壬基酚聚氧乙烯醚在碱性印染废水中的降解

The degradation of nonylphenol ethoxylates in the alkaline dyeing wastewater

通过静态和动态连续降解实验,揭示了壬基酚聚氧乙烯醚(NPEO,Nonylphenol ethoxylates,浓度6.25~12.5 mg·L-1)在碱性牛仔布印染废水中的去除规律.批式活性污泥实验表明,厌氧环境下,随着p H值的增加,壬基酚(NP,Nonylphenol)产生受到抑制,短链NPEO(环氧乙烯加成数1~3,NP(1~3)EO)总浓度水平虽然只有500~900μg·L-1,却呈现增加趋势;好氧环境下,尽管NPEO总量降解率超过85%,但产生的各种短链NP(1~3)EO和短链壬基酚聚氧乙烯醚酸酯(NPEC,Nonylphenol polyethoxycarboxylate)浓度区间为10~110μg·L-1,碱性环境下两类物质总量最低,不足100μg·L-1.耦合厌氧水解和好氧曝气的连续实验表明,增设填料的厌氧折板水解池出水中短链NP(1~3)EO的总浓度增至4000~5000μg·L-1,这与厌氧环境下一部分NPEO附着在废水杂质和厌氧污泥上,在污泥龄较长的附着型污泥作用下,生成了大量的NP(1~3)EO有关;好氧段出水中NP(1~3)EO浓度降至230~610μg·L-1,短链NPEC(NP(1~3)EC)总量上升到800~1000μg·L-1,NP(1~3)EC由NP(1~3)EO转化来的可能最大.印染出水中NP及NP(1~3)EO受厌氧段出水中NP及NP(1~3)EO浓度影响明显.

The degradation of nonylphenol ethoxylates( NPEO),with a concentration of 6. 25 ~ 12. 5 mg·L-1in the simulated alkaline denim dyeing wastewater,was investigated. The results of anaerobic batch experiment showed that the total concentration of NP and short-chain NPEO( NP( 1 ~ 3) EO)was around 500 ~ 900 μg·L-1although the removal efficiency of total NPEO was more than 50%. The increase in p H was benefit for the production of NP( 1 ~ 3) EO but was not fit for the removal of NPEO. The results of aerobic batch test show that,the concentration of total short-chain NPEC( NP( 1 ~3) EC) decreased to 100 ~ 200 μg·L-1in effluent,although the removal of total NPEO was above 85%,and the acidic environment was better for the production of NP( 1 ~ 3) EC. The continuous experiment of coupling anaerobic and aerobic processes showed that anaerobic sludge,with a longer sludge retention time,was helpful to accumulate NP and NP( 1 ~ 3) EO to 4000 ~ 5000 μg·L-1. The total concentration of NP( 1 ~ 3) EC in the effluent of the aerobic unit was elevated to 800 ~ 1000 μg·L-1with a significant decrease of NP( 1 ~ 3) EO. It was probably that the effluent NP( 1 ~ 3) EO was the residual of the anaerobic process and the NP( 1 ~ 3) EC was mostly transformed from NP( 1 ~ 3) EO in the aerobic process.