Mendeleev University of Chemical Technology of Russia, Moscow, Russia:

E. N. Kuzin, Cand. Eng., Associate Prof., Dept. of Industrial Ecology, e-mail: e.n.kuzin@mail.ru
N. E. Kruchinina, Dr. Eng., Head of the Dept. of Industrial Ecology, Dean of the Faculty of Biotechnology and Industrial Ecology, e-mail: krutch@muctr.ru

Wastewater treatment of metalworking processes from oil products is a complex and urgent task. Strict requirements on the part of the water utility and organizations that control the discharge of industrial effluents into water bodies dictate the need to search for new and improve traditional methods for removing oil products from water. Physico-chemical purification and, in particular, coagulation is the fundamental process of water purification. Unfortunately, traditional reagents based on aluminum or iron salts have long been obsolete, and modern titanium-containing reagents are too expensive. Sample of a complex titanium-containing coagulant was studied in the processes of wastewater treatment of gear-cutting, hardening and rolling sections. Oil products were chosen as the key pollutant. It has been established that, in terms of their effectiveness, complex titanium-containing reagents are significantly superior to both the mixed coagulant based on aluminum and iron sulfates and the traditional and most common aluminum sulfate. Regardless of the type of waste water, the residual concentration of oil products in water when using a complex coagulant was at the solubility limit and amounted to ~1 mg/dm³. The use of complex titanium-containing reagents ensured the minimum residual content of suspended solids, and also made it possible to reduce the sedimentation time of coagulation sludge and their filtration time by 1.5–2.0 times compared with a mixture of salts and individual aluminum sulfate respectively. Based on the data obtained as a result of the experiments and a preliminary environmental and economic calculation, it was concluded that the use of complex titanium-containing coagulants in the processes of wastewater treatment of metallurgical enterprises from oil products and suspended solids was highly promising.
The researches were carried out using D. Mendeleev Center for collective use of scientific equipment, within the framework of the project No. 075-15-2021-688.

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