Dear  Mohammed Sonbol,  ...

Published by

Dear  Mohammed Sonbol,  there are many causes of filamentous bacteria including nutrient deficiency, sludge age, organic loading rate, slug loading,  sulfur loading and others.   Contact Environmental Leverage Inc for technical support.  http://www.environmentalleverage.com/index.html

  You can send them a small (100 ml) sample for microscopic examination and they will send you a detailed technical report indicating the probable root-cause of your problem.  

Best wishes,