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1、 含毒有机废水生物处理前的预处理大量的资料表明，我国目前及今后相当长一段时间内的环境问题主要是水环境问题，水环境问题又主要是有机废水的污染问题。因此，有机废水的治理是环保工作中极其重要的一面。 有机废水无害化处理的首选方法是生物处理。这是由生物处理所具有的处理的相对彻底性（ 无二次污染或二次污染较小）以及运行费用低廉等优点决定的。根据有机废水处理方面的特性可以将其划分为以下3类：废水中的有机物易于生物降解，同时废水中的毒物含量很少。这类废水主要是生活污水和来自以农牧产品为原料的工业废水等； 废水中的有机物易于生物降解，同时废水中的毒物含量较多。这类废水主要来自印染、制革废水等；废水中所含的有机
2、物难于生物降解（生物降解速度极其缓慢），同时，废水中毒物可能较多、亦可能较少。这类废水主要来自造纸、制药废水等。第类废水可直接进行生物处理。第类废水较为复杂，此处不作讨论。本文主要对第 类废水中的毒物作用机制及应对措施加以讨论。1、毒物及其作用机制废水中凡是能延缓或完全抑制微生物生长的化学物质，统称为有毒有害物质，简称毒物。这些毒物，从化学性质上来分可划分为有机物和无机物两大类。从处理的角度又可划分为能被生物处理段去除、转化的物质（如H2S、苯酚等，或称非稳定性毒物）和不能被生物处理段去除、转化的物质（如NaCl、汞、铜等，或称稳定性毒物）两大类。毒物对微生物的作用机制主要有如下方式：（1）损
3、伤细胞结构成分和细胞外膜。如：70%浓度的乙醇能使蛋白凝固达到杀菌作用；酚、甲酚、表面活性剂作用于细胞外膜，破坏细胞膜的半透性。（2）损伤酶和重要代谢过程。一些重金属（铜、银、汞等）对酶有潜在的毒害作用，甚至在非常低的浓度下也起作用。这些重金属的盐类和有机化合物能与酶的-SH基结合，并改变这些蛋白质的三级和四级结构。（3）竞争性抑制作用。当废水中存在一种化学结构与代谢物质相类似的有机物时便会发生。因为二者都能在酶的活性中心与酶相结合，它们的竞争将抑制中间产物的形成，使酶的催化反应速率降低。（4）对细胞成分合成过程的抑制作用。当某些化学物质的结构类似于细胞成分的结构时，它们便会被细胞吸收并同化，
4、结果是合成无功能的辅酶或导致生长停止。这种作用最典型的例子便是磺胺酸。（5）抗生素对核酸的抑制作用。不少抗生素能专一地抑制原核生物的蛋白质合成，如链霉素会抑制氨基酸正确结合于多肽上。（6）抗生素对核酸的抑制作用。如丝裂霉系C会选择性地阻止DNA的合成，从而抑制微生物的生长。（7）对细胞壁合成的抑制作用。如青霉素便是通过干扰细胞壁的合成从而达到抑制微生物生长的效果。2、菌种承受毒物的能力及菌种驯化法需说明的是，微生物中存在不少能耐受常用代谢毒物的菌株，有的甚至能利用它们作为能源。化学物质对微生物的抑制作用与其浓度有直接关系，并随微生物的驯化而发生变化，经过驯化的微生物对有毒物质的适应能力将逐步加
5、强。微生物这种巨大的适应性（变异性）是由它们的小体积决定的。如一个微球细胞仅具有约100 000个蛋白质分子所能容纳的空间，如此小的体积决定了那些近期用不着的酶是不能储备的，许多分解代谢酶类只有当存在合适的基质时才会产生。在某些条件下这类可诱导的酶可占蛋白质总含量的10%.正是微生物的这种变异性，才使生物法处理含毒有机废水成为可能。但任何微生物承受毒物的能力都是有一定的极限的（此时的浓度叫极限允许浓度），正是这种极限又要求含毒物有机废水在生物处理前需要一定的预处理。前已说过，微生物由于其体积的细小，而具有巨大的适应性（变异）。因此可以采用人工改变微生物生活环境的方法进行诱导变异，让微生物直接适
6、应原水中毒物浓度或提高微生物对毒物的去除能力。这种方法对稳定性毒物及非稳定性毒物均适用，是处理含毒有机废水的一种基本方法。在城市生活污水处理厂中，当进水中酚的浓度突然增加到50 mg/L时，便会对生物处理系统产生巨大的破坏作用。严重时，会导致全系统的崩溃。可是，某焦化厂采用适应性变异的方法对菌种进行驯化即菌种驯化法，使微生物内的酶逐步适应了这种毒物的大量存在，便将这种毒物当成其底物而加以分解吸收。实际运行表明，进水中酚的平均浓度为117.5 mg/L时，酚的去除率高达99.6%.含酚废水处理是应对一种不稳定性毒物的例子，当毒物很稳定时，亦可采用这种驯化方法以提高微生物对毒物的承受能力。但须注意
7、，这种毒物的浓度必须满足最终出水排放标准或另外采取其它措施加以控制。3、预处理方法前已说过，驯化是生物处理法中应对毒物的一种基本方法。但任何微生物承受毒物的能力都是有一定的极限的，毒物浓度超过极限允许浓度时就需要一定的预处理。目前，预处理法主要有稀释法、转化法和分离法。 3.1稀释法污水中的毒物之所以成为毒物，是与其浓度有关的。当其浓度超过某一极限允许浓度时，毒物就成为毒物；在极限允许浓度以下时，毒物就不表现出毒性甚至成为营养。当废水中毒物浓度超过生物处理的极限允许浓度时，为保证生物处理的正常进行，可采用简单的稀释法，将废水中毒物浓度降低到极限浓度以下。根据废水中毒物的稳定或非稳定性质，结合实
8、际情况，可采取3种不同的稀释法：污水稀释法，处理出水稀释法，清水稀释法。（1）污水稀释法。不同的污水中所含的物质不同，将它们混合起来，彼此稀释，可将毒物浓度降低到极限允许浓度以下，这便是污水稀释法。它最简单、最经济，是首选方法，不论毒物的性质是稳定或非稳定均适用。少量的工业废水混入大量的城市污水中，几乎所有的毒物浓度都会被降低到极限允许浓度以下。但是，少量的工业废水彼此间混合后，毒物浓度仍有可能在极限允许浓度以上，仍需继续采取其它措施。污水稀释法除了上面所说的不同单位所排废水之间的大稀释外，还有同一工厂不同车间所排废水之间的小稀释。比如，制革工厂中，脱毛工段所排的灰碱废水中S2-的浓度高达1
9、000 mg/L以上，但脱毛工段所排的灰碱废水只占全厂总排水量的5%左右，只要建一较大的调节池（停留时间HRT一般在12 h左右），不同工段所排废水在此搅拌混合后，总出水中S2-的浓度便可降低到100 mg/L以下。这对后续处理非常有利。（2）处理出水稀释法。这种方法只适用于废水中的毒物为非稳定这一单一情况。处理出水稀释法又有两种：曝气池池型采用完全混合式；处理出水回流稀释法。出于经济方面的考虑，方法应是首选。实例：制革废水中S2-的存在对生物处理具有极大的危害，生物处理的1极限允许浓度为30 mg/L.制革废水经调节池调节稀释后，进入曝气池时S2-仍然在50 mg/L 以上。以前，许多设计单
10、位主张采用分隔处理，即先把灰碱废水单独进行脱S预处理，把进水中的S2-降低到30 mg/L以下，再进行综合处理。有经验表明，可采用处理出水稀释法来消除S2-对生物处理的影响，不需要进行分隔处理，而直接进行综合处理。东南大学设计的南京制革厂废水处理站，采用的处理流程为调节池初沉池生物处理，生物处理采用的是氧化沟，该氧化沟沟宽6 m，有效水深3 m，沟内水流平均流速0.4 m/s，做如下两个假定：废水进入氧化沟后经过1周的循环，其中的S2-经曝气氧化后全被去除（被氧化成单体硫或硫代硫酸盐）；废水一进入氧化沟后，横向扩散很好，横断面上各点水质完全相同。按S2- 的极限允许浓度30 mg/L进行计算，
