浅谈中密度纤维板废水处理

浅谈中密度纤维板废水处理福建省林业勘察设计院陆继光１中密度纤维板生产的水量、水质及废水特点１．１水量废水主要来源于木片洗涤和热磨制浆。木片水洗的工艺用水，一般以木片在水洗机中的浓度控制，通常采用３．５％～６％（一般用４％），相应的用水量为１５．７～２...     

湿法生产硬质纤维板废水治理技术

湿法生产硬质纤维板废水,在木材综合利用工业中,用水量大,污染严重,排放的废水中含有大量地细小纤维及有机物,对水体,农业、渔业及人民身体健康均有较大危害。 为了减轻污染,回收并充分利用废水中的有用物质,国内各纤维板厂近几年来将纤维板废水循环使用,逐步提高纤维板废水的回用率,有的工厂已经将纤维板废水回用率提高到90%以上。大大提高了经济效益,减轻了对环境的污染。     

中密度纤维板废水处理工程的设计方案

中密度纤维板生产车间主要分为削片间、水洗间、中密度纤维板车间和热能中心4部分,其生产工艺划分为剥皮与削片、筛选与水洗、纤维制备与施胶干燥、铺装与热压、毛板处理以及裁板等工段.中纤板废水主要来源于木片水洗和热磨挤出水,其水质成分类似于制浆造纸工艺中的化学机械浆废水,其中含有纤维素、半纤维素、糖类、树脂类、单宁、果胶质及大量的泥砂、树皮等.这类废水不仅具有较高的CODcr、BOD5及SS,同时具有很高的色度和浊度.     

对纤维板有机废水中温消化过程中几个问题的探讨

通过几年来对湿法生产硬质纤维板高浓度有机废水中温消化处理的小试,中试及生产规模的运转试验,对纤维板有机废水中温消化过程中几个主要问题有了较深刻的认识。 由于湿法生产硬质纤维板所使用的原料及工艺决定了所产生的废水水质的性质。该废水有机物浓度高,其化学需氧量CODcr高达2～3万。废水中的物染物质为木质素,细胞碎片,木材中的胶体有机物质,木材中分离出来的可溶性有机物质,生产过程中所投加     

沈阳市纤维板厂污水处理工程简介

沈阳市纤维板厂是我院1969年设计,1971年建成投产。因为当时没有合适办法处理纤维板废水,因此没能做到三同时,留下了欠帐。沈阳市纤维板厂根据沈阳市环境保护局的要求,于1981年开始计划建设纤维板污水处理工程。当我院完成了湿法生产硬质纤维板高浓度有机废水的实验并获得成功,通过省级技术鉴定后,该厂就正式委托我院承担这     

利用纤维板生产中废水提取物制造木材胶粘剂的研究

利用纤维板生产中废水提取物与过量甲醛(甲醛溶液与粉状废水提取物的重量比为1～5:1)在酸性条件下可制成纤维板废水提取物-甲醛复合体,此种复合体反应液中的过量甲醛再用尿素或苯酚吸收,从而制成尿素(或苯酚)改性纤维板废液胶。采用上述二步法制成的改性纤维板废液胶可节省化工原料20%以上,用此种胶压制的人造板各项物理及力学指标达到采用纯化工原料胶所具有的水平。     

竹木混合纤维制备工艺研究

竹木混合纤维的制备直接关系到竹木复合中密度纤维板生产工艺路线的选择。此项研究在比较分析竹、木纤维形态差异的基础上,考察了笮木片混合磨浆的可行性和影响纤维质量的主要工艺参数。结果表明,在适宜的工艺条件下,可以采用竹木片混合磨浆工艺制备用于中密度纤维板生产的竹木混合纤维,在实验室条件下：竹木片混合比和磨浆时间和对纤维质量影响显著。     

竹木混合纤维制备工艺研究

竹木混合纤维的制备直接关系到竹木复合中密度纤维板生 产工艺路线的选择。此项研究在比较分析竹、木纤维形态差异的基础上,考察了竹木片混合 磨浆的可行性和影响纤维质量的主要工艺参数。结果表明：在适宜的工艺条件下,可以采用 竹木片混合磨浆工艺制备用于中密度纤维板生产的竹木混合纤维;在实验室条件下,竹木片 混合比和磨浆时间对纤维质量影响显著。     

解决高温季节石蜡粘上网的几点措施

１问题的提出石蜡是石油分馏过程中得到的一种性质不活泼的疏水物质。为增加纤维板的耐水性，在生产中向浆料施加石蜡。乳化石蜡工艺是国内湿法纤维板生产中应用最广泛的一种施加法，其优点是被乳化的石蜡微粒颗粒度小、稳定性高、施胶效果好。但是我国南方地区的纤维板厂，在盛夏季节采用乳化石蜡施胶工艺易产生石蜡微粒沾上网现象。笔者通过对湿法纤维板施胶、成型过程的深入研究，认为造成石蜡微粒粘上网的主要是浆温过高所致，而现有的热磨浆池设计欠周，在高温季节散热不良是浆温过高的主要原因。湿法纤维板生产工艺中配套的热磨贮浆池…     

国外湿法硬质纤维板生产现状及对策

随着刨花板和中密度纤维板的发展，硬质纤维板生产发展的势头开始受到抑制，湿法硬质纤维板产量已基本超于停滞或略呈下降趋势，湿法硬质纤维板企业保持竞争力的关键，是提高产品质量和劳动生产率，而对环境的不利影响则要减少到最低限度，废水污染问题仍是湿法纤维板生产的主要问题，总的趋势是湿法纤维板生产将逐渐被淘汰，对我国众多的中小型湿法硬质纤维板厂进行技术改造，是摆脱湿法生产困境的必由之路。在对湿法硬质纤维厂进行     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.