engleski

Use of electrocoagulated metal sludge in brick manufacture

In the last decade, electrochemical processes have been increasingly used to treat various types of wastewater. The treatment of oily wastewaters of mineral origin was carried out in three stages using stainless steel (SS), iron (Fe) and aluminum (Al) electrodes as the last stage of the process. The product of the electrochemical process of wastewater treatment is the treated water and the generated sludge, which consists mostly of metals whose composition depends on the electrode material used during the process. The objective of this research was to reduce the environmental impact of landfilling electrocoagulated metal sludge (EMS). EMS was conventionally dried in the oven and used as a partial substitute for clay in the production of laboratory bricks. Five batches of bricks were produced, namely control bricks (100% clay) and modified bricks with 1%, 5%, 10% and 20% EMS in combination with clay. After the bricks were made, they were dried at 105°C and then fired at a temperature of 950°C. The proportion of EMS is the main factor that determines the quality of the bricks produced. No surface deformations occurred during the firing of the modified bricks. Bricks with a lower EMS content had higher compressive strength, while bricks with a higher EMS content of 20% had higher values in initial water absorption, water absorption, absorption during the 5-hour firing process, and saturation coefficient. The ecotoxicity test by bacteria Vibrio fischeri of the modified brick samples was conducted. The brick with 20% conventionally dried sludge was found to be nontoxic. The concentration of individual elements was measured in all bricks, which can be attributed to the material of the electrodes used in electrochemical wastewater treatment process. Special attention was paid to the elements present in the structure of stainless steel, iron and aluminum, whose concentrations did not increase significantly.

Oily wastewater ; electrocoagulated metal sludge ; conventional drying ; bricks ; ecotoxicity

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