The document discusses monitoring of effluents from paper and pulp mills. It provides background on the papermaking process and how it can lead to water pollution. Key pollutants from pulp and paper mills include organic compounds from lignin in wood. The document outlines different types of effluent measurements that can be taken, including characterizing effluents and monitoring recipient water conditions. It emphasizes the importance of monitoring temporary discharges, as they often account for the majority of pollutants released. The goal of an environmental measurement system is to provide early warnings of issues and support effluent control within the plant.

1. MONITORING OF
EFFLUENTS FROM PAPER &
PULP MILLS
Presented By
Anuradha Verma

2. Introduction
History of papermaking
The pulp and paper industry as a pollution source
Identification of compounds hazardous to human health
Normal and temporary discharges of pollutants
The object and the problems
Effluent control
Environmental Measurements
Characterisation of effluents
Steps to be taken during disturbances in plant
Production control and environmental care
Environmental measurement system
CONTENTS

3. Introduction
The manufacture of pulp and paper is a resource-
intensive industry that consumes large amounts of
energy, water, and trees. It is a mature industry that
is innovative and adapts rapidly to technological
change in order to remain competitive in the
international market.
The technologies exist for substantially reducing
emissions, particularly those that are a risk to human
health. The implementation of environmental protection
will have to proceed in a manner that sustains the
economic health of the pulp and paper industry, yet
ensures human health and environmental quality. To
tackle this problem in a cost-effective manner it is
necessary to understand the nature of the problem, and
identify the specific compounds that endanger human
health and environmental quality.

4. History of Papermaking
 Egyptian papyrus and Chinese silk cloths were the first writing
materials. The first true paper, prepared from fibrous cellulose-
containing plant material, was manufactured in China in the year 105
A.D. At that time, Chinese clothing was made largely from China grass
(Boehmeria nivea), a common fibrous plant.
 The first paper mill in Lower Canada was established in 1803, in the
village of St. Andrews. Until Confederation, these mills were generally
small, and depended upon linen and cotton rags and recycled rope,
jute cloth, flax wastes and straw, for their raw feedstock.
 In about 1850, John Taylor of the Don Valley Paper Mill, Toronto, was
the first to develop and later patent a Canadian process for making
wood pulp. The use of wood as a cellulosic feedstock was the first
major technological break-through in paper-making in 1,700 years.
Today in Canada, 144 large pulp and paper mills consumer vast
quantities of wood, and produce both raw pulp and finished papers for
the world market.

5. The pulp & paper industry as a pollution source
Paper-making requires good quality pulp, so we should now about
 Wood: composition of the primary substrate.
 Chemical and mechanical processing.
COMPOSITION OF WOODY MATERIAL
The three main component groups of wood are cellulose, hemicellulose, and
lignin.
 Cellulose (50%): . cellulose is generally not easily attacked by
bacteria and moulds, because of the protective hemicellulose and
lignin covering that enwraps the cellulose fibres.
 Hemicellulose(25%) and
 Lignin (25%): It is very difficult to degrade. When slow degradation
does take place, phenolic compounds, which are generally toxic, are
released. The aromatic content of lignin is 51%.
It is the phenolic compounds released from lignin during the chlorine
bleaching of pulp that are responsible for a large percentage of the
toxic compounds released in pulp mill effluents.
 Extractives (1.5 – 5%): Generally present in mill wastes at much lower
concentrations than phenolic materials, some of these compounds are
relatively toxic, and can significantly reduce water quality and
marine habitat in the lakes and rivers that receive mill effluents.

6. PulpingProcesses:
The purpose of pulping is to free the cellulose fibres from the other wood
components in as pure and undamaged a condition as possible .
Type of Pulping:
1. Stone-groundwoodprocess:first widely used pulping ; damaged fibers that
lacked strength
2. Kraftpulping:high quality fiber; the other major advantage is the spent-
liquor system, which recovers tall oil (fatty and resin acids), turpentine,
bioenergy, and recycles inorganic chemicals.
3. Chemithermo-mechanicalpulping(CTMP):extremely high yield of pulp; does not
incorporate a recycling-recovery step; releases large amounts of lignin and
extractives, greatly increases the potential for release of concentrated
toxic effluents.

