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Steadily increasing production cost in the paper industry require more efficient resource allocation and utilization of recycled materials and the use of renewable materials and additives to become more environmentally friendly. With this project, 100 g/m² TAPPI handsheets from industrial processed OCC fiber material were produced, without starch and starch in cooked and uncooked form, air-dried at 23°C and contact-dried at 120°C. Starch addition levels were 6.0, 18.0 and 24.0 kg/mt (12.0, 36.0, and 48.0 lbs./st) for pearl and cationic starch, and 2.0, 6.0 and 8.0 kg/mt (4.0, 12.0, and 16.0 lbs./st) for tapioca starch. Fines were measured with a Britt Jar devise having a 75 μm (200 mesh) screen. The highest tensile index improvement of 35.71% for uncooked tapioca starch at an addition rate of 16 lbs./st. The highest tear index improvement of 1.86% was for pearl starch at an addition rate of 12 lbs./st for the cooked & contact dried application. The highest burst index improvement of the produced handsheets was for uncooked & contact dried cationic starch at an addition rate of 12 lbs./st with an improvement of 21.49%. Application of pearl starch showed the largest difference in fines content at the 12 lbs./st and 48 lbs./st of fiber concentrations, reducing the fines content by 22.2% and 24.7% based on solids content respectively. Pearl starch outperformed cationic and tapioca starch products and showed the highest potential for fiber savings and net profit value.

The study tested a designed and built pilot scale packed bio-tower system under continuous operation using pre-clarified municipal wastewater. Performance was evaluated by measuring the removal of chemical oxygen demand and nitrogen ammonia. The pilot scale packed bio-tower system had a diameter of 1209 mm (4 ft.) and a height of 3,962 mm (13 ft.) and contained Bentwood CF-1900 bacteria growth media with a surface area of 6,028.80 ft² (560.09 m²). The municipal residential sewage was fed into a 1,481 l (375 gal.) recirculation reservoir at a temperature of 15°C (59.0°F) and a flow rate between 7,571 l/d (2000 gal/d) and 90,850 l/d (24,000 gal/d) and recirculated through the bio-tower with a fixed recirculation rate of 75.7 l/min (20 gal/min). The influent COD value reduction achieved is between 63.4% and 84.8%, whereas the COD influent value varied between 87 mg/l and 140 mg/l. The influent NH3-N reduction achieved was between 99.8% and 91.8% whereas the influent NH3-N value was between 28.8 mg/l and 18.6 mg/l at a flow rate between 7571 l/d (2000 gal/d) and 90,850 l/d (24,000 gal/d).

The study tested the performance of a batch-type recirculating laboratory scale bio-tower for the treatment of municipal wastewater. Performance tests were done with a HACH DR-1900 spectrophotometer include chemical oxygen demand, total phosphorus and nitrogen ammonia. This study showed that the recirculated laboratory type bio-tower containing 0.276 ft3 (0.008 m3) of polypropylene growth media with a surface area of 6.624 ft2 (0.615 m2) can reduce the chemical oxygen demand between 70% to 87%. NH3-N reduction was found to be between 94% to 96%, and total phosphorus reduction was between 69% and 87% for flow rates of 0.6 l/min to 1.5 l/min.

Anaerobic digestion can utilize renewable resources to produce energy in the form of biogas. Cow manure inoculum contains the microorganisms needed for this application and unrecycled paper waste can be used as a substrate. The use of these feedstocks together is not well studied. Finding ideal operating parameters and modelling biogas production is vital for future integration of anaerobic digestion. The use of various models when examining anaerobic digestion is important to ensure the best models are used for future research and industrial applications. Office paper and cow manure were combined at the different substrate to inoculum ratios with a total solids content of 6% at 38.4°C for 15 days. Four models (Time-Lag, No-Lag, Modified Gompertz, and Modified Logistic) were fitted to the experimental data to find which model best represented each biogas production process. Models varied in the accuracy of their fit to the data and no single model had the lowest RMSE values for each treatment. The digester containing a paper to manure ratio of 2:1 produced the most biogas (82 mL biogas/g VS), but the 5:1 reactor had the greatest biogas production potential over a longer period based on the model parameters (maximum cumulative biogas yield and biogas production potential). More biogas was produced in this study compared to other works reported in the literature, showing that this combination of co-digestion substrates could be expanded upon in the future. New models need to be examined or developed for these systems to better represent this co-digestion process for future research and commercial applications.

