evaluated as an alternative amendment in bedding plant production. `Sweet Dreams' geranium (Pelargonium × hortorum) and `Crystal White' zinnia (Zinnia angustifolia) were grown in square 10-cm pots in one of five media. Media contained 0%, 20%, 40%, 60%, or 80% de-inked paper sludge by volume. All mixes contained 10% perlite, and peatmoss was used to bring the volume to 100%. Initial chemical and physical characteristics of the media were determined. Plants were grown in a greenhouse for 8 weeks, and then plant height, shoot dry weight, and average plant width were determined. Media containing 20% or less paper sludge had an average pH of 4.4, whereas those containing more sludge had an average pH of 7.0. Cation exchange capacity of the media decreased significantly as the volume of sludge increased. Media containing 60% or more paper sludge were better aerated, but held less water than those made with 40% or less de-inked sludge. Geraniums grown in 20% or less paper sludge were at least 18% taller than those grown in medium containing 40% or more de-inked sludge, but average dry weights and plant widths of these plants were unaffected by the media. Zinnia plants grown in 20% or less paper sludge produced four times more shoot dry weight and were at least 34% taller and 20% wider than those grown in 40% or more sludge. Overall, zinnias grown in 40% or more sludge were unacceptable for commercial sale. A volume of 20% de-inked paper sludge could safely be included in potting media used for production of `Sweet Dreams' geranium and `Crystal White' zinnia.

ENVIRONMENTAL EFFECTS OF DEINKING SLUDGE APPLICATION ON SOIL AND SOILWATER QUALITY

The pulp and paper industry produces deinking sludge, a waste by-product rich in organic matter andpotentially beneficial to agricultural soils. Field experiments were performed with deinking sludge and a mix of deinkingand secondary (combined) sludge to measure the environmental impact associated with landspreading. Treatmentsconsisted of three application rates of deinking (6, 12, and 18 dry t/ha) or combined sludge (8, 16, and 24 dry t/ha)associated with three rates of supplementary mineral nitrogen fertilizer, and a control plot. Chemical analyses of deinkingand combined sludge indicated that no organic and inorganic contaminants were present at problematic levels, except forcopper (191 g/g). Soil monitoring of the nutrients and heavy metals in experimental plots showed no significantdifference (p = 0.05) between sludge treatments and the control after two years of sludge application. Monitoring ofnitrate in the soil water indicated a linear relationship (p = 0.08) with the additional nitrogen level. High sludge and lownitrogen application rates were associated with reduced nitrate concentration in the soil water. Detrimental environmentaleffects were not observed with deinking and combined sludge. Compared to the control, potato yield tended to decreasewith deinking and combined sludge applications while barley yield increased with combined sludge applications.

Deinking sludge influences biomass, nitrogen and phosphorus status of several grass and legume species

In a greenhouse study, deinking sludge was evaluated as a soil amendment supplemented with four nitrogen (N) fertilization levels for the growth of the grasses Agropyron elongatum (Host.) Beauv. (tall wheatgrass), Alopecurus pratensis L. (meadow foxtail), Festuca ovina var. duriuscula (L). Koch (hard fescue), and four levels of phosphorus (P) for the growth of the legumes Galega orientalis Lam. (galega), Medicago lupulina L. (black medic), Melilotus officinalis (L.) Lam (yellow sweet clover). Fertilizers were applied on the basis of sludge level to maintain uniform carbon (C)/N or C/P ratios across sludge treatments. In one experiment, sand was mixed with 0, 10, 20 or 30% sludge while, in a second experiment, mineral soil was mixed with 0, 27, 53 or 80% sludge (vol/vol). In sand mixtures of 30 and 20% sludge, grasses had similar or greater growth than in unamended mineral soil when N was added at about 6.5 and 8.4 g kg−1 deinking sludge, respectively. For all legumes but Medicago lupulina, P at about 0.8 g kg−1 sludge was required for these sand mixtures. In soil mixtures of 53 and 27% sludge, grasses grew well when supplemental N was about 5.3 and 6.9 g kg−1 sludge, respectively. Legumes required P at 0.5 and 1.2 g kg−1 sludge, respectively. In general, growth was closely related to total amount of added N or P in spite of the wide range of C/N or C/P ratios. When growing in media amended with sludge, grasses needed higher tissue N concentration for an equivalent growth than in control soil; legumes had similar tissue P concentration. The grasses Agropyron elongatum and Alopecurus pratensis as well as the legumes Melilotus officinalis and Galega orientalis are promising species for field testing, based on dry matter production. Deinking sludge can be used as soil amendment when adequate N and P supplements are provided. Key words: Soil amendment, papermill sludge, Agropyron elongatum, Alopecurus pratensis, Festuca ovina, Medicago lupulina, Galega orientalis, Melilotus officinalis

