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Text File | 1989-01-03 | 49KB | 1,688 lines

            Flocculation, Precipitation & Dewatering



                           Dave Wright
                           P.O. Box 45
                        Mequon, WI 53092
                         Copyright 1989


































                            CONTENTS






                1. Water treatment           - Page 3


                2. Chemical conditioning     - Page 4


                3. Sedimentation             - Page 10


                4. Dewatering                - Page 11


                5. Consistency and accuracy  - Page 13


                6. Field testing             - Page 14


                7. Trouble shooting          - Page 17


                8. Safety                    - Page 19


                9. Summary                   - Page 20


               10. Glossary                  - Page 21


               11. Index                     - Page 26



The  portion we will be primarily concerned with is  waste  water
from metal finishing operations. It is used to clean, cool, treat
and finish products that we manufacture.

As  the  water  is used in the various  processes,  it  picks  up
natural  and  unnatural  contaminants  or  "pollutants".  Natural
contaminants  are usually minerals such as calcium and  magnesium
(these  are  the primary components of "hard"  water).  Unnatural
contaminants  can  be any one of, or combination  of,  substances
such  as  alkalis or acids,  oil, bacteria,  metallic  particles,
paint particles, etc.

In order to maintain a greatly needed natural resource, the Clean
Water  Act,  as well as other Federal and local  laws  have  been
enacted.  These  essentially require you to  remove  contaminants
from  the  waste  stream,  if  they  exist  in  quantities  above
prescribed limitations.

Removal  usually  can be accomplished in a variety of  ways.  The
method  we  will address is the most commonly  used  in  Industry
today.   It  is  also  the  oldest  known  technique  for   water
purification.  It  is known as clarification.  The  clarification
process incorporates coagulation, flocculation, sedimentation and
usually  dewatering.  Each is a distinct process.  If  conditions
adversely affect any one of the three steps, the results will  be
less than desired.

In  water  treatment, the use of chemicals  for  coagulation  and
flocculation  revolves around the need to remove solid  materials
from the water. Most treatment depends upon our ability to remove
colloidial  turbidity  and/or  color. A colloidial  system  is  a
solid,  liquid or gas mixed together in another solid, liquid  or
gas  so that no separation occurs upon standing. An example of  a
colloid  is fog. Fog is a mixture of gas and liquid. In  water  a
colloidial system refers to cloudy, colored or turbid water  such
as  you might find in most rivers and lakes. In  wastewater,  the
colloid  could  be  any  number of  pollutants.  The  removal  of
suspended  material  from  water  is an  important  step  in  the
treatment or purification process.















Neutralization.

The first step in conditioning is almost always pH adjustment  or
"neutralization".  This  involves using acid  and/or  caustic  to
achieve  the  desired pH. When heavy metals are involved  the  pH
range  is  usually  8.0  - 10.0. The  pH  adjustment  is  usually
accomplished   with  automatic  metering  pumps  tied  to  a   pH
probe/controller, although it can be done manually in small batch
type systems. Sometimes this step is all that is needed as far as
chemical treatment.

Chemicals commonly used for pH adjustment are as follows:

Alkalinity sources:

A. Lime
     1. is inexpensive to purchase.
     2. does requires preparation.
     3. can be overdosed.
     4. can start coagulation.
     5. can give better settling.
     6. can aid in dewatering.
     7. does add to sludge volume.
     8. buffers sludge for EP testing1.

B. Magnesium Hydroxide
     1. is relatively safe to handle.
     2. has a low risk of overdose (maximum  pH  of  9.0).
     3. requires little preparation.
     4. may be cost effective.
     5. is not widely used at this time.


C. Sodium Hydroxide
     1. is more expensive to purchase.
     2. is easy to handle.
     3. requires no preparation.
     4. does not add to sludge volume.
     5. is most commonly used Alkalinity source.


Acidity Sources:

A. Sulfuric Acid
     1. is most common source of Acidity.

B. Spent pickle liquor.
     1. may be cost effective.
     2. can add to treatment problems.



1Proposed changes in testing may negate this benefit.
Coagulation

The  second  step usually involves the addition of  a  coagulant.
They  can be inorganic or organic in nature. The purpose  of  the
coagulation step is to destabilize or neutralize oils, grease and
suspended  solids to permit removal. It is primarily  a  chemical
reaction  and is best accomplished in an area of high  agitation,
commonly known as a "fast mix zone".

This  step  reduces  or neutralizes the  surface  charge  of  the
particles  enough  to  permit collision and  enlargement  of  the
particle  size  by  agglomeration.  After  the  addition  of  the
coagulant  to the pH adjusted solution, microfloc or pinfloc  may
begin to be visible to the eye.

Inorganic coagulants

A  number  of  coagulants  are  available  in  the   marketplace.
Aluminum  and  Iron  salts are the  most  widely  used  inorganic
coagulants.   These  include  alum  (aluminum  sulfate),   sodium
aluminate,  ferric  sulfate,  ferrous  sulfate  (copperas  oxide,
ferris hydroxide) and ferric chloride. These products are  simple
salts  similar  to  table salt. Ordinary  table  salt  is  sodium
chloride. Ferric chloride and aluminum sulfate (alum) are similar
salts in terms of general chemistry.  All of these chemicals with
the exception of sodium aluminate are acid salts which lower  the
pH  of water. Depending on the initial raw water  alkalinity  and
pH,  another  chemical  (lime  or  caustic)  must  be  added   to
counteract  the  pH  depression  of  the  primary  or   inorganic
coagulant.

Polymer coagulants

In  recent years, the process of polymerization has been used  to
develop  products  which could act as  coagulants.  Polymers  are
unlike  simple inorganic salts in that they they consist of  many
separate  chemical  units linked together into a  long  chain.  A
monomer  is  the  single  building block which  may  be  used  to
construct  a  polymer.  A dimer equals  two  building  blocks  or
monomers.  A polymer consists of a number of monomers, which  may
vary considerably in length, structure and characteristics.

