Biomass use in chemical and mechanical pulping with biomass-based energy supply

The pulp and paper industry is energy intensive and consumes large amounts of wood. Biomass is a limited resource and its efficient use is therefore important. In this study, the total amount of biomass used for pulp and for energy is estimated for the production of several woodfree (containing only chemical pulp) and mechanical (containing mechanical pulp) printing paper products, under Swedish conditions. Chemical pulp mills today are largely self-sufficient in energy while mechanical pulp mills depend on large amounts of external electricity. Technically, all energy used in pulp- and papermaking can be biomass based. Here, we assume that all energy used, including external electricity and motor fuels, is based on forest biomass. The whole cradle-to-gate chain is included in the analyses. The results indicate that the total amount of biomass required per tonne paper is slightly lower for woodfree than for mechanical paper. For the biomass use per paper area, the paper grammage is decisive. If the grammage can be lowered by increasing the proportion of mechanical pulp, this may lower the biomass use per paper area, despite the higher biomass use per unit mass in mechanical paper. In the production of woodfree paper, energy recovery from residues in the mill accounts for most of the biomass use, while external electricity production accounts for the largest part for mechanical paper. Motor fuel production accounts for 5–7% of the biomass use. The biomass contained in the final paper product is 21–42% of the total biomass use, indicating that waste paper recovery is important. The biomass use was found to be about 15–17% lower for modelled, modern mills compared with mills representative of today's average technology.     

Water management initiatives in sugarcane molasses based distilleries in India

Molasses based alcohol distilleries in India are one of the most polluting industries; in addition, they are high consumers of raw water. Growing scarcity of high quality freshwater as well as stringent regulatory standards is compelling these units to explore appropriate water management options. This paper provides an overview of the water use and effluent treatment status in Indian distilleries and the challenges faced by this sector. Practices adopted by progressive Indian distilleries to minimize freshwater use are illustrated through case studies. Further, the R&D focus pertaining to wastewater treatment and disposal is also summarized.     

A QUARTER CENTURY OF INDUSTRIAL WATER USE AND A DECADE OF DISCHARGE CONTROLS1

This paper explores the trends in industrial water intake, discharge, recycling, and gross water use to see whether or not the 1972 Clean Water Act (CWA) has had an impact on industrial effluent discharge. Quinquennial Census data indicate that the levels of discharge, both generally and per unit of product, have been falling for as long as these data have been gathered. Trends in gross water use and recycling ratios suggest that during the 25 years of record production processes were gradually modified so that less total water was discharged and less was used per unit of output. Untreated discharge as a percent of all discharge fell fairly steadily across all industries until 1973 and continued to fall in 1978 in the major BOD-discharging industries. By 1978, 75 percent of the pulp and paper effluent and 40 percent of the food processing effluent was treated. The consistent increase in treated discharge in the pulp and paper mills, with their large component of BOD-related process discharge, was not matched by parallel trends in the steel, petroleum, and chemicals industries with their relatively smaller amounts (and percents) of process discharge. This suggests that the CWA may have been responsible in part for the change in the former. In the pulp and paper industry, there is further evidence that the CWA has influenced wastewater discharge. Although, for the century as a whole, pulp and paper mills discharged less water, and more discharge was treated, in 1978 than in 1973, these trends were especially dramatic among firms in the Northeast where controls were likely to have been most stringent. Finally, using the only direct evidence we have, it appears that the drop in discharge levels and the increasing amounts of treatment had a significant effect on the amount of BOD discharged to surface and ground water. In 1973 the pulp and paper mills in Wisconsin discharged an average of about 868,000 lbs/day; by 1982, despite increased levels of production, they discharged less than 10 percent of that. There is no doubt that industrial water use changed over the 25 years of record. Although the evidence is circumstantial, it appears that the CWA and the environmental ethic which spawned it played an important part in some aspects of the shifts.     

