American Meat Institute Conference on Worker Safety, Human
Resources and the Environment Kansas City, Missouri
Brian Mulinix, P.E. Brian Bakke, P.E. HDR Engineering, Inc. March 20, 2013
Wastewater Design &
Best Practices
Overview
•
Wastewater – what are we treating
•
Preliminary Treatment
•
Anaerobic Treatment
•
Aerobic Treatment
•
Nitrogen Removal
•
Phosphorus Removal
•
Tertiary Treatment
•
BOD
5•
TSS
•
FOG
•
TKN
•
Phosphorus
•
Proteins
•
Fats
•
Carbohydrates
•
Partially-Digested
Feed
•
Manure
•
Urine
What Are We Treating?
OR
What are We Treating?
• Slaughterhouse
– Proteins (blood, meat, etc.)
– Fat
– Partially digested feed from stomachs and intestines
– Manure from pens
– Urine from pens, kidneys, bladders, etc.
• Processing
– Proteins
– Fat
– Carbohydrates
• Animal Feeding Operations
– Manure
– Urine
What Type of Food is Being Treated?
Example Protein Fat Carbohydrates
Slaughterhouse Processing
•Hams Some Some (from the pickle liquor)
•Bacon Little (from the pickle liquor)
•Cooked Sausage Little
•Chicken-Fried Steaks (from the breading)
Rendering
Pretreatment Can Shift Type of Food
•
DAF reduces fat and some protein
•
Ferric pretreatment greatly reduces both fat and
protein
•
Many carbohydrates
– Go into “true solution”
Determine Waste Loads from Food
•
Protein BOD
5= TKN x 6.25 x 0.8
•
Fat BOD
5= FOG x ( 1.7± )
•
Carbohydrate BOD
5=
Why is Type of Food Important?
•
Anaerobic Sludge Production
•
pH Buffering
– Proteins make their own alkalinity
– Fats and carbs require alkalinity for buffering
•
Nutrient Requirements
– Proteins are a complete food source
– Fats and carbs are deficient in nutrients and micronutrients
•
Different Physical Characteristics
– Fats may coat media, float
Fat Protein Carbs 1 1.5 - 2 4 - 5
Swine Farms are Slightly Different
•
Swine farm waste is similar to human waste without
the dilution water
•
Virtually everything has been through digestive or
urinary tract
•
Pigs have utilized much of readily-digestible food
(energy), leaving less easily-digestible to treat
What is Your Discharge Requirement?
•
Municipality
– Limits specific to system
– Surcharges
•
Land Application
– Agronomic rates•
Direct Discharge
– Effluent guidelines – Nutrient limitsScreening
•
Remove solid materials, prevent avoidable BOD
and TSS
•
Types:
– Static Screens – Vibrating Screens – Rotary Screens – Channel ScreensGravity Clarifiers
Removal BOD 20-30% TSS 30-40% TKN 10-20% FOG 50-60%Dissolved Air Flotation
Removal Without Chemicals With Chemicals BOD 30-40% 60-80% TSS 50-60% 70-80% TKN 20-30% 40-60% FOG 50-70% 70-90%Anaerobic Treatment – A Marvelous Tool
•
Reduce CBOD
5by 85-90%
•
Reduce TSS by 70-80%
•
Biogas produced containing 74±%
•
Accept/treat shock organic loads
•
Serves as equalization
•
Accomplishes with minimal energy required and
Anaerobic Degradation of Organic Materials
