【作者】 王宏勋；

【导师】 沈韫芬； 张晓昱；

【作者基本信息】 华中科技大学 ， 生物医学工程， 2004， 博士

【摘要】 草浆是中国大多数造纸厂的主要浆种,草浆碱法蒸煮黑液是造纸厂废水主要污染源。由于存在硅含量低、热值低和规模小的特点,现阶段最成熟的黑液治理方法——碱回收法并不适应草浆碱法蒸煮黑液的治理。虽然现阶段很多大型造纸厂均采用碱回收的方式进行黑液治理,但由于投资大、运行费用高,造成厂家不使用碱回收装置,偷排黑液;而中小造纸厂没有实力建设碱回收装置,黑液成为污染环境和制约造纸行业发展的严重问题。本论文旨在从资源化和生物处理的角度着手,为草浆碱法蒸煮黑液治理提供新的处理模式和工艺。通过对30株具有木质素降解能力的白腐菌株处理不同黑液体系特性研究及不同菌系处理效应分析,结果表明:不同种属菌株具有不同的处理特性:云芝属的菌株S1B具有较强的降低体系pH的能力,可以有效将体系pH由pH7降低到pH2以下,酸析出体系中大多数木质素,去除COD负荷60%以上;多孔菌属的菌株CD4可以将体系pH由pH3调节到中性,COD去除率达到50%左右;平菇属的菌株BP2可以分泌漆酶,去除体系酸溶木质素,降低幅度达到80%左右;香菇属的菌株AX2具有一定的酸溶木质素降解效果;融合株处理特性显示在木质素降解和COD去除上不同菌株之间可能具有协同效应。纯粹光解预处理对于白腐菌处理黑液没有显著的促进作用。对产酸菌株S1B的特性研究表明,体系pH、黑液负荷和碳源对于菌株S1B产酸有显著的影响,其处理黑液可以选择如下条件:起始体系pH6-7之间,COD负荷控制在13000mg/L以下,添加0.5%的淀粉类碳源,温度选择在25℃-40℃之间,不添加相关的营养盐。菌株S1B、AX2、BP2、CD4及其混合培养处理黑液特性表明,菌株S1B可以有效降低体系pH,是处理黑液体系的主效菌株。混合培养并不能有效提高菌株S1B耐受高碱性和高负荷的能力,反而一定程度上抑制了菌株S1B的产酸特性,菌株S1B适合单株培养处理黑液。菌株CD4可以有效降低菌株S1B处理黑液出水的体系COD和调高体系pH。不<WP=4>同菌株与菌株CD4混合培养表明,菌株组合BP2+CD4混合培养可以有效去除出水中酸溶木质素含量。 确定白腐菌处理黑液模式为:菌株S1B单株培养处理,菌株组合BP2+CD4混合培养后续处理,产生COD负荷在3000-4000mg/L、pH中性、酸溶木质素含量在0.2g/L左右的出水。研究UV-Fenton、超声、菌糠过滤、耐碱菌微酸化、厌氧-好氧、内电解辅助工艺对白腐菌处理的影响,发现菌糠过滤+耐碱菌微酸化前处理模式效果明显,50%左右的黑液被吸收,体系pH12-13降低到pH6左右,出水pH适应于后续菌株;厌氧-好氧+内电解为较好的后处理工艺,可以将体系COD负荷降低到200mg/L以下。进行不同单元操作的放大研究,确定菌糠过滤—耐碱菌微酸化—产酸菌酸析—降解菌群调节—厌氧水解—接触氧化—内电解处理的黑液处理工艺,经20天的连续处理证明可以实现黑液的有效处理。本论文首次将白腐菌调节pH特性应用到污水处理体系中,通过产酸代谢调节黑液体系体系pH,实现体系木质素的析出和碱性的消除。同时利用白腐菌对小分子木质素的降解,实现白腐菌调节pH和木质素降解能力的协同。本论文首次将菌糠应用于难降解污水的预处理中,利用菌糠吸附和白腐菌固体体系中对污染物的强降解特性,产生可以有效处理高碱性芳香化合物污染体系的单元操作。该论文的研究,为黑液白腐菌治理提供了理论与技术实践途径。更多还原

【Abstract】 Most paper making industry in China takes the herbaceous material as the pulp and thus the alkaline wheat straw pulping black liquor is the main wastewater produced by paper mills. For the moment, the best process method of black liquor-chemical recovery is unsuitable for the treatment of alkaline wheat straw pulping black liquor for the characteristics of little silicon content, low caloric value and small scale. Because the investment and run expense are too high for many paper mills, the black liquor is still the main source of environmental pollution and the main difficulty in development of papermaking industry.The thesis focused on bioprocess of alkaline wheat straw pulping black liquor and provided a new technology in its treatment.It was showed in the study of characteristics of 30 strains of white rot fungi in black liquor treatment that photodissociation did not have obvious promoting effect on black liquor treatment by white rot fungi. Different species of the strains presented distinct characteristics. Strain S1B had strong ability of pH decline and it could reduce the system pH effectively from pH 7 below pH 2. Most of the lignin in the system was acidulated and the COD removal ratio reached over 60%. Strain CD4 could adjust system pH from pH3 to neutral, and the COD removal ratio reached about 50%. Strain BP2 could secrete laccase and remove almost about 80% acid-soluble lignin from the system. Strain AX2 had certain ability of acid-soluble lignin degradation. The study of fusants showed possibly synergistic effect of different strains on lignin degradation and COD removal.The study of the characteristics of strain S1B showed that the system pH, the load of black liquor and carbon resource had prominent effect on acid generation by strain S1B.The possible conditions in black liquor treatment was as follows: original system pH between pH6-7, COD under 13000mg/L, with supplementation of 0.5% carbon resource, temperature between 25℃ to 40℃ , without any salts. <WP=6>The study of black liquor process by strain S1B, AX2, BP2, CD4 and their mixed culture indicated that strain S1B was the major strain in the process which declined system pH effectively. Mixed culture did not improve the ability of strain S1B in resistance of high alkali and high load, and on the contrary restrain the acid generation of strain S1B. Therefore, single culture was more suitable for strain S1B in black liquor process.Strain CD4 could reduce the system COD of the filtrate of strain S1B and increase the system pH effectively. The study of different strains cultured with strain CD4 showed that the mixed culture of strain BP2 and strain CD4 removed the acid-soluble lignin of the filtrate effectively.The final process mode of black liquor by white rot fungi was decided that strain S1B was singly cultured first, then strain BP2 and strain CD4 were mixed cultured. Finally the filtrate was with the characteristics of COD between 3000-4000mg/L, pH neutral, the content of acid-soluble lignin about 0.2g/L.After the study on the effect of different aided methods, such as UV-Fenton, ultrasonic, filtration through fungal culture, acidification by alkali-proof strain, A/O process and interior electrolytic method on black liquor treatment by white rot fungi, it showed that the combination of filtration through fungal culture and acidification by alkali-proof strain was the better pre-processing. And consequently 50% black liquor was absorbed and the system pH was declined from pH12-13 to pH6. The combination of A/O process and interior electrolytic method was the better post-processing which declined the system COD under 200mg/L.After the study of scale up of different unit operations, the process technology of black liquor was achieved: filtration through fungal culture- acidification by alkali-proof strain-acidulation by acid generation by white rot fungi-pH adjustment with - A/O process-interior electrolytic method. And after 20-day continuous process the black liquor was treated effectively.The characteristic of pH adjustment更多还原