Roisin Reidy 03 Jun 2014 More in Water & Wastewater Pall, Mann+Hummel and Veolia: May’s top 3 news stories on FiltSep.com News 1. Pall buys Filter Specialists Inc 2. Mann+Hummel takes 50% stake in membrane specialist Microdyn-Nadir 3. Floating first for Veolia Water Technologies