Acid-Forming Bacteria Methane-Forming Bacteria Complex Organics Organic Acids Methane + CO2 + smallamt. Cell Mass
Waste Conversion
(minimal energy lost, minimal BOD reduction)
Waste Stabilization
(waste energy converted to methane energy, big BOD
Anaerobic Treatment Technologies
•
Low Rate
– Anaerobic lagoon
•
Medium Rate
– Anaerobic contact system
– Anaerobic SBR
•
High Rate
– Upflow Anaerobic Sludge Bed (UASB)
– Anaerobic filters; upflow, downflow, expanded bed
Anaerobic Treatment Comparison
Low Rate Medium Rate High Rate
Process/Reactor Lagoon
Contact
process ASBR UASB Filters Loading,
lbs BOD5/1000 ft3/day 15 – 30 60 – 160 60 – 375 >160 160 - 625
HRT, days 3.5 – 15 1 – 10 0.5 – 10 0.25 – 1.5 0.5 – 2.0
SRT, days unknown,
but long >20 >30 >100 30-100
In summary, anaerobic lagoon is lightly loaded with a long detention time and sludge age – and all the more robust for it
Covered Anaerobic Lagoon
Storm Water Collection Synthetic or
Natural Cover
Peripheral Biogas Collection
Design Considerations / Common Operating
Problems
•
Solids Accumulation
– FOG at lagoon < 350 mg/L
– Prevent sand, mud, grit, paunch manure, pen waste,
truck bedding, etcL keep out of lagoon
– Measure/plot grease cover and settled sludge thickness Spring, Summer and Fall
– Remove sludge every Fall to maximize active volume
– < 15% of WAS digests in lagoon, serves more for thickening; remove WAS sent 1-2X/year
Design Considerations / Common Operating
Problems (cont.)
•
Anaerobic Temperatures
– Ideally 95°F
– Can go as low 82-86°F, or lower for shorter periods
•
Chemicals
– Chlorides: sudden swings of > 1,200 mg/L may disrupt anaerobic treatment
• Processing plants with brine chills, pickle liquors
Design Considerations / Common Operating
Problems (cont.)
• Chemicals (cont.)
– Sulfates/Sulfides
• Sulfates typically from water supply
– Ferric sulfate in pretreatment
– Processing mucosa
– Tannery wastewater
• Sulfates in anaerobic influent reduced to hydrogen sulfide
– Reduces methane generation
– At high concentrations can be toxic to methanogens
» Rule of thumb – COD:S < 4:1
– Most in effluent, but released in biogas (depending on pH and temperature)
– For every 26 mg/L H2S in the liquid, 1% in gas phase (35⁰C)
– For each 1 mg/L sulfide in effluent, requires 2 mg/L of dissolved oxygen to oxide back to sulfate
Design Considerations / Common Operating
Problems (cont.)
•
Chemicals (cont.)
– Quaternary Ammonium Compounds (Quat)
• Inhibitory levels at 5-15 mg/L active ingred.
– Macronutrients: nitrogen, phosphorus, potassium
– Micronutrients
• Cobalt, copper, manganese, molybdenum, nickel
(0.1 mg/L deficient)
Meat Processing Plant
Anaerobic Lagoon Effluent
