Most industrial enterprises mistakenly transport spent ion-exchange resins from water treatment plants to ordinary municipal solid waste landfills along with residual construction debris. According to the requirements of the Law of Ukraine on Waste Management, such granulated polymers require mandatory decomposition and safe incineration or high-temperature thermal treatment. Incorrect classification of these residues leads to significant fines during inspections. Violation of environmental regulations in handling chemically active sorbents threatens a prolonged suspension of the operating license for the facility's entire water treatment plant.
Financial consequences for thermal power plants and chemical plants
The accumulation of toxic substances in the resin matrix is influenced by the degree of saturation of the granules with heavy metals. The presence of chromium and cadmium ions in the spent sorbents increases the hazard class of the material.
Waste classification under codes 19 09 05* and 19 08 06*
Spent cation exchangers and anion exchangers from the technological water treatment system for drinking or industrial purposes are registered in reporting documentation under the code 19 09 05*. If chemical demineralization was carried out during the purification of technological wastewater, the material is usually classified under the category 19 08 06*. The chemical composition determines the method of treatment. Regeneration of resins with solutions of hydrochloric acid at a concentration of 6% or sodium hydroxide at 4% allows for a partial restoration of the material's exchange capacity.
Requirements for container sealing and transportation by special vehicles
Transportation of wet sorbents is carried out in special plastic IBC tanks or steel drums. Temporary storage of waste at the station site is limited to 30 days. The collected materials are transported by specialized freight vehicles of the UtilVtorProm company, which are certified for the transport of class 9 hazardous goods. Drying of the sorbent during transportation causes cracking of the polymer granules. To prevent dust generation and the release of toxic vapors, the moisture content in the containers is maintained at a level of at least 40%. Long-term storage of spent resin in open storage facilities leads to rapid oxidation of the styrene-divinylbenzene matrix under the direct influence of oxygen.
Thermal destruction in incinerator furnaces at a temperature of 1100 °C
Direct incineration of fully spent sorbents is carried out in specialized rotary kilns at a working temperature of 1000 °C to 1200 °C. High-temperature thermal treatment ensures the complete destruction of the polymer's organic base and prevents the formation of hazardous compounds such as dioxins and furans. A multi-stage flue gas cleaning system captures residues of sulfur dioxide and hydrogen chloride. The ash residue obtained after incineration accounts for less than 5% of the initial waste volume and is subject to disposal at a specialized landfill. Some sulfonated coal resins lose their mechanical strength after just 3 cycles of acid regeneration.
Physicochemical characteristics of KU-2-8 and AV-17-8 grade sorbents
The polymer matrix of ion exchangers is based on a copolymer of styrene and divinylbenzene. The strongly acidic cation exchanger of the KU-2-8 grade contains active sulfonic acid groups in hydrogen or sodium form. The strongly basic anion exchanger of the AV-17-8 grade is produced with trimethylammonium functional groups, which intensively bind anions of strong and weak mineral acids in an aqueous medium. The operating temperature does not exceed 120 °C. The full exchange capacity of high-quality material reaches 1.8 mole-equivalents per liter at a commercial product moisture content of about 50%. During long-term operation, iron oxides and high-molecular-weight organic compounds clog the pores of the resin, significantly impairing the kinetics of ion exchange in the column. Worn-out polymer loses its ability to regenerate and turns into hazardous waste.
Organization of transfer of spent sorbents for processing
The decommissioning process of worn ion-exchange materials should begin with an inventory of residues and instrumental determination of their chemical composition. Laboratory analysis of leachate solutions allows for a more accurate determination of the level of heavy metal contamination of the granules and selection of the optimal method for further processing. Drawing up a waste passport is a mandatory step before signing the material transfer agreement. The UtilVtorProm enterprise provides services for the collection, transportation, and safe recycling of spent resins with a full range of permit documentation.