Portland cement solidified construction waste using MSW leachate and phosphate admixtures

Many dumping sites all over the world release leachate into the environment. The primary goal of this study was to convert raw municipal solid-waste leachate in dump sites into a solid material by combining Portland cement (PC), construction waste, and dicalcium phosphate (DCP) or potassium dihydrogen phosphate (KDP). The application takes into account concurrent goals such as preventing leachate discharge into the environment and making use of nearby and disposed-of construction waste. The leachate sample was collected from an Iranian dump. Chemical analysis was used to determine metals, COD, alkalinity, total nitrogen, and the sulfate and chloride anions. In the solidification process, three different types of mixtures were created, each containing 2 kg of construction waste, 0.2 kg of Portland cement, and 0.5 kg of leachate as the base mixture. To some of the samples, 0.2 wt% DCP or KDP was added to the base mixture. The results show that the solidified construction waste with cement and leachate reduces heavy metal emissions by 28.8–64.4%. Heavy metal release is reduced by 57 to 99% and 93 to 100%, respectively, when 0.2% DCP and KDP are added to the mixture.