Construction of lightweight Foamed Cement Banking (FCB) embankments usually requires temporary sites for air-pressure machinery. This study proposes casein, a milk protein, as an additive in cement-treated soils for constructing lightweight embankments to reduce milk waste and the necessity for air pressure machinery. The effects of mixing time, casein content (0 - 8%), and cement quantity (100 and 150kg/m3) on the dry density, unconfined compressive strength (UCS), and coefficient of permeability of cement-treated soils were determined. Furthermore, the durability of the cement-treated soils mixed with casein to wet and dry cycles and its impact on the pH of water was determined. It was established that adding 5% of casein to cement-treated soils and mixing for 10 minutes produced lightweight embankment materials with complaint strength (>300kPa), durability and permeability(10-3cm/s), minimal environmental impact and promoted sustainability.