7. Discharges of PollutantsFormal Discharges Temporary Discharges
An industrial plant is represented by
normal condition when processes are
operating in the intended fashion. In
this situation the emissions to the
recipient will stay at a fairly stable
level. This represents the normal
discharges.
In industries there are
disturbances due to manual
mistakes, equipment failure, stops
for maintenance etc. Under these
conditions there is always a risk of
accidental or temporary
discharges. The temporary
discharges are highly unwanted.
They can give rise to uneven
running conditions in both the
production and effluent treatment
facilities and there is a risk that
valuable chemicals are lost.
Example: In the forest products
industry an overflow of water
containing wood fibers. These
fibers have lost most of their value
even if they are recovered from a
sedimentation lagoon.

8. Study of Control
of Effluents From:
Swedish Pulp and
Paper Industry

9. Temporary Discharges : Monitoring
In the Swedish Pulp and Paper Industry as
a whole, between 30—50% of emitted
chemicals and fibres were due to
temporary discharges (short duration even
<1 hr).
• When it comes to the design of a
monitoring system, these are very
important factors to consider. Variation in
fiber content in the collected effluent from a
sulphate pulp mill before external
treatment. We can distinguish what could
be called a normal level of emission, and
also a lot of temporary discharges. One
finds that in this particular case 70% of the
fiber content is due to temporary
discharges. To retain these fibres in the
process we can have information useful to
us. Many of the peaks are undoubtedly
small and they are so rapid that it is of
course not possible to do anything about
them. In the case of the larger peaks,
however, we found that their cause could
be traced and actions initiated to cut them
down. Here valuable virgin fibres could
otherwise have been lost.

10. The object & the problems
Three types of environmental measurements
are:
(i) in-plant measurements
(ii) measurement of effluents
(iii) measurement of recipient conditions.
These measurements can form the basis:
(1) for actions inside the plant, and
(2) for reports to authorities.

11. Effluent control
In order to perform the effluent control we need:
1. A description of the effluents; that is what
substances they contain.
2. A relevant way of characterizing these
effluents; that is what parameters should be
used for measurement.
3. Knowledge of the information desired by
authorities
4. Knowledge of measurement and of analytical
techniques.

12. Effluent control
In order to perform the
effluent control we need:
1. A description of the effluents;
that is what substances they
contain.
2. A relevant way of
characterizing these effluents;
that is what parameters
should be used for
measurement.
3. Knowledge of the information
desired by authorities
4. Knowledge of measurement
and of analytical techniques.
Inside the plant we need:
1. A description of internal
streams.
2. Process knowledge.
3. Knowledge of measurement
techniques.
4. Simple decision rules
("operators guide").
5. Process control knowledge.
6. Production control knowledge

13. Environmental Measurements
(1) First we have the internal
measurements, primarily close to the
machinery.They essentially serve to give
alarm so that rapid actions can be taken at
disturbances. One can very often use simple
measurement techniques— for example
 measurement of level,
 temperature,
 conductivity.
Some of the actions could be automatic.
(2) Secondly, measurements have to be
made at points where effluents reach the
recipient. Usually this is after some sort of
external treatment facility and the delay
time can be long.
(3) Measurements in the recipient should
describe the status of the recipient—like
dissolved oxygen content, pH. In most cases
this is a matter of long term changes.

14. What is to be done by plant personnel under plant
disturbances?
 flows can be automatically switched over to tanks and
treated separately
 personnel rapidly initiates actions on the basis of very
simple rules of the yes-or-no-type.
This might not be sufficient and the operator has to interact
with his process on the basis of process-knowledge.To his
help he might have a computer-based process control
system.
 In some cases this control system might be designed to
initiate directly the proper changes itself.
 It may occur that a disturbance persists for a longer time or
that the running conditions of a process have to be
changed significantly. If so, the interactions with
neighboring processes may have to be considered, so that
production volume and product quality can be maintained.

