Mitryasova, O. CHRONICLES OF THIRST: DOCUMENTING MYKOLAIV'S WATER SECURITY CHALLENGES AND SOLUTIONS IN A WAR-AFFECTED CITY: Monograph. Mykolaiv: PMBSNU, 2026, 124 p.

CHRONICLES OF THIRST: DOCUMENTING MYKOLAIV'S WATER SECURITY CHALLENGES AND SOLUTIONS IN A WAR-AFFECTED CITY Fig. 1.17. Ejector, where the process of chlorination of water takes place (photo by Marina Ilyasova). The summer period (1.0–2.5 mg/dm³), when the heat and active algal blooms in the Dnieper required increased protection. Increasing the dose helped to overcome bacterial threats and prevent spoilage of water in the sun-heated pipes of the city network. After the initial disinfection, the water was directed to the mixing chambers, where the coagulation process began. Since the Dnieper water contains many small suspended particles that are too light to settle on their own, special substances — coagulants — were added to it. For water purification in Mykolaiv, the following were traditionally used: Aluminum sulfate, as the most common reagent, which, when it enters water, forms flakes similar to "white snow". These flakes, like magnets, attract dirt particles, bacteria and algae residues. Polyaluminum chloride, a more modern coagulant that works effectively even at low water temperatures, ensuring stable cleaning quality in winter. As a result of this chemical reaction, heavy "flakes" (floccules) were formed, which, under the influence of gravity, began to settle to the bottom of the sedimentation tanks. It was at this stage that the muddy river water began to acquire the transparency to which Mykolaiv residents were accustomed. This decades-old chain — vacuum chlorination + precision coagulation —was ideal for working with fresh water. However, it is these structures and chemical algorithms that will be completely powerless when, in April 2022, salt water from the estuary, the chemistry of which is fundamentally different from the Dnieper, enters the system. 29