"I'm really excited about the challenge of going up against Europe's best teams," said Tandy. "There are six European titles in our group, which says all you need to know about the pool.
"Toulouse are a great club and are always tough opponents.They have big names in the squad with a strong overseas influence and are always competitive in Europe. As the recently crowned French champions, their current squad is clearly as strong as ever.
"Leicester are familiar opponents for us. We have been up against them in Europe a few times so we know just what to expect.They are known for their physical ability but that is something we always pride ourselves on as well. Our games against Leicester are always tough and tight matches.
"Treviso could hold the key to this group. They are a team that will be under-estimated by teams outside the Pro12 and, like last year, I can see them causing some upsets.All the teams can beat each other but that's what makes it such an exciting pool."
Meanwhile the Scarlets will be under a new head coach when they play their 106th Heineken Cup match in October - but Simon Easterby is no stranger to European club rugby's elite tournament.
Easterby played in 56 tournament matches for the Welsh club and will now be in charge when they clash with defending champions Leinster Rugby, ASM Clermont Auvergne and tournament debutants Exeter Chiefs in Pool 5.
"It's probably one of the toughest pools in the draw but it's great for us to have the European champions," said former Ireland back rower, Easterby.
"We know Leinster well from our domestic league and they have set the standard for teams in Europe and the quality they have. They will be looking for their third title in succession, so that in itself is a big challenge and we'll have a lot of work to do, but this Scarlets team is ambitious and wants to pit itself against the best and that is what Europe is all about.
"We've played Clermont in Europe previously and last season played them in our pre-season fixtures. They have a great coaching set-up, they just like Leinster are one of the powerhouses of Europe and have quality throughout and will be targeting Europe particularly after not quite taking the opportunity over Leinster in the semi-final this year.
"For an added bit of spice, there's our former Scarlet favourite Regan King to contend with at Clermont as well - so that will present a challenge in itself.
"Exeter are the newcomers and again we have played them in three pre-season friendlies. They have surprised a lot of people - they're an effective side, well-drilled and with a good set-piece and ultimately they don't lose a lot at home.
"It's an exciting draw for our supporters, plenty in there to get our loyal support going and for us it will be about getting off to a good start like we did last season in Europe.
"Home games will be crucial and the crowds we're now attracting at Parc y Scarlets will give us an edge in the crucial first home fixtures in the early part of the campaign."
Cardiff Blues, the only Welsh club to qualify for the knockout stages last season, are in Pool 6 with a double French challenge from Toulon - who they beat in the 2010 Amlin Challenge Cup final - and Montpellier.
They also face a potential clash with two former Blues favourites, Andy Powell and Nick MacLeod, when they take on Sale Sharks.