Concentration levels of PM2.5 and PM10 paper dust were measured in a book production facility using a quantitative single subject study. Dust concentration data was collected in three processes of a book manufacturing facility; paper recycling, the digital pressroom and the digital bindery. Data was collected using the DustTrak DRX 8533 Aerosol Monitor, focusing on particulate sizes of PM2.5 and PM10. The data was used to determine if paper dust in the book production industry reached concentration levels that could have negative respiratory health effects on surrounding employees and to determine which process within the studied facility had the highest concentrations of paper dust. The study revealed that the paper recycling warehouse had the highest concentrations of paper dust. It was also determined that the paper recycling warehouse could cause negative respiratory health effects on surrounding employees. Further research is needed to determine the extent of those effects and potential remediation.

Currently most deinking technologies are dependent upon flotation and dissolved air flotation (DAF) technology in order to separate inkjet ink from fiber and water. Much of this technology is based on ink that is extremely hydrophobic. This made flotation and DAF very easy to use because the ink in the water would very easily move with the air in flotation and be brought to the surface, after which the ink can be skimmed and the pulp can be used. Now that small scale printing has become the norm, there has been a move to high quality, small scale printing. This involves the use of a hydrophilic ink. Hydrophilic ink cannot be easily separated from water and fiber the same way the hydrophobic ink can be. With low concentrations of hydrophilic ink in the process water stream, it can be absorbed into the process but as the hydrophilic ink concentration rises alternative methods will be needed in order to separate inkjet ink from water. One solution is to find a method to effectively increase ink particle size. This will enable the ink particles to be filtered or to have an increase ecacy of removal during flotation. In this thesis, one solution is discussed about how electric field and electric plasma technologies can be used to increase particle size and help purify process water in recycle mills. This plasma treatment can very effectively bring ink particles together so that they may be separated by another method. There are two methods by which this may take place. One is polymerization and the other is electro-coagulation. These processes can work side by side to bring ink particles together. This plasma treatment process creates free radicals by stripping off hydrogen atoms from surrounding organic matter. These free radicals then react with the high alkene bond content within the ink to create a very large covalently bonded molecule. This is the new mechanism that is being investigated in this thesis. The other action that is taking place is electro-coagulation. Plasma treated ink can be filtered out using a cellulose acetate or cellulose nitrate membrane or they can be filtered using paper or fiber glass filters as well. The extent at which these can be filtered out is dependent on the size of the pores of the filter. In this study, it was shown that the plasma treatment was able to clean water with a fairly small amount of energy. It was also found that treatment time and concentration had very little eect on the outcome of the treatment ecacy. One factor that did have an effect was the pH. At very high pH values the process became noticeably less eective. The high pH essentially eliminated the electro-coagulation aspect of the treatment process and also hurt the polymerization aspect as well because of lower amount of hydrogen atoms available for the plasma to create free radicals. A model of the process was used to try to give the reader an idea of the ecacy that the process would have in an industrial scale process. The model assumes that two types of ink particles exist. One is ink that has a radical and another in which the ink does not have a radical. The model also assumes that if ink is at all polymerized, ink is filtered out with the 0.8 micron filter. The model assumes three reactions; initialization, propagation and partial termination. The partial termination is a result from the general chemical structure of ink. Ink has many double bonds in its general structure which makes termination very unlikely to occur, so the model assumes that on average when two radials interact that only one is eliminated. This model is only supposed to give the reader an idea of the ecacy of the process. The numbers provided in the model will change very significantly in a different system. The evidence behind polymerization aspect of the process comes from two main sources. One is the small molecule analysis from methanol after being exposed to the plasma and the other from the plasma being exposed to allyl alcohol. The small molecule analysis shows that the process generates free radicals on organic molecules. Methanol was exposed to the plasma and then the resulting GC/MS analysis showed that 1,2-ethanediol was present, this showed that the electric discharge process was able to create free radicals on organic molecules in the liquid phase. Using a similar process the plasma discharge process was exposed to a mixture of allyl alcohol, water and propanol and water in two separate experiments. The difference between these two molecules is an alkene bond that is between the carbon two and carbon three atoms. The particle size of both samples was then analyzed and it was shown that the solution with allyl alcohol had an average particle size about an order of magnitude larger than the solution with propanol in it. Because of all the evidence discussed here and in the rest of the thesis we believe that the plasma treatment of ink has both polymerization and electro-coagulation aspect. This process could also be a potential solution to the water soluble ink problem that will soon face the recycling industry.

Office waste paper is one of the fastest growing segments of the recycled fiber industry. Toner particles are rigid, insoluble and difficult to disperse and detach from fibers. Therefore papers made from recycled office waste having high toner content will contain noticeable ink particles. This work will consider an alternative way of efficient de-inking using plasma polymers which will not affect the fibers chemically or mechanically. The focus is development and characterization of plasma-deposited films to serve as a barrier film for the adhesion of ink toner to the paper fibers and thereby enhance ink lift off from the fibers. The plasma treated paper is coated with fluorocarbon (PFE) and polyethylene glycol (PFE) films, with constant thickness of PFE and varying the thickness of PEG by 1500, from 1500 to 4500, for the three cases studied (PFE greater than PEG, PFE=PEG, PFE less than PEG). Handsheets were made using virgin fibers to eliminate effects of fillers. Once the sheets were coated and printing performed, they were re-pulped and both the slurry and the de-inking surfactant were placed in a flotation cell. Handsheets were made from the collected foam and stock and were scanned for particle count. The results indicated higher ink loss for the cases with increased thickness of polymer films. A handsheet with a 7500 film (PFE = 3000 and PEG = 4500) showed 61% ink removal compared to 38% for handsheets with no film deposited. There was also less material loss for the cases with higher polymer film thickness.