The effects of recovering fibre and fine materials on sludge dewatering properties at a deinked pulp mill

The manufacture of deinked pulp generates large amounts of waste for disposal. The yield loss in the production of recycled paper can be up to 25%. The use of landfills for waste disposal is very expensive and will be prohibited in Europe in the next few years. Thus, there is a great pressure to improve the material efficiency and to reduce the amount of waste that is produced at deinked pulp mills. However, the issue is complex because an improvement of the material efficiency at one process unit may deteriorate the performance of other stages. For example, the attempts to increase the fibre yield in the deinking processes can lead to poor sludge dewatering properties, resulting in that there are no added advantages for the mill anymore.This work aims to determine the limitations between the sludge dewatering properties and the improvements in material efficiency at a deinked pulp mill by investigating the dewatering properties of sludge samples that contained variable amounts of fine screening and flotation froth rejects. The results show that the deinked pulp mill material efficiency can be increased without weakening the sludge dewatering properties if the fibre content is not reduced below a certain limit. The material efficiency can be increased either by (1) recovering fibres at an acceptable quantity where the fibre content does not decrease below the limiting point or by (2) recovering fine materials simultaneously with fibres in a way that maintains the fibre content above a limiting point. The first method provides an opportunity for deinking mills to increase the yield, even though the increase is less than 2 percentage units. With the simultaneous recovery of fibres and fine materials using the second method, it would be possible to improve the material efficiency at the deinked pulp mill by approximately 5 percentage units without affecting the dewatering of the combined sludge.     

EFFECT OF THE PAPER INDUSTRY ON WATER QUALITY OF THE LOWER FOX RIVER1

ABSTRACT: The Lower Fox River, Wisconsin, hosts the densest concentration of paper mills in the US., with 18 located along a 4Gde stretch between Lake Winnebago and Green Bay, Lake Michigan. Some of these companies use only primary, others also secondary, waste treatment techniques. Comparison of the quantities of wastes discharged with the legal limits indicates that all plants discharge only 40-50 percent or less of the allowable suspended solids; most discharge < 50 percent of the allowable BOD. This is equal or better than the performance of paper companies elsewhere in the state. Reductions in pollutant discharges have corresponded to improved water quality, though too much BOD is still discharged to be adequately assimilated by the Fox River. The relatively low current level of discharges means permit levels would have to be drastically cut to make any significant impact on water quality. Only a few companies might be seriously affected by such changes. Flow and temperature related permits would likely be more effective, but more difficult to comply with for the industry. Toxic substances are also a potential problem, particularly chlororganic compounds that can form in situ from the chlorine frequently used for pulp bleaching.     

国内外造纸行业水污染排放标准比较研究

中国是造纸大国,制浆造纸在中国属于重污染行业。2008年国家发布的《制浆造纸工业水污染物排放标准》对整个行业可能排放的污染物提出了要求。本文通过将该标准与国外造纸行业相关的水污染物排放标准进行比较研究,找出我国标准与国外的差别,并为完善我国造纸行业水污染物排放标准提出建议。     

Regulation of discharge of organochlorines from pulp mills in Canada

Organochlorines are a group of chemicals including dioxins and furans, at least some of which are highly toxic to humans. Organochlorines are formed as a byproduct of the chlorine bleaching process in pulp mills, as well as in other ways. Current federal and provincial environmental protection legislation in Canada is too general to adequately deal with the problem of organochlorine discharge. In Sweden and Germany strict new guidelines have been set for the discharge of organochlorines; strict guidelines are also planned for Alberta. The author recommends that new regulations, dealing specifically with organochlorine discharge, be promulgated under the new Canadian Environmental Protection Act. The new regulations should apply equally to all pulp mills. Strict enforcement, through cooperation of federal and provincial authorities, is also advised.     

Toxic releases from paper made with recovered wastepaper versus virgin wood fiber: A research note

Toxic Release Inventory (TRI) data were used to compare average releases (kilograms per metric ton) of paper mills using primarily recovered wastepaper versus mills using primarily virgin wood fiber. Annual releases, for 79 mills, of chlorine, chlorine dioxide, chloroform, acids (hydrochloric and sulfuric), volatile organics (methyl ethyl ketone, methanol, and acetone), and ammonia were compared over the years 1987–1992. Both types of mills reported generally lower toxic releases in 1992 than in 1987; however, toxic releases in all categories were significantly lower from mills using recovered wastepaper than from mills using virgin wood fiber, strongly demonstrating that recycling has added benefits beyond reduced resource consumption. These results suggest that environmental policy should concentrate as much on increasing demand for recycled paper and developing wastepaper collection infrastructure as it does on end-of-pipe pollution abatement.     

