TAILIEUCHUNG - Treatment of Pulp and Paper Mill Wastes

An important barrier to quick process changes is the industry’s slow capital-turnover rate. A survey in 1997/8 revealed that the median age of paper ma- chines in Europe was 23 years (Berkhout, 2005). Recent research undertaken in the USA suggests a potential negative correlation between environmental innovation and sunk costs. The research suggests that no matter what the regulator does, because there will be much lobbying and negotiations undertaken as a part of the permitting process, regula- tors tend to favour existing actors over potential new entrants. The indirect impact this can have on the innovation process can be potentially huge since. | 10 Treatment of Pulp and Paper Mill Wastes Suresh Sumathi Indian Institute of Technology Bombay India Yung-Tse Hung Cleveland State University Cleveland Ohio . POLLUTION PROBLEMS OF PULP AND PAPER INDUSTRIES Pulp and paper mills are a major source of industrial pollution worldwide. The pulping and bleaching steps generate most of the liquid solid and gaseous wastes Table 1 1 . Pulping is a process in which the raw material is treated mechanically or chemically to remove lignin in order to facilitate cellulose and hemicellulose fiber separation and to improve the papermaking properties of fibers. Bleaching is a multistage process to whiten and brighten the pulp through removal of residual lignin. Pulping and bleaching operations are energy intensive and typically consume huge volumes of fresh water and large quantities of chemicals such as sodium hydroxide sodium carbonate sodium sulfide bisulfites elemental chlorine or chlorine dioxide calcium oxide hydrochloric acid and so on. A partial list of the various types of compounds found in spent liquors generated from pulping and bleaching steps is shown in Table 2 2-4 . The effluents generated by the mills are associated with the following major problems Dark brown coloration of the receiving water bodies result in reduced penetration of light thereby affecting benthic growth and habitat. The color responsible for causing aesthetic problems is attributable to lignin and its degradation products. High content of organic matter which contributes to the biological oxygen demand BOD and depletion of dissolved oxygen in the receiving ecosystems. Presence of persistent bio-accumulative and toxic pollutants. Contribution to adsorbable organic halide AOX load in the receiving ecosystems. Measurable long-distance transport 100 km of organic halides such as chloroguaiacols thereby contaminating remote parts of seas and lakes 5 . Cross-media pollutant transfer through volatilization of compounds and absorption of .

• Hoá dầu
• Asymptotic Expansion
• Homogenisation and Multiscale
• Topology Optimisation
• Composite Structures
• constituent materials
• materials and structure
• Laminated shells
• Asymptotic theory for thin two ply shells
• Thin two ply shells
• Kinematic formulae
• Singular perturbation
• Banach space
• Evolution equation
• Initial layer
• Radiative transfer
• Neutron transport
• measures suggest
• surprising given
• tài liệu báo cáo nghiên cứu khoa học
• cách trình bày báo cáo
• kiến thức toán học
• báo cáo toán học
• công trình toán học