Transcript Land Application of Food Process/Rinse Water

Land Application of Food
Process/Rinse Water
California League of
Food Processors
Brown and Caldwell
Kennedy/Jenks Consultants
Manual of Good Practice for Land Application of Food
Processing/Rinse Water
Rob Neenan
Director of Regulatory Affairs
California League of Food Processors
Background
• CLFP, in conjunction with Brown and Caldwell and
Kennedy-Jenks developed the first Manual in 2002
for fruit and vegetable processors.
• The objective was to provide a comprehensive
science-based guide to processors and consultants.
• RWQCB staff expressed some concerns about
several elements of the 2002 Manual, including text
regarding salinity, source control, and BOD loading
rates.
• CLFP recognized the need to address concerns and
obtain a common agreement as to what should be
expected/required of application sites.
• In 2006 CLFP collected financial contributions from
members to revise the document.
2006 – 2007 Manual Revision Project
Objectives
• Provide detailed technical guidance to industry based
on the best available science.
• Encourage implementation of best practices.
• Promote clear and consistent risk-based regulatory
requirements.
• Improve the level of communication and cooperation
between processors and Board staff.
• Coordinate CLFP efforts with other industry
wastewater research initiatives.
• Identify areas where further research would be
useful.
Project Participants
CLFP Consultants and Working Group
Consultants:
• Brown & Caldwell: Rob Beggs, Ron Crites
• Kennedy-Jenks: Sharon Melmon, Gary Carlton, Bob
Chrobak
Steering Committee:
• RWQCB Staff: Pamela Creedon, Wendy Wyels, Bert
Van Voris, Jo Anne Kipps
• State Water Board: Wayne Verrill
• Food Processors: Tim Ruby, Tim Durham, Ray
Medeiros, Dennis Tristao, Ben Hall, Doug Langum
• Others: Paula Hansen, Dan Burgard, Troy Elliott,
Matt Wheeler, Burt Fleischer
Project Timeline
• Formation of Manual working group—March 2006
• First meeting of working group—May, 2006
• Subcommittee meetings– June to October, 2006
• Oct. 2006—first draft completed
• Oct – Jan 07 review of the draft document
• February 27, 2007 workshop
• Spring 2007--Manual presented to RWQCB for
adoption as a guidance/reference document (but not
a regulatory document).
Next Steps
• Present the document to the Regional Board
• Distribute the document to industry
• Possible annual training classes
• Continue to pursue funding for additional research
Manual Contents
• Introduction
• Salinity Control
• Beneficial Reuse
• Distribution
• Regulatory
• Monitoring
• Process Water
• Research Needs
• Site Characteristics
• Examples
• Crops and Climate
• Appendices
• Loading Rates
Appendix Material
• Glossary
• Anti-Degradation Policy
• Form 200 and Information Needs
• Monitoring Wells
• Soil Evaluation
• Groundwater Transport
• Measuring Salinity and Organics
Chapter 1
Introduction
Subcommittees
• Development of a Waiver
• BOD Loading Rate
• Point of Compliance
• Soil Monitoring
Waiver Subcommittee
• Rob Beggs
• Dan Burgard
• Bob Chrobak
• Wendy Wyels
BOD Subcommittee
• Bob Chrobak
• Ron Crites
• Troy Elliott
• Jo Anne Kipps
• Tim Ruby
• Wayne Verrill
Point of Compliance
• Rob Beggs
• Dan Burgard
• Gary Carlton
• Tim Durham
• Burt Fleischer
• Bill Jennings
• Bert Van Voris
• Matt Wheeler
Soil Monitoring
• Rob Beggs
• Dan Burgard
• Wayne Verrill
Chapter 2
Beneficial Reuse
Chapter 3
Regulatory Constraints for
Land Application
California Framework
• Porter Cologne Act
– Cannot impact beneficial uses of GW
• Basin plans
– Define beneficial uses for each region
• Anti-degradation policy
– GW protection beyond beneficial uses
– Best Practicable Treatment and Control
Best Practicable
Treatment and Control
• Show progress by:
– Comparing process water treatment and
control options
– Segregating high-strength wastes
– Demonstrating source reduction
Waste Discharge Requirements
• Submit Report of Waste Discharge in advance
• ROWD defines planned operations and
wastewater management strategy
• ROWD includes
– Site and facility description
– Water balance
– Cropping plan
– Monitoring plan
Waiver Programs
• Existing waivers
– Small processors and wineries
– Ag commodity waste
– Non-toxic industrial waste (soil amendment)
• Potential low-threat waiver
– Low constituent loading
– Appropriate management
– Lowest “relative risk” category in Manual
Chapter 4
Process Water Characteristics
Potentially Limiting
Constituents
• Nitrogen
• Organics
• Salinity
Nitrogen
• Process water typically contains
organic N and ammonium
• Converted to nitrate in moist,
well-aerated soil
• Plants take up nitrate and ammonium
• Nitrate may be leached from soil or lost
to denitrification
Measurement of Nitrogen
• Analyze process water for:
– Total Kjeldahl Nitrogen (TKN)
• Organic N + Ammonium (NH4+)
– Nitrate (NO3-)
– Ammonia (NH3)
• Refer to Chapter 7 for guidance on
evaluating nitrogen balance
Organics
• Decaying plant/animal residue
• Enhances soil humus and fertility,
boosting crop production
• Rapid aerobic decomposition can lead