A  synthetic polymer is man made. Instead of coming from a  mine,
they  come  from  the mind. They have usually been  built  for  a
specific need, although they may find their way into other  uses.
Natural  polymers are derived from starch, lignin or other  plant
or  animal  tissue (Human skin is a protein  polymer).  The  term
polyelectrolyte(s) refers to all water soluble polymers used  for
clarification. This term is often misleading, and over used.

The  utilization of organic, inorganic, and/or  alloyed  polymers
can  be  advantageous  when used in  comparison  to  conventional
inorganic coagulants.


Alum  for  instance  is one of the  most  widely  used  inorganic
coagulants.  It has a number of disadvantages. Among  others  it;
requires  alkalinity to form a floc, works best in a very  narrow
pH range or "envelope" (6.8-7.5), is corrosive in liquid form and
the sludge developed can be difficult to dewater.

Polymers can offer several advantages as a coagulant.
     1. They are effective over a broader pH range, thus do not
        require pH adjustment after clarification.
     2. They are easy to handle.
     3. The volume of sludge produced can be effectively reduced.
     4. The resulting sludge contains less water, and can be more
        easily dewatered.
     5. They are usually well suited for landfill  (when  judged
        non-hazardous).  Their  sludge  can  support  vegetation,
        inorganic sludges will not.

Chemical Emulsion Breaking

Solutions such as alkaline cleaners, coolants, food manufacturing
by-products  etc.  usually contain oil or  grease  (discussed  in
depth  elsewhere in this course) in the form of an  emulsion.  An
emulsion is a stable mixture of two immiscible liquids.   Various
chemical agents are used to destabilize and break an oil in water
or  water  in oil emulsion. They must be carefully  selected  and
blended for specific types of emulsions and often specific  types
of  equipment.  They  must  be  capable  of  dispersing   evenly,
migrating   to  the  film  interface  rapidly,  and   effectively
neutralizing  and stabilizing the effects of the emulsifier.  De-
emulsification  may be accomplished chemically by acid  addition,
use of primary inorganic coagulants, and/or inorganic, organic or
alloyed polymer emulsion breakers.

Coagulant aids.

Often  confused  with flocculents are coagulant aids.  These  are
usually a "clay" such as Bentonite or Hectorite. These  materials
have high swelling capabilities when combined with water and form
gel-like masses. This swelling capacity is a beneficial  property
for  clarification  as  an  extremely  large  surface  area    is
generated  by small particle sizes. This swelling is a  capillary
action and the particles tend to act as the nucleus of floc being
formed.  Formation of floc is almost independent of pH.  However,
this  same property can make clay slurries difficult  to  prepare
and handle. The primary use of these materials is to form a dense
enough  floc to promote effective settling. They can also act  as
weighing  agents  due  to their  high  specific  gravities.  This
property  helps  overcome inhibited settling caused  by  high  or
excessive flow rates.

Other types of coagulant aids are inorganic reacted polymers such
as  Polyhydroxyalumina,  Sodium Aluminate and  organics  such  as
Polyamines  and Polyquats. They have many advantages  over  clay.
They are easy to handle and do not add to sludge volume.

 Chelated and/or Complexed Solutions

No discussion of wastewater treatment seems to ever pass  without
the  mention  of chelation or complexed metals, and how  to  deal
with   it.  The  dictionary  definition  of  chelation  is   "The
inactivation of metallic ions in a solution by an organic reagent
with  whose molecules the metallic ions are strongly bound  in  a
relatively  inactive ring structure". Everyone  understand  that?
Metal  finishers  are  beginning  to  reckon  with  the  problems
associated with these materials. For our purposes you should know
that some chemicals provide a benefit, such as keeping hard water
deposits  from  depositing on burner tubes or holding  metals  in
solution.  This  can  prolong the life of the  bath  and  prevent
sludge precipitation in the process. These same chemicals can  do
exactly  the same thing in the treatment system, and can  prevent
or inhibit sludge precipitation in the waste water process too.

Typical  products to watch for are Gluconates, EDTA and  Ammonia.
Virtually  any of these solutions can be dealt with, as  long  as
proper  testing and treatment procedures are utilized. These  can
take many forms. Chelators can usually be dealt with, but at  the
very  least it means , addition of larger volumes (more  expense)
of  chemicals  to break them. Some chemicals used to  break  down
Chelated solutions are Calcium Chloride, Sulfates, Permanganates,
Synthetic  Polymers and proprietary solutions such as the  family
of Carbamates.

The best way to deal with them is to avoid them. Carefully  weigh
the  benefit versus the cost of treatment. If you must  use  them
consult   your   supplier  of  treatment  chemicals   for   their
recommendation  of treatment. To many variables exist for  me  to
list  all  the  methods of treatment, but I  can  provide  a  few
examples  of  methods currently being used. Copper is  the  metal
most  often  used  as an example because it is one  of  the  most
tightly bound metals with EDTA.




















Methods to remove chelated or complexed metals.

I  have listed various methods that I use when trying  to  remove
chelated  or complexed metals. Do not assume that these  are  the
only  ways  to accomplish the removal. These are  meant  only  as
guidelines. If in trouble, consult your water treatment supplier.
They are listed in order of simplicity and economy.


A. Inorganic Coagulant (Calcium Chloride, Polyhydroxyalumina, etc.)
     1. add inorganic coagulant at 100-2000 ppm.
     2. pH to 9-10.
     3. add organic flocculent (Anionic or Cationic).


B. Organic or alloyed Coagulant (typically low wt. Cationic)
     1. add organic coagulant (dosages may vary).
     2. pH to 9-10.
     3. add organic flocculent (Anionic or Cationic).


