Removal of Phosphate by Paper Mill Sludge: Adsorption Isotherm and Kinetic Study

Phosphate ions have been removed from aqueous solution by paper mill sludge. The influences of experimental conditions such as pH, amount of adsorbent, initial concentration of phosphate, adsorption isotherm and adsorption kinetics of paper mill sludge were studied. The adsorption of phosphate was more efficient in the basic pH region (pH 12). Pseudo second-order model fits better than the pseudo first-order model for adsorption kinetic data and indicates the adsorption process is based on chemisorptions. The calculated activation energy (Ea) is 37.01 J/mol which further suggests that the sorption of phosphate by paper mill sludge was based on chemical adsorption. Consequently, the equilibrium isotherm data were fitted well to Langmuir isotherm with maximum adsorption capacity of 12.65 mg/g. From the study, it showed that paper mill sludge has the potential to be utilized as a cost effective and high capability adsorbent for removal of phosphate from aqueous solutions

Press Dewatering of Sludge with Applications of an Electric Field

In the paper industry today, there is a rising concern over the question of what to do with the paper mill sludge. Although in the past most of the sludge was sent to a landfill, this disposal method is becoming less and less acceptable due to increasing environmental concerns, decreasing landfill space and increasing costs. Since sludge contains a large fraction of water, one of the alternatives is to increase the dewaterability of the sludge through the use of electrokinetic forces. Increased dewatering of the sludge would allow for more economical alternatives to sludge disposal, such as incineration, as well as decrease the sludge handling, transportation, and disposal costs by reducing both volume and weight. The main objective of this thesis was to determine if the application of an electric current through a sludge press would increase the amount of dewatering in the sludge. A simulated press that allowed for the sludge to be pressed in-between two charged screens and water to be collected from both the top and bottom of the press was designed and constructed. During experimentation, drainage amounts and final sludge consistency was collected under varying voltage applications and compared to a control run with no voltage. From the results, it could be concluded that the application of an electric field did indeed help increase the dewaterability of the sludge. The results also show that ion migration does take place in the sludge with positively charged particles carrying water molecules towards the negatively charged screen. Further studies in applying this concept at higher pressing consistencies as well as other applications is recommended

Acetic acid separation from anaerobically treated palm oil mill effluent by ion exchange resins for the production of polyhydroxyalkanoate by Alcaligenes eutrophus

Separation of acetic acid from palm oil mill effluent (POME) to increase its concentration by an anion exchange resin was examined as a preliminary study for its recovery from POME that had been anaerobically treated by sludge from a palm oil mill. This paper concerns the acetic acid thus separated for producing bacterial polyhydroxyalkanoate (PHA) by Alcaligenes eutrophus. It was found that sludge particles in POME strongly inhibited the adsorption of acetic acid on the anion exchange resin. Removing the sludge particles from the POME facilitated the separation of acetic acid from the POME efficiently. The concentrated acetic acid thus obtained from anaerobically treated POME could be used as a substrate in the fed-batch production of polyhydroxyalkanoate by Alcaligenes eutrophus

Adsorbent materials from paper industry waste materials and their use in Cu(II) removal from water.

This paper deals with the removal of Cu2+ from water using adsorbent materials prepared from paper industry waste materials (one de-inking paper sludge and other sludge from virgin pulp mill). Experimental results showed that de-inking paper sludge leads to mesoporous materials (Vmic/VT = 0.13 and 0.14), whereas the sludge from virgin pulp mill produces high microporous adsorbents (Vmic/VT = 0.39 and 0.41). Adsorbent materials were then used for Cu2+ removal from water at acid pH. During water treatment, heavy metals lixiviation from adsorbent materials was not produced. However, important Ca and Mg leaching was observed. Final pH significantly increases after treatment of water with adsorbent materials probably due to their elevated CaCO3 content. In general, highest Cu2+ removal was obtained using adsorbent materials from de-inking paper sludge. This result could be due to their higher content in oxygenated surface groups, high average pore diameter, elevated superficial charge density, high CaCO3 amount and high Ca and Mg exchange conten