11、理论上可得该氧化沟进水S2-的最大允许浓度为 7776 mg/L.从30 mg/L到7776 mg/L可以看出稀释法的巨大作用。当然，在实际运行中，两条假定不可能完全做到，故实际进水最大允许浓度远远不能达到7776 mg /L.根据该厂长达12年的稳定运行经验表明，在调节池出水S2-不超过100 mg/L 的情况下，S2-对氧化沟的稳定运行是完全没有影响的，而且氧化沟出水S2-始终在排放标准1 mg/L以下。这是稀释法成功应用的一个例子。（3）清水稀释法。这种方法只有在废水中的毒物为稳定性毒物，不能采用处理出水稀释，工厂内部及其附近又没有其它废水可以用来稀释它，而且这种毒物又不能采用分离法或转
12、化法去除时才能使用。这是由于这种方法的不经济性。采用清水稀释本身就要花费大量的水费；原水采用大量的清水稀释后，处理投资和运行费都要增加。随着环境管理的加强，已由浓度排放控制过渡到排放总量控制。实例：南京某石化公司化工二厂废水处理站，进水COD为6 000 mg/L，但同时含有CaCl 250 000 mg/L，如此高的盐度将会极大地抑制生物处理的正常运行，所以在生物处理之前必须对盐加以适当处理。考虑到生物处理对CaCl2无去除或转化作用，其它的分离或转化方法又不经济，该厂地处郊区，附近无其它工厂或本厂的另类废水可利用来稀释，故设计单位与甲方商量后采用了清水稀释法，即将原水加清水稀释10倍，将C
13、aCl2浓度降为5 000 mg/L后，再进行深井曝气法处理，取得了满意的效果。3.2转化法化学物质只有在特定的情况下才会表现毒性，比如，硝基苯毒性较大，转化为苯胺后，毒性就大为降低。Cr6+的毒性很大，可是被还原为Cr3+后，毒性就大为降低。所以，可以通过化学方法，将有机废水中的毒物转化为无毒或毒性较低的物质，以保证生物处理的正常进行。这种方法对稳定性毒物或非稳定性毒物均适用。采用这种方法一定要注意两个问题：转化后，稳定性毒物的浓度必须在生物处理极限允许浓度以下，非稳定性毒物的浓度必须保证生物处理的正常运行；最终出水中，毒物浓度也应满足排放标准。实例：化工废水中的硝基苯是一种毒性较大，可生化
14、性较差的物质。直接对它进行生物处理，由于毒物负荷的限制，使得生化曝气池的BOD负荷极低，效率不高。故绝大多数工程在废水进入曝气池之前进行预处理，用化学法（比如亚铁还原）将硝基苯转化为苯胺，苯胺与硝基苯相比，其毒性大为降低，而且可生化性大幅提高，使曝气池BOD负荷大大提高。3.3分离法利用分离的手段，将废水中的毒物转移到气相或固相中去，以保证废水生物处理的正常运转，这便是分离法的原理。此法对稳定性或非稳定性毒物均适用。采用这种方法时应注意如下几点：分离后，废水中稳定性毒物浓度必须在生物处理的极限允许浓度之下，非稳定性毒物的浓度必须保证生物处理的正常运行；必须保证最终出水各项指项（包括毒物）达到国
15、家排放标准；转移到气相或固相的毒物必须进行妥善处理，不允许出现二次污染。实例：制革废水中S2-是一种毒物，我们可以向废水中投加Fe2+使之形成FeS沉淀去除，出水可以直接进行生物处理而不受S2-的影响，沉淀的FeS可以送去制砖或进行填埋处理；亦可以向废水中加酸，将废水中的S2-形成H2S吹脱到空气中去，用NaOH吸收后形成Na2S再回用于制革生产。4、结语为保证生物处理的正常进行，可采用的消除毒物影响的措施是很多的，如何从繁多的方法措施中选择一个最佳方案，是一个全系统优化课题。优化的原则是：废水中各项指标（包括毒物）必须达到国家排放标准；必须保证生物处理的正常运行；在此基础上，应努力追求工艺流
16、程简单、投资省、运行费用低、无二次污染以及管理方便。实例一：制革工厂中，灰碱废水中含有大量的S2-.为消除S2-的影响，可采用的措施有如下几条：采用分隔处理，向废水中投加MnSO4，曝气，将废水中的S2- 氧化成单体硫或硫代硫酸盐；采用分隔处理，向废水中投加Fe2+，使之形成FeS沉淀而去除；采用分隔处理，向废水中投加酸，使之形成H2S，再用NaOH吸收；综合处理，向废水中投加MnSO4，曝气，将废水中的S2-氧化成单体硫或硫代硫酸盐；综合处理，向废水中投加Fe2+，使之形成FeS沉淀而去除；其它方法。在这么多的方法中，东南大学经过多年的探索，最终总结出一条最佳工艺方案：不进行分隔处理，直接进
17、行综合处理，调节池的HRT延长到12 h，搅拌混合后，可将废水中的S2-降低到100 mg/L以下，初沉后，曝气池采用完全混和型的氧化沟，可直接消除S2-的影响并将其去除。国内数十项此类工程的实际运行经验表明：这套综合措施是完全可行的。实例二：南京某炼油厂某股废水中，COD为3000 mg/L，NH3-N 200 mg/L，S2-150 mg/L.S2-的浓度已经超过生物处理的极限允许浓度，故在进行生物处理之前必须先解决好S2-的问题。在确定废水处理工艺流程.这种方法就本段来看是完全可行的，但因该废水中HN3-N浓度较高，必须采用A/O法进行处理，被氧化过的S进入A/O段后，处理池中的厌氧环境
18、又会将S还原为S2-，其毒性又恢复释放出来，必将破坏生物处理的正常运行。故采用这种方法从全流程上来看是不行的。最终选定的方案是采用投加Fe盐沉淀去除的方法。/Porganization system and working mode, the selection of a number of municipal strengthening group to build innovation and strengthen the organization of the basic level organizations advanced model.(seven) the manual work
19、 of the Communist Youth League Organization published and League branch of manual work, to promote the use of two manuals in the citys organizations at various levels. The county committee, directly under the group (work) is under the jurisdiction of grassroots League and group (total) using branch
