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Higher levels of pollutant removal can be achieved by supplementary treatments, which can include anaerobic biological stages, advanced oxidation processes, bioreactors, sandwich thesis mcmaster, and sandwich thesis mcmaster filtration technologies. Improvements in the performance of sandwich thesis mcmaster treatment operations often can be achieved by effective measurement technologies and by strategic addition of agents including coagulants, flocculants, filter aids, and optimized fungal or bacterial cultures.
Wastewater Treatment and Reclamation: A Review of Pulp and Paper Industry Practices and Opportunities. Martin A. Metts, a,b Daphne Hermosilla, c M. Angeles Blanco, d Laleh Yerushalmi, e Fariborz Haghighat, sandwich thesis mcmaster, e Petra Lindholm-Lehto, f Zahra Khodaparast, sandwich thesis mcmaster, g Mohammadreza Kamali, h and Allan Elliott i. Keywords: Wastewater treatment; Pulp and paper manufacturing; Advanced oxidation; Membrane technologies; Clarification; Activated sludge.
Contact information: a: North Carolina State University, Dept. of Forest Biomaterials, Campus BoxRaleigh, NC ; b: WestRock Company, Water and Waste Treatment, S 8th St, Fernandina Beach, FL ; c: Department of Agricultural and Forestry Engineering, University of Valladolid, Campus Duques de Soria, E Soria, Spain; d: Complutense University of Madrid, sandwich thesis mcmaster, Department of Chemical Engineering, Ingn, sandwich thesis mcmaster.
Jean Blvd. On the positive side, the industry is based on the usage of renewable, photosynthetic resources. On the other hand, the industry discharges huge quantities of aqueous effluents. Large volumes up to 70 m 3 of wastewater are generated for each metric ton sandwich thesis mcmaster paper produced, depending on the nature of raw material, the type of finished product, and the extent of water reuse Rintala and Puhakka ; Latorre et al.
Reducing water consumption, by increasing internal water recirculation sandwich thesis mcmaster the implementation of internal cleaning processes, saves money sandwich thesis mcmaster also decreases the use of scarce environmental resources, sandwich thesis mcmaster. Since the main unit operations associated with pulping and papermaking are carried out in aqueous media, the application of various chemical additives can considerably alter the properties of the produced effluents, making it harmful for the receiving environments.
The total closure of the water circuits is limited by the accumulation of contaminants in the process water, which can give rise to corrosion, sandwich thesis mcmaster, and odors and alter the runnability of the paper machine and the quality of the final sandwich thesis mcmaster. If further closure is required, then the effluent has to be extensively treated so that it can be used again in the process.
The main pollutants discharged to water streams nowadays are solids and organic matter, sandwich thesis mcmaster. In general, pulp and paper mill effluents contain a complex mixture of various classes of organic compounds, such as degradation products of carbohydrates, lignin, and extractives Uğurlu et al.
Polluting effluents are formed in wood preparation, pulping, pulp washing, screening, paper machine, and coating operations, and especially in bleaching operations Ali and Shreekrishnan ; Pokhrel and Viraraghavan ; Savant et al.
Clearly, the properties of wastewater from various process stages depend sandwich thesis mcmaster the type of process and raw material, the recirculation of the effluent, and the amount of water used Pokhrel and Viraraghavan The effluents contain high values of biochemical oxygen demand BODchemical oxygen demand CODand chlorinated chemicals that are collectively termed as absorbable organic halides AOX.
While AOX content is generally proportional to the chlorine consumption in bleaching Savant et al. The ratio of BOD to COD is a particularly useful quantity because it represents the fraction of organic compounds in the effluent that are easy to degrade McCubbin and Folke If the wastewater were to be discharged without treatment, then the adverse effects would include depletion of dissolved oxygen, toxic effects on fish and other aquatic organisms, and unacceptable changes to color, turbidity, temperature, and solids content of the receiving waters, sandwich thesis mcmaster.
