CASE STUDY: Remove Colour and COD from Tea Wash Water

Equipment Capacity/Flow Rate

Low Flow

Compounds of Concern

COD & Colour

Influent Concentration

510 mg/L & 1550 Pt-Co (Apparent)

Treatment Targets

40 mg/L COD & no colour

Unit Energy Consumption

tbc

Water pollution occurs when harmful substances contaminate waterways, degrading water quality and rendering it toxic to humans or the environment.

The presence of colour in discharge water is often caused by dissolved organics and tannins which are created during the tea manufacturing process. This colouration effects not only the aesthetic appearance of the water, but when this wastewater is discharged to nature, photosynthesis activity becomes limited, which has detrimental effects on aquatic ecosystems.

Moreover, releasing untreated wastewater into the ecosystem can result in:

Bioaccumulation of chemicals in the food chain
Population decreases in aquatic species

Chemical Oxygen Demand

Manufacturers must also adhere to strict limits of Chemical Oxygen Demand (COD) for wastewater which is to be discharged into the environment. Failure to comply with local limitations set for colour and/or Chemical Oxygen Demand* (COD) can result in loss of permit, operational downtime, limited production volume and severe fines, not to mention reputational and environmental damage.

*COD is used as a measure of organic pollutants in water and is expressed in milligrams per litre (mg/L) or parts per million (ppm).

The Project

A tea plantation based in an area of natural beauty, owned by British multinational consumer goods manufacturer, approached Arvia to help them to treat their process discharge water. As this tea wash wastewater was going to be discharged to an area of natural beauty, it was a strict requirement to ensure that contaminants were removed and also to eliminate the colouration.

The client’s objectives were to:

Achieve the 40 mg/L target discharge consent for COD
No visible colour (colouration measured in Platinum Cobalt Units)

By adopting a wastewater treatment process which has the ability to remove trace levels of organics and reduce COD, manufacturers meet regulation and prove commitment to the protection of the environment.