Presented in Partnership with:
 
 

Ask the Expert Question-and-Answer Archive
(Wastewater Treatment)

by Mike McGinness, EcoShield Environmental Systems, Inc.
May, 2009

COD Increase After Wastewater Treatment

Q. Im using two white rot fungi for the biotreatment of simulated effluents containing textile dyes. The treatment is performed at small scale inoculating the fungus (50ml of a fungal preculture)in 450ml of wastewater in 1L flasks. Ive found that the treatment is more effective (in terms of percentage of decolourisation) when the wastewater is supplied with nutrients (malt extract). This, obviously increases the COD value of the starting wastewater, but after treatment, despite a high reduction of colour (up to 70% decolourisation)I measured an increased COD value! How do you think it is possible? Could I suppose that fungal growth (the fungal can grow in this conditions) release some organic compounds in the wastewater? Im confident on the sperimental procedure, the data have been repeated three times.

A. The fungi only need to remove one or more atoms or re-arrange the existing atoms of the dye molecule, to remove the dye color, non of which will reduce the COD, Chemical Oxygen Demand. The nutrients added to support the Fungi increase or add to the COD. The Fungi themselves also have a COD. Once the color has been removed by the fungi, the COD can be removed, barring any toxic constituents, by treating the waste water with a typical aerobic or biological oxidation process that converts COD and BOD into dense, easy to gravity settle biomass (fat, happy dense bacteria).

Sincerely,

Mike McGinness

 

| Home | Subscribe | Regulations | Compliance Assistance | News | Resources | Resource Locators | Directories | Online Training | About | Search | NASF.org |


The information contained in this site is provided for your review and convenience. It is not intended to provide legal advice with respect to any federal, state, or local regulation.
You should consult with legal counsel and appropriate authorities before interpreting any regulations or undertaking any specific course of action.

Please note that many of the regulatory discussions on STERC refer to federal regulations. In many cases, states or local governments have promulgated relevant rules and standards
that are different and/or more stringent than the federal regulations. Therefore, to assure full compliance, you should investigate and comply with all applicable federal, state and local regulations.