30 40 50 60 70 80 90 100 0 500 1000 1500 2000 3 /4 /0 7 4 /1 5 /0 7 5 /2 7 /0 7 7 /8 /0 7 8 /1 9 /0 7 9 /3 0 /0 7 1 1 /1 1 /0 7 1 2 /2 3 /0 7 2 /3 /0 8 3 /1 6 /0 8 4 /2 7 /0 8 6 /8 /0 8 7 /2 0 /0 8 8 /3 1 /0 8 1 0 /1 2 /0 8 1 1 /2 3 /0 8 1 /4 /0 9 2 /1 5 /0 9 3 /2 9 /0 9 5 /1 0 /0 9 6 /2 1 /0 9 8 /2 /0 9 9 /1 3 /0 9 1 0 /2 5 /0 9 1 2 /6 /0 9 1 /1 7 /1 0 2 /2 8 /1 0 4 /1 1 /1 0 5 /2 3 /1 0 T e mp e ra tu re (° F ) C B OD (mg /L )
CBOD mg/l Volatile Acids TEMP (ºF)
Micronutrient Addition
Reactions to upsets, not
causes:
•
Drop in biogas
production
•
Low pH
•
Increase in ORP
•
High volatile acids
•
Increased
acid:alkalinity ratio
If performing poorly,
check:
•
New plant operations,
like processing mucosa
•
Temperature
•
Quats
•
Sudden chloride swings
•
Nutrients and
micronutrients
Aerated Lagoons/Basins
• Hydraulic and Sludge detention time 1-5 days
• Detention time, not oxygen transfer rate dictates size
• As CBOD5 drops, TSS climbs due to microorganism growth
Advantages
•
Simple to operate
•
No sludge to handle
•
BOD reduction
• 50% in winter • ≥75% in summer•
Convert anaerobic
effluent to aerobic
•
Nitrify NH
3under
certain conditions
Disadvantages
•
Electrical energy req’d
•
TSS increase
•
Nitrification requires
• Longer detention time
• Temperatures > 50°F
•
Small influent flows
require vertical-wall
tanks
Activated Sludge Process
Aeration Clarification Biomass Recycle Biomass WasteActivated Sludge is like a loop with no beginning and no end
• Continuous or semi-continuous – CBOD oxidation
– Nitrification
• Represents most wide-spread used in meat and poultry industries
• Conversion into settleable solids
• Develop ideal biomass
• Balance of floc and filament-forming organisms
Influent
BOD Only Activated Sludge
•
Design Parameters to consider
– Dissolved oxygen supply – Maintain 2.0 mg/L DO
– Alkalinity – Maintain pH 6.5 – 7.9
– Detention/contact time – 4 to 8 hours
– Mixed Liquor Concentration – 2,000 to 3,000 mg/L
– Oxygen Uptake Rate – 40 to 50 mg/L/hour
– Sludge age – 1 to 3 days
– Temperature range – 10 to 30 deg. C.
Consumes:
Typical Meat Industry Activated Sludge
Aeration Basin Final Clarification
RAS
WAS Anaerobic Lagoon
Anaerobic Influent Anaerobic Effluent
Pork/Beef Poultry Meat Proc. Pork/Beef Poultry Meat Proc.
CBOD5(mg/L) 1200-1300 600-1800 600-1600 200-400 150-250 150-250 TKN (mg/L) 120-300 60-180 50-150 110-270 55-160 45-135 Nitrate/Nitrite (mg/L) ≤4.0 ≤4.0 ≤4.0 0.0 0.0 0.0 Phosphorus (mg/L) 20-50 15-30 20-45 18-45 13.5-27 18-40 BOD:N:P 100:10:1.67 100:10:1.67 100:10:3.0 100:60:10 100:50:10 100:40:14
Ammonia Nitrification
• 2-step conversion
– Ammonia to Nitrite - Nitrosomonas
– Nitrite to Nitrate - Nitrobacter
• Design Parameters to consider
– Dissolved oxygen supply – Maintain 2.0 mg/L DO
– Alkalinity – Maintain pH 6.5 – 7.9
– Detention/contact time – 4 to 24 hours
– Mixed Liquor Concentration – 3,000 to 5,000 mg/L
– Oxygen Uptake Rate – 40 to 50 mg/L/hour
– Sludge age – 8 to 15 days depending on temperature
– Temperature range – 10 to 30 deg. C.
