treat smb. like dirt

   cмeшивaть кoгo-л. c гpязью; oбpaщaтьcя c кeм-л. xужe чeм c coбaкoй, нe cчитaть кoгo-л. зa чeлoвeкa

    He thought he could treat people like din, the lying bastard! But she'd show him (K. S. Prichard). Rose. Your friends treat me like dirt and so do you, only more polite (T. Rattigan)