The Purpose Of This Tender Is To Hire The Necessary Services To Carry Out A Correct Exploitation, Conservation And Maintenance Of The Sanitation Systems Of The Terra Alta Group (Bot, Arnes, Corbera D'Ebre, Fatarella, Gandesa, Horta De Sant Joan, Pinell De Brai, Prat De Compte And Vilalba Dels Arcs), According To The Instructions Collected In The Particular Technical Specifications (Pptp). Quality Set In It And That Meet The Requirements Of Directive 91/271/Eec Of The Council, Of May 21, 1991, On The Treatment Of Urban Wastewater And Royal Decree 509/1996, Of March 15, On The Development Of Royal Decree-Law 11/1995, Of December 28, Which Establishes The Rules Applicable To The Treatment Of Urban Wastewater.