Effects of De-inking Sludge on soil Properties and Corn Growth

The large amount of organic carbon content present in de-inking residues makes them attractive for use in agricultural soils as an organic soil amendment. Greenhouse bioessays were undertaken to evaluate the agronomic value of de-inking sludge (DS). It was incorporated in a sandy soil to study the effects of different rates of de-inking residue amendments and N fertilizer combinations on soil properties and growth of corn. Particular attention was given to trace element concentrations. In a split factorial design, three variables were investigated: harvest time (after 20, 40, and 60 days), application rates of DS (0, 35, 70, and 105 t·ha–1), and four N rates (0, 140, 280, and 420 kg·ha–1). Chemical analyses of the fresh residues did not indicate the presence of heavy metals at levels potentially toxic to the environment. Soil chemical properties were clearly improved following the incorporation of DS. For example, adding different amounts of DS had a significant impact on the pH, the cation exchange capacity, and soil moisture. In addition, salinity was not affected with DS application. Seed germination was high in all the treatments and was not significantly influenced by DS application. Moreover, results on vegetative growth indicated a good relationship between the C:N ratio and biomass production. The DS combined with supplemental fertilizer seems to have a positive effect on plant growth. Overall, these results suggest that the limiting factor in de-inking paper sludge valorization is the amount of N available to the plant. Also, no other toxic products were found that could be harmful to the environment.

Response of Several Grass and Legume Species to Paper Deinking Sludge

Paper recycling generates large quantities of de-inking sludge, which is disposed of mainly by landfilling. More ecological disposal alternatives include land application and use as a container nursery medium. In this study, raw de-inking sludge was evaluated as a medium component supplemented with applications of four N fertilization regimes for the growth of three grass species (Festuca ovina duriuscula, Agropyron elongatum, Alopecurus pratensis), and four regimes of P fertilization for the growth of three Rhizobium-inoculated legumes (Medicago lupulina, Galega orientalis, Melillotus officinalis). Fertilizer was applied on the basis of sludge rate to maintain a uniform C: N ratio across sludge treatments. In one experiment, sand was mixed with 0, 10%, 20%, and 30% sludge by volume and 20% perlite, while in a second experiment, mineral soil was mixed with 0, 27%, 53%, and 80 % sludge and 20% perlite. Results indicate that shoot dry weight of all species increased with the amount of sludge in the mixture in tests with sand. In the soil mixture experiment, grasses showed the best response to treatments of 53% sludge mixture at the two highest N treatments. In general, shoot dry weight was more directly related to the total amount of N applied than to the C: N ratio of the substrate. The nutritional status (foliar N and P) also was investigated for one grass and one legume species.

Response of Several Grass and Legume Species to Paper Deinking Sludge

Paper recycling generates large quantities of de-inking sludge, which is disposed of mainly by landfilling. More ecological disposal alternatives include land application and use as a container nursery medium. In this study, raw de-inking sludge was evaluated as a medium component supplemented with applications of four N fertilization regimes for the growth of three grass species (Festuca ovina duriuscula, Agropyron elongatum, Alopecurus pratensis), and four regimes of P fertilization for the growth of three Rhizobium-inoculated legumes (Medicago lupulina, Galega orientalis, Melillotus officinalis). Fertilizer was applied on the basis of sludge rate to maintain a uniform C: N ratio across sludge treatments. In one experiment, sand was mixed with 0, 10%, 20%, and 30% sludge by volume and 20% perlite, while in a second experiment, mineral soil was mixed with 0, 27%, 53%, and 80 % sludge and 20% perlite. Results indicate that shoot dry weight of all species increased with the amount of sludge in the mixture in tests with sand. In the soil mixture experiment, grasses showed the best response to treatments of 53% sludge mixture at the two highest N treatments. In general, shoot dry weight was more directly related to the total amount of N applied than to the C: N ratio of the substrate. The nutritional status (foliar N and P) also was investigated for one grass and one legume species.

