问题 问答题 简答题

水的化学性状评价指标有哪些?

答案

参考答案:PH;硬度;氮化物;氯化物;硫酸盐;溶解氧(DO);生化需氧量(BOD);化学需氧量(COD);总需氧量(TOD);总有机碳(TOC)
PH决定于它所含氢离子及氢氧离子的多少。硬度是指溶于水中的钙、镁等盐类的总含量,铁及其他矿物质有时也占一小部分。氮化物包括有机氮、蛋白质、氨氮。亚硝酸盐氮。有机氮是指有机含氮化合物的总称。蛋白氮是指已经分解成较为简单的有机氮。氯化物自然界的水一般含有氯化物。硫酸盐天然水中均含有硫酸盐,且多以硫酸镁的形态存在。溶解氧(DO)指溶解在水中的含氧量,其含氧与空气的氧分压、水温有关。BOD(生化需氧量):水中有机物被需氧性细菌作用所消耗的溶解氧量。COD(化学需氧量):在一定条件下,以强氧化剂如高锰酸钾、重铬酸钾等氧化水中有机物所消耗的氧量。可作为水中有机物含量的一间接指标。总需氧量(TOD):指一升水中还原物质(有机物和无机物)在一定条件下氧化时所消耗的氧的毫升数。总有机碳(TOC):指水中全部有机物的含碳量,它只能相对表示水中有机物的含量。

单项选择题
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     In the depths of my memory, many things I did with my father still live.These things have come to
represent,in fact,what I call__1__and love.
      I don't remember my father ever getting into a swimming pool.But he did__2__the water.Any kind
of __3__ride seemed to give him pleasure.__4__ he loved to fish;sometimes he took me along.
      But I never really liked being on the water, the way my father __5__.I liked being at the water,
moving through it,__6__it all around me.I was not a strong__7__, or one who learned to swim early,
for I had my__8__.But I loved being in the swimming pool close to my father's office and__9__those
summer days with my father,who  10   come by on a break.I needed him to see what I could do.My
father would stand there in his suit, the  11   person not in swimsuit.
      After swimming, I would go  12   his office and sit on the wooden chair in front of his big desk,
where he let me  13   anything I found in his top desk drawer.Sometimes,if I was left alone at his desk
   14   he worked in the lab, an assistant or a student might come in and tell me perhaps I shouldn't be
playing with his  15   . But my father always   16   and said easily,"Oh, no, it's  17   ."Sometimes he
handed me coins and told me to get  18  an ice cream…
      A poet once said,"We look at life once, in childhood; the rest is  19   ."And I think it is not only
what we "look at once, in childhood" that determines our memories,  20   the person who, in that
childhood, looks at us.
( )1. A. desire      
( )2. A. avoid        
( )3. A. boat        
( )4. A. But          
( )5. A. expected    
( )6. A. having      
( )7. A. swimmer      
( )8. A. hopes        
( )9. A. spending    
( )10. A. should      
( )11. A. next        
( )12. A. away from  
( )13. A. put up      
( )14. A. the moment  
( )15. A. fishing net
( )16. A. stood up    
( )17. A. fine        
( )18. A. the student
( )19. A. memory      
( )20. A. as          
B. joy            
B. refuse        
B. bus            
B. Then          
B. desired        
B. to leave      
B. rider          
B. faiths        
B. saving        
B. would          
B. only          
B. out of        
B. break down    
B. the first time
B. office things  
B. set out        
B. strange        
B. the assistant  
B. wealth        
B. but            
C. anger        
C. praise        
C. train        
C. And          
C. wished        
C. make          
C. walker        
C. rights        
C. wasting      
C. had to        
C. other        
C. by            
C. play with    
C. while        
C. wooden chair  
C. showed up    
C. terrible      
C. myself        
C. experience    
C. or            
D. worry        
D. love          
D. bike          
D. Still        
D. did          
D. get          
D. runner        
D. fears        
D. ruining      
D. ought to      
D. last          
D. inside        
D. work out      
D. before        
D. lab equipment
D. turned out    
D. well          
D. himself      
D. practice      
D. and