The synthetic production of bleach produces calcium carbonate, which in most cases is discharged into watercourses or generally into the environment, causing considerable damage to the environment. In accordance with the legal and regulatory framework for waste management in Cameroon, private companies are obliged to implement waste management processes as part of their environmental management policies. With this in mind, we carried out a study on "the recovery of calcium carbonate from bleach production by the synthetic method in the city of Douala, Cameroon". The study consisted in choosing the process to be implemented for the valorization of precipitated calcium carbonate, taking the case of a crawling insect repellent, and assessing the impact of this crawling insect repellent on cockroaches and fry.