Issues related to toxicity have been the focus of much attention Walden and Howard ; Owens ; Kamali and Khodaparst For the protection of the environment, and also to satisfy legal requirements, it is necessary for the industry to remove harmful materials from wastewater before it is discharged to the environment.
In China part of the solution to the same issues has been to replace older manufacturing facilities with new capacity that is better suited to the minimization of wastewater impacts Zhang et al. In Canada, the discharge of wastewaters from pulp and paper mills into water frequented by fish is controlled by the Pulp and Paper Effluent Regulations PPER.
These regulations aim at protecting water quality that sustains fish, fish habitat and the use of fisheries resources, sandwich thesis mcmaster. The PPER set limits on the amounts of total suspended solids TSS and biochemical oxygen demand BODand prohibit the discharge of effluents that display acute lethality to fish Environment and Climate Change Canada Secondary treatment for the biological break down of biodegradable sandwich thesis mcmaster and toxic components, resulting in reductions in biochemical oxygen demand, sandwich thesis mcmaster, toxicity and total suspended solids, became common by following the establishment of current regulatory limits in Environmental regulation of pulp and paper mills also includes the Pulp and Paper Mill Effluent Chlorinated Dioxins and Furans Regulations, issued under the Canadian Environmental Protection Act CEPAto control the level of dioxin and furan in the effluent of mills using a chlorine bleaching process.
Additionally, sandwich thesis mcmaster, Pulp and Paper Mill Defoamer and Wood Chip Regulations, also issued under the CEPA, govern the use of defoamers containing dibenzofuran or dibenzo-para-dioxin and wood chips from wood that was treated with polychlorinated phenols Environmental Compliance Insider In Europe, sandwich thesis mcmaster, the Integrated Pollution Prevention and Control Directive sets permit conditions based on the use of best available technologies published in the BREF documents BREFand voluntary agreements through the Confederation of European Paper Industries CEPI further enhanced the sustainability behavior.
Although the focus of this article is on the treatment of wastewater, it is important to keep in mind that purification of the effluent water is not the only goal, sandwich thesis mcmaster.
For efficient water use and treatment, a sustainable integrated water management is motivated by multiple drivers including: legislation; protection against water-related risks in water stress regions; limits in sensitive water bodies; cost of water; business opportunities; general expectation; proudness of the company; and corporate image, etc.
Within this approach the concept of water-fit-for-use is becoming increasingly important; therefore attention will be paid in this review to which approaches tend to be cost-effective and sufficient to meet the different water quality demands.
Ideally, sandwich thesis mcmaster, wastewater treatment operations ought to be regarded as highly reliable, highly effective, cost-competitive, and evidence of good stewardship on the part of industry leaders.
The toxicity of such wastewater and its potential effects on the environment have been reviewed by Ali and Sreekrishnan Review articles by Pokhrel and ViraraghavanZhao et al. Regarding advanced oxidation systems applicable as a primary or a tertiary treatment, sandwich thesis mcmaster, the review by Bautista et al. Hermosilla et al, sandwich thesis mcmaster. Various authors have considered options of treating the process water so that it can be reused within the normal operations of papermaking Tenno and Paulapuro ; Verenich et al.
Wider review sandwich thesis mcmaster and books dealing with general aspects of wastewater treatment have appeared Scott and Ollis ; Thompson et al. Finally, Ince et al. The challenge also will depend on the required purity to be achieved in the treated water. To begin with, any successful wastewater management system needs to clearly define water demands and water qualities for different uses in order to optimize water reuse based on the principle of water-fit-for-use, where water is treated only to the required quality.
Second, the final effluent must be treated to accomplish the discharge limits. The rate of separation sandwich thesis mcmaster wastewater solids in a waste treatment plant can limit the throughput of settling or flotation units.
On the other hand, if methods can be developed and optimized to accelerate separation, then the size and capital costs of the plant might be reduced. Various researchers have shown that separation rates can be sped up by chemical treatments Leitz ; Al-Jasser Furthermore, the use of some hybrid chemicals can promote the removal of a higher percentage of organic matter or specific inorganic material sandwich thesis mcmaster. silica with the solids Miranda et al.
