【作者】 陈洪雷；

【导师】 詹怀宇； 陈元彩；

【作者基本信息】 华南理工大学 ， 制浆造纸工程， 2011， 博士

【摘要】 制浆造纸废水排放量大,色度深,且具有很高的COD和BOD,在这种废水中存在大量的有机污染物,如一些细小纤维、木质素及含氯漂白过程中形成的氯代酚等木质素衍生物,尤其这些氯化有机成分,传统的废水处理方法很难将其去除,积累在环境中,给周围生态造成了严重污染,因此污染问题已经成为制约制浆造纸工业发展的关键。物理和化学方法可用于制浆造纸废水的处理,但成本较高,对有机氯化物的降解能力较差。相对来说,生物法可有效降解制浆造纸废水中的污染物,且成本低,不会造成二次污染,受到人们广泛关注。在以前的研究中,人们多利用白腐菌、厌氧或好氧污泥去处理制浆造纸废水,但随着环保意识的提高,传统的生物处理方法越来越不能满足人们要求,必须在现有基础上进一步强化其对废水的净化功能。同时,制浆造纸工业还产生了大量的造纸污泥和废纤维,这些物质中含有丰富的木质纤维成分,如不能得到有效利用,将会造成资源的极大浪费。基于上述原因,本研究中利用统计实验方法构建优势降解菌群,并用该菌群强化好氧颗粒污泥,提高污泥的制浆造纸废水净化能力。针对废水中含有大量有机氯合物,进行原生质体融合实验,构建可高效降解有机氯化物的重组菌。此外,将制浆造纸废水、造纸污泥和猪粪便进行协同发酵生产生物沼气,从而使制浆造纸工业废弃物作为优良的纤维原料用于生物能源生产。本研究对强化制浆造纸废水的生物处理,提高制浆造纸企业废水处理系统的处理效率,以及造纸工业废弃物的资源化利用具有重要意义。围绕上述研究目的,为快速分析制浆造纸废水的品性参数,采用比值-导数光谱建立制浆造纸废水的色度检测方法。利用比值-导数光谱中366nm处的吸收值计算废水的色度,而且检测过程中避免了废水pH值及其中悬浮物的影响,因此,检测前无需调节pH值和去除悬浮物,简化了检测程序,降低了人为因素引起的误差。该方法具有较高的准确度和精密度,色度检测范围在50-390 C.U.之间时,相对误差在±5%以内,可以满足制浆造纸废水的色度测定要求。基于同样的目的,利用化学计算学辅助的光谱方法建立制浆造纸废水COD快速检测方法,分别根据UV-vis光谱（模型1）和相应的导数光谱（模型2）建立了两个较正模型,在0-405 mg/L的检测范围内,两模型的较正系数分别为0.9954（模型1）和0.9963（模型2）,验证实验显示,模型2的平均相对误差为4.25%,较模型1（5.00%）低,说明模型2具有更高的准确度。新方法检测过程中无需耗用化学药品,成本低,无污染,耗时短,简化了COD测定步骤,减少了人为操作引入的误差,克服传统测定方法结果重现性对实验人员操作技能的依赖。以6株菌Agrobacterium sp.,Bacillus sp.,E. cloacae,Gordonia sp.,Pseudomonas stutzeri.和Pseudomonas putida.为出发菌株用于降解制浆造纸废水的COD,首先通过部分因子设计（FFD）实验,采用6因素两水平实验设计,COD去除率作为响应值,用于鉴别哪一种或哪几种菌对制浆造纸废水的降解有显著性影响,筛选得到4株对废水降解起积极作用的菌株。利用最陡坡度法快速接近废水降解过程中最佳细胞浓度,在FFD和最陡坡度法实验基础上,利用响应面分析（RSM）进一步对制浆造纸废水处理过程中菌体细胞浓度进行优化,并建立可以根据变量预测废水COD去除率的二次模型。研究表明,当各菌在废水中的细胞浓度(OD₆₀₀)分别为:0.35（Agrobacterium sp）、0.38（Bacillus sp.）、0.43（Gordonia sp.）、0.38（P. putid）时,对废水COD的降解效果最优。检证结果显示,COD的去除率为（65.3±0.5）%,与模型预测值66.7%非常接近。利用构建的优势降解菌群强化好氧颗粒污泥,提高其针对制浆造纸废水的降解能力,在厌氧处理的基础上,原始好氧污泥处理后,废水COD由629 mg/L降至203mg/L,废水色度由118 C.U.降至91 C.U.;而强化好氧污泥处理后,废水COD由629mg/L降至146mg/L,废水色度由118 C.U降至72 C.U.。以供试菌Pseudomonas putida.和Psathyrella candolleana.为出发菌株进行原生质体融合实验,融合原生质体再生后,根据不同融合子的色泽、质地等菌落形态及其相互间的拮抗现象分离出20株融合菌株,分析鉴定它们针对五氯酚（PCP）的降解特性。同时,根据导数光谱建立测定PCP的新方法,利用该法可以快速鉴定各重组菌的氯代酚的降解能力。结果表明,其中4株重组菌Xz6-1, Xz6-3, Xz6-5和Xz8-2具有显著的PCP降解性能,PCP去除率分别为75.98%、66.12%、28.40%和43.26%,Xz6-1的去除率最高,比亲本Pseudomonas putida（PCP去除率为54.27%）提高了27.71%。利用重组菌XZ6-1和亲本Pseudomonas putida强化好氧颗粒污泥,结果显示,原始污泥的PCP降解率仅为10.69%,而由Pseudomonas putida和XZ6-1强化的颗粒污泥的PCP降解率提升至21.20%和30.03%。结合制浆造纸废水、造纸污泥以及猪粪便协同发酵生物沼气,采用2%的发酵物料浓度,选用三因素、两水平全因子FFD实验设计考察影响沼气发酵的主要因素,分析结果显示,C/N、温度T和初始pH值均对生物沼气产率具有显著影响。根据前人的研究成果,确定35℃为发酵温度,通过正交实验验证发酵过程中适中的C/N和pH值,优化后的生物沼气发酵工艺条件为物料浓度为2%,温度为35℃,C/N为25,初始pH值为7.5,此条件下,可以得到368mL CH₄,发酵结束后废水的COD和BOD较原始制浆造纸废水分别降低了28.97%和72.40%。更多还原

【Abstract】 The pulp and paper industry produces a strongly colored effluent with high levels of biochemical oxygen demand （BOD） and chemical oxygen demand （COD）. These effluents contain large amount of organic matter, including fine fibers, lignin and associated bleaching by-products such as chlorophenols and benzodioxins etc, in particular, chlorinated organics, most of them being difficult to eliminate by conventional waste water treatment processes and accumulated in the environment. Therefore, pollution problem caused by the pulp and paper mill effluent has been one of the important environmental problems. Although physical and chemical methods are available for treatment of pulp and paper mill effluent, they are less desirable than biological treatment because of cost-ineffectiveness and residual effects. Biological treatment is known to be effective in reducing the organic load and toxic effects of pulp and paper mill effluent. There are a number of biological methods such as using fungus, anaerobic or