C. Ferrous Sulfate
     1. add Ferrous Sulfate at pH of 3-4 (dosages may vary).
          a. 10-1000 ppm Cu = ppm 8X Ferrous Sulfate.
          b. above 1000 ppm Cu = 1:1 Ferrous Sulfate.
     2. react at least 5 minutes.
     3. pH to 9
     4. add organic flocculent (Anionic).


D. Carbamates (MRA-1)
     1. pH 7-9
     2. add chemical in following ratio per 1000 ppm of total
        metal ion:
          a. Cr = 46X (hex-valent) Not recommended, reduce first
          b. Cr = 23X (tri-valent)
          c. Ni = 14X
          d. Cu = 13X
          e. Zn = 12X
          f. Cd =  7X
          g. Pb =  5X
          h. Ag =  4X
     3. react (mix) for 1 hour.
     4. add flocculent.

If  chelation  is a real problem, methods C & D may be  the  only
viable  options.  Other  methods using other  chemicals  such  as
Xanthatates  and Permanganates have been used. My experience  has
shown that they generally do not provide better or safer  results
than the listed methods.





Flocculents
Following  coagulation  a flocculent is often  added.  These  are
invariably synthetic polymers of medium to high molecular weight.
These polymers are classified by their ionic charge into:
          a. anionic - negatively charged
          b. cationic - positively charged
          c. nonionic - neutral charge (usually slightly anionic)
          d. amphoteric - capable of developing either a positive
             or negative charge depending on environment.
Flocculents while classified as to ionic charge, do not  function
as  neutralizers  like coagulants. Their primary function  is  to
provide  an  effective bridging mechanism through  adsorption  or
entrapment of the coagulated particles. This produces the  large,
heavy  floc which speeds the settling process. In simpler  terms,
the flocculent acts as a glue to collect, and adhere to particles
that  have  been coagulated, so that they gain enough  weight  to
settle.  They permit the higher throughput rates often needed  in
production  situations.  The adsorption of  suspended  solids  is
primarily  a  mechanical  process  as  opposed  to  the  chemical
reaction  of  coagulation. This is why longer, slower  mixing  is
used to prevent the mechanically bonded floc from breaking up  or
shearing.  The table below will show you why we want to  increase
the  size  of  the floc from  "micro-floc"  to  "macro-floc"  for
settling purposes. Small particles require longer settling times.
By increasing particle size, you decrease settling time, allowing
faster process times or flows.

        Diameter of      Typical        Time required to
         particle (mm)   description    settle one foot
         10              gravel               0.3 sec.
          1              sand (coarse)        3.0 sec.
          0.1            sand (fine)         38   sec.
          0.01           silt                33   min.
          0.001          bacteria            55   hrs.
          0.0001         colloid part .     230   days
          0.00001        colloid part.      6.3   yrs.
          0.000001       colloid part.      63+   yrs.

The  most  common  flocculent seen in  an  industrial  wastewater
system  is an anionic polymer of high molecular weight. They  are
commonly  delivered  in  two forms.  Emulsion  systems  have  the
advantage of being able to be used with little mixing or make  up
time. They can be fed directly from drums or bulk into  equipment
(i.e.  Stranco  or similar units) that will dilute  and  mix  the
material  to the proper use concentration. Dry polymers  must  be
mixed  well  in  advance and may require from 4 to  24  hours  of
mixing prior to use. They must usually be mixed into a  temporary
holding  area  or what is commonly referred to as a  "day  tank".
Typically a 0.25 - 0.5% solution is made. That means if the  tank
holds 50 gallons and it was empty you would mix in .25 gallons of
the liquid polymer or .25 lbs of a dry polymer. This solution  is
then  metered  into  the system  holding  the  coagulated  water.
Dosages  must  be  determined with proper  testing,  but  typical
starting  points  would be 1-20 parts per million  (ppm)  of  the
dilute polymer.

The  coagulated,  flocculated  water  will  then  pass  into  the
sedimentation  or  clarification phase. As  the  aggregated  floc
settles,  the clarified water can be separated from the  sediment
more commonly known as sludge. The process is not 100% efficient.
Treated  water  will still contain some suspended matter  in  the
form of carryover flocs.

Many   different   pieces   of  equipment   are   available   for
clarification. Circular clarifiers and Lamellas made in a  number
of design variations and by many manufacturers are on the market.
Each  one claims to have it's own attributes such as  efficiency,
ease  of  maintenance, space requirements or  economy.  They  all
share  the same basic principle of slowing the flow of liquid  to
allow  the heavier particles to settle out as sludge.  The  water
then  goes  to other treatment such as polishing  filters  or  to
discharge.  The  sludge is then collected and usually sent  to  a
dewatering device.






































Once the clarification and/or filtration has taken place and  the
sludge has been collected, economics of disposal dictate that  as
much  water  as  possible be  removed  to  facilitate  subsequent
processing or disposal. Disposal costs are based on volume rather
than  weight,  so the drier cake means that you are  sending  out
(and paying for) less water shipped with the sludge.

Centrifuges have been used for liquid/solids separation for  many
years. They are relatively inexpensive, compact and can have high
throughput capacities. The downside of centrifuges are that  they
are relatively high maintenance items, not neccesarily  efficient
and must be very carefully selected for each application.

Bag  filters are sometimes seen as final sludge  treatment.  They
are  very attractive in initial cost, but usually do not  provide
the percentage of solids neccesary for economical disposal.   The
cost  of  the  bags or media must also be weighed  on  an  annual
basis. These systems are usually best for very low volume systems
as their cost to purchase, can quickly be offset by their cost to
operate.

Media  filters have been used in some applications. These can  be
had  in  a variety of forms with a number of features.  They  can
automatically  index the media, draw a vacuum through  the  media
and can optionally apply heated air to the filtered material.  As
in  bag  filters, the cost and disposal of the  media  should  be
carefully analyzed for the specific application.

