Splitting the header & value which is in same cell & retain only values

In a .csv file i have column header& value in the same cell  I want to split & retain only values in the cell no header with it 

this is the sample data

for example tec_class=dynamic1_tecclass I want only dynamic_tecclass

TRV_DROP_DATA; bem_class=;tec_class=dynamic1_tecclass;hostname=[];environment=[];support_level=[];object_class=;object=;parameter=;da_oncall=;origin_key=[];drop_it=YES;END
TRV_DROP_DATA; bem_class=;tec_class=dynamic2_tecclass;hostname=[];environment=[];support_level=[];object_class=;object=;parameter=;da_oncall=;origin_key=[];drop_it=YES;END
TRV_DROP_DATA; bem_class=;tec_class=dynamic1_tecclass