摘要:
The water quality of car washing wastewater pretreated by car wash in different scales was investigated. The results showed that there was no significant difference between the large scale and small scale car wash in the qualified rate of 85% and 77.19%respectively, but different water quality characteristics in the unqualified index between them; the contents of the suspension and LAS in small car wash are higher than that in large scale car wash, and the concentration maximum value of the suspension in the sample can reach 1.95×103mg/L, which is 5 times of the emission standard; although the qualified rate of LAS in large car wash is slightly lower than that in the small car wash, the average value of LAS concentration in small car wash is 11.87mg/L,which is 2.6 times of large car wash with 4.54mg/L; while for large car wash, it can be found that the total phosphorus concentration is significantly higher, with an average value of 5.54mg/L which is more than 5 times of a small car wash with 1.03mg/L; the reason is because the two types of car wash pretreatment facilities scale is different, making the residence time of water is different, and in addition, washing method and detergent are different, resulting in differences in the concentration of pollutants. So now we need to reform the existing depot pretreatment facilities, to improve the processing ability, promote the use of non phosphorus detergent agent, and the corresponding design specifications should be given according to the operation scale aiming at the car wash pretreatment facilities design, in order to improve the success rate.%针对不同规模的洗车场的洗车废水预处理出水进行了水质调查,结果表明:在合格率上大规模与小规模洗车场的没有太大的差异分别为85%和77.19%,但就具体不合格指标而言小规模洗车场与大规模洗车场有着不同的的水质特征,其中小型洗车场中的悬浮物和LAS的含量较大规模洗车场而言更高,取样中其悬浮物浓度最大值可达1.95×103mg/L,是排放标准的5倍之多;对于LAS浓度虽然在合格率上大型洗车场略低于小型洗车场,但小型洗车场LAS浓度的平均值达11.87mg/L,是大型洗车场4.54mg/L的2.6倍;而对于大型洗车场可以发现其总磷浓度明显偏高,其均值达到5.54mg/L,是小型洗车场1.03mg/L的5倍多;归其原因是由于两类洗车场的预处理设施规模有所不同,使得水的停留时间长短不同,加之二者采用的洗涤方式及洗涤剂的不同,最终导致其污染物浓度产生差异.由此说明现在还需要对车场现有的预处理设施进行改造,以提高其处理能力,提倡使用无磷洗涤剂剂,并针对洗车场预处理设施的设计依据经营规模给出相应的设计规范,以提高达标率.