【正文】 and Solutions. Wastewater can be treated anaerobically (ANAMET) followed by an activated sludge stage, or by a biofilm aerobic method alone or in bination with an activated sludge stage.Some of the methods used for wastewater treatment in a paper and pulp industry are as follows:Dissolved Air Flotation (DAF)Sand filtrationFloofilter?, bining flotation and filtration in one unitLamella sedimentationHighloaded pressure sand filtrationMembrane filtrationThe Purac DAFRapide? is an improved Dissolved Air Flotation (DAF) system, which increases the surface loading by four to six times while still reducing capital costs. The new DAF technology was first installed at Fiskeby Board AB in Sweden as a final chemical precipitation treatment after a biological treatment plant. The second installation of DAFRapide? was successfully started at the beginning of 2004 for production of 1,300m179。/h of raw water for Stora Enso Nym246。lla39。s production of pulp and fine paper.Advanced Treatment by Chemical Oxidation of Pulp and Paper Effluent from a Plant Manufacturing Hardboard from Waste Paper This study attempts to evaluate the applicability of chemical oxidation processes to polish biologically treated effluent of a plant manufacturing hardboard from waste paper to ply with the discharge limit of 120 mg l1 chemical oxygen demand (COD). In the first step, a chemically assisted settling was applied. The optimum results were obtained with alum plus lime with the alum dose of 200 mg l1. In the second step, chemically assisted settling effluent was fed into an activated sludge system and over 80% COD removal was achieved. In the last step of the experimental study, a series of ozone oxidation and Fenton oxidation methods were tested to remove residual COD. Ozone oxidation provided 80% COD removal. An ozone dose of 40 mg min1 with a reaction time of two hours was found to be optimum. Catalytic ozonation by using ferric iron, as well as high pH ozonation, Fenton process and H2O2/O3 oxidation did not prove to be more efficient than plain ozonation under this study conditions.EnzymesThe use of enzymes for wastewater treatment in the pulp and paper industry is reviewed as a new possibility. There is currently a lot of research activity in the enzymology of lignin degradation. Ligninase, cellulase, peroxidase, etc. are the most important enzymes, especially peroxidase, which is used for color removal in bleaching effluents. It is also possible to mix enzymes together with special microbes, which normally do not have high enzyme activity, and remove recalcitrant and harmless pounds from wastewater. The use of novel enzymes and rDNA technology in sludge and wastewater treatment will also be discussed.Paper RecyclingDepending of the agents to bleach the pulp, waste water has to be treated. Bleaching with peroxides, oxygen and ozone is not as efficient as using chlorine or chlorine dioxide, but the water has generally a very low or no amount of to treatment chemicals. By using chloride or chloride dioxide, the water contains these agents which increase the AOX. On the other hand, chloride bleaching is the most efficient.The waste water of paper recycling contains also particles which have to be filtrated. Rests of plastics, metal parts (paper clips, etc.) other waste have to be removed.The Treatment of Pulp and Paper Mill Effluent: A ReviewThe manufacture of paper generates significant quantities of wastewater。 as high as 60 m3/tonne of paper produced. The raw wastewaters from paper and board mills can be potentially very polluting. Indeed, a recent survey within the UK industry has found that their chemical oxygen demands can be as high as 11 000 mg/l. This paper reviews the processes involved in paper making and examines the effects which they could have on the environment. It also evaluates the treatment processes which are used to minimise these effects. In line with the majority of UK practice, it focuses mainly on aerobic biological treatment and, in particular, on the activated sludge process. This means that there is an indepth discussion about the problems associated with filamentous bacteria and sludge “bulking”. The paper also discusses the way in which anaerobic digestion can be applied to the treatment of liquid wastes from the manufacture of paper.Application of UltrafiltrationComplexation Process for Metal Removal from Pulp and Paper Industry WastewaterIn recent years, the pulp and paper industries have been trying different technologies to reduce fresh water consumption in paper mills. This has led to a fast development of new wastewater treatment technologies for industrial reuse. Lately, watersoluble polymeric ligands have shown to be powerful substances to remove trace metals from industrial wastewater through ultrafiltration (UF). In the present study, polyethyleneimine (PEI) and polyvinylalcohol (PVA) were used as watersoluble polymeric macroligands. The UF experiments were carried out in stirred deadend cells. The membrane used was formed from polyvinilidene fluoride (PVDF). The performance of watersoluble polymeric ligands was evaluated by determining metal removal and chemical oxygen demand (COD). In general, the plexation–ultrafiltration process was efficient for metal removal from wastewater, leading to a better effluent quality when pared to ultrafiltration without any ligands addition.Advanced Oxidation of a Pulp Mill Bleaching Wastewater the degradation, by several advanced oxidation reactions, of a pulp mill ECF bleaching effluent, was studied. The initial biodegradability of the organic matter present in the effluent, estimated as the BOD5/COD, was low (). When the effluent was submitted to ozonation and to five different advanced oxidation systems (O3/UV, O3/UV/ZnO, O3/UV/TiO2, O2/UV/ZnO, O2/UV/TiO2), the biodegradability increase five minutes of reaction, the O3/UV system appears as the most efficient in to transform the organic