A book with pages that can be torn out to filter drinking water has proved effective in its first field trials.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/bug-killing-book-pages-clean-murky-drinking-water
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/bbc-uk
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-supply
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/drinking-water
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/water-quality
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/south-africa
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ghana
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/bangladesh
[9] http://admin.indiaenvironmentportal.org.in/category/thesaurus/developing-countries
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/africa
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/south-asia