Hydrometers for Wastewater Treatment

Hydrometers are one of the simplest yet most essential tools for analyzing liquids. Consisting of a long-necked glass container designed to float freely in whatever liquid being tested, their depth of flotation indicates its relative density while their neck can be calibrated to read off specific characteristics like specific gravity or alcohol content.

Hydrometers operate according to Archimedes’ principle that states a solid suspended in a liquid will be lifted up by an equal force as that which it displaces; consequently, as density of liquid decreases further the hydrometer will sink; hydrometers can then be calibrated according to different applications such as for alcohol brewing or soil testing.

When using a hydrometer, it is crucial that the container be clean and free from bubbles. Furthermore, it’s recommended to check that both sample and hydrometer temperatures match; otherwise correction tables may help facilitate adjustments if they differ significantly. When submerging a hydrometer into sample, be careful not to scrape walls while sliding it in so as to get false readings; once completely submerged then spin to release any air bubbles before taking measurements from meniscus on side of container.