It was a good year for waste management companies Waste Management (NYSE: WM), Republic Services (NYSE: RSG), and Clean Harbors (NYSE: CLH). All three saw their stock prices rise between 32% and 36% for the year. And it was an absolutely stellar year for Casella Waste Systems (NASDAQ: CWST), which saw its stock more than double in price. Compared to an 11.2% gain for the S&P 500, those results should have investors singing a happy tune.