delete assets that are older than 30 days

I think you can write this as

    cancellableDeleteOldAssets = app.configuration.getString("old.assets.age").map(scheduleDeletion(_.toInt)

    def scheduleDeletion(oldAssetAgeInDays) = Akka.system.scheduler.schedule(FiniteDuration(15, TimeUnit.MINUTES), FiniteDuration(1, TimeUnit.DAYS))(
        AssetsDao.deleteAssetsOlderThan(now.toDateTime.minusDays(oldAssetAgeInDays)))