Naturally, landfills can produce some objectionable smells – after all, they are huge deposits of human waste. As our landfills grow, so potentially do the smells, which is why controlling these odors is becoming an increasing focus for landfill engineers and landfill neighbours. Fortunately, many waste companies are kicking it into high-gear by implementing innovative changes that control pungent exhaust along with poisonous gases from landfills. Landfill gas emissions typically include, in order of highest to lowest amount - methane, carbon dioxide, nitrogen, oxygen, ammonia, non methane organic gases, sulfides, hydrogen and carbon monoxide. The ones you can smell are the ammonia and sulfides (which cause extremely unpleasant odours even at very low concentration levels.)Traditionally, waste operators applied deodorizers and odor neutralizers to mask the smells. But these days, many landfill companies and councils companies employ a range of strategies that might surprise you.First, one of the easiest ways to mitigate the fumes is by practicing daily and long-term coverage, whereby layers of soil are spread across the site each day. (Typically, a 12-inch thick layer is enough to do the trick). Most landfill sites now also plant vegetation over the landfill site once it’s no longer an active pit. Generally this is good soil for planting, but bear in mind that the layers of residual garbage underneath keep decomposing so the ground level continues to slowly drop. Not in massive amounts, but enough so that the top vegetation is typically low level.Another way waste management companies are controlling landfill odours is by extracting and diverting the gas given off by decomposing rubbish. Some of this gas is turned into energy. As waste breaks down, landfills leach out gases that are both toxic and smelly. Ammonia and hydrogen sulfide are the two biggest culprits. Ammonia has a really strong, “in-your-face” pungent odor and hydrogen sulfide smells a bit too much like rotten eggs. All this may not mean the local rubbish tip smells like roses, but it certainly goes along way to making sure it doesn't smell much anymore and importantly, making the air around them a lot safer.