Rotary  drum  filters  can  offer  some  unique  advantages  when
processing  sludges.  A perforated tubular drum  is  "precoated".
Precoating is a procedure that is sometimes used with  filtration
devices.  Usually when a pre-coat is done it entails the  use  of
Diatomecous  Earth, more commonly known as Clay, applied  to  the
filter  media. This will achieve a higher percentage  of  solids,
but you must remember, you are also preloading it with solids.  A
vacuum  is  applied to the center of the rotating  drum  and  the
sludge is fed onto and coats the precoat. It is then scraped  off
with  a  blade that indexes in a few thousandths of an  inch  per
revolution.  Recently  units as I have described have  been  used
with  precoat  materials such as coal fines, that  add  BTU's  to
sludges   that   can  be  directly   incinerated   (i.e.non-metal
containing paint sludges).

Filtration of sludge in an industrial application, usually  means
a  plate and frame filter press. They are  relatively  efficient,
maintenance  free  and  produce a fairly  dry  filter  cake.  The
disadvantages are that they are usually higher in initial cost.







Sludge  Dryers  have come on the market recently. They  can  take
your  sludge coming out of a filtration device at  10-40%  solids
and  dry  it to 60% or more. There are a number of units  on  the
market  utilizing  different  technologies.

Key  elements when considering one of these units are, what  will
it  do with my sludge, how does your regulatory agency  view  the
equipment   and  who  else  is  using  the  particular  piece  of
equipment you are looking at?















































In   order  to  obtain  consistent  results  without   continuous
adjustments  in  chemical  feed it is  important  to  supply  the
treatment  system  with  a well mixed, homogeneous  feed  of  the
solutions  to be treated. When placed in holding tanks  solutions
tend  to  stratify rendering the chemical dosages used  when  the
tank  is full, versus half full, inaccurate. At best  this  means
poor  economy,  at worst - discharge violations. For  these  same
reasons,  we  must periodically sample  and  test  representative
samples  of the effluent to be treated. This testing need not  be
formal  once you have established a track record. After  learning
what  to look for it can usually be "tested" by simply drawing  a
beaker of the solution and observing it. This procedure should be
done  frequently. It is easy, quick and can avoid  many  problems
before they get out of hand.









































Basic  procedures  are  available for testing  of  untreated  and
treated  wastewater.  According to the EPA "it is  impossible  to
determine coagulant dosages from theoretical calculations".

Trouble shooting is accomplished by running down methodical trial
and  error  procedures  versus  a  "shotgun"  or  "let's   change
everything approach".

Using these methods, identification of the equipment, procedures,
chemicals and dosages needed to treat your waste stream should be
a little easier.

Jar Testing

Required equipment and materials are as follows:

          1. gang stirrer or jar tester.
          2. standard beakers to fit the machine.
          3. samples of the water to be treated. (approx. 1 gal.)
          4. samples of the materials being used to treat the
             wastewater, in the state of dilution that they are
             being used.
          5. a method of determining pH.

The actual procedure is quite simple although care must be  taken
to  run  the test carefully and accurately so  that  results  are
meaningful  and reproducable. Before doing any physical  testing,
try to determine the process parameters so that you can duplicate
the actual process as closely as possible.

          1. Place an equal and appropriate amount of the
             material to be tested in each of the beakers.

          2. Start the machine at high speed (usually 80-100
             R.P.M.). This is the flash mix phase where treatment
             chemicals are introduced. They should be added
             quickly and in the proper order. (pH adjust first,
             followed by inorganic and/or organic coagulants) Add
             various concentrations (say 0.2 - 2.0 ppm) to each
             while maintaining one as a "control" with nothing
             added.

          3. When one minute has elapsed after chemical addition,
             slow the mixer speed to approximately 30-40 R.P.M.
             Add final chemicals or flocculents if needed. Run
             for three minutes and then drop to 10 R.P.M. for 15
             minutes.

          4. At the end of the 15 minute period, lift out the
             paddles and allow to settle for at least 10 minutes.





When finished with the jar test, the following information should
be recorded:
          1. Date and time.
          2. Raw water analysis. (pH, color, tss, etc.)
          3. Chemical dosages and procedure.
          4. Time of first visible floc.
          5. Settling time during 10 R.P.M. stage.
          6. Appearance of treated water clarity and floc.

(At  this  point 3-4 samples of the same waste  would  be  tested
showing the advantages and disadvantages of different  chemicals,
pH ranges, settling rates, filtrate, etc.)

Thickening test

          1. Add slurry to a 1000 ml. graduated cylinder.

          2. Add flocculent.

          3. Gently mix contents by inverting several times or
             using a plunger.

          4. After mixing, record settling time.

          5. Use the same procedure for all tests, varying
             flocculent dosage and type to obtain best practical
             dosage rate.

(This test procedure can also be used for clarification testing.)

Buchner Filtration Test

          1. Attach a Buchner funnel and vacuum flask to a vacuum
             source.

          2. To 200 ml. of sludge add 0.5% flocculent.
             (% by weight of sludge)

          3. Mix gently, preferably by pouring from one beaker to
             another, four or five times.

          4. Pour the coagulated sludge into the funnel and apply
             vacuum. Vacuum should simulate that applied in the
             plant.

          5. Measure the filtration efficiency by recording the
             time required to obtain a break in the vacuum.
             Alternate methods involve measuring the time
             required to collect a given volume of filtrate or
             filtrate collected in a given period of time.




Filter Leaf Test

The  filter  leaf  test, using a 0.1  square  foot  filter  leaf,
provides  more  sophisticated data and a check  on  the  previous
technique. Briefly the test involves immersing the leaf into  the
slurry for a specified time to pick up cake.

          1. Place leaf in slurry for one minute (vacuum applied)
             to pick up cake.

          2. Remove leaf from slurry, hold upright, allow cake to
             drain for two minutes.

          3. Remove vacuum and measure cake thickness.

          4. Remove cake from leaf and weigh.

          5. Dry cake in oven and weight to determine moisture
             content.

          6. Measure filtrate volume and note clarity.



































This list is not meant to be all inclusive. It is constructed  to
help  you get out of immediate trouble or to buy enough  time  to
call in some help.



