The upgrade was carried out by local joiner Richard Bergant.
Lochaber Friendship Group for the Visually Impaired received cash windfall.
Event will take place on April 19 in St Andrew’s Church, Fort William.
SW proposed three options in January to replace its leaking £11m Clachan Seil Waste Water Works.
The project has so far raised £100,000 since its public sale began in January.