Environmental awareness and paper recycling

The collection and utilization of recovered paper has increased over the past decades all over the world and this trend will continue. However, paper recycling is limited by the availability of resources, as well as by their recovery and quality. The paper describes how environmental awareness plays an important role in overcoming these limits. Firstly, the works carried out within the framework of COST Action E48 – “The limits of paper recycling” – are presented. These works have analysed the most important driving forces for extending the collection of recovered paper in Europe and established that environmental awareness is a key factor. Secondly, different initiatives for the development of environmental awareness and promotion of paper recycling – mainly based on information and educational campaigns, with special emphasis on child education – are presented

Estudio de la floculación en la fabricación de papel

El presente trabajo tiene como objetivo realizar un estudio detallado de los fenómenos de floculacion que tienen lugar en el proceso de fabricación de papel, como base para el control del estado de floculacion, en línea, en una maquina de papel. Se identifican y caracterizan los fenómenos mecánicos y químicos que tienen lugar durante la floculacion de las suspensiones de pasta y se establece la influencia de las variables que los determinan. Para ello se han efectuado los siguientes estudios: - caracterización de las suspensiones de pasta de papel con el fin de establecer la influencia de las características de las fibras, cargas, agentes floculantes y condiciones de operación sobre los fenómenos de floculacion. El estudio se ha llevado a cabo bajo los siguientes puntos de vista: físico, químico, electrocinético, mecanismo de floculacion y reológico. - estudio de la influencia de la salinidad sobre los procesos de floculacion. Para ello se ha realizado un estudio del consumo de floculantes, del comportamiento electrocinetico y del comportamiento reólogico en función de la salinidad del medio.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEpu

Internal Treatment of Process Waters in Paper Production by Dissolved Air Flotation with Newly Developed Chemicals. 1. Laboratory Tests

New chemicals, based on the synergistic effect between inorganic polyaluminium salts and organic cationic polyelectrolytes, have been tested for the chemical optimization of a dissolved air flotation (DAF) unit, used as internal treatment of process waters in a paper mill based on 100% recovered paper. Laboratory tests have demonstrated that polyamine modifications of the aluminum salts are the most efficient in the removal of contaminants, the combination of a polyaluminium nitrate sulfate salt and a polyamine being the most efficient. This chemical has been studied under different conditions, such as different dosages or in combination with a flocculant for the treatment of waters from different paper grades production, and the results have demonstrated a good performance at laboratory scale. Therefore, a field trial has been recommended for assessing its potential benefits at mill scale, which will be described in a future paper

Use of talc to control problems associated with dissolved and colloidal material in papermaking

Increasingly stringent environmental standards and market demands are forcing pulp and paper mills to minimize both their water usage and their effluent discharge. Higher rates of process water reuse in pulp and paper mills leads to increased amounts of dissolved and colloidal substances in the process water, which is a major factor limiting further closure of the water circuits. This study explores the use of different types of talcs as control agents for dissolved and colloidal material contained in white water from paper mills using recovered and coated paper as raw materials. It also identifies the kinds of talcs that can be used to control detrimental properties of the white water

Evaluation of MF and UF as pretreatments prior to RO applied to reclaim waste water for fresh water substituion in a paper mill: A practical experience

A pilot plant study has been carried out to compare the effectiveness of different low pressure membrane systems (microfiltration and ultrafiltration) as pretreatments for a reverse osmosis system producing high quality reclaimed water from the effluent of a municipal wastewater treatment plant receiving a high percentage of industrial wastewater. The reclaimed water will be used to substitute fresh water in a paper mill. Although the implemented systems showed several problems derived from the unstable quality of the feed water, they were solid enough to keep a constant permeate quality; i.e. percentages of salt rejection above 99%, efficiencies in the removal of microorganisms to lower values than 1 CFU/100 mL, and final COD results below the detection limit (<5 mg L−1). In short, the quality of the produced reclaimed water was good enough to be used substituting fresh water in a paper mill. An enhanced monitoring of the quality of the water feeding the municipal wastewater treatment plant and an improved corresponding management of the treatments performed in there may be one of the keys to the success of this type of reclamation initiatives. Achieving constant disinfection, an appropriate design of the plants, and a good performance of cleaning operations were very important factors to be considered in order to fight against fouling. Temperature and the soaking time of chemical membrane cleanings were particularly well-optimized for the success of the treatment. Chloramines were compared to free chlorine as disinfection agent achieving satisfactory results

Fluorescent in situ hybridization and flow cytometry as tools to evaluate the treatments for the control of slime-forming enterobacteria in paper mills

