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The pulp and paper industry traditionally consumes high levels of water and energy and the reduction of fresh water use with emphasis on process water management and wastewater recycling are key factors for the growth of this industry. The use of fresh water has reduced significantly during the last decades. The main reasons for this include increased environmental legislations relating to effluent discharge, and hefty costs arising from either the supply of fresh water or treatment of wastewater thus effecting the marketing potentials. Although using recovered paper as raw material has an advantage of saving energy, water and landfill space, attention needs to be paid to treating the wastewater due to discharge regulations and standards. Wastewater sent to a treatment facility is regarded as waste. It is treated only with the purpose not to cause a negative impact to the environment. Although the level of impurities and toxic substances in treated wastewater satisfies the discharge standards, it often limits recycling potential because it adversely affects manufacturing processes and paper quality. Methods for removing these impurities and toxic substances include various physical and biological methods and the intended reuse of the water determines type and level of treatment required. This study aims to explore the possibility of introducing advanced technologies such as enhanced coagulation and flocculation, and membrane separation to improve wastewater recycling in a commercial paper mill. A commercial plant water circuit was first analysed and a water balance was proposed to reduce the water consumption from 10m3 to 6m3/tonne product. The quality of treated wastewaters and associated parameters from commercial individual processes were analysed to forecast the plant influent flows and predict pollutants concentrations in wastewater. Although organics in wastewater were mostly processed through biodegradation, non-biodegradable recalcitrant compounds limit its potential for reuse, thus a tertiary treatment is proposed. Enhanced coagulation and flocculation yielded very promising results, especially for colour removal. The treatment was able to achieve the target colour value. The desirable COD output values were also achieved by varying coagulation/flocculant ratio. For membrane separation, different units of operation and pollution parameters were examined. Results indicate that membrane technology produced higher colour removal efficiencies (96% for NF and 87% for UF) compared to enhanced coagulation and flocculation (61%). However, when it comes to removing COD, enhanced coagulation and flocculation was able to achieve a removal efficiency of 46% COD, compared to 43% for NF and 20% for UF. Amongst the three methods, UF, if used as a stand-alone method, failed to reduce the COD level to the target value. However, when feedwater was pre-treated with coagulant, UF was able to produce a similar COD removal rate to NF. Pre-treating feedwater also reduced fouling of membranes. Between the two membrane cleaning agents used, alkaline was shown to be more effective in reducing fouling. Backwashing was also investigated and found to be effective in prolonging membrane lifespan. However, despite the reduction in fouling, irreversible fouling still happened. Although membrane technology performed better in the removal of colour, retrofitting a membrane system into an existing plant can be difficult, requires the implementation of appropriate pre-treatment technology to control fouling resulting in higher capital and operating costs compared to enhanced coagulation and flocculation.

The Pigeon River watershed has been the focus of a ¬¬major recovery project to reintroduce fish and other aquatic species into the river where they were historically present. A paper mill at Pigeon River Kilometer/Mile (PRKM 102.1/PRM 63.2) began operations in 1908 and discharged effluents which had a detrimental impact on the aquatic wildlife. Recent modifications to the mill have significantly improved effluent quality such that most aquatic organisms are recolonizing the river. The present study is a baseline survey of crayfish species in the Pigeon River and its tributaries; it also includes a comparison of the mean Catch Per Unit Effort (CPUE) in four different reaches of the stream and documents diversity upstream and downstream of the paper mill. Crayfish are important to the aquatic ecosystem and food web because they serve as cutters that help to break down leaf litter and carrion and are also a food source for predators. Crayfish were collected using modified minnow traps and electroshocking and by snorkeling along ‘turning’ rocks; the method used was based on characteristics of the stream reach sampled, including water depth, flow, transparency, and type of substrate. A total of 1,320 crayfish specimens representing seven species was collected during the eight month study. Crayfish were found in nine Pigeon River tributaries , in the main stem of the Pigeon River upstream of the paper mill (PRKM 102.1/PRM 63.2), and below the Progress Energy Dam (PRKM 61.1/PRM 38.0). No crayfish were found downstream of the paper mill in the river itself; however, crayfish were found downstream from the Progress Energy Dam down to the Pigeon River’s confluence with the French Broad River.

The Pigeon River was severely impacted beginning in the early 1900s by a paper mill located in Canton, North Carolina. The mill discharged chemical byproducts into the Pigeon River until 1992 when the paper mill modified their processes. As a result, water quality improved but the status of salamander species in the Pigeon River was unknown. Worldwide amphibian declines over the last 20 years have drawn attention to the need for more research and a better understanding of species-specific habitat relationships. There is concern about amphibian population declines because amphibians are critical to the balance of ecosystems and are considered exceptional indicators of environmental health. The objectives of this study were: 1) to conduct a baseline survey of salamander species composition in the Pigeon River watershed, 2) to determine if salamander populations differ above and below the Canton paper mill, and 3) to attempt to explain variance in salamander abundance, richness and diversity by comparing water quality and substrate characteristics among streams. Eight stations were examined on the Pigeon River, with four stations located above the paper mill and four stations below. We also chose three stations on each of four tributaries, Big Creek, Fines Creek, Jonathan Creek and Richland Creek. Snorkel surveys were completed in the summer of 2009. Five of eight species of stream salamanders were found that historically existed in Haywood County, NC: Eastern hellbender, Blue Ridge two-lined salamander, shovel-nosed salamander, black-bellied salamander and spring salamander. No salamanders were found in the main channel of the Pigeon River below the mill. Eastern hellbenders and Blue Ridge two-lined salamanders preferred substrates consisting of rubble and avoided bedrock. Percent rubble was the only variable retained in substrate models and was positively related to salamander abundance, richness and diversity. Conductivity, salinity, and water temperature were higher in the Pigeon River below the mill than at all other sites. Salamander abundance was explained by dissolved oxygen, pH, and stream width in water quality models. The results of this study suggest salamander abundance was negatively associated with the Pigeon River below the mill because of poor water quality and not habitat availability.

Papermaking is a highly energy intensive process. A paper mill utilizes biomass and fossil fuel energy to provide steam and electricity for plant operations. Biomass is a renewable energy source that is derived from wood waste during the production of virgin fiber. Fossil fuels are non-renewable resources used to meet the remaining energy demand at the mill. A mill may produce a paper product that contains a certain percentage of recycled fiber and virgin fiber. The type of fiber and paper grade directly impacts the amount and source of energy consumed in a paper mill. There is a correlation between the increase in recycled fiber and the increase in fossil fuel use which contributes to the total carbon dioxide output at the mill.A model was developed to calculate the energy balance in a paper mill producing unbleached kraft linerboard with a pulp yield of 52 percent. The total carbon dioxide output was determined for the production of 100 % virgin fiber and 100 % recycled fiber. It was then compared with actual data from an undisclosed linerboard mill. This helped determine the accuracy of the results.This study determined that replacing virgin fiber with recycled fiber increases fossil fuel consumption during linerboard production; however, virgin fiber had the highest total carbon dioxide output for the paper mill. Using the available data from the model, replacing one ton of virgin fiber with one ton of recycled fiber will decrease carbon dioxide output by 1.5 tons.