Evaluation of the Removal of Cod and Bod in Wastewater from Bus Washing Using Coagulation, Flocculation and Aerobic Biological Treatment

Abstract

Wastewater treatment is a complex task, especially when it is understood that it is used for multiple uses; one of the uses in which a large number of pollutants are used is for washing cars, especially buses and trucks use a large amount of solvents, detergents and soaps of different compositions, which are difficult to remove from water , especially because they act as emulsifiers between substances not soluble in water and the water that dissolves and eliminates them together with the internal and external dirt of buses and trucks. In Colombia, the implementation of a standard that has made the amount of contamination, that residual water can carry is more restrictive, before being poured into a sewer collection pipe, this is evaluated in terms of chemical oxygen demand (DQO) and biological oxygen demand (BOD5), these parameters define the quality of the water to be collected. The University of Santander provides scientific and technical consultancy services to the community of companies in the Santander region and the company PARBER is a local consultant, which is in search of solutions for the environmental problems of the wastewater from the laundries of cars, for this study agreements were made between the parties to search for wastewater treatment systems, which can be used by car wash industrialists and to be able to comply with the standards established in the new legislation; For this purpose, a sampling methodology for wastewater, jar tests and a water aeration device were developed that simulate the processes consecutively and also independently, to determine the capacity of removal of COD and BOD5 from wastewater. ; the scenario used was a car wash, which is a client of Industrias PARBER, which facilitated the tributary water for all the tests and also provided its facilities for the assembly of a prototype of aeration, to perform the aerobic biological treatment test ; composite samples of 4 hours of laundry were taken, which has a 24-hour service, with higher flow rates in the morning hours, in which the analyzed samples were taken; the analyzes were carried out in the water laboratory of the University of Santander, to determine the degree of contamination, also jars tests were performed, to simulate the operations of coagulation, flocculation and sedimentation, as part of the possible treatment to be applied to the waters residuals of the laundry of cars..