Industrial Wastewater Treatment

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Industrial Wastewater Treatment

• MetcalfEddy 2004 Wastewater Engineering
  Treatment and Reuse. McGraw-Hill
• ???? ?????????????? (2542)????????????????????????
  ? ????????????????????????????
• Eckenfelder W.W. (2000) Industrial water
  pollution control. McGraw-Hill
• Sung S. Handouts ????????????????????? Anaerobic
  Treatment

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Undesirable industrial wastewater characteristics

• Causing DO depletion
• Suspended solids
• Industrial pollutants, e.g. phenol, causing
  tastes and odour in water and are carcenogenic
• Heavy metals, CN-, and toxic organics
• Color and turbidity, e.g. textile, pulppaper
  industries

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Undesirable industrial wastewater characteristics
(cont.)

• N and P causing eutrophication
• Recalcitrant substances, e.g. N compounds found
  in the textile industry, are toxic
• Oil and floating material causing unsightly
  conditions
• Volatile materials, e.g. H2S and volatile
  organics, creating air-pollution problems
• Aquatic toxicity

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Sources of industrial wastewater

• Domestic wastewater
• Process wastewater
• Cooling wastewater once pass or multiple recycle
  system

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Variation of industrial wastewater

• Volume and strength of industrial wastewater are
  usually defined in terms of units of production,
  e.g. m3/ton of pulp and kg BOD/ton of pulp for a
  pulp and paper mill waste
• Variation depends on the diversity of products,
  process operations contributing waste, operations
  batch or continuous

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Solid Matrix
TS TSS TDS

VS VSS
VDS
TFS FSS FDS
particulate organic
soluble organic
soluble inorganic
particulate inorganic
salts
sand, silt
T Total S Solids or Suspended D Dissolved V
Volatile F Fixed
Source Sung S. handouts
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Example Molasses
Source Sung S. handouts

• CODtotal157430mg/l
• CODfiltered132450mg/l
• VFA5690mg/l
• TS158900mg/l
• VS128000mg/l
• TSS73670mg/l
• VSS59330mg/l
• TKN500mg/l
• NH4-N100mg/l
• pH3.59

TS TSS TDS

VS VSS
VDS
TFS FSS FDS
85230
158900
73670
128000
59330
68670
30900
14340
16560
CODfiltered/CODtotal84 Low pH VS/TS80.6 Nut
rient requirement (COD/TKN) Ammonia/TKN0.2 Salt
content/ Grit removal
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Industrial wastewater treatment

• Pretreatment e.g. equalisation, neutralisation,
  oil and grease removal
• Primary treatment e.g. screening, grit removal,
  gravity sedimentation
• Secondary treatment e.g. activated sludge,
  trickling filter, incineration, chemical
  precipitation
• Tertiary treatment e.g. chlorination, carbon
  adsorption, ion exchange

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Types of treatment operation

• Physical operations
• Chemical processes
• Biological treatment

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?????????????????????????????? ? ???????????
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?????????????????????????????? ? ???????????
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Physical treatment

• Screening
• Skimming
• Flotation
• Grit chambers
• Equalisation
• Sedimentation

• Centrifugation
• Filtration
• Activated carbon adsorption
• Membrane filtration

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Screening

• ????????????????????????????????????????????????
  ???? ?????? ?????? ??????? ????
  ??????????????????????????????????????????
• ??????????????????????????????????????????????????
  ???????????? Sludge ????? Weirs
  ?????????????????? ??????????????
• Screening ???????????????????????? ?????????????
  ?????????????????????????????? ???????????????????
  ?????
• ?????????????? Unit ??????????????????????????????
  ???????????????????????????????????????????

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????????????????????????????
???????????????????
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Design of Screening
?????? ??????????? ??????????????
1. ??????? ??????? (??.) ??????? (??.) 4-8 25-50 8-10 50-75
2. ?????????????????? (??.) 25-75 10-50
3. ?????????????????? (????) 45-60 75-85
4. ??????????? (?./?.) 0.3-0.6 0.6-1.0
5. Head loss ????????? (??.) 150 150
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Skimming

• ????????????????????????????? ???? ?????? ????
  ???????
• Skimming tank ????????????????????????????? ?
  ????????????? ????????????????????????????????????
  ?
• ?????????????????????????????????
• ???????????????????????? 1-15 ????
  (????????????????????????? 3 ????/????

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Flotation

• ??????????????????? ??????????????????????????????
  ?????????????????????????????????????
• ?????????????????????????????????????????????????
  ???????????????????????? (Skimming)
• ?????????????????????????? ??? ???????????????????
  ????????????????????????????????????????
• ?????????????????? ???? FOG ??????????????????????
  ?????????????

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Dissolved-Air Flotation (DAF)
Dispersed-Air Flotation
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Grit Chambers

• Grit ??? ??????????????????????????????
  ?????????????????????? (SG1.5-2.7) ???? ????
  ???? ?????? ?????? ???????? ?????????? ?????????
  ??????? ???
• Grit ????????????????? 1) ????????????????????????
  ????????????????????????????????? 2)
  ????????????????????? ?????????? 3)
  ??????????????????????????????? Sludge Digester
  ??? ????????????????? 4) ??????????????? Inert
  Material ?????????????? ??? Sludge Digester
  ??????????????????????????????????

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?????????????? Proportional Weir
??????????????????? Grit Chamber

• ???????????????????????????????? Dia 0.21mm ???
  HRT 60 s, Horizontal Velocity 0.3m/s and Settling
  Velocity1730m3/m2.d ?????????????????????????????
  ???? ????????????

