油菜秸秆腐解对自然水体的影响研究

Study on the Effect of Decomposition of Rape Straw on Natural Water

为探究农田废弃物弃置水体对水环境质量的影响,对油菜秸秆在水中的腐解过程进行了实验研究。通过测量pH、DO、COD、氨氮、硝氮、总磷等水质指标来动态监测水质的变化。结果表明:DO含量初始为2mg/L,水体迅速转换为厌氧状态并保持稳定,35d后水体DO恢复至2~3 mg/L;水体中的COD含量在第3d达到最大值25mg/L,然后迅速下降,此后保持在15 mg/L左右;NH+4-N则在实验过程中缓慢增加,并在35d后维持在较高水平即10mg/L,而NO_3^--N、NO_2^--N含量较低,NO_3^--N含量为0.13mg/L,NO_2^--N含量为0.02 mg/L,TP含量则呈逐渐增加的趋势。油菜秸秆腐解的过程是厌氧腐解过程,此过程中各指标发生关联性的变化。随着时间的增长,水体由黑臭逐渐变清澈,说明水体具有一定的自净能力。

In order to explore the effect of farmland waste disposal on water environment quality, experiment was conducted to study the decomposition process of rape straw in water. Through the measurenlent of pH, DO, COD, amnlonia nitrogen, nitrate nitrogen, total phosphorus and other water quality-indicators to dynanfieally monitor the changes of water quality-. The results showed that the pH changed little during the whole experimental period and remained in the range of 6. 5 to 7. 5. The initial DO concentration was 2 mg/L. The water quickly converted to anaerobic state and remained stable. After 35 days, the DO recovered to 2 to 3 mg/L; The COD concentration in water reached the maxinmnl value of 25 mg/L on the 3rd day-, then decreased rapidly, and then remained at about 15 mg/L. NH4 -N concentration increased slowly during the experiment, after 35 day-s, it maintained at a relatively high level of 10 mg/L, while NO3-N, NO2-N concentrations were low, NO3-N concentration was 0. 13 mg/L, and NO2-N concentration was 0. 02 mg/L. The TP concentration showed a gradually increasing trend. The process of rape straw decomposition is anaerobic decomposition process, and during this process, the correlation between the indicators changes. As time grows, the water body gradually changed from black and odor to clear and clean, indicating that the water body has certain degree of self-purification.