Page 103 - Energy from Toxic Organic Waste for Heat and Power Generation

88 Energy from Toxic Organic Waste for Heat and Power Generation

The potential pollutants from pulp and paper mill are divided into
four principal categories based on their phase/state like liquid, solid, gas or
particle, etc.

7.3.1 Categories of Potential Pollutants
(i) Water effluents
• Suspended solids including bark particles, fiber, pigments, and dirt.
• Dissolved colloidal organics like hemicelluloses, sugars, lignin com-
pounds, alcohols, turpentine, sizing agents, adhesives like starch and
synthetics.
• Color bodies, primarily lignin compounds and dyes.
• Dissolved inorganic such as NaOH, NaSO, and bleach chemicals.
• Thermal loads.
• Microorganisms such as coliform group.
• Toxic chemicals.
(ii) Solid wastes
• Sludges from primary and secondary treatment and causticizing in
kraft mill recovery section.
• Solids such as grit bark and other mill wastes.
• Ash from coal fired boilers.
(iii) Particulates
• Fly ash.
• Chemical particles primarily sodium and calcium-based.
• Char from bark burners.
(iv) Gases
• Malodorous sulfur gases such as mercaptans and HS.
• Oxide of sulfur.
• Steam.
7.3.2 Sources of Waste Generation

The sources of these waste generation and other gaseous emissions in the
paper and pulp making process are listed as follows [9].
(i) Waste water generation
The possible sources of waste water generated at the each step of the
pulp and paper making process are detailed as follows
1. Initial phase
− Washing wooden chips in large-scale pulp and paper mills using
wool as raw material.
− Washing of bagasse for separation of pith.
− Washing of rice/wheat before pulping.