城市污水管网对水质的生化改善特性

研究建立了一套长1 200 m的城市污水模拟管网,分析研究了城市污水管网对水质的生化改善特性。研究表明,污水经过1 200 m管网输送后,水中TCOD、NO3--N和NH3-N含量均发生了变化,其中TCOD、NO3--N含量分别由292~420 mg·L-1、0.26~0.6 mg·L-1降低至205~315 mg·L-1、0.13~0.29 mg·L-1,NH3-N含量由31~50 mg·L-1上升为35~66 mg·L-1。采用三维荧光分析了水中有机物的变化情况,结果表明,蛋白质及腐殖质的含量均沿程减少,而蛋白质发生了蓝移,腐殖质则发生了红移,表明其物质的化学结构发生了改变。结合有机物的分子量分析可知污水中高分子量(蛋白质等)及部分中等分子量有机物(腐殖质)向小分子量有机物(乙酸等)转化。进一步的研究表明,管网中微生物改变了水中有机物的构成,将不饱和性有机物转变为易于生物利用的饱和性物质,从而提高了污水的生化性。

Improvement in biodegradability of wastewater quality in urban sewer system

Improvement in biodegradability and hence enhancement of wastewater quality in the urban sewer system was studied via a simulated urban sewer system totaling 1 200 m.TCOD,NO3--N and NH3-N content were changed during the process of sewage transportation.TCOD and NO3-N content were reduced from (292 to 420)mg·L-1 to (205 to 315)mg·L-1 and from (0.26 to 0.6)mg·L-1 to (0.13 to 0.29)mg·L-1,respectively.NH3-N content however increased from (31 to 50)mg·L-1 to (35 to 66)mg·L-1.Transformation of organic matter was analyzed by three-dimensional fluorescence spectroscopy,showing a reduction in the content of protein and humic substances.We observed a blue shift occurring for proteins and a red shift occurring for humic substances,indicating a potential change in chemical structure.Molecular weight(MW) analysis showed conversion of high MW(proteins,etc.) and some medium MW organics(humic substances) into low MW organics(acetic acid,etc.).Further studies showed that microorganisms possibly changed the composition of organics,such that unsaturated organics were transformed into saturated substances that could be easily utilized by microorganisms.Consequently,the biodegradability of the wastewater was improved.