Consumes:
4.57 g O2 / g NH4-N
Traditional Nitrification/Denitrification
25% O2 25% O2 40% Carbon (BOD) 40% Carbon (BOD) 60% Carbon (BOD) 60% Carbon (BOD) Nitrification-Aerobic Denitrification-Anoxic 4.57 g O2/g NH4-N oxidized 3.5-6 g COD/g NO3-N reduced 7.14 g CaCO3/g NH4-N oxidizedrecover 3.57 g CaCO3/g NO3-N reduced
1 mol Nitrite (NO2-) 1 mol Nitrite (NO2-) 1 mol Nitrate (NO3-)
½ mol Nitrogen Gas (N2) 1 mol Ammonia (NH3/ NH4 +) Autotrophs Heterotrophs 75% O2 75% O2
Nitrogen Removal Processes
•
Single Stage Nitrification-Denitrification
•
Simultaneous/Combined Nitrification Denitrification
•
Sequential BOD-Nitrification-Denitrification
•
Biological Options
– Suspended Growth
Nitrogen Removal Processes - Classic
Zoned
Wuhrman
Ludzack-Ettinger
Modified Ludzack Etinger (MLE Process)
Bardenpho
(4 stage Phoredox)
Step Feed
Tilmann WRP, Los Angeles
Effluent:
NH4-N < 1 mg/L TN < 10 mg/L
Nitrif/Denitrif: +70% TN Removal
Modified Ludzack-Ettinger (MLE) system
Aeration Basin Final Clarifiers RAS (1Q) WAS Anoxic Basin
Mixed Liquor Return (4Q) (nitrate source) From Anaerobic Lagoon TN 200 mg/L 40mg/LTN Carbon Alkalinity
0% 20% 40% 60% 80% 100% 0 2 4 6 8 10
Recycle Ratio (RAS + MLSS)
Nitrif/Denitrif: 6-8 mg/L Effluent TN
Aeration Basin Final Clarifiers RAS (1Q) WAS Anoxic BasinMixed Liquor Return (4Q) (nitrate source) From
Anaerobic Lagoon
4-Stage Bardenpho system
TN 200 mg/L 7 mg/LTN Carbon, Alkalinity Post-Anoxic Basin Reaeration Basin Carbon TN 40 mg/L
Pork Plant – Effluent Nitrogen
0 5 10 15 20 25 30 35 40 45 501-Nov-08 3-Jan-09 7-Mar-09 9-May-09 11-Jul-09 12-Sep-09 14-Nov-09 16-Jan-10
To ta l N it ro g en , m g /L Effluent TN
Probably lost nitrification
Switched from Final Clarifier to UF Membranes Influent TKN averaged 199 mg/l
Simultaneous Nitrification/Denitrification
•
Biological process occurring concurrently in same
reactor
•
Relies on dynamic balance of DO/BOD/NH
3•
Utilizes control of aeration by DO or ammonia
concentration
•
Reduces oxygen requirements and recovers
alkalinity
Simultaneous Nit/Denit
25% O2 40% Carbon 60% Carbon Nitrification-Aerobic Denitrification-Anoxic 1 mol Nitrite (NO2-) 1 mol Nitrite (NO2-) 1 mol Nitrate (NO3-)½ mol Nitrogen Gas (N2) 1 mol Ammonia (NH3/ NH4 +) Autotrophs Heterotrophs 75% O2 3.43 g O2/g NH4-N oxidized 2.1-3.6 g COD/g NO3-N reduced 5.7 g CaCO3/g NH4-N oxidized
Nitrogen Removal Simultaneous
SBR
Oxidation Ditch
Biodenitro
– Cyclic Aeration
Two Zone Activated Sludge with DO Control
Effluent:
NH4-N < 4 mg/L TN < 6 mg/L
Simultaneous Nit/Denit
SND Basin Final Clarifiers RAS (1Q) WAS From Anaerobic Lagoon Carbon Alkalinity Post Aeration NH3 / DO Control• Target effluent NH3 in first stage
• Target DO in first stage 0.01-0.15 mg/L
Potential Advantages
•
Elimination of
separate tanks,
internal recycle
•
Simpler process
design
•
Reduction of carbon,
oxygen, energy, and
alkalinity
consumption
Potential Disadvantages
• Limited controlled aspects of the process
• Floc sizes
• Internal COD storage
• DO profile within floc
• Slower Growth Rates
• Larger Tank Sizes
• Sludge bulking,
filamentous bacteria growth
• Complex instrumentation
Anammox
25% O2 40% Carbon Nitrification-Aerobic Denitrification-Anoxic 1.83 g O2/g NH3-N oxidized 0 g COD/g NO2-N reduced 3.1 g CaCO3 /g NH3-N oxidized 1 mol Nitrite (NO2-) 1 mol Nitrite (NO2-) 1 mol Nitrate (NO3-)½ mol Nitrogen Gas (N2) 1 mol Ammonia (NH3/ NH4 +) Autotrophs Heterotrophs 40-50% O2 75% O2 60% Carbon
Definition
Developed in Europe
Bacteria
• Autrophic – Use CO2 as Carbon
Growth Conditions
• Anaerobic/Anoxic
• Temperature 20-35°C
• Very slow growers –
– Long sludge age > 30 days
• NH4+ : NO2- ratio ≈ 1 : 1.32
– pH (neutral range)
– Nitrite (maintain at <40 mg/L)
– Free Ammonia (maintain at <10 mg/L)
• Once Grown Very Stable - Can be stored for months with no food.
