When we went to the Euro4 2008 and Euro5 2010 (and the American equivelent) emmission standards many heavy vehicle manufacturers tried many different methods to meet those standards. Most acheived Euro4 but could not improve on it. The biggest cost to most the those who met the standard was hugely reduced engine life. Ie 1.5 million klms between rebuilds down to as low as half a million. Many involved very complex and expensive systems with very short lives.
The Europeans very quickly hit on the adblue system. Whilst still expensive it acheived very good results even up to Euro6 standard with minimal to no reduction in life of engines. The exhaust systems are still prohibitivly expensive, up to $20,000 for a muffler, but we are getting a million plus klms out of them.
Adblue is an aqueos urea the is injected into the exhaust stream where it vapourises into ammonia and then utilising magic (well not really but it could be) and the milion dollar exhaust system it cleans the particles out of the exhaust.
It does use up some adblue , I go through about 100 litres per 3000 litres of deisel, so 1 adblue tank per 2 refuels. Almost allservice stations that sell diesel now also sell adblue. All of the big players in road transport are now going to adblue.