Trickling Filters for The Removal of Residual Organic Matter in The Dairy Industry. A Review

Abstract

Dairy industries have grown enormously in many regions of the world due to the demand for milk products. Dairy industries release large quantities of wastewater containing high chemical oxygen demand (COD), biological oxygen demand (BOD), organic and inorganic substances, which, if not properly treated, contaminate water resources. In the present work we consider analyzing the treatment of residual organic matter in the dairy industry, where trickling filters is a sanitation technology t hat uses microorganisms that adhere to a medium with a large surface area to remove mainly soluble organic matter such as BOD and COD as the wastewater passes through the medium. All trickling filters require primary treatment of suspended solids to prevent clogging of the filter med ia. Because trickling filters are designed to remove soluble organic matter, they are not expected to have high pathogen removal rates. This system, the removal efficiency achieved for BOD ranges from 69 - 78 % and for COD from 65 - 80 %, suspended solids removal from 38 to 56 %, for total dissolved solids from 20 to 36 % and other aggregates such as turbi dity and color removal from 32 to 54 % and 25 to 42 % respectively. Membrane technology is an alternative to biotreatment used for BOD reduction in dairy wastewater replacing secondary clarifiers in membrane waste treatment plants (Kanwar et al., 2017). The trickling filter in this regard is potentially a viable option, as it is a simple and reliable biological treatment process and an appropriate option for small and medium-sized communities, requiring less space and time for BOD removal. This dairy wastewater treatment system presents an attractive alternative from a technical and economical point of view.