No description available.

In the absence of any significant legislation, paper recycling in South Africa has grown to a respectable recovery rate of 43% in 2008, driven mainly by the major paper manufacturers. Recently introduced legislation will further boost the recovery rate of recycled paper. Domestic household waste represents the major remaining source of recycled paper. This source will introduce greater variability into the paper streams entering the recycling mills, which will result in greater process variability and operating difficulties. This process variability manifests itself as lower average brightness or increased bleaching costs. Deinking plants will require new techniques to adapt to the increasingly uncertain composition of incoming recycled paper streams. As a developing country, South Africa is still showing growth in the publication paper and hygiene paper markets, for which recycled fibre is an important source of raw material. General deinking conditions pertaining to the South African tissue and newsprint deinking industry were obtained through field surveys of the local industry and assessment of the current and future requirements for deinking of differing quality materials. A large number of operating parameters ranging from waste mixes, process variables and process chemical additions, typically affect the recycled paper deinking process. In this study, typical newsprint and fine paper deinking processes were investigated using the techniques of experimental design to determine the relative effects of process chemical additions, pH, pulping and flotation times, pulping and flotation consistencies and pulping and flotation temperatures on the final deinked pulp properties. Samples of recycled newsprint, magazines and fine papers were pulped and deinked by flotation in the laboratory. Handsheets were formed and the brightness, residual ink concentration and the yield were measured. It was determined that the type of recycled paper had the greatest influence on final brightness, followed by bleaching conditions, flotation cell residence time and flotation consistency. The residual ink concentration and yield were largely determined by residence time and consistency in the flotation cell. The laboratory data generated was used to train artificial neural networks which described the laboratory data as a multi-dimensional mathematical model. It was found that regressions of approximately 0.95, 0.84 and 0.72 were obtained for brightness, residual ink concentration and yield respectively. Actual process data from three different deinking plants manufacturing seven different grades of recycled pulp was gathered. The data was aligned to the laboratory conditions to take into account the different process layouts and efficiencies and to compensate for the differences between laboratory and plant performance. This data was used to validate the neural networks and select the models which best described the overall deinking performances across all of the plants. It was found that the brightness and residual ink concentration could be predicted in a commercial operation with correlations in excess of 0.9. Lower correlations of ca. 0.5 were obtained for yield. It is intended to use the data and models to develop a predictive model to facilitate the management and optimization of a commercial flotation deinking processes with respect to waste input and process conditions. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2011.

No abstract available. / Thesis (M.Dev.Studies)-University of KwaZulu-Natal, Durban, 2005.

De-inking sludge generated from pulp and paper industry is considered hazardous since it may contain heavy metals such as Cd, Cr, and Pb. Hence, the de-inking sludge needs to be treated before being disposed of. Sludge combustion is a proven disposal technology, which generates fly ash containing a portion of the heavy metals that may leach out under uncontrolled conditions. The aim of this thesis is to implement a new multi-zone temperature combustion technique (Low-High-Low temperature combustion, LHL) to help contain and immobilize the heavy metals within fly ash particles. During the LHL, the waste will be initially fed into a low-temperature zone (<1100 K) and then subjected to the high-temperature treatment (~1480 K) that will be followed by another low-temperature zone (~1100 K). / This dissertation describes the detailed design and construction of a novel pilot-scale combustion facility, called the Multi-Mode Combustion Facility (MCF), used as a multidisciplinary research tool for investigating the thermal remediation of contaminated solid residues. The MCF is capable of operating in two different modes: Fluidized-Bed combustion mode (FBC) and Single burner furnace mode (SBF). However, this project focuses on the FBC mode (minimum fluidization velocity of 0.42 m/s and bed temperature of 1073 K). / This research compares the combustion characteristics of de-inking sludge obtained in the LHL and in the conventional combustion techniques. The following properties of particulates were studied: morphological evolution of solid particles, structural porosity, metals interactions with fly ash particles, and leachability. / The LHL's final supermicron spherical fly ash went through a molten phase with submicron particles attached to the fly ash particles surfaces. Thus, reducing its porosity to 19%. However, the amorphous final fly ash obtained in the conventional technique reveals 32% porosity. It was found that the physical characteristics of the final LHL's fly ash are the main cause for the reduced heavy metals leachability rates of 0.18, 0.046, and 0.92% for Cd, Cr, and Pb, respectively. The conventional technique had 53.28, 16.79, and 5.20% of Cd, Cr, and Pb respectively, leaching out due to the high porosity percentages. In conclusion, the LHL technique allows for controlling the heavy metals emission from FBCs, while using a waste to energy approach and maintaining environmentally acceptable gas emission levels.

Thesis (Ph.D.)--Chemical Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Hsieh, Jeffery; Committee Member: Breedveld, Victor; Committee Member: Empie, Jeff; Committee Member: Forney, Larry; Committee Member: Singh, Preet

No description available.

published_or_final_version / abstract / Environmental Management / Master / Master of Science in Environmental Management