20、ratio shall not be less than 70%.Three, to further strengthen the groups leadership and team building(a) to strengthen the leagues leadership at all levels of construction. Continue to do a good job of municipal Party Committee Organization Department on the strengthening of the Communist Youth Leag
21、ue cadres management opinions implementation. To promote the group counties (autonomous counties, cities) Commission and city directly under the group (workers) appointed to carry out the Five team building activities. Improve the League Association Department working mechanism. Conscientiously fulf
22、ill the duties of CO, combined with the city group directly under (the) Committee of the general election and the adjustment, actively jointly with the unit where the party organization department good group leadership selection with the work. Do a good job in municipal Party committee assistant com
23、mittee leadership and leading cadres of the annual assessment work, adhere to and improve the assistant secretary of the Communist Youth League talk system group To weave individual conversation and collective conversation, to strengthen the committees of all levels, the Standing Committee of the St
24、anding Committee, the establishment of a sound system of central group learning, the system of investigation and study, the system of important issues and the reporting system.(two) to strengthen the work of education and training of cadres to conscientiously implement the Central Committee. On the
25、implementation of grassroots cadres training project and opinions on carrying out the mission municipal CYL Cadres training project implementation opinions, full implementation of the project of the City Youth League cadres training education. Focus on the county grassroots cadres and workers focuse
26、d on training, the new school system vocational training League cadres, for the Municipal Organization Department jointly held the third session of the Communist Youth League system training cadres in party. Focusing on the construction of new socialist countryside, strengthening village cadres and
27、rural construction team group member of the young team, the county organizations at various levels throughout the year is expected to train 100 00 rural grassroots cadres, plans to train 1000 village secretary of the village Party branch.(three) actively promote grassroots cadres election work. Unde
28、r the unified leadership of the party organization, to strengthen grassroots organizations direct work, standardize the election work rules and procedures, in the designated candidate, open competition to democratically elected branch secretary at the same time, actively and steadily the development
29、 of Township, streets and other grassroots organizations in the direct election of the pilot work, on the basis of summarizing the experience and gradually expand the scope of the pilot, and gradually formed a set of measures and cadres election system.(four) to strengthen the cadres testing exercis
