Waste Management is the third standalone investment made by Igneo in New Zealand in recent years.
The others are First Gas, a natural gas transmission, storage and distribution business, and Tuatahi First Fibre, the second largest fibre-to-the-premises broadband network.
Maehl said it would be "business as usual" at Waste Management following the purchase.
Igneo - an autonomous investment team in the First Sentier Investors Group - invests in high-quality, mature, mid-market infrastructure companies in the utilities and transport sectors in the UK, Europe, North America, Australia and New Zealand.
Igneo says it works closely with portfolio companies to create long-term sustainable value through innovation, a focus on ESG and proactive asset management.