废纸制浆造纸废水封闭循环处理工艺

本文介绍了废纸造纸制浆废水的特点、在零排放和废水封闭循环中遇到的问题以及解决措施，介绍了几种目前比较常用的废纸制浆连纸循环水处理工艺及其发展状况。     

四川省制浆造纸行业可持续发展建议

造纸业是与民生关联度极高的行业.为改变国内造纸行业污染局面、整合企业规模、合理原料结构、提高技术装备、改革落后生产工艺,国家先后出台了多项政策规定.特别是2008年新的<制浆造纸工业水污染物排放标准>(GB3544)颁布后,四川省制浆造纸行业面临巨大的整改压力.如何抓住产业调整机遇,加快产品结构调整和生产方式转变,努力...     

对小纸厂碱回收可行性的初步评价

本文对小型造纸厂的碱回收在技术上和经济上的可行性进行了分析,作出了当前是中、小型造纸厂搞碱回收的有利时机的初步评价。     

Design of a representative and cost-effective sampling programs for industrial wastewater with examples from bleached kraft pulp and paper mills

The diagram constructed for selection of sampling methods indicates that, for a systematic error, E ≤ 13%, grab sampling (GS) may be used to characterize effluents with variation coefficient of flow ≤ 120% and of contaminant concentrations ≤ 10%. For the whole studied range of variation coefficient of contaminant concentrations (2–82%), time-proportional compositing (TC) method may be applied with E ≤ 10% for effluents characterized by variation coefficients in flow < 90%. The more complicated flow-proportional compositing (FC) method is required only for effluents with larger variation coefficients or to produce more precise results. The diagram constructed for selection of sampling frequencies indicates that sequential sampling at intervals of approximately 60 min may be applied with E ≤ 10% for effluents characterized by variation coefficients ≤ 30%. Practical application of the diagrams, constructed using normal series, was checked against monitoring data from two pulp and paper mills in Vietnam. The two diagrams provided results on sampling methods and frequencies in good agreement with those obtained from actual monitoring data with percentages of agreement cases of 80 and 75%, respectively. The approach was applied in design of a monitoring program at the Bai Bang integrated pulp and paper mill in Vietnam.     

Management of treated pulp and paper mill effluent to achieve zero discharge

Pulp and paper mills are one of the major effluent generating industries in the world. In most cases, mill effluent (treated or raw) is discharged back into a river, creek, stream or other water body; resulting in negative environmental impacts, as well as social concerns, among the downstream users. Pulp and paper mill effluent management, which could result in zero discharge into downstream water bodies, would present the best management option to address socio-environmental concerns. This paper presents such an effort aimed at closing the water cycle by using treated effluent from the mill to irrigate forage and fodder crops for producing animals feed. The treated effluent is delivered from the mill through gravity into a winter storage dam of 490ML capacity. For irrigation applications on 110ha of farmland, which is 42% of the total farmland, the water is pumped from the winter storage dam to five individual paddocks with Centre Pivot (CP) irrigators and one rectangular paddock with a Soft Hose Travelling (SHT) irrigator. From October 2001 to June 2006, a total of 2651mm of wastewater was applied at the farm. The impact assessment results, obtained from field monitoring, investigations and analysis, indicated that the closed water cycle effluent management strategy described had resulted in a lessening of the impact on water resources usually associated with paper mills. However, social attitudes to the use of crops that have been irrigated with recycled waters and the resulting impact on market value of the produce may still be a major consideration.     

CO2-free paper?

Black liquor gasification–combined cycle (BLGCC) is a new technology that has the potential to increase electricity production of a chemical pulping mill. Increased electricity generation in combination with the potential to use biomass (e.g. bark, hog fuel) more efficiently can result in increased power output compared to the conventional Tomlinson-boiler. Because the BLGCC enables an integrated pulp and paper mill to produce excess power, it can offset electricity produced by power plants. This may lead to reduction of the net-CO₂ emissions. The impact of BLGCC to offset CO₂ emissions from the pulp and paper industry is studied. We focus on two different plant designs and compare the situation in Sweden and the US. The CO₂ emissions are studied as function of the share of recycled fibre used to make the paper. The study shows that under specific conditions the production of “CO₂-free paper” is possible. First, energy efficiency in pulp and paper mills needs to be improved to allow the export of sufficient power to offset emissions from fossil fuels used in boilers and other equipment. Secondly, the net-CO₂ emission per ton of paper depends strongly on the emission reduction credits for electricity export, and hence on the country or grid to which the paper mill is connected. Thirdly, supplemental use of biomass to replace fossil fuel inputs is important to reduce the overall emissions of the pulp and paper industry.     