This study investigated the application potential of Black Soldier Fly Larva Hermetia illucens Stratiomyidae: Diptera (L.1758) for wastewater treatment and the removal potential of chemical oxygen demand, ammonia, and phosphorus of and liquid manure residue and municipal waste water containing 1% solids content. Black Soldier Fly Larva were found to reduce the concentration of chemical oxygen demand, but unfortunately, increase the concentration of ammonia and phosphorus. The ability of Black Soldier Fly Larva to feed on organic waste of Liquid manure residue showed that Black Soldier Fly Larva increase their weight by 365% in a solution with 12% solids content and by 595% in a solution having 6% solids content. The study also showed that Black Soldier Fly Larva have the ability to survive in a solution of 1% solids content and have the ability to reduce chemical oxygen demand by up to 86.4% for liquid manure residue and 46.9% for municipal wastewater after 24 hours. Generally, ammonia increased by 43.9% for Liquid manure residue and 98.6% for municipal wastewater. Total phosphorus showed an increase of 11.0% and 88.6% increase for liquid manure residue and municipal wastewater respectively over the 8-day study. Transparent environments tend to reduce the COD content more than the dark environment, both for the liquid manure residue (55.8% and 65.4%) and municipal wastewater (71.5% and 66.4%).

The potential usefulness of an invasive common reed as biomass feed to a biorefinery was investigated. This investigation focused on the cellulosic fiber and a comparison of with and without a hot-water extraction (HWE) pretreatment process step. Handsheets were made before and after bleaching and compared to handsheets made from other pulped grass family (Poaceae) fibers. Machine-made simulated copy-grade paper was compared with and without HWE at varied percentages of reed replacement for hardwood fiber in the furnish. The HWE appeared to cause a dramatic increase in the tensile and burst strength while the tear strength reduced slightly. The effects of HWE on woody biomass strength properties were compared.

Nowadays, recycled paper is broadly used due to environmental reasons. Furthermore, the addition of starch as a dry strength additive improves the properties of recycled paper. Poly-Lactic Acid (PLA), a product from bio-refinery process, has recently been shown to act as a promising strength additive that could be used in combination with starch to further improve the strength of paper. In this study, the use of PLA of three molecular weights (MW) in combination with four different starches was investigated. Three recycled pulps from different origins, with the kappa number of 27.9 to 66 were used. Paper handsheets were made, and selected paper properties were tested. The results indicate that handsheets properties were influenced by the MW of PLAs, the type of starch used, and the lignin content of the pulp. The paper handsheets made from lignin-rich pulp (pulp A, kappa number 66), combined with 0.1% medium MW PLA (PLA_1) and 0.9% cationic starch containing 0.43% N gave the highest improvement for tensile strength, wet tensile strength, air and water resistance. This result verifies that a higher kappa number pulp has better attraction to the hydrophobic PLA. Moreover, the higher charge cationic starch led to higher tensile strength due to the increase of affinity to the anionic fiber surface. Interestingly, results show that amphoteric starch is a promising substitute for high cationic charge starch when combined with the medium MW PLA to improve tensile strength of paper. This study demonstrated that a starch-PLA blend represents a promising approach in improving properties of recycled paper.

Increasing the filler content in paper to reduce the cost of materials is an ongoing effort among papermakers. Selecting the proper calcium carbonate additive for each type of paper is the key to achieving this goal. Calcium carbonate is the most widely used filler material in the paper industry. On average, it is applied at levels of 18% to 30%. Quality requirements of each type of paper vary widely, according to use; understanding the effect that different types of calcium carbonate have on paper properties allows producers to choose the best filler for each use. Given that the market for uncoated digital printing paper is expected to grow, this study focused on selecting the optimal calcium carbonate for the production of uncoated digital printing paper made from 100% eucalyptus pulp. In this study, 13 varieties of calcium carbonates were used to prepare handsheets for the detailed analyses of structural, optical, and strength properties. The samples included nine varieties of precipitated calcium carbonate (PCC) (two rhombic and seven scalenohedral, covering a particle size range from 1.2 μm to 2.9 μm) and four varieties of ground calcium carbonate (GCC) (three anionic and one cationic, with a particle size range of 0.7 μm to 1.5 μm). From the results of this study, we determined that the optimal calcium carbonate for uncoated digital printing paper made from eucalyptus pulp is scalenohedral PCC with a particle size of 1.9 μm, because of its positive effects on caliper, stiffness, brightness, and opacity.

Anaerobic digestion can be used to degrade food waste and recover energy. Methane is a biogas that can be efficiently converted in electricity. Organic loading rate, temperature, time, pH, carbon to nitrogen ratio are important factors to be operated in the bioreactors and still are challenges in this process to increase biogas production. It has been reviewed the single phase and two-stage bioreactors in the anaerobic digestion of food waste as well organic loading rates and the rate of methane produced.