A Biofiltration System

A bio-filtration system using a biofilm contact reactor has been developed to remove organic contaminants from wastewater.

Our biofilm is used as a biological scrubber, removing organic matter, and trapping solids, removing them from wastewater. When the biofilm becomes too thick and heavy to remain attached within the system, it is shed, providing for a novel means to remove waste biofilm biomass from the system. At the same time a new biofilm develops without interrupting the operation of the system.

In conventional water filtrations systems, the biofilms that form during the filtration process are separated out or pumped to a separate collection tank. However, these conventional systems have to be stopped from time to time to remove the sediment.

This invention holds the following advantages over the conventional filtration system:

•       Biological contaminants and solid materials are continuously separated out of the water without the need to disrupt operation to clean the packed bed

•       This system requires no additional settling tank

•       The system does not use filters that need to be cleaned or can become clogged with use

•       Only a small amount of waste is produced from the filtration process leading to a lower environmental impact.

•       The design of the filter allows for a greater aeration rate than a conventional filter, allowing for quicker breakdown of organic matter

•       The system has a smaller footprint than conventional filters of the kind

•       Almost no (or none) pre-fabricated components are required

•       Small capital outlay to implement, especially if an existing water cooling tower is on site

In this invention, a tower with a packed bed of porous substrate material is provided, designed efficiently distribute wastewater over the substrate, with the simultaneous draft of air in the opposite direction, ensuring effective aeration of the system without additional energy required to power aeration.

Contaminated water enters the tower through the water inlet and a biofilm of a mixed population of microorganisms develops on the surface of the packed bed material. The biofilm covers a large surface area and, as it thickens, it serves as a biological scrubber to remove and break down organic contaminants.

The resulting biological sludge and solid waste matter is constantly removed by making use of a highly effective in-line separation method to produce a small volume of concentrated waste stream and a separate filtered water stream.

•       Wineries producing cellar effluent

•       Production facilities that produce water with an organic waste  component

•       Wastewater management companies

•       Continuous bio-filtration producing separate streams of waste and filtered water

•       The system separates solid and organic waste material from water in one tank

•       No filters are used in the invention which means less clogging than traditional filtration systems

Professor T.E. Cloete, Vice-Rector Research & Innovation, Stellenbosch University.

Ms DM du Plessis, PhD Student, Department of Biochemistry, Stellenbosch University .

Dr. M Botes, Researcher, Department of Microbiology, Stellenbosch University.