TRENDS IN FRESHWATER INFLOW TO SAN FRANCISCO BAY FROM TUE SACRAMENTO-SAN JOAQUIN DELTA1

ABSTRACT: Outflow from the Sacramento-San Joaquin river system (Delta outflow) provides about 90 percent of the freshwater flow to San Francisco Bay. Because this river system also supplies most of the water used in California, some believed that annual freshwater flow to the Bay had declined by as much as 50 to 60 percent as water use increased. Consequently, we studied trends in actual Delta outflow and precipitation for the period 1921 to 1986, which is when Delta outflow data are available. We found that there has been no decrease in the annual Delta outflow over this period. In fact, a statistically significant increase in annual Delta outflow of 87 cfa/yr has occurred during the period 1921 to 1986. One reason that Delta outflow has increased is because precipitation has increased faster than water use. Other contributing factors include increased runoff from land use changes, water imports from other areas, and the redistribution of ground water. In addition, statistically significant seasonal trends in Delta outflow were found. Over the period 1921–1986 Delta outflow decreased in April and May and increased from July through November. Changes in other months were not statistically significant. These seasonal changes result primarily from the operation of upstream flood control and water development projects, which store water in the spring and release it in the summer and fall. These seasonal changes are also influenced by a climatic shift that has decreased spring snowmelt runoff and increased late summer through winter precipitation.     

Pollution performance of firms from pulp and paper industries

The water pollution emissions by 13 of the largest pulp and paper companies, developed on the basis of monthly reports filed with the US Environmental Protection Agency (EPA) by these companies, indicate a wide disparity in the amount of pollution discharged by them into the nation's waterways. Furthermore, the net discharge of pollution in waterways by all firms is positive, which indicates that all the firms in the study pollute the nation's waterways to some degree. Information presented in this study will be useful for public issues, such as evaluating the effectiveness of the Clean Water Act, government's water pollution policy and abatement strategy, and management's effectiveness in abating water pollution.     

JUDICIAL RESOLUTION OF TRANSBOUNDARY WATER CONFLICTS 1

ABSTRACT: Transboundary water conflicts occur under four circumstances. Because water is mobile, more than one political unit or owner has power to use water as it sequentially moves through the hydrologic cycle. Even when water doesn't move, jurisdictional conflicts occur because multiple political units regulate water simultaneously. When a river is a boundar uncertainty of ownership or jurisdiction occurs as the river shifts its course through natural processes. Lastly, limitations on who may use water may be imposed by export bans or more indirect measures like taxation. Legal solutions to transboundary conflicts are limited to litigation, legislation, and negotiated agreements. This paper examines the judicial solution.     

Sustainable use of water in the Aegean Islands

Water demands in the Aegean Islands have increased steadily over the last decade as a result of a building boom for new homes, hotels, and resorts. The increase in water demand has resulted in the disruption of past sustainable water management practices. At present, most freshwater needs are met through the use of the limited groundwater, desalinated seawater, and freshwater importation. Wastewater reclamation, not used extensively, can serve as an alternative source of water, for a variety of applications now served with desalinated and imported water. Three alternative processes: desalination, importation, and water reclamation are compared with respect to cost, energy requirements and long-term sustainability. Based on the comparisons made, water reclamation and reuse should be components of any long-term water resources management strategy.     

Impact of government regulations on pollution performance of pulp and paper firms

A comparative study of water pollution emissions of pulp and paper companies for the period 1978–1983 indicates a reduction in emissions for most firms. This improvement in pollution performance is attributed to the federal government's water pollution policy. Although there is an overall decline in water pollution, some firms have actually increased their emissions. Furthermore, there is still a wide disparity in each company's performance, although the differences are narrowing.     

Establishment of permit limits for mill effluent

Various governmental regulatory agencies are responsible for establishing regulations on the discharge of chlorinated organic compounds from pulp and paper mills. The procedures for setting permit limits are the basic topic of this article. Different methods of determining permit limits are set forth and discussed in a number of references, including documents of the Environmental Protection Agency. This paper discusses in detail the application of one particular methodology—the lognormal model approach. In this paper we utilize a real data set and include the necessary calculations required to set up permit limits. The basic tenets of the permit process are such that if limits are set too low, operators who are in full regulatory compliance will still be frequently cited, and if limits are set too high, operators who are not in compliance will seldom if ever be cited. Thus there is a great need for these effluent limits to be determined with great care, both to protect the environment receiving the wastewater and the industry producing the wastewater.