Water and Process Fluid Filtration in the Pulp and Paper Industry

Water is used throughout the entire paper making process. As much as 25,000 gallons of water is required to produce a ton of paper. Water is used in chip washing, pulp washing and in paper making process. It is also used for process cooling and steam generation.

Paper mills are located near an abundant supply of fresh water. Water used in the pulp production and paper making sourced from:

  • Ground Water (i.e. Well Water)
  • Surface Water (i.e. River, Lake, Reservoir)
  • Recycled Water

The water is pumped directly from a river, lake or reservoirs. Water scarcity and mandated consumption limits are leading the industry to evaluate ways to treat, reuse and recycle process water or white water.

The recycled water and surface water supplies can be contaminated by airborne debris, silt, sand, pollen, algae, and other suspended solids. All these water sources can also be contaminated with pipe scale and corrosion by-products. Regardless of the source, all water used in the pulp washing and paper making processes must be filtered!

Much of the water used in chip and pulp washing, as well as the water used in the paper making process (head box), is pumped and sprayed through nozzles. Consistent and reliable filtration is a critical aspect of the paper making process. Ultimately, inadequate filtration leads to partially or completely plugged nozzles. Plugged nozzles and/or restricted flow through the nozzles can cause productivity and quality problems. Spray Nozzle Protection is very important.

Effective and efficient filtration is also important for paper quality and profitability of the mill. Passage and deposition of large particles can reduce the quality of the finished product.

Economic and environmental pressures to reduce water consumption and wastewater generation are leading the pulp and paper industry to focus on ways to reuse and recycle water. The contaminants generated throughout the process (pulp making => pulp wash => paper making) are organic and inorganic, and soluble and insoluble. Methods for removing these contaminants from the water include filtration, biological systems and membrane systems. The intended reuse of the water determines type and level of treatment required. Sometimes filtration will be the only requirement. In some cases, filtration will be the pre-treatment step; other times filtration will be a post-treatment or polishing step. However, filtration for the removal of suspended solids will be required in every case.

Effective removal of the smaller and lighter suspended solids is extremely critical. Ideally, you want a positive barrier that will capture and remove particles large and small, and light and heavy. You also want to minimize maintenance and labor which would make bag and cartridge filtration a poor choice. The Zero Gravity Filters permanent media Spring Filter is a coil wound with a variable pitch that allows the filter element to open evenly from top to bottom ensuring that all contaminants are completely cleaned off the filter element with every backwash. The ZGF Spring Filter is manufactured with precision raised nidges. These nidges create an absolute gap that allow the Spring Filter to capture > 99% of spherical particles larger than the micron rating of the filter.

ZGF Spring Filter technology effectively and efficiently captures and removes oversized solids / particles, and is:

  • fully automatic – the self-cleaning process is initiated based on pressure differential, and accomplished in seconds without interrupting flow to the process
  • consistent & reliable
  • non-disposable
  • energy efficient – operates on line pressure, utilizing a minimal amount of electricity and air during backwash
  • environmentally responsible – uses <0.75 % of total water volume for backwash
  • able to remove particles down to 20 micron

ZGF Spring Filter technology is the ideal choice to remove suspended solids and oversized particles throughout the pulp wash and paper making process, including:


If true life-cycle costs are considered, typically the payback on ZGF Spring Filter technology can be realized in less than 1 year. This is based on ZGF Spring Filter technology:

  • having no moving parts,
  • operating costs of less than $100 per year, and
  • a 5-year guarantee on the Spring Filter element.

ZGF technology can be installed in a variety of processes and applications.

To get a better understanding on where ZGF technology can provide value in the Pulp & Paper industry, click on one or more of the Process Diagram links below.  The process diagrams show you where a ZGF technology can be implemented in a specific process and the benefits it provides.

ZGF Spring Filter technology meets all purchasing and performance criteria by effectively and efficiently capturing and removing suspended solids.

ZGF technology will provide value because it is:

  • fully automatic
  • consistent & reliable
  • non-disposable
  • energy efficient - utilizing a minimal amount of electricity and air during purge/backwash
  • able to remove particles down to 20 micron
  • able to provide value throughout the mill and help optimize each process by effective and efficient contaminant capture and removal

The product data sheets provide a detailed description and comprehensive overview of each product technology. If you want to learn more about ZGF EZ Clean or Tornado technology, then click on one of the links to download the:

Seeing is believing!

Some people need to see something in operation to really get it.  Click on the links below to see how each technology works.

  • Spring Filter animation – The animation shows the basic principle of operation.
  • Spring Filter video - See the coil open and shimmer and the contaminants disappear!
  • Phoenix animation – The animation shows the basic principle of operation.
  • Phoenix video - The narrated video explains and allows you to see how the Phoenix works; and you can see how all debris is removed during backwash when the Spring Filter opens and shimmers

ZGF technology provides value

Click on ZGF Phoenix vs Bag Filter to see a how a ZGF customer was able realize a simple payback in 8 months.

ZGF technology can provide significant value in several operations and applications. Click on Success Stories to jump to the Success Stories / Case Studies page to learn how ZGF technology provides value. 

To learn how a paper manufacturer thought out of the box and utilized ZGF Spring Filter technology to reduce total operating costs while being more environmentally responsible, click on:

Simplicity, consistency, reliability and the lowest cost of ownership make ZGF technology the best solution and value for all your filtration needs!

ZGF is your preferred partner.

 Filtration should not be a burden.

 Filtration should be a tool that improves quality and reduces cost.

Let us help you meet your objectives and make your job easier!


 ZGF has the experience and dedication to customer satisfaction that you are looking for. Contact us or request a quote today.