Werribee Sewage Farm
Werribee Sewage Farm or, more formally, the Western Treatment Plant of Melbourne Water, is an 110 km² sewage treatment farm adjacent to the town of Werribee, 30 km west of the city of Melbourne, Victoria, Australia, on the coast of Port Phillip Bay. It forms part of the Port Phillip Bay (Western Shoreline) and Bellarine Peninsula Ramsar Site as a wetland of international importance.

Sewage treatment
The plant was established in the 1890s and began treating sewage from Melbourne in 1897. It treats 55% of Melbourne’s sewage ”“ about 485 ML/day. Treated effluent is used on the farm to irrigate 85 km² of pasture for grazing 15,000 cattle and 40,000 sheep. It is also supplied to the Werribee market garden area to grow vegetables and to irrigate sports grounds, parks and gardens. The remaining effluent is discharged to the bay under an accredited EPA Victoria licence.

The Werribee Sewage Farm is one of Australia’s best-known sites for recreational birding, with about 270 species of birds recorded there. On the south-western boundary lies the 1550 ha Murtcaim Wildlife Area, containing one of the last unmodified areas of saltmarsh on Port Phillip. The sewage treatment lagoons, Lake Borrie, creeks, saltmarsh and coast host large numbers of sedentary and migratory waterbirds and waders. It adjoins the Spit Nature Conservation Reserve and is one of the few wintering sites for the critically endangered Orange-bellied Parrot. Access to Werribee Sewage Farm for birdwatching is by permit only; permits can be obtained from Melbourne Water.