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• Aerated Grit Chamber ????????????????????????????
  ????????????? ?????????????????????????????? Grit
  ??????? ??????????????????????????????????????????
  (???????????)
• ???????? Aerated Grit Chamber 1)
  ????????????????????????????????????????
  CoagulationFlocculation 2)?????????? ??? BOD5
  ??????????????????????? 3) ???? Head Losses ????
  4) ?????????????????????????? Skimming 5)
  ?????????????????? Grit ?????????????????

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Equalisation

• ??????????????????????????????????????????????????
  ???????????????
• ??? Equalisation ?????????????????????????????????
  ??????????????????????????????????????????
  ????????????????????????????? ???????????????
  ??????????????????????????

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????????? Equalisation Basin

• ?????????? Equalisation Basin ????????????????????
  ???????????????? 10-20 ??????????????????????????
  ??????????????????????????? ??????????????????????
  ???????????????????????? ?????????????????????????
  ?????????????? ???????????????????????????????????
  ?
• ?????????????????? ??????????????????????????????
  31 ??? 21 ??????????????????????????????????????
  ?????????????????
• Mixing ??? Aeration ??????????????????????????????
  ????????????????? ??????????????????
  ????????????????????????? ????????????????????????
  ???? 0.004-0.008kW/m3 ????????????????????????????
  ??? 0.01-0.015m3/m3.min

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????????????????????????? Equalisation Basin
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Sedimentation

• Discrete settling
• Flocculant settling
• Zone settling
• Compression settling

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Primary sedimentation

• ?????????????????????????????????????????????
• ???????????? 1st Sedimentation ??????? Flocculant
  Settling ?????????????????????????
  ??????????????????? ?????????????????????
• ??????????????????????????????????????????
  Colloids ?????????????????????? ???? P, ????????
• Design parameters overflow rate, HRT
  ???????????????????????????????? Lab-scale

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???????????????????

• Horizontal Flow ????????? ?????? ??????????
  ??????? ???? ?????????????????????????????????????
  ????????, ?????????????????????????, hL ?????????
  ?????????, ????????????????????????????????
  ???????????? ???? ????????????????????????????????
  ??????????????????
• Solid Contact ?????????????????????????
  Horizontal Flow ??????????????????????????????????
  ?????????????????????????? ???????????????????????
  ????????? ????????????????? ?????????? Anaerobic
  ??????????????????? Sludge

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??????????????????? (???)

• Inclined Surface ????????????????????????????????
  ???? ???? ??????????????????????????????????????
  ??????????????????????????????? ??????????????
  Upgrade ????????????? Overloaded
• Stacked or Two-Tray ?????????????????????????????
  ?????????????????????
• Proprietary Systems ????????????????????????????
  ? ????????????????????????????????????????????????
  ?????????????????????? ? ???????

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???????????????????

• ???????????? Overflow rate, HRT, Weir-loading
  rate, ??????? ??????? (???), ?????????????
  ????????????????????????????????? (?? Design
  Criteria)
• ??????????????????? Overflow rate ???HRT
  ??????????? SS ??? BOD5

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Secondary sedimentation

• ??????????????????????????????????????????????????
  ???????????
• ??????????????????????????????????????
  ?????????????????????????????????????????? (Zone
  settling)
• ?????????????????????? Surface overflow rate
  (16-32 m3/m2-d), Solid loading rate (3.6-6.0
  kg/m2-hr) ??????????????? 3.5-5.0 ????
  ???????????????????????????????? Sludge
  ???????????????????

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Centrifugation

• ??????????????????????????????????????????????????
  
• ????????????????????????????????????
  Centrifugation ????? Solid ?????? 10-25
  ????????????????????????
• ?????????????????????????????????????????????????
  ????????????????? ????????? Solid ?????? 85-90

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Filtration

• ??????????????????????????????-???????????????????
  ??????????????????????????????????????????????????
  ?????
• ??????????????????????? 2 ??? ??? (1) Surface or
  cake filtration (???? ????????????, Filter press)
  (2) Depth filtration (???? ?????????????)

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• ??????????????? Filtration rate (5 ??? 10
  m3/m2-hr ?????? Rapid sand filter ??? High-rate
  filter ????????) ???????????????????????????????
  Media

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Activated carbon adsorption

• ???????????? ?????????????????????????????????????
  ?????????????????????????
• ???????????????????? Polishing ???????????????????
  ?????????????????
• ??????????????????????????????????????????????????
  ????? ??????????????????????????????
  ?????????????????????????????????????
  ???????????? ?????????? ??????????????????????????
  ???????????????????????????????????????????????
• ???????????????????????????? Isotherms

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Freundlich Isotherm
Langmuir Isotherm
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Membrane Filtration

• ??????????????????????????????????????????????????
  ???/???? ???????????????????? (0.0001-1.0 µm)
• ????????? Membrane ??????????
• Microfiltration (MF), Ultrafiltration (UF),
  Nanofiltration (NF), Reverse osmosis (RO),
• Dialysis
• ??? Electrodialysis (ED)

Pressure-driven
Diffusion
Electromotive force
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Osmotic Flow
Fw water flux rate, kg/m2.s, m/s kw water
mass transfer coefficient, s/m, m/s.bar ?Pa
average imposed pressure gradient, kg/m.s2,
bar ?p osmotic pressure gradient, kg/m.s2,
bar Qp permeate flow, kg/s, m3/s
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Membrane Configurations
Hollow Fiber
Tubular Modules
Spiral Wound
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Membrane Bioreactor