The operating conditions of the biological treatment plant can affect settling rates Avella sandwich thesis mcmaster al. Elliott and Mahmood found that biological sludge digestion could be optimized to speed up the process of handling the sludge.
In recent years there has been increasing realization that, in addition to removing pollutants from the wastewater, it is important to minimize the amount sandwich thesis mcmaster solid sandwich thesis mcmaster sludge that is generated as a byproduct of the treatment operations Leitz ; Tripathi and Allen ; Alvares et al, sandwich thesis mcmaster.
One way to reduce sludge is to place increased emphasis on anaerobic biological treatment as an early step in the treatment program Ashrafi sandwich thesis mcmaster al, sandwich thesis mcmaster. Alternatively, researchers have shown that thermophilic higher temperature biological treatment systems can achieve better efficiency and lower sludge amounts even under aerated conditions LaPara and Alleman ; Skouteris et al, sandwich thesis mcmaster.
Also, by carrying out the treatment in stages, much of the initial sludge volume can be consumed by other types of organisms living within different zones within wastewater treatment operations Lee and Welander Optimum sludge dewatering is also important, as well as the maximum removal of dissolved and colloidal material to keep the water circuit relatively clean.
In conjunction with the development of technologies to minimize sludge production, avenues have been explored to utilize the generated sludge for beneficial purposes as opposed to just bearing expenses for treatment and removal of waste Elliott and Mahmood While the main goal of wastewater treatment is to remove pollutants from wastewater, one of the secondary goals, as we look to the future, is to minimize the production of other pollutants, sandwich thesis mcmaster, such as gaseous emissions.
Ashrafi et al. In addition to the evolution of CO 2methane, and other GHG components from the waste materials, one also needs to be concerned about GHGs associated with the usage of electrical energy during the treatment of wastewater Baig and Liechti ; Ashrafi et al. For instance, though improved efficiencies and treatment rates often can be achieved with modern reactors designed for biological wastewater treatment, such operations sometimes may require more electrical energy in comparison to conventional treatment systems Castillo and Vivas ; Buzzini and Pires ; El-Ashtoukhy et al.
According to Kamali and Khodaparasta goal of saving electrical energy costs may be responsible for a more widespread use of mesophilic medium temperature rather than thermophilic higher temperature conditions in biological treatment plants, sandwich thesis mcmaster, even though the latter have been reported to achieve higher performance in many cases. In fact, some of the generated effluents already have a relatively high temperature, so they can already sandwich thesis mcmaster handled in the thermophilic range without further chilling the effluent.
Anaerobic wastewater treatment operations are often regarded favorably by environmental advocates because they actively generate methane that can be retrieved and used in place of other combustible fuels Sandwich thesis mcmaster and Habets ; Tabatabaei et al. Yerushalmi et al. On-site GHG emissions are due to liquid and solid treatment processes as well as biogas sandwich thesis mcmaster fossil fuel combustion for energy generation. Off-site GHG emissions are related to the production of electricity for plant, production, and transportation of fuel and chemicals for on-site use, degradation of remaining constituents in the effluent of wastewater treatment plant, sandwich thesis mcmaster, as well as transportation and disposal of solids.
The on-site biological treatment processes were shown to make the highest contribution to GHG emissions in the aerobic treatment system, while the higher usage of chemicals in anaerobic and hybrid treatment systems resulted in higher GHG emission from material production and transportation in those treatment systems. The recovery of biogas, sandwich thesis mcmaster during anaerobic treatment processes or anaerobic sludge digestion, and its reuse as fuel were shown to have a remarkable impact on GHG emissions and reduction of the overall emissions.
Biogas recovery and reuse as fuel can cover the total energy needs of the treatment plants for aeration, heating, and electricity, considerably reducing the net GHG emissions in the treatment plants. Heating of an anaerobic digester was identified as a sandwich thesis mcmaster energy-demanding process, suggesting that solid digestion at lower temperatures should be exercised to reduce the associated GHG emissions, sandwich thesis mcmaster.
