Manufacturing Waste From Pulp & Paper Industry

The pulp and paper industry is among the greatest contributors to manufacturing waste in the world. The major reason can be the high amount of water and energy consumption during production. This poses a big threat to the environment in both the short and long run, and thus requires the need for active waste reduction. But we could take necessary measures, we must first understand the sources of these manufacturing wastes. So let us jump to the following section to know.

Where Is Paper & Pulp Industry Manufacturing Waste Coming From?

1. Manufacturing Process

The first step in paper manufacturing is pulp making. This includes a range of processes like:

• Debarking

• Chipping of wood

• Chip washing

• Chip digestion

• Pulp screening and filtering

• Pulp thickening

• Pulp washing

Both mechanical and chemical processes are used in the paper industry. In mechanical processes, the pulp yield is increased using mechanical pressure, disc refiners, heating, and light chemical processes. Whereas in chemical pulping, chips are cooked in pulping liquors at high temperatures and under specific pressure. While the mechanical process yields higher production than the chemical process but is of low quality/properties than the latter. (Do you know you can check the physical properties of a paper using UECIN’s Paper physical testing machine.)

Almost 5-10% of the lignin is produced from the raw materials in the pulping process. This lignin couldn’t be removed from the pulp and hence makes the paper dark in color. When it comes to making white paper, through bleaching, the following chemicals are used in sequence:

• Chlorine (C1)

• Alkali (E1)

• Hypochlorite (H)

• Chlorine Dioxide (D1)

• Alkali (E2)

• Chlorine Dioxide (D2)

1. Water Waste

Water is a significant resource in almost all the pulping processes. And different pulping processes require different amounts of water. The varied process and types of chemicals used, lead to distinctive wastewater generated from pulping and bleaching.

A lot of water is used to produce a ton of pulp, and most of it is polluted, particularly wastewater generated from chemical processes. The various stages that cause the most pollution include:

• Preparation of wood

• Pulping

• Washing of pulp

• Screening or filtering

• Bleaching

• Papermaking and coating

The various wastewaters generated from the pulping processes include:

• Lignin

• Carbohydrate and extractives

• Resin acids

• Unsaturated fatty acids

• Chlorinated resin acids

• Diterpene alcohols

• Juvaniones

• AOX or Chlorinated organic compounds

The characteristics and strengths of the wastewater largely depend on the pulping processes, mechanical or chemical.

1. Solid Waste

Solid wastes too are among the major problems of the pulp and paper industry. These mainly include:

• Treatment sludges

• Lime slaking grits

• Lime mud

• Green liquor dregs

• Boiler and furnace ash

• Scrubber sludges

• Wood processing residuals

The treatment sludge results from the wastewater treatment plant. Dregs and mud come from the caustic process, ash from the power boiler, and scrubber sludge from the paper mill. The characteristics of all the solid waste generated are the organic exception of boiler and furnace ash.

1. Air Pollutants & Emissions

The major emission of the paper and pulp industry is water vapor. While other pollutants are sulfur oxides, nitrogen oxides, volatile organic compounds, and total reduced sulfur compounds.

ConclusionAs a paper testing equipment supplier, exporter, and manufacturer, we are fully cognizant of the manufacturing waste resulting from the paper-making processes. We aim to contribute to the sustainable development of the nation and therefore keep making continuous efforts in that direction. Get in touch to know more about our instruments and equipment.

Universal Engineering Corporation is an organization which designs and manufactures a wide range of testing instruments for pulp, paper & packaging industries