DIY water filter

How to make water filter using coal

Stuck in the wild with no clean wa­ter? Learn how to make a sim­ple wa­ter fil­ter from these read­i­ly-avail­able tools.

Safe­ty pre­cau­tions

At­ten­tion! This fil­ter does not pu­ri­fy wa­ter of bac­te­ria and heavy met­al ions.

Reagents and equip­ment

  • char­coal;
  • plas­tic bot­tle with a wide neck;
  • cot­ton balls;
  • ham­mer;
  • nap­kin.

Step-by-step in­struc­tions

Wrap the char­coal in a nap­kin and pul­ver­ize it with the ham­mer. Make some holes in the bot­tom of the plas­tic bot­tle. In­sert some cot­ton balls, then add some char­coal. Cov­er with an­oth­er lay­er of cot­ton balls. Your makeshift fil­ter is ready!

Process de­scrip­tion

As the dirty wa­ter pass­es through the fil­ter, the cot­ton ball lay­ers trap the largest par­ti­cles of dirt. Mean­while, char­coal, with its myr­i­ad pores and crevices, traps the small­er pol­lu­tant mol­e­cules in a process called ad­sorp­tion. The rel­a­tive­ly large pol­lu­tant mol­e­cules “stick” to the char­coal’s sur­face, while the wa­ter mol­e­cules, mi­nus­cule in com­par­i­son, pass eas­i­ly through the fil­ter. This fil­ter can cleanse wa­ter of large par­ti­cles and some or­gan­ic com­pounds but is pow­er­less against micro­organ­isms and heavy met­als. Boil any fil­tered wa­ter to make it suit­able to drink.