THE FORERUNNERS OF MODERN WASTEWATER TREATMENT PLANTS AND CIRCULAR WATER MANAGEMENT. by JP Zurdo The circular shape of the foundation in the photo is functional: it’s designed to support a large reservoir of water in the process of treat-ment. But it’s also symbolic, the harbinger of water management as it is conceived today, when there is a pressing need for perfect treat-ment of our everyday water. It’s circular because wastewater treatment combines sanitation, cleaning, and reuse to achieve a high-quality supply of water for both human and agricultural use. The seeds of this future closed circuit were already seen in the first Spanish water treatment facilities in the late 1920s. Very gradually, they began to germinate into legislation and greater awareness, when the protection of a number of rivers overrun with urban and industrial waste became part of that virtuous circle. It was nothing less than a recognition of the vital role of nature, discerned by some pioneers back in the 1950s. The photo, from 1964, shows one of these facilities which were the precursors of modern wastewater treatment, designed by Entrecan-ales y Távora and sister to at least four other contemporaneous water treatment facilities. Its mission was to pour an unprecedented volume of drinking water into Zaragoza: 4,000 liters per second could be treat-ed thanks to eight accelerator decanters with 100 square meters of rapid filters. The following year, it was as if another mighty Ebro River had sprung up in Aragon’s thirsty capital city.