Abhatoo - Centre Nationale de Documentation

Wastewater from wastewater treatment plants (WWTPs) often requires further treatment before it can be safely reused. Lime is a common and affordable material used for this purpose, but its production can generate significant environmental impacts. This study developed an eco-friendly and effective lime substitute from eggshell waste for wastewater treatment. First, pre-treated wastewater effluent from WWTP El Jadida, Morocco, was collected and characterized. It was found that COD, BOD5, and TSS values showed non-conformity from Moroccan discharge standards, as well as high concentrations of heavy metals such as cadmium (Cd), zinc (Zn), aluminum (Al), chro-mium (Cr), manganese (Mn), lead (Pb), silver (Ag), beryllium (Be), copper (Cu) and cobalt (Co). These pollutants represent a potential risk to human health and the environmental ecosystem. To reduce this pollution, the optimal mass of lime powder obtained by thermal treatment of eggshell waste was determined by testing a concentration series of 6, 12, 18, 24, 30, and 36 g·L-1. The findings confirmed that the addition of the optimal dose of prepared lime (24 g·L-1) resulted in a significant reduction in pollution parameters, with abatement rates of 77% for BOD5, 63% for COD and 66% for TSS, respectively. Furthermore, the eco-friendly lime substitute also showed promise in reducing the colorization rate for dyes by 84% and removing heavy metals through precipitation. However, the generated by-product loaded with toxic pollutants should be encapsulated in eco-materials to ensure safe operation and contribute to a sustainable management strategy for wastewater treatment.