30、e. To study the development of XX city from 2006 to 2008 cadres testing exercise planning. To select outstanding cadres to the central mission in Beijing, Shanghai, Guangzhou and other central organs and sending work in developed areas. With the Central Committee the implementation of the western re
31、gion and ethnic minorities cadres training plan . To carry out the eighth batch of municipal organs attachment cadre management, selection, training work. The outstanding cadres to start the National Development Bank XX branch testing exercise.(five) to strengthen the group construction. The main po
32、sition to play the role of Youth League cadre education and training as the city, in accordance with the requirements of post training, further curriculum scientifically and rationally, adopt arrangement menu course, basic theory includes group work, focus, hot and difficult issues, to enhance the c
33、ontent and practice; to strengthen the construction of teaching staff, the integration of teachers, establish a quality teacher training team, establish and implement course evaluation system; take delivery of training to the countryside, on-site training, and increase the rural grassroots cadres tr
34、aining efforts.Four, efforts to strengthen the work of young talent(a) to tenth XX young 54 medal in recognition of the publicity, and actively explore the XX youth service. 54 Medal of institutionalization, standardization and socialization mechanism. Give full play to the XX award in recognition o
35、f 54 youth medal Association, Youth Award winner in the 54 chapter, investigation activities. Who won the Youth Service medal, dedication to the society to create conditions, build the stage. During the 54, named in recognition of the tenth XX young 54 medal. The association of XX editing of young t
36、alent , the exchange of information and communication platform for the XX of outstanding young talents.(two) the establishment of municipal Party committee of young talent information database. In accordance with the feasible, effective, classification management, implement step by step principle, t
37、he establishment of municipal Party committee of youth talent database; guiding organizations at various levels generally established the young talent database, construction of city, county (directly under the Communist Youth League), grassroots organizations three young talent information database
38、the relevant information collection system, and gradually establish the citys young people, the Communist Youth League youth talent information network, provide information platform for young talent resource development.Five, take effective measures to strengthen the mission management(a) to strengt
39、hen the mission management work. Strengthen the dues collection and management, continue to adhere to the dues collection regularly reporting system, the annual comprehensive award in recognition of the tour and the tour one vote veto system audit system. Do statistical work in the group. The group