aerobic sludge reactor to treat this type of wastewater, have been presented. However, as people increasing awareness of the environment protection, these traditional methods could not meet the people’s needs any more. Meanwhile, pulp and paper mills also produced a lot of waste paper sludge and waste fibers, which contain a large amount of carbohydrate components. It will be a great waste of resources if these materials can’t be utilized reasonably. Based on the above situation, a mixed-culture community was constructed by statistical experimental design in this study for the degradation of pulping effluents, and intensified aerobic granular sludge with this mixed-culture community in order to improve the capability of sludge for degrading pulping effluents. Aim at the problem of organic chlorides in pulping effluents, a protoplast fusion experiment was carried out and a recombinant strain was constructed with an ability of degrading chlorophenols efficiently. In addition, biogas was produced by using the mixture of pulping effluent, waste paper sludge and manure from pig farm. The waste from pulp and paper mills was used as resources. The result of study is significant to enhance the biotreatment of pulping effluents and promote resource utilization of waste from pulp and paper mills.According to our research purpose, in order to analyze character parameters of pulping effluents rapidly, a new method is proposed for determination of chroma in pulping effluent by using ratio spectrum–derivative spectrophotometry. A linear regression equation was obtained. The ratio derivative value at 366 nm was used to calculate chroma, which is not affected by pH value and suspended solid in pulping effluent, so the procedure does not require adjusting pH value and removing suspended solid before detection of chroma. The test procedures were simplified and the error caused by human factors was avoided. The method has high precision and accuracy with a relative difference within±5% when the chroma of samples is in the range of 50-390 color unit （C.U.）. The new method was satisfactorily applied for determination of chroma in pulping effluent. To the same purpose, a method for the determination of COD in pulping effluent was described based on chemometrics-assisted spectrophotometry method. Two calibration models were established by inducing UV-visible spectroscopy （Model 1） and derivative spectroscopy （Model 2） combined with chemometrics software Smica-P. Correlation coefficients of two models are 0.9954 （Model 1） and 0.9963 （Model 2） respectively when COD of samples is in the range of 0 to 405 mg/L. Confirmatory experiment showed that average relative error of Model 2 （4.25%） was lower than that of Model 1 （5.00%）, which indicated predictability of Model 2 was better than that of Model 1. Chemometrics-assisted spectrophotometry method did not need chemical reagents, testing time was shortened evidently.Statistically based experimental designs were used to construct a mixed-culture community for maximizing COD degradation of pulping effluents by the use of six different strains, i.e., Agrobacterium sp., Bacillus sp., Enterobacter cloacae, Gordonia, Pseudomonas stutzeri, and Pseudomonas putida. Significant effects of single and mixed strains on COD degradation were quantified first by applying a fractional factorial design （FFD） of experiments, and four strains were selected as the main driving factors in the process of biodegradation of effluents. Then the Steepest Ascent method was