                 OBSERVATION RESPONSE PROCEDURES

Metals not removed -

1. Errors in jar tests, chemical additions, or flow rates.
Corrective  Action:   Check  jar  tests  for  incorrect  chemical
additions and/or dosages.

2. The pH is off prescribed range.
Corrective Action: See pH.

3. Chelated metal compounds exist in the influent.
Corrective Action: Check jar tests for incorrect chemical type,
additions points and/or dosages.

Cloudy effluent -

1. Clarifier overflow rate is too high.
Corrective Action: Reduce system flow rate.

2. Floc is too fine and light to settle out of the wastewater.
Corrective  Action:   Check  jar  tests  for  incorrect  chemical
additions and/or dosages.

3. Sludge blanket is too deep and becoming mixed with wastewater.
Corrective  Action: Drop the sludge blanket level, do NOT  remove
the entire blanket!

4. Surfactant cloud point has been reached due to temperature.

pH Problems -

1. Effluent pH is too high.
Corrective Action: Check pH probe, controller, meter and chemical
source.

2. Effluent pH is too low.
Corrective Action: Check pH probe, controller, meter and chemical
source.

Poor Sludge Quality -
1. Overpumping from clarifiers.
Corrective  Action:  Adjust duration and/or frequency  of  sludge
pump(s) from clarifier.

2. Overpumping from Thickener.
Corrective  Action:  Adjust duration and/or frequency  of  sludge
pump(s) from clarifier.
3. Sludge blanket has been removed from clarifier.
Corrective  Action:  Adjust duration and/or frequency  of  sludge
pump(s) from clarifier.

4. Sludge conditioning and chemical additions are not correct.
Corrective  Action:   Check  jar  tests  for  incorrect  chemical
additions and/or dosages.

5. Soupy or wet sludge discharging from the Filter press.
Corrective  Action:   Check  jar  tests  for  incorrect  chemical
additions  and/or dosages or Filter press is not full at  end  of
cycle.

6. Sticky sludge from Filter press.
Corrective  Action:  Oil  or  live  paint  carry  over  from  the
treatment  process.  Check skimmers, separators,  clarifiers  and
chemical dosages.

Polymer lumps or "Fish Eyes" -

1. Non-potable water is not flowing into the disperser properly.
Corrective Action: Check the polymer disperser.

2. Polymer feed or concentration is off prescribed dosage.
Corrective  Action:  Check  dilution and  flow  calculations.  If
correct   consult   equipment  manual  or  supplier   on   proper
preparation procedures.

3. Inadequate mix time or dilution ratios.

Effluent flow variations (large fluctuations) -

1. Flow meter not operating properly.
Corrective Action: Check and repair if necessary.

2. Process transfer pump(s) not operating properly.
Corrective Action: Check and repair if necessary.

Sludge squeezing from filter press during filling operations -

1. Press plates not properly aligned.
Corrective Action: Check, align and repair if necessary.

2. Cake residue on press or plates.
Corrective  Action: Clean plates between cycles and  leave  press
closed when not in use.

Residue on Filter press -

1. Sticky sludge with high oil or live paint content.
Corrective Action: See Sticky sludge.

System failure for no apparent reason -
1. Gremlins, Extra terrestrials or Possession.
Corrective Action: Exorcism.



Included  in  this section but applicable to all aspects  of  the
wastewater system is safety. Most are common sense, but should be
reviewed periodically to prevent becoming overlooked.

Wastewaters  can cause irritation to skin on contact. The use  of
protective  equipment  such as rubber gloves and  eye  protection
should be implemented at all times.

Ladders,  railings and platforms should be  checked  periodically
for security and stability.

Make sure obstructions are marked to prevent hitting ones head.

When  working  on  or over equipment never do  it  alone.  If  an
accident  should  occur,  the  odds  are  better  if  someone  is
available to help or call for help.

Many polymers become very slippery when wet. Therefore in case of
a spill do not try to wash them down with water. Use an absorbent
such as oilsorb, vermiculite or sawdust.

































Another  point  to consider in operation of your  system  is  the
utilization of your vendors. Demand the performance that you  are
paying for. They can (or should be able to) describe how a  piece
of equipment works or  how to determine the correct chemical  and
dosage  for your system. They should also be able to  communicate
with you, in terms you understand.

It  is important to remember that wastewater treatment is not  an
exactly always scientific.  The definition of  scientific is that
which "agrees with the rules, priniciples, or methods of science;
accurate;   systematic;  exact.  In  other  words,  to  fit   the
definition  it must follow a set of rules. Industrial  wastewater
treatment  does not fit this definition. The more experience  you
have, the more you will come to find that if you give me a set of
rules, I can break them, especially with flocculents. That is why
testing is essential to determine if what you have set out to  do
has, in fact, been accomplished.













































ACTIVATED  CARBON:  Carbon which is treated by  high  temperature
heating with steam or carbon dioxide producing an internal porous
particle structure.

AERATION TANK:  A vessel for injecting air into the water.

ALUM:   A  hydrated  aluminum  sulfate  (A12  (SO4)3  14  H2O  or
potassium  aluminum  sulfate or ammonium  aluminum  sulfate.   It
contains 9.1% aluminum.

ANAEROBIC BIOLOGICAL TREATMENT:  Any treatment method or  process
utilizing  anaerobic or facultative organisms, in the absence  of
air, for the purpose of reducing the organic matter in wastes  or
organic  solids  settled  out from  wastes.  Typically  found  in
municipal waste treatment.

ANION:  Ion with a negative charge.

ANIONIC: Containing a negative charge or charges.

BACKWASHING:  The process of cleaning a rapid sand or  mechanical
filter by reversing the flow of water.