40、service award in recognition of the advanced units, standardization, promoting group management work institutionalized.(two) to strengthen the organization of research and information exchange efforts. Grassroots carry out research, efforts to form a number of theoretical results. Make full use of t
41、he network carrier, to explore the establishment of electronic group service system, promote the work of Communist Youth League information.Attachment 4:XX municipal Party Committee Propaganda Department of the Communist Youth League work pointsIn 2006, the Communist Youth League propaganda ideologi
42、cal work XX to Deng Xiaoping theory and the important thought of Three Represents as guidance, study and implement the partys sixteen and the spirit of the the fifth Plenary Session of the 16th CPC Central Committee implementation of the eight plenary session of the two committee, the citys cultural
43、 work conference, the Propaganda Department of the meeting and the the fourth Plenary Session of the 15th CPC Central Committee permanent mission spirit, closely around 11th Five-Year XX the goal of full implementation of Scientific Outlook on Development, emancipating the mind, seeking truth from f
44、acts, keep pace with the times, close to reality, close to life, close to the young, persevere grasp orientation, grasping deepening, grasping construction innovation, further improve the groups propaganda and ideological work ability, unity To guide the majority of members of the youth to achieve t
45、he 11th Five-Year planning tasks, the overall construction of a well-off society, building a socialist harmonious society to make new contributions.One, adhere to the Three Represents important thought and Scientific Outlook on Development education to guide the youth, to further strengthen the ideo
46、logical and political education of youth(a) armed with youth science theory. Unremittingly with Deng Xiaoping theory and the important thought of Three Represents armed members of youth education, to promote the study and implement to expand the depth and breadth. To study and implement the importan
47、t thought of Three Represents with the establishment and implementation of Scientific Outlook on Development combine with the implementation of the requirements of constructing socialist harmonious society with Scientific Outlook on Development, carry out education as an important part of the theory
48、 of armed youth in the new period, strengthen the establishment and implementation of Scientific Outlook on Development education, educate and guide the youth to fully understand the great significance of establishment and implementation of Scientific Outlook on Development, in-depth understanding of the Scientific Outlook on Development era back The king, the practice foundation, basic connotation, historical status, spirit and practice requirements, a profound understanding of Scientific Outlook on Development with Marxism