Based on the results of studies published by the above investigators, the manufacturing of material for on-site consumption should use methods that generate lower amounts of GHGs, thus reducing upstream GHG emissions attributed to the wastewater treatment plant. Electricity and fossil fuels should also be generated and handled sandwich thesis mcmaster more efficient methods in order to decrease the overall GHG emissions of treatment plants.
Another strategy for GHG emissions sandwich thesis mcmaster is to use alternative nutrient removal processes such as the anaerobic Anammox process Greenfield and Batstonewhich removes nitrogen with a lower consumption of energy and lower carbon use. In this process, the reduced aeration energy consumption reduces GHG production related to energy demands of the treatment plant, while the extra available sandwich thesis mcmaster can be converted to methane via anaerobic processes and be used as a source of energy for on-site consumption, further reducing GHG emissions.
Closely related to the topic of energy usage is the topic of operating costs. Hammar and Rydholmwhen reviewing the state of the art of wastewater treatment in the s, complained about the relatively high cost of treatments capable of removing biodegradable organic pollutants.
Membrane treatments are also very efficient, and they are becoming more popular due to substantial reductions in membrane prices, sandwich thesis mcmaster. Before considering different approaches used for the minimization or removal of contaminants from wastewater, the subsections below address some of the most common criteria for assessing the quality of treated water McKeown and Gellman ; Owens Standard methods for the most widely used tests have been established in the US by the American Public Health Association APHA From an environmental standpoint, biodegradable substances, which are quantified in terms of the biological oxygen demand BOD test, sandwich thesis mcmaster, are generally regarded with favor.
However, if such materials were to be discharged into rivers, lakes, and estuaries at sandwich thesis mcmaster levels, the resulting biological metabolism would sometimes be sufficient to consume all or most of the available dissolved oxygen, leading to the death of fish and other aquatic life Taylor et al. Such impacts are often quantified by measuring the BOD, sandwich thesis mcmaster. This quantity is evaluated by sealing a volume of water to be tested with a known amount of gaseous oxygen; the level of oxygen gas in the container is measured five days later BOD 5 testafter microbes have had a chance to reproduce and to consume the decomposable organic materials APHAStandard Method As can become evident from inspection of the contents of Table A see Appendixthe BOD test is among the most frequently used methods to characterize untreated and treated wastewaters.
It has been recently shown that microbial consortia that have become acclimated to the degradation of lignin-related compounds can reduce the BOD levels in the pulp-and-paper wastewaters below levels that are normally achievable by using indigenous microorganisms Ordaz-Diaz et al. The oxidizable matter in a wastewater also can be measured by the chemical oxygen demand COD test APHA The COD test takes advantage of the relatively rapid reaction of potassium dichromate with the oxidizable materials in the water sample.
The results from BOD and COD tests will be different if the wastewater sample contains difficult-to-biodegrade oxidizable compounds or toxic materials that inhibit biological activities. Thus the ratio of BOD to COD is often reported as a way to quantify the relative recalcitrance of organic compounds in wastewater Yeber et al. This value, which is often in a range between about 0. The color of an organic chemical compound, i.
its ability to absorb visible light, generally requires a sufficiently long sequence of single and double carbon-carbon bonds, i. a conjugated structure Adachi and Nagao
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sugar intake by age 4. Ayurvedic Herbal Remedies for Diabetics that Contain Polyphenols. Data was collected from the Women's Health Study between – to identify whether Full Article. Wastewater Treatment and Reclamation: A Review of Pulp and Paper Industry Practices and Opportunities. Martin A. Hubbe,*,a Jeremy R. Metts, a,b Daphne Hermosilla, c M. Angeles Blanco, d Laleh Yerushalmi, e Fariborz Haghighat, e Petra Lindholm-Lehto, f Zahra Khodaparast, g Mohammadreza Kamali, h and Allan Elliott i The pulp and paper (P&P) industry worldwide has Password requirements: 6 to 30 characters long; ASCII characters only (characters found on a standard US keyboard); must contain at least 4 different symbols;
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