Effects of Three Organic Residues on Growth of Woody Ornamental Plants Produced in Containers

Three ornamental species (Spiraea japonica `Little Princess', Physocarpus opulifolius `Nanus', and Prunus × cistena) were potted in seven different substrates. The control substrate contained peatmoss, composted conifer bark, and fine crushed gravel (5:4:1, by volume). In the other six substrates, peatmoss was partially or completely substituted by different proportions of three organic residues (10% or 50% of the mixture made up of fresh bio-filters, 5% or 10% in composted sewage sludges, and 10% or 40% in composted deinking sludges). Four fertilization regimes (0, 200, 400, and 600 mg N/liter in the form of soluble fertilizer 20–20–20) were applied weekly onto containers. The experimental design was a split-plot with six replications. Physical and chemical analysis of the organic residues proved that the composted sewage sludges were richer in minerals than the other residues. Moreover, fresh bio-filters and composted deinking sludges were less granular than composted sewage sludges. The 10% proportion of each organic residue, combined with the other materials, was the most-adequate proportion and did not reduce the growth of plants (height, aerial and root dry matter). In addition, a dose of 400 mg·liter–1 generally gave good results, especially for fresh bio-filters and for composted sewage sludges. However, it is preferable to use a higher dose (600 mg·liter–1 if composted deinking sludges are used.

FERTILIZATION VALUE OF THREE ORGANIC RESIDUES AS AN AMENDMENT TO MEDIA USED TO PRODUCE CONTAINER-GROWN WOODY ORNAMENTAL PLANTS

The agricultural valorization of waste, rich in organic matter and minerals, is one of the best economical and ecological methods of disposal. This study was carried out to evaluate the release of mineral elements restrained in fresh bio-filters, composted sewage sludges, and composted de-inking sludges, and their effects on growth of Physocarpus opulifolius `Nanus' produced in containers. The physical and chemical analysis of the organic residues proved that the fertilization value of composted sewage sludges was greater than the other residues. Moreover, the granular characteristics of fresh biofilters and composted de-inking sludges were finer than composted sewage sludges. Each organic residue was combined, in proportion of 10%, with peatmoss, composted conifer bark, and fine crushed gravel. The regular leaching of container medium showed that the composted sewage sludges release a higher quantity of major mineral elements. Physocarpus opulifolius `Nanus' plants were larger than those plants grown in the control substrate (without residue). The results obtained in media containing fresh bio-filters or composted de-inking sludges were similar to those obtained in the control substrate.

Effect of surfactant and particle size reduction on hydrolysis of deinking sludge and nonrecyclable newsprint

Disposal of sludge from deinking mills represents a significant proportion of operating costs. Bioconversion of the cellulosic fraction of deinking sludge (DIS) to ethanol greatly reduces disposal costs while producing an environmentally friendly fuel. In this study, the cellulosic fraction of newsprint and deinking sludge was hydrolysed to produce fermentable sugars. For newsprint, a particle size of 1 to 1.5 mm provided optimal reaction rates in batch reactors over practical hydrolysis times, and reducing sugar concentrations as high as 35 g/L could be achieved using a fed-batch reactor configuration. For both newsprint and DIS, the hydrolysis rate increased nonlinearly with enzyme loading. Tween-80 only marginally improved sugar production but was able to release sugars from cellulosic substrates in the absence of lytic enzymes, in an amount proportional to the surfactant concentration and the substrate particle size. DIS was relatively recalcitrant to enzymatic hydrolysis, possibly due in part to inhibition by hydrophobic constituents. (c) 1995 John Wiley & Sons, Inc.

Mass balance of polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzodioxins (PCDDs) in a recycling paper mill

An extensive investigation on the input, formation and fate of PCDD/Fs in a recycling paper mill was carried out. Samples from different stages of the production process were analysed and a PCDD/F mass balance was calculated. The main PCDD/F input in the production process came from the waste paper, the main PCDD/F output resulted from the deinking sludge. No measurable amounts of PCDD/Fs are formed during the deinking or the paper-making processes. The PCDD/F concentrations in the recycled paper are about three times lower than the concentrations in the corresponding waste paper.