以土壤清洗復育土壤並以NTU-1移除溶液中正十六烷

Abstract

本研究目的主要在於探討如何利用土壤清洗的方式移除土壤中的烷類污染，並利用Rhodococcus erythropolis NTU-1能夠生物降解並包覆烷類的特性，處理溶液中的烷類，達到生物復育土壤的目的。 研究顯示，本實驗所使用的液態礦物培養基能夠清洗被烷類污染的土壤。以研究中的實驗條件為例，土壤粒徑大小為20/50 mesh、正十六烷添加量為4 ml n-C16/g soil的0.5 g土壤，經分析土壤中會含有3.2 ml n-C16/g soil，利用100 ml培養基以批次攪拌清洗10秒後，培養基中約含800 ppmv n-C16。 為了避免土壤中的水溶性物質，如有機酸或礦物質，在土壤清洗的過程中溶於清洗所使用的培養基，影響NTU-1於培養基中的生長，所以本實驗以自來水與去離子水預清洗土壤並烘乾，才將土壤用於後續實驗操作。 將清洗過土壤的培養基植入NTU-1培養72小時，初始植菌量為5 ml礦物培養基菌液(OD600nm約為1.0)。72小時之後，NTU-1可以透過生物降解與物理包覆移除95%培養基中的正十六烷。 探討影響培養基清洗效果的因素時，提高培養基的溫度有最好的清洗效果。以本研究為例，土壤粒徑大小為20/50 mesh、正十六烷添加量為4 ml n-C16/g soil的0.5 g土壤，利用100 ml培養基與污染土壤一起煮沸5分鐘，以沸騰時培養基液體的流動取代攪拌清洗。培養基能夠清洗土壤中約20%的正十六烷含量，進一步培養NTU-1達72小時後，經分析，NTU-1能移除培養基中約95%的正十六烷。

For bioremediation, we focused on how to apply soil washing method with MSM (mineral salt medium) to wash n-hexadecane (n-C16) on soil. Furthermore, we apply Rhodococcus erythropolis NTU-1 (NTU-1) biofloccules and biodegradation for n-hexadecane removal in MSM. Firstly, results showed that nearly 800 ppmv n-C16 can be washed by 100 ml MSM from 0.5 g contaminated soil of which the particle size is 20/50 mesh and the added volume of pollutant is 4 ml n-C16/g soil. By analyzing with GC-FID, soil will contain 3.2 ml n-C16/g soil after added n-C16 as pollutant. Secondly, to avoid hydrosoluble compounds in soil being desolved in MSM during soil washing, which may constrain the biodegradation ability of NTU-1, we have to pre-wash soil. Being pre-washed by both tap water and DI water, soil can be used for subsequent experiments. After incubated in MSM used to wash contaminated soil for 72 hours, NTU-1 will remove approximately 95% of total n-C16 in MSM by both biodegradation and biofloccules. Last but not least, the washing effectiveness of MSM can be promoted by increasing the temperature of MSM. Results showed almost 20% of total n-C16 can be removed from 0.5 g soil whose particle size is 20/50 mesh and the added volume of pollutant is 4 ml n-C16/g soil during soil washing at 100℃. After 72 hours NTU-1 incubation, almost 95% of total n-C16 in MSM will be removed.