25NL: River trips and villain confuses me. Help on river?

[SirFelixCat]

Villain is a bit loose preflop and is an overall loser (26/18/4) over 2700 hands. To be honest though, I had not seen anything that would cause him to be as big of a loser in the game as he has been. He seemed reasonable (keep in mind most of the hands were dm'd).

All that being said, the river donk really shocked the hell outta me and I was thoroughly confused as to what he'd do this with. Thoughts on his range here and what's your river play, but feel free to comment on all streets.

Full Tilt Poker - No Limit Hold'em Cash Game - $0.10/$0.25 Blinds - 5 Players - (LegoPoker HH Converter)

SB: $36.20
BB: $39.35
UTG: $25
<u>CO: $40.50</u>
<u>Hero (BTN): $88.75</u>

<font color="black">Preflop:</font> Hero is dealt A[img]/images/graemlins/spade.gif[/img] T[img]/images/graemlins/diamond.gif[/img] (5 Players)
UTG folds, <font color="red">CO raises to $0.85</font>, Hero calls $0.85, 2 folds

<font color="black">Flop:</font> ($2.05) 7[img]/images/graemlins/heart.gif[/img] 9[img]/images/graemlins/heart.gif[/img] T[img]/images/graemlins/heart.gif[/img] (2 Players)
<font color="red">CO bets $2.05</font>, Hero calls $2.05

<font color="black">Turn:</font> ($6.15) T[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">CO bets $6.15</font>, <font color="red">Hero raises to $17.30</font>, CO calls $11.15

<font color="black">River:</font> ($40.75) 3[img]/images/graemlins/spade.gif[/img] (2 Players)
<font color="red">CO bets $8.50</font>, Hero ???