Iz konteksta slijedi da se radi o postrojenju, uređaju za pročišćavanje vode, a ne o nekakvom malom (kućanskom) pročistaču; to se obično naziva „(waste water) treatment/purification plant/facility“

Garber E, ENGLESKO - HRVATSKI STRUKOVNI RJEČNIK - GRADITELJSTVO:
water treatment plant - postrojenje za pročišćavanje vode (hid.)


„World Information Service on Energy
....
The seepage water collected is conducted to the water treatment plant.“
( http://www10.antenna.nl/wise/index.html?http://www10.antenna... )


„U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
...
Seepage water from the collection system installed along Coastal Ridge Drive (Figure 2) is pumped to a treatment facility where it is mixed with acid to neutralize the pH. The treated water is then discharged to the Petoskey Waste Water Treatment Plant.
( http://www.atsdr.cdc.gov/HAC/pha/BayHarborCement/BayHarborHC... )


„Seepage flow from the Cârnic waste rock stockpile will be pumped into the pit lakes system, in case it subject to acidification, then it will be treated in situ or in the wastewater treatment plant.“
( http://www.mmediu.ro/home/rosia montana/E04/EN-LANDSCAPE.pdf )


“FreePatentsOnline
Method for purifying waste water, and purification plant for carrying out said method
...
The invention relates to problematic waste water with highly concentrated impurities, for example seepage water from a refuse dump, which is anaerobically degraded in an anaerobic treatment zone (digester) and the digested sludge arising therefrom is mechanically de-watered.”
( http://www.freepatentsonline.com/6709593.html )