employed to approach the experimental design space, followed by an application of response surface methodology to further optimize the proportion of cell concentration for different strains in pulping effluent. A quadratic model was found to fit COD removal efficiency. Response surface analysis revealed that the optimum levels of the tested variables for the degradation of COD, and optimized cells concentrations (OD₆₀₀) of four strains in mixed-culture community were 0.35 Agrobacterium sp., 0.38 Bacillus sp., 0.43 Gordonia sp., and 0.38 P. putid., respectively. In a confirmatory experiment, three tests were performed by using the optimized conditions, and a COD removal efficiency of （65.3±0.5） % was observed, which was in agreement with the prediction. The aerobic granular sludge was intensified with the mixed-culture community constructed in this study. The pulping effluent was treated firstly with anaerobic sludge, and followed by further treatment of aerobic granular sludge and intensified aerobic granular sludge, respectively. COD of pulping effluent was decreased from 629mg/L to 203mg/L and chroma declined to 91C.U. from 118C.U. after treatment by original aerobic granular sludge. By contrast, the efforts of intensified aerobic sludge was better, COD was dropped to 146mg/L from 629mg/L, and chroma declined to 72C.U. from 118C.U.A new strain with an ability of degrading chlorophenols efficiently was constructed by protoplast fusion between Pseudomonas putida and Psathyrella candolleana. 20 recombinant strains were screened and used to degrade pentachlorophenol （PCP） synthetic wastewater in order to determine their capabilities of chlorophenol degradation. Also, a new method quantifying PCP was proposed based on derivative spectroscopy, which can detect PCP content in synthetic wastewater within a short time, so chlorophenol biodegradability of recombinant strains could be measured rapidly. The results indicated that the removal efficiency of PCP in synthetic wastewater by 4 recombinant strains viz., Xz 6-1, Xz 6-3, Xz 6-5 and Xz 8-2 were 75.98%, 66.12%, 28.40% and 43.26%, respectively which showed that the removal rate was improved by 27.71% by Xz6-1 as compared with Pseudomonas putida （removal rate of PCP is 54.27%）. The aerobic sludge was intensified by Xz6-1 and Pseudomonas putida respectively, so as to improve it’s capabilities of chlorophenol degradation. The results showed that PCP removal rate of original sludge was only 10.69%, but this value was enhanced after intensification. The removal rates of PCP were 30.03% and 21.20% after treatment with the sludge intensified by Xz6-1 and Pseudomonas putida respectively.The mixture of pulping effluents, waste paper sludge and pig manure was used to produce biogas by anaerobic fermentation. A moderate feeding concentration of 2% was selected. Significant effects of three factors including carbon-nitrogen ratio （C/N）, temperature （T） and initial pH value were quantified by applying FFD experiment. The results showed that three impact factors were significant for biogas production. The temperature was fixed （35℃） based on the research of the predecessor, and further optimized C/N, initial pH value by using the orthogonal experimental design. Finally, the optimal C/N （25） and pH （7.5） were fixed. Biogas production is 368mL under the condition of feeding concentration of 2%, temperature of 35℃, C/N of 25 and pH value of 7.5, COD and BOD of pulping effluent were reduced by 28.97% and 72.40% after anaerobic fermentation.更多还原