BACTERIA:  Microscopic living cells which are biologically  close
to plants and range in size from 0.2 to 2.0 microns.

BACTERICIDAL:  Bacteria-destroying.

BAFFLES:   Deflector  vanes, guides, grids, gratings  or  similar
devices constructed or placed in flowing water or sewage.

BIOCHEMICAL  OXYGEN  DEMAND  (BOD):   A  measure  of  the  oxygen
required  to  oxidize  the  organic  material  in  a  sample   of
wastewater   by  natural  biological  processes  under   standard
conditions.   This test is presently universally accepted as  the
yardstick  of pollution and is utilized as a means  to  determine
the  degree of treatment in a waste treatment  process.   Usually
given in mg\l or ppm units, meaning milligrams or oxygen required
per  liter of wastewater, it can also be expressed in  pounds  of
total oxygen required per wastewater or sludge batch.

BIOCIDE:  Pesticide.

BOD:  See BIOCHEMICAL OXYGEN DEMAND.




BULKING:   A  phenomenon that occurs in activated  sludge  plants
whereby  the  sludge  occupies excessive  volumes  and  will  not
concentrate readily.

CATION:  Ion with a positive charge.

CATIONIC: Containing a positive charge or charges.

CENTRATE:  Liquid discharged from a centrifuge.

CENTRIFUGE CAPACITY FACTOR:  Bowl area expressed as the area of a
gravity settling tank with an equivalent clarification capability
with that of the centrifuge.

CHEMICAL OXYGEN DEMAND (COD):  The amount of oxygen required  for
the chemical oxidation of organic matter in a liquid.

CHLORINATION:   The application of chlorine to water,  sewage  or
industrial wastes, generally for the purpose of disinfection, but
frequently   for  accomplishing  other  biological  or   chemical
results.

CLARIFICATION:   Process  of  removing  turbidity  and  suspended
solids by settling.  Chemicals can be added to improve and  speed
up the settling process through coagulation.

CLARIFIER:  A settling tank.

CLAYS:   Aluminum silicates less than 0.002mm (2.0 um)  in  size.
Therefore, most clay types can go into colloidal suspension.

CLUMPING: A term coined by John Lindstedt of Artistic Plating  to
denote good floc formation. (i.e. "it clumps up nicely")

COAGULATION:  The clumping together of solids to make them settle
out  of solution faster.  Coagulation of solids is brought  about
with  the  use  of  certain chemicals,  such  as  lime,  alum  or
polymers.

COAGULATION  CHEMICALS:   Hydrolyzable  divalent  and   trivalent
metallic  ions  of  aluminum (Al3+), magnesium  (Mg2+)  and  iron
(Fe3+)  salts.  They include alum ( aluminum sulfate:  Al2  (So4)
3.14  H20),  quicklime  ( calcium oxide:  CaO)2),  sulfuric  acid
(H2SO4), anhydrous ferric chloride (FeC13).  Lime and acid affect
only   the   solution   pH  which  in   turn   causes   coagulant
precipitation, such as that of magnesium.

COAGULATION    AND   FLOCCULATION:    Processes   which    follow
sequentially  and  are distinguished primarily by  the  types  of
chemicals used for their initiation and the size of the particles
developed.   Coagulation  is the conversion of  finely  dispersed
colloids  into small floc upon the addition of electrolytes  such
as inorganic acids, bases and salts.

COLLOID:   A finely divided dispersion of one  material  (0.01-10
micron-sized  particles), called the "dispersed phase"  (solids),
in  another  material called the  "dispersion  medium"  (liquid).
Normally negatively charged.

CONCENTRATION:   The  total mass of the  suspended  or  dissolved
particles  contained in a unit volume at a given temperature  and
pressure.

CONTAMINATION:   A general term signifying the introduction  into
water  of  microorganisms,  chemicals,  wastes  or  sewage  which
renders the water unfit for its intended use.

DEALKALIZING:   The  ion exchange process for  the  reduction  in
alkalinity caused by the salts of weak acids.

DEMINERALIZATION:  The total removal of all ions.

DEWATERING:  Process used to reduce the water content of  sludges
to the level that they can be handled as damp solids rather  than
liquids.

DISINFECTION:  The process of killing the larger portion (but not
necessarily all) of the harmful and objectionable  microorganisms
in or on a medium.

DISSOLVED  OXYGEN (D):  The oxygen dissolved in sewage, water  or
other  liquids, usually expressed either in milligrams per  liter
or   percent  of  saturation.   It  is  the  test  used  in   BOD
determination.

DISTILLATION:  Vaporization of a liquid followed by  condensation
of the vapor.

EFFLUENT:   A  liquid which leaves a unit operation  or  process.
Process  water or other liquids, partially or completely  treated
or  in  their natural states, flowing out of a  reservoir  basin,
treatment plant or any other unit operation.  An influent is  the
incoming stream.

EMULSIFIER:   An  emulsion stabilizer (soap in case  of  oil  and
water).

EMULSION-STABLE:   A heterogeneous system consisting of at  least
one  immiscible  liquid  dispersed  in another  in  the  form  of
microscopically visible droplets.

EXCELL:  A patented form of stabilized Chlorine Dioxide  used  to
treat  potable and industrial waters, inhibit  bacterial  growth,
improve  taste,  sanitize and control odor. It also has  uses  in
the  reduction  of  Cyanide and the break down  of  Phenols.  EPA
registration No. 9150-3. EPA establishment No. 9150-R.I.-58700H1.



FERMENTATION:  The process carried out by microorganisms that can
partially decompose organic compounds into lower molecular weight
acids or alcohols.

FERRIC CHLORIDE:  Anhydrous ferric chloride (FeC13) is a chemical
coagulant.  Ferric ions are Fe3+ and ferrous ions are Fe2+.  Both
are used in phosphorus precipitation.

FILTRATE: Liquid discharged from a filter.