Anammox Providers
•
Paques BV
– Upflow gravity separation
•
Anita Mox
TMby Veolia Water Technologies
– Plastic biofilm carriers– Similar to MBBR
•
DEMON
®by World Water Works
– WAS cyclone separation
Anammox (DEMON
®)
Operational Philosophy
1 process cycle of the DEMON involves 4 time-controlled phases:
• Aeration phase
• Fill / React phase
• Settling phase • Discharge phase Standard Effluent 90% removal NH4-N 10% production NO3-N 80% removal TN
Full Scale Operation
•
Regular sampling
•
Sensors: pH, DO, conductivity,
NH
3-N
•
Regular Operation
– DO range of 0.3-0.4 mg/L
(during aeration phase)
– pH typically 7.0
•
Avoidance nitrite accumulation
DEMON
®Design Requirements
•
Pretreatment
– Most BOD, TSS removed
– Pre-storage tank (6-12 hrs HRT)
•
Design parameters
– Total/soluble COD, TKN, NH3-N, Alkalinity, PO4-P, TSS, Temperature, pH
– Flow (aver/max); sludge processing
•
Tank reactor
DEMON
®Major Components
Seed Sludge Aeration
System
Instruments & Controls
Tank
Comparison
N2 CO2 emissions > 4.7 t CO2/t N NO3 C-source 2.3 lb Methanol/lb N NH4 Energy 1.27 kWh/lb N Nitrification/Denitrification N2 CO2 reduction -0.4 t CO2/t N NO2 / NH4 C-source 0 lb Methanol/lb N NH4 Energy 0.50 kWh/lb NDEMON®-system
Demon Results - Sidestream
Heidelberg, Germany
Biological Phosphorus Removal
•
Many Process Options
•
Anaerobic Zone key to process
– Grow Phosphorus Accumulating Organisms (PAOs)
•
Typically achieves <1.0 mg/L
•
High influent Sol BOD/P is required
– carbon/VFA addition via fermentation
•
Process stability is key. Conditions that favor the
right PAO populations are need to be understood
Biological Phosphorus Removal
Modified (5-stage) Bardenpho
UCT Modified UCT VIP (Virginia Initiative Process) Effluent: TP < 1 mg/L OP < 0.5mg/L
Chemical Phosphorus Removal
•
Chemical Options
– Ferric Salts (Ferric Chloride, Ferrous Chloride)
– Alum
– Sodium Aluminate
– Lime
•
Reaction: FeCl
3& PO
4FePO
4& 3Cl
•
Dosage: Theory : 5.24 lbs FeCl
3/ lb P
Actual: 10.48 lbs FeCl
3/ lb P
Typical Chemical Treatment Opportunities
Primary Secondary Tertiary Polish
Solids Processing
Tertiary Treatment
•
Treatment Goal – Remove additional TSS, TN, TP
not captured in secondary treatment processes.
•
Simple TSS Removal
– Tertiary Clarifier
– Cloth Filter Disk
– Sand Filter
•
More Complex
– Membrane Bioreactor – Ultra Filtration – ROTN Removal
• Biologically Active Filter (BAF)
American Meat Institute Conference on Worker Safety, Human
Resources and the Environment Kansas City, Missouri
Brian Mulinix, P.E. Brian Bakke, P.E. HDR Engineering, Inc. March 20, 2013