Utilize the input text as a context reference, choose the right relationship between water treatment and water from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

They said Bilfinger's new Chief Executive Per Utnegaard has hired investment bank Lazard to find a buyer for the unit, which makes filters, water treatment technology and gear for water wells.

Answer: product_or_material_produced