I have the pure nutbag. Oppenent is tight passive. Can I induce a bluff on the the river? Smaller river bet?

Party Poker No-Limit Hold'em, $ BB (10 handed)

saw flop|saw showdown

BB ($55.50)
UTG ($40)
Hero ($55.80)
UTG+2 ($56.25)
MP1 ($38.85)
MP2 ($43.70)
MP3 ($55.25)
CO ($13.25)
Button ($48.75)
SB ($7.10)

Preflop: Hero is UTG+1 with , . SB posts a blind of $0.25.
UTG calls $0.50, Hero raises to $2.5, 5 folds, Button calls $2.50, 2 folds, UTG calls $2.

Flop: ($8.25) , , (3 players)
UTG checks, Hero bets $5, Button calls $5, UTG folds.

Turn: ($18.25) (2 players)
Hero bets $10, Button calls $10.

River: ($38.25) (2 players)
Hero bets $20, Button folds.

Final Pot: $58.25

i don't think so. He likely has a missed flush draw but many tight passive people still check it down. I think I bet it a little stronger on the flop and turn like 6 and 12-14 which would be more if you bet 6 on the flop. If he's willing to chase for 10, he'll pay a little more.