Prysm Group has announced the acquisition of waste management trade show RWM from Ascential to boost its environmental division. RWM, in partnership with recycling, energy, water and waste management show CIWM, will complement existing Prysm events including The European Contamination Expo Series, Hazardous Waste Expo, Land Remediation Expo, The Flood Expo and The Marine & Coastal Civil Engineering Expo. Terms were not disclosed.