FLOC: Particulate matter that has been agglomerated. Whether  the
agglomeration  has proceded enough to be called floc is a  matter
of individual judgement.

FLOCCULENTS:  Those water soluble organic polymers that are  used
alone or in conjunction with inorganic coagulants to  agglomerate
solids. The large dense flocs resulting from this process  permit
rapid and more efficient solids-liquid separations.

FLOCCULATION:  The formation of flocs. The process step  followed
by   the   coagulation-precipitation   reaction.   It   is    the
agglomeration  by organic polymers of the small, slowly  settling
particles formed during coagulation and/or neutralization.

GANG MIXER: A multiple unit stirrer. See JAR TEST.

HEAVY  METALS:  the general term used for the  ions  of  metallic
elements, such as Copper, Zinc, Nickel, Chrome and Lead. Commonly
removed  from the waste stream by the formation of  an  insoluble
precipitate, usually in the form of a metallic hydroxide.

INFLUENT:  The  influent is the stream  entering  the  wastewater
treatment system.

INORGANIC: Compounds not containing carbon. Non plant or animal.

MACRO-FLOC:  The  stage  of  flocculation  when  large,   rapidly
settling particles are present.

MICRO-FLOC:   The  stage  of  flocculation  when  small   visible
particles have started to form.

MILLIGRAMS  PER  LITER: This is a weight per  volume  measurement
used in water and wastewater analysis. It is interchangable  with
"parts per million" (ppm)

ORGANIC: Compounds containing carbon. Plant or animal matter.

PARTS PER MILLION:  This is a weight per volume measurement  used
in  water  and  wastewater analysis. It  is  interchangable  with
"milligrams per liter". Chemical dosages are often referred to as
parts per million, i.e. 150 ppm of polymer.



PINFLOC: See micro-floc

POLYELETROLYTES:  A  term  used to  describe  any  water  soluble
organic polymer.

POLYMER(S):  Synthetic  chemicals used  to  improve  coagulation,
flocculation and settling in waste water treatment systems.

PRECIPITATE: An insoluble solid that separates from a solution.

PRECIPITATION: The phenomenon which occurs when a substance  held
in solution passes out of that solution into solid form.

RETENTION  TIME:  Volume of the vessel divided  by  the  flowrate
through the vessel.

SLUDGE BLANKET: An accumulation of solid matter hydro-dynamically
suspended  within  an  enclosed  body of  water,  such  as  in  a
clarifier.

SLUG: A large "dose" of chemicals or a chemical treatment that is
applied internally or at one time.

SUPERNATE: The liquid standing above a sediment or precipitate.

SUSPENDED  SOLIDS:  The wastes that will not sink  or  settle  in
wastewater.

SUSPENSION:  Very small particles which are  uniformly  dispersed
throughout a liquid such as water.

SYNERGISM:  The  improvement  in performance  achieved  when  two
agents are working together.

THRESHOLD TREATMENT: Minimum quantity of chemicals to prevent  an
unfavorable chemical reaction from taking place.

TOTAL SOLIDS: The total amount of solids in a wastewater both  in
solution and suspension.

VOLUME SOLIDS: Solids content based on volume.

WEIGHT SOLIDS: Solids content based on Weight.













Absorbent, 19
Accuracy, 2
Acid, 4, 5, 6, 22
Acidity, 4
Acids, 3, 22, 23, 24
ACTIVATED, 21, 22
Adsorption, 9
AERATION, 21
Agglomeration, 5, 24
Agitation, 5
Alkalinity, 4, 5, 6, 23
Alkalis, 3
Alloyed, 5, 6, 8
Alum, 5, 6, 21, 22
Aluminate, 5, 6
Aluminum, 5, 21, 22
Ammonia, 7
Ammonium, 21
Amphoteric, 9
ANAEROBIC, 21
Analysis, 15, 24
ANION, 21
Anionic, 8, 9, 21

BACKWASHING, 21
Bacteria, 3, 9, 21
Bacterial, 23
Bacteria-destroying, 21
BACTERICIDAL, 21
BAFFLES, 21
Bags, 11
Bases, 22
Batch, 4, 21
Bentonite, 6
BIOCHEMICAL, 21
BIOCIDE, 21
BIOLOGICAL, 21, 22
Blanket, 17, 18, 25
BOD, 21, 23
Bound, 7
Break, 6, 7, 15, 20, 23
Bridging, 9
BTU's, 11
Buchner, 15
Buffers, 4
BULKING, 22

Calcium, 3, 7, 8, 22
Calculations, 14, 18
CaO, 22
Carbamates, 7, 8
CARBON, 21, 24
Carryover, 10
CATION, 22
Cationic, 8, 9, 22
Caustic, 4, 5
CENTRATE, 22
Centrifuge, 22
Centrifuges, 11
Charge, 5, 9, 21, 22
Chelated, 7, 8, 17
Chloride, 5, 7, 8, 22, 24
CHLORINATION, 22
Chlorine, 22, 23
Chrome, 24
Clarification, 3, 5, 6, 10, 11, 15, 22
Clarifier, 17, 18, 22, 25
Clarity, 15, 16
Clay, 6, 11, 22
CLAYS, 22
Cleaners, 6
Cloudy, 3, 17
Coagulant, 5, 6, 8, 14, 22, 24
Coagulated, 9, 10, 15
Coagulation, 3, 4, 5, 9, 22, 24, 25
COD, 22
Colloid, 3, 9, 23
Colloidal, 22
Complexed, 7, 8
Concentration, 9, 18, 23
Conditioning, 2, 4, 18
Consistency, 2
Consistent, 13
CONTAMINATION, 23
Controller, 4, 17
Conversion, 22
Coolants, 6
Copper, 7, 24
Copperas, 5
Corrective, 17, 18
Corrosive, 6
Cost, 4, 7, 11
Cr, 8
Cu, 8
Cyanide, 23

