Pajaro Valley Water Management Agency (PVWMA) Water Resources Center uses photovoltaic (solar panels) to generate… https://www.rawpixel.com/image/3261883/free-photo-image-aquifer-wastewater-cityFree Image from public domain license
Schuylkill Water Works, Philadelphia: panoramic view with the river. Coloured engraving by J.C. Armytage after W.H. Bartlett. https://www.rawpixel.com/image/13967874/image-person-art-waterFree Image from public domain license
Franco-Prussian War: soldiers using the new army filter-van. Wood engraving. https://www.rawpixel.com/image/13998813/franco-prussian-war-soldiers-using-the-new-army-filter-van-wood-engravingFree Image from public domain license