15. Characterization of effluents
Increased conductivity can often be associated with the increase in
the amount of a specific chemical compound
Consequence: measurements should be performed close to the
processes before mixing with other streams. These monitors
should preferably work continuously.
characterization of the emissions into the recipient: Three
approaches
1. Characterize the emission directly in terms of its potential
danger to the recipient.
Example: Determination of biological oxygen demand.
2.Second approach could be to characterize the emission in terms
of reasonably well definedsubstances.
Example: emitted tons of wood fibres per month.
3. Another approach a translation has eventually to be made
between the emission of a certain quantity of a substance and
its environmental effects

16. Source of Water Pollution & Characterization of emissions
 Dissolved organic matter like carbohydrates and lignins (very resistant
against decomposition and coloured brown).
 There is also colloid matter and solid particles of sizes from small fibre
fragments in the micron range to entire wood fibres.
 There might also be filler materials, like china clay, from the
papermaking process.
How to Characterize?
 Consumption of oxygen by organic matter- BOD
 Affect light penetration- Color
 Settlement on the bottom of recipient- Suspended solids

17. Uncertain Results from BOD, Suspended Solids & Color
Suspended solids content:
 There may well be components that also contribute to the
oxygen demand.
 There are components that by scattering of light may affect the
optical properties of the recipient and also fibres, which in fact
do not remain suspended, but settle rather fast. So no relevant
information.
Color :
 The colour parameter does not take light scattering into
account. Perhaps it is used as an indirect measure of the
brown-coloured lignins.
BOD: The 5- or 7-day analysis is only of histroical value with
uncertain results.
So we can go for COD(chemical Oxygen Demand) & TOC(total
organic Carbon)

18. Production Control & Environmental Care
Production control :
Proper coordination of the activities in the plant and a good use of the
storage capacities.
The environmental implications of production control are:
(i) Since the storage capacities are entered as restrictions in a production
control system, there should in principle under planned conditions be
no possiblities for over-running storage tanks.
(ii) The most important consequence of a production control system is that
disturbancies can be taken care of with least possible consequences
to the production volume. It is also possible in advance to evaluate the
consequences of changes in the production system.
(iii) By using strategies that well utilize the storage capacities, the number
of events when storage tanks are full, and thus represent a potential
risk of overflow, can be reduced also when disturbances occur.
In larger process industries, like the pulp and paper industry, we
now see computer-based production control systems .

19. Environmental Measurement System
Main task:
 To supply an indirect measure of the
emissions from the mill
 To give alarm signals in critical situations, to
supervise sensors and
 To present information in an accessible way
to mill management and operators

20. How it is done?
 Each separate process is checked and each department is supervised
as a single unit
 The separate process effluents and the final effluent to the recipient
are watched in the same way.
 The aim of the system is to give an alarm as soon as possible so that
appropriate action can be taken with a minimum of delay. (These
alarms are graded by the computer according to a previously chosen
set of priorities). Some of the alarms must be acknowledged by the mill
personnel.
 Each morning the computer presents a report giving details of
stoppage times for major equipment and mean values and standard
deviations of the measurements from the various sensing devices.
The report also includes laboratory data and finally a list of alarms
during the previous twenty-four hour period.
 Communication with the computer takes place via two terminals, one
in the control room and one in the laboratory. The system includes 50
digital and 40 analogue sensors, most of them of conventional type.

21. Liquid Effluents from New Pulp and Paper Manufacturing
Parameter Maximum value
pH 6-9
COD 300 mg/l and 15 kg/t for kraft and
CTMP pulp mills; 700 mg/l and 40 kg/t
for sulfite pulp mills; 10 mg/l and 5 kg/t
for mechanical and recycled
fiber pulp; 250 mg/l for paper mills
AOX( adsorbable organic Halogens) 40 mg/l and 2 kg/t (aim for 8 mg/l and
0.4 kg/t for retrofits and for 4 mg/l and
0.2 kg/t for new mills) and 4 mg/l for
paper mills
Total phosphorus 0.05 kg/t
Total nitrogen 0.4 kg/t
Temperature < 3°C

22. References
archive.greenpeace.org/toxics/repo
rts/tcf/tcf.html
publications.gc.ca/Collection-
R/LoPBdP/BP/bp292-e.htm
www.ifc.org/ifcext/enviro.nsf