DEALKALIZING, 23
Deflector, 21
DEMINERALIZATION, 23
Deposits, 7
Destabilize, 5, 6
Dewatering, 1, 2, 3, 4, 10, 23
De-emulsification, 6
Diatomecous, 11
Dilute, 9
Dilution, 14, 18
Dimer, 5
Dioxide, 21, 23
Disadvantages, 6, 11, 15
Discharge, 10, 13
Disinfection, 22, 23
Dispersion, 23
Disposal, 11
Dissolved, 23
DISTILLATION, 23
Dosage, 15, 18, 20
Dosages, 8, 9, 13, 14, 15, 17, 18, 24
Dose, 25
Drier, 11
Drum, 11
Drums, 9
Dry, 9, 11, 12, 16
Dryers, 12

Economics, 11
Economy, 8, 10, 13
EDTA, 7
Efficiency, 10, 15
Effluent, 13, 17, 18, 23
Electrolytes, 22
Elements, 12, 24
Emulsion, 6, 9, 23
EMULSION-STABLE, 23
Entrapment, 9
Envelope, 6
EP, 4
EPA, 14, 23
Equipment, 6, 9, 10, 12, 14, 18, 19, 20
EXCELL, 23

FACTOR, 22
Facultative, 21
Fe, 22, 24
Feed, 13, 18
FERMENTATION, 24
Ferric, 5, 22, 24
Ferrous, 5, 8, 24
Filtration, 11, 11, 12, 15
Floc, 6, 9, 10, 15, 17, 22, 24
Flocculent, 8, 9, 15
Flocculents, 6, 9, 14, 20, 24
Flocs, 10, 24
Flowrate, 25
Fluctuations, 18

Gang, 14, 24
Gluconates, 7
Gravity, 22
Grease, 5, 6

Hectorite, 6
Heterogeneous, 23
Hex-valent, 8
Hydroxide, 4, 5, 24
Hydro-dynamically, 25

Immiscible, 6, 23
Incinerated, 11
Influent, 17,sRJC    1725...       0...       0...       0...       0...       0...       0...       0...       0...       0
Ionic, 9
Ions, 7, 22, 23, 24
Iron, 5, 22

Jar, 14, 15, 17, 18, 24

Lamellas, 10
Landfill, 6
Lead, 24
Leaf, 16
Lime, 4, 5, 22
Lumps, 18

Macro-floc, 9, 24
Magnesium, 3, 4, 22
Maintenance, 10, 11
Media, 11
Metallic, 3, 7, 22, 24
Metals, 4, 7, 8, 17, 24
Mg, 21, 22
Microns, 21
Micron-sized, 23
Microorganisms, 23, 24
Micro-floc, 9, 24, 25
Milligrams, 21, 23, 24
Minerals, 3
Mixing, 9, 15
Ml, 15
Molecular, 9, 24
Molecules, 7
Monomer, 5
MRA, 8

Negative, 9, 21
Neutral, 9
Neutralize, 5
Ni, 8
Nonionic, 9
Non-hazardous, 6
Nucleus, 6

OBSERVATION, 17
Odor, 23
Oils, 5
Oilsorb, 19
Organic, 5, 6, 7, 8, 14, 21, 22, 24, 25
Organics, 6
Overdose, 4
Oxidize, 21
OXYGEN, 21, 22, 23

Paint, 3, 11, 18
Particle, 5, 6, 9, 21
Pb, 8
Permanganates, 7, 8
Pesticide, 21
PH, 4, 5, 6, 8, 14, 15, 17, 22
Phenols, 23
Phosphorus, 24
Pinfloc, 5, 25
Plating, 22
Polishing, 10
Polyamines, 6
POLYELETROLYTES, 25
Polyhydroxyalumina, 6, 8
Polymer, 5, 6,7, 9, 18,19,22, 24, 25
Polyquats, 6
Positive, 9, 22
Potable, 23
Potassium, 21
Ppm, 8, 9, 14, 21, 24
Precipitation, 1, 7, 22, 24, 25
Precoat, 11
Press, 11, 18
Probe, 4, 17

Reagent, 7
RESPONSE, 17
RETENTION, 25

Safety, 2, 19
Salts, 5, 22, 23
Sand, 9, 21
Science, 20
Sedimentation, 2, 3, 10
Settling, 4, 6, 9, 15, 22, 24, 25
Silicates, 22
Silt, 9
Skimmers, 18
Sludge, 4, 6, 7, 10, 11, 11, 12, 15, 17, 18, 21, 22, 25
SLUG, 25
Slurries, 6
Soap, 23
Sodium, 4, 5, 6
Solids, 5, 9, 11, 12, 21, 22, 23, 24, 25
Soluble, 5, 24, 25
Solution, 5, 7, 9, 13, 22, 25
Solutions, 6, 7, 13
Stabilized, 23
Stirrer, 14, 24
Stranco, 9
Stratify, 13
Sulfate, 5, 8, 21, 22
Sulfates, 7
Sulfuric, 4, 22
Summary, 2
SUPERNATE, 25
Supplier, 7, 8, 18
Surfactant, 17
Suspended, 3, 5, 9, 10, 22, 23, 25
SYNERGISM, 25
Synthetic, 5, 7, 9, 25

Testing, 2, 4, 7, 9, 13, 14, 15, 20
Tests, 15, 17, 18
Thickener, 17
Thickening, 15
THRESHOLD, 25
Tri-valent, 8
Tss, 15
Turbidity, 3, 22

Um, 22

Vacuum, 11, 15, 16
Vermiculite, 19
Visible, 5, 15, 23, 24
Volume, 4, 6, 11, 15, 16, 23, 24, 25

Wastes, 21, 22, 23, 25
Wastewater, 3, 7, 9, 14, 17, 19, 20, 21, 24, 25

Xanthatates, 8

Zinc, 24
Zn, 8
Zone, 5

                                                        10/88