These multi-step purification methods result in very high cost of operation, difficult to operate and scale up, time consuming purification process and relatively low recovery.
At first, the four-headed shower was difficult to operate.
The systems were difficult to operate and seemed to be set up for nerds.
I found it difficult to operate in the music industry as a 25-year-old woman.
Toyota has said that worn pedals can become difficult to operate or become stuck partly depressed.
Juan Prieto, MSF Yemen's head of mission, said it has become difficult to operate in Yemen.
For several months there were inquiries, and it's difficult to operate under such circumstances".
A parallel system that runs alongside the journals might be difficult to operate, he said.
F.B.I. officials said it was difficult to operate surreptitiously in the closed society of Los Alamos.
Given the shorter intercity distances, European railroads have found it more difficult to operate viable TOFC services.
Toyota said their accelerator pedals can become worn and difficult to operate or stick in a partly depressed position.
