Patent ID: 8512725

Claim:
A method of controllably releasing an anti-microbial agent into a fluid comprising the steps of: contacting the fluid with a solid material comprising an anti-microbial agent containing one or more of silver oxide (AgO), copper (II) oxide, and zinc (II) oxide dispersed in a hydraulic cement binder in a ratio of between 50:50 to 95:5 wt % of the solid material; abrading an interface of the solid material and removing particles therefrom to expose an underlying surface of the solid material to the fluid, thereby facilitating release of the anti-microbial agent into the fluid from the underlying surface of the solid material and/or from the removed particles, wherein the step of abrading the interface of the solid material comprises providing at least one solid body not made of the solid material and agitating the fluid or otherwise causing the at least one solid body to collide on a controlled basis with the interface of the solid material, wherein the step of agitating the fluid comprises containing the fluid and the or each solid body in a vessel and recirculating the fluid through the vessel, such that the flux of fluid into or out of the vessel causes the or each solid body to collide with the solid material, and wherein an interior surface of the vessel is coated with the solid material.