Slime formation is a serious problem nowadays in the paper industry. Some enterobacteria are associated with the formation of slime deposits in paper and board mills. Detection and characterization of slime forming bacteria, belonging to the genus Enterobacter, Raoultella, and Klebsiella have been achieved by fluorescence in situ hybridization (FISH), using one probe based on the enterobacterial repetitive intergenic consensus sequence and other two rRNA targeted oligonucleotide probes. The effects of three kinds of antimicrobiological products (biocides, dispersants, and enzymes) on these enterobacterial cells were analyzed by flow cytometry (FC). Biocides Butrol 1009 and 1072 were the most effective microbiocides against all enterobacterial cells analyzed, reaching 90% of dead bacteria after 24 h. However, the enzymatic treatment (Buzyme) was not equally efficient on enterobacteria and its microbiocide capacity varied depending on the type of microorganism. FISH and FC were effective tools to detect important slime forming enterobacteria and to select specific treatments to control microbial problems in the paper industry

pH and particle structure effects on silica removal by coagulation

Producción CientíficaCoagulation is presented as an efficient alternative to reduce the silica content in effluents from recovered-paper mills that are intended to be recycled by a final reverse-osmosis (RO) step. Coagulation pretreatment by several polyaluminum chlorides (PACls) or FeCl3 was optimized prior to the RO process. PACls with low alumina content and high basicity achieved almost a 100 % removal of silica at pH 10.5. A good reduction of the silica content was attained without regulating the pH by adding one of these PACls. Silica removal was related to the structure of the produced clots in which cylindrical particles produced higher silica removal. All coagulants removed more than 50 % of the chemical oxygen demand (COD).Comunidad Autónoma de Madrid - (Proyecto P2009/AMB-1480)Ministerio de Ciencia e Innovación - (Proyecto CTM2008-06886-C02- 01)Comisión Europea - (Proyecto 211534

Development of a Simple and Robust Kinetic Model for the Production of Succinic Acid from Glucose Depending on Different Operating Conditions

Succinic acid (SA) is one of the main identified biomass-derived chemical building blocks. In this work we approach the study of its production by Actinobacillus succinogenes DSM 22257 from glucose, focusing on the development and application of a simple kinetic model capable of representing the evolution of the process over time for a great diversity of process variables key to the production of this platform bio-based chemical: initial biomass concentration, yeast extract concentration, agitation speed, and carbon dioxide flow rate. All these variables were studied experimentally, determining the values of key fermentation parameters: titer (23.8–39.7 g·L −1 ), yield (0.59–0.72 gSA·gglu −1 ), productivity (0.48–0.96 gSA·L −1 ·h −1 ), and selectivity (0.61–0.69 gSA·gglu −1 ). Even with this wide diversity of operational conditions, a non-structured and non-segregated kinetic model was suitable for fitting to experimental data with high accuracy, considering the values of the goodness-of-fit statistical parameters. This model is based on the logistic equation for biomass growth and on potential kinetic equations to describe the evolution of SA and the sum of by-products as production events that are not associated with biomass growth. The application of the kinetic model to diverse operational conditions sheds light on their effect on SA production. It seems that nitrogen stress is a good condition for SA titer and selectivity, there is an optimal inoculum mass for this purpose, and hydrodynamic stress starts at 300 r.p.m. in the experimental set-up employed. Due to its practical importance, and to validate the developed kinetic model, a fed-batch fermentation was also carried out, verifying the goodness of the model proposed via the process simulation (stage or cycle 1) and application to further cycles of the fed-batch operation. The results showed that biomass inactivation started at cycle 3 after a grace period in cycle 2.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEComunidad de MadridMinisterio de Ciencia e Innovaciónpu

Influence of Water Quality on the Efficiency of Retention Aids Systems for the Paper Industry

It has been reported that about 10-15% of the fresh water intake in a paper mill is used for feeding and diluting retention aids, so significant savings could be achieved by replacing fresh water with process water. Water from different sources and qualitiessfresh water, the outflow from an internal ultrafiltration placed in the machine circuit of a paper mill, and water from a membrane bioreactor used to treat the final effluent of this paper millswere used to prepare a dual retention system consisting of a cationic polyacrylamide and bentonite. While the behavior of bentonite was not significantly affected by the quality of the water used in its preparation, the efficiency of the cationic polyacrylamide was reduced to about 12% when it was prepared with water with high anionic trash content and conductivity as a result of a partial neutralization of the charged groups. The effect of nonionic chemical oxygen demand on the efficiency of the polymer was negligible

The application of advanced oxidation technologies to the treatment of effluents from the pulp and paper industry: a review

Producción CientíficaPaper industry is adopting zero liquid effluent technologies to reduce fresh water use and meet environmental regulations, which implies water circuits closure and the progressive accumulation of pollutants that must be removed before water re-use and final wastewater discharge. The traditional water treatment technologies that are used in paper mills (such as dissolve air flotation or biological treatment) are not able to remove recalcitrant contaminants. Therefore, advanced water treatment technologies, such as advanced oxidation processes (AOPs), are being included in industrial wastewater treatment chains aiming to either improve water biodegradability or its final quality. A comprehensive review of the current state of the art regarding the use of AOPs for the treatment of the organic load of effluents from the paper industry is herein addressed considering mature and emerging treatments for a sustainable water use in this sector. Wastewater composition, which is highly dependent of the raw materials being used in the mills, the selected AOP itself, and its combination with other technologies, will determine the viability of the treatment. In general, all AOPs have been reported to achieve good organics removal efficiencies (COD removal >40%; and about an extra 20% if AOPs are combined with biological stages). Particularly, ozonation has been the most extensively reported and successfully implemented AOP at an industrial scale for effluent treatment or reuse within pulp and paper mills; although Fenton processes (photo-Fenton particularly) have actually addressed better oxidative results (COD removal ≈65-75%) at lab scale, but still need further development at large scale.Comunidad Autónoma de Madrid - (Proyecto P-2009/AMB/1480)Ministerio de Ciencia e Innovación - (Proyecto CIT-310000-2008-15