For drain water, how to differentiate the sources of the alkaline drain water, between cement & caustic soda?
The pH for drain water sample at my place is high,>11, we assume the sources is from cement because the construction site is nearby. But now, the construction is finished and they have clean the drain, but the pH is still high, and maybe it’s from other sources, maybe caustic soda because nearby have waste water treatment plant, the plant use caustic soda. So, now, how I want to know which sources? Is there any lab method can differentiate it?