Pulp & Paper Wastewater Treatment – paper mills are highly complex and contain various processes to convert pulp from wood or recycled material into the final paper product. By their operational nature, facilities are large consumers of natural resources and have the potential to be severe polluters of air, water and soil.
For every tonne of paper produced, it takes around 50 cubic metres – or 50,000 litres – of water to produce. Across the industry, there is an ever-increasing demand to reduce costs associated with wastewater treatment and a more active need to reuse water wherever possible. This also resonates reputationally with the end consumers who are increasingly interested in products made by sustainable and environmentally considerate manufacturers.
According to industry experts, about 85% of Pulp & Paper industry water use is for process water, which is contaminated during the manufacturing process with sediments, effluent solids, chlorinated organic compounds, organic halides (AOX), and chemical oxygen demand (COD) and biological oxygen demand (BOD) contaminants. As an example of how water is consumed within this industry, the pulp is made mechanically or chemically and is then bleached and further processed to suit the grade of paper in manufacture. Up to a staggering 85% of the total effluent, volume is generated in the bleaching stage and this water must be carefully managed to prevent pollution.
Additionally, used paper is often blended with virgin fibres to be reformed into new paper. During the deinking process for paper which is intended to be recycled, chemicals are used to remove the printing inks. These chemicals and the colour from the inks must then be removed from the wastewater as they are not safe for human and aquatic consumption.
With environmental and regulatory policies tightening across the globe, the need for businesses in the pulp and paper industry to meet strict wastewater challenges has never been more prevalent.
Treating Wastewater in the Pulp and Paper Industry
Dissolved air flotation is a water treatment process that clarifies wastewaters by the removal of suspended matter such as oil or solids. The removal is achieved by dissolving air in the water or wastewater under pressure and then releasing the air at atmospheric pressure in a flotation tank basin.
One technique for water collection in the Pulp Paper Wastewater Treatment system which can help in the fight to conserve water is rainwater harvesting. This method involves collecting rainwater from roofs for future use. Given that the UK gets an average of 33 inches of rain a year, the potential to accumulate thousands of gallons is well within reach. Experts estimate that for every inch of rain that falls on a catchment area of 1,000 square feet, you can expect to collect approximately 600 gallons of rainwater. Ten inches of rain falling on a 1,000 square foot catchment area will generate about 6,000 gallons of rainwater.
Other treatment options include primary treatment such as clarification to remove solids and particulate matter, and secondary biological treatment processes for removing biodegradable organic matter and decreasing the effluent toxicity. Tertiary treatment technologies such as membrane filtration, UV disinfection, ion exchange, and granular activated carbon can also be employed to further treat effluent water to higher qualities.
Storage Tank Requirements
The types of waster plant we can provide storage tanks for include the following. All systems are manufactured in close cooperation with the leading manufacturers of dosing pumps, instrumentation and other ancillary components.