Reducing Decomposition Time in Landfills by an Aerobic Process

This experiment was performed to determine if sludge produced by the paper industry could be composted faster by promoting the aerobic degradation process. To perform this experiment, I chose a sludge produced by a virgin pulp mill. Once I collected sludge, it was dewatered to a moisture content of sixty-five percent or less. As soon as the sludge was dewatered, I set up four separate composting systems, three of which were run under aerobic conditions and one that was run under anaerobic conditions. The anaerobic conditions only had sludge and plastic for its bulking agent. In the aerobic systems there were three different types of bulking agents used; pine bark, plastic and compost. In the aerobic systems air was introduced into the system. To determine how fast each of the processes was composting, I collected the gases that were produced by each of the systems. The gases that are produced by an anaerobic process was carbon dioxide and methane, whereas an aerobic process produces carbon dioxide and water. Therefore, by analyzing the gases produced by each of the systems periodically and determining the amount of carbon dioxide produced by each of the systems, one can determine the rate of decomposition of the sludge for each of the separate systems. Also the chemical oxygen demand (COD) was determined for each of the system, before and after the degradation occurred. COD was used to measure that content of organic matter in the sludge. This also helped in determining the degradation that has occurred in each of the systems

Process for purification of waste water produced by a Kraft process pulp and paper mill

The water from paper and pulp wastes obtained from a mill using the Kraft process is purified by precipitating lignins and lignin derivatives from the waste stream with quaternary ammonium compounds, removing other impurities by activated carbon produced from the cellulosic components of the water, and then separating the water from the precipitate and solids. The activated carbon also acts as an aid to the separation of the water and solids. If recovery of lignins is also desired, then the precipitate containing the lignins and quaternary ammonium compounds is dissolved in methanol. Upon acidification, the lignin is precipitated from the solution. The methanol and quaternary ammonium compound are recovered for reuse from the remainder

An application of artificial neural network classifier for medical diagnosis

In recent year, various models have been proposed for medical diagnosis, which broadly can be classified into physical-based approaches and statistical-based approaches. Uncertainty and imprecision are the most important problems in medical diagnosis, other many problems in medical diagnostic domains need to be represented at varying degrees of diagnosis to be solved. Moreover, classification is very important in computer-aided medical diagnosis. In this respect, Artificial Neural Network (ANN) have been successfully applied and with no doubt, they provide the ability and potentials to diagnose the diseases. Therefore, this research focuses on using ANN to classify medical data. ANN model with two layers of tunable weights were used and trained using four different backpropagation algorithms while are the gradient descent(GD), gradient descent with momentum(GDM), gradient descent with adaptive learning rate(GDA) and gradient descent with momentum and adaptive learning rate(GDX). The network was used to classify three sets of medical data taken from UCI machine learning repository. The ability of all training algorithms tested and compared to each other on all datasets. Simulation results proved the ability of ANN for medical data classification with high accuracy and excellent performance and efficiency. This research provides the possibility of reduce costs and human resources. Increasing speed to find the results of medical analysis by using ANN also contributes in saving time for both physicians and patient

Anaerobic co-digestion of acetate-rich with lignin-rich wastewater and the effect of hydrotalcite addition

The methane potential and biodegradability of different ratios of acetate and lignin-rich effluents from a neutral sulfite semi-chemical (NSSC) pulp mill were investigated. Results showed ultimate methane yields up to 333 ± 5 mL CH4/gCOD when only acetate-rich substrate was added and subsequently lower methane potentials of 192 ± 4 mL CH4/gCOD when the lignin fraction was increased. The presence of lignin showed a linear decay in methane production, resulting in a 41% decrease in methane when the lignin-rich feed had a 30% increase. A negative linear correlation between lignin content and biodegradability was also observed. Furthermore, the effect of hydrotalcite (HT) addition was evaluated and showed increase in methane potential of up to 8%, a faster production rate and higher soluble lignin removal (7–12% higher). Chemical oxygen demand (COD) removal efficiencies between 64 and 83% were obtained for all samples.Peer ReviewedPostprint (author's final draft

Electrokinetic Treatment of Sludge

Disposal of sludge has become a major issue in the pulp and paper industry because of the decreased space in landfills and the possibility of pollution from the sludge. By increasing the amount of solids in the sludge (dewatering), the sludge could be disposed of using less land or by incineration, composting, or other method. The dewatered sludge is easier to handle also because of its decreased volume. The method of dewatering which was used for the experiment was by electrokinetics. Electrokinetics is the technology of separating solids and liquids from suspensions of finely divided solids or colloidal particles using an electrical potential. Using four different power levels, a final solids level of 5.9% was reached and a decreased volume of almost 50%. This data showed that electrokinetics does have the potential to greatly reduce the volume of material which needs to be disposed of. It may also be able to increase the solids level to a higher level with further modification