to anaerobic soil conditions
• Must balance loading to crop demand
Measurement of Total Organics
• Use 5-day Biochemical Oxygen
Demand (BOD5)
– Chemical Oxygen Demand (COD) test may
overstate BOD
– Total organic carbon (TOC) captures nonbiodegradable fraction
Salinity
• Sources may include supply water,
processing, sanitation chemicals
• Risk of leaching to groundwater if land
application system is not well managed
• Likely to be the limiting constituent for
land application and cropping
Measurement of
Process Water Salinity
• Want to quantify only the minerals
– Analyze for individual ions
– Correlate sum of ions with fixed dissolved
solids (FDS)
– Use FDS x correction factor
• Total dissolved solids (TDS) analysis is
a sum of minerals and non-minerals
Irrigation Water Quality
• Most crops tolerate irrigation water with
EC of 0 to 1 dS/M
• Yield losses occur at EC of >3 dS/M
• Refer to Table 4-1 for Irrigation Quality
Guidelines
Chapter 5
Site Characteristics
Climatic Factors
• Rainfall
• Evapotranspiration (ET)
• Temperature
Topographic Factors for Crop
Irrigation
Percent Slope Limitations
• <2 Slight
• 2-6 Moderate
• 6-12 Severe
• >12 Very Severe
Soil Characteristics
• Soil texture
• Soil depth
• Infiltration rate
• Soil chemistry
Soil Treatment Factors
• Filtration – removal of suspended solids
• Adsorption – removal of P, NH4,metals
• Organic content – sustainable
infiltration, adsorption, energy, fertility
Soil Infiltration
• Infiltration rate
• Available water holding capacity
• Deep percolation
• Depth of soil, > 2 ft
• Depth to groundwater, > 2 ft during
application season
Soil Chemistry
• pH
• Electrical conductivity (EC)
• Cation exchange capacity (CEC)
• Exchangeable sodium percentage
(ESP)
• Soil nutrients, N,P,K
Groundwater Quality
• Preapplication backgound quality
• Determine preapplication flow direction
• Hydropunch versus permanent wells
Chapter 6
Crop Selection
Crop Water Use
• Reference ET, Crop Coefficients
• ETc = ETo·Kc
• Pan ET can also be used to estimate
ETo
Crop Coefficients
Table 6-6. Crop Coefficients for Perennial Forage Crops (Doorenbos and Pruitt, 1977)
Condition
Crop
Alfalfa
Minimum
Mean
Peak
Grass for hay
Minimum
Mean
Peak
Clover, grass legumes
Minimum
Mean
Peak
Pasture
Minimum
Mean
Peak
Humid
(light to moderate wind)
Dry
(light to moderate wind)
0.50
0.85
1.05
0.40
0.95
1.15
0.60
0.80
1.05
0.55
0.90
1.10
0.55
1.00
1.05
0.55
1.05
1.15
0.55
0.95
1.05
0.50
1.00
1.10
Kc (minimum) represents conditions just after cutting.
Kc (mean) represents value between cuttings
Kc (peak) represents conditions before harvesting under dry soil conditions. Under wet conditions increase values by 30
percent.
Nutrient Uptake
Table 6-7. Nutrient Uptake Rates for Selected Crops (USEPA, 1981)
Crop
Lb/acre·year
Nitrogen, N
Phosphorus, P
Potassium, K
200-600
115-200
20-30
35-50
155-200
220
Coastal bermudagrass
350-600
30-40
200
Kentucky bluegrass
175-240
40
175
Quackgrass
Reed canarygrass
210-250
300-400
25-40
35-40
245
280
Ryegrass
160-250
50-75
240-290
Sorghum-Sudan
Sweet clover
Tall fescue
Orchardgrass
180-260
155
130-290
220-310
18-26
18
27
18-45
90-140
90
270
200-280
Barley
110
13
18
Corn
155-220
18-27
100
Cotton
65-100
13
36
120
13
60
Forge crops
Alfalfa
Bromegrass
Field crops
Grain Sorghum
Rooting Depth and N Loading
• Rooting depth - Deeper roots provide
more opportunity for nutrient uptake.
• Matching N uptake with available N –
difficult because of mineralization lag
• Match annual N uptake rates, monitor
soil nitrate, modify application timing if
necessary.
Salt Uptake
Table 6-9. Yield and Salt Removal of Various Crops
Average Yield
dry tons/acre
Salts Removed
lb/acre
Ash
%
Alfalfaa
6.6
2093
16%
Barleya
3.9
759
10%
Cornb
11.7
1750
7.5%
Winter wheatb
5.2
1321
13%
Tall Fescuea
8.4
2083
12%
Source: Tim Ruby, Del Monte Foods Company
Process water spray irrigation site located outside Boise, ID, three year average
b Process water surface irrigation site. Kingsburg, CA, one year
a
Apply nutrient and salt uptake for calculations in Chapters 7 and 12.
Chapter 7
Loading Rates and
System Design Approach
Avoiding Unintended Consequences
Development/
Application of Risk Categories
Development/
Application of Risk Categories
Risk Category
Description
1 (lowest)
Loading rates substantially below agronomic rates.
Waiver may be appropriate for low flows.
2
Loading rates up to agronomic criteria, minimal risk of
unreasonable groundwater degradation.
3
Loading rates above agronomic criteria, but within
calculated capacities.
4 (highest)
Loading rates above calculated capacities; pilot testing
recommended to prove efficacy.
Objective: Encourage greater reuse with lower loading rates.
Loading-Rate Based
Planning and Design
• Nitrogen
• Organic (BOD)
• Salts
• Others (hydraulic, TSS, specific ions,
etc.)
Nitrogen
Nitrogen Loading Rate
Categories
Risk
Category
1
2
3
Criteria
(% of Crop N Requirements)
<= 50%
50% to 150%
> 150%
Organic
Organic Loading Rate
Categories
Table 7-5. Organic Loading Rate Risk Categories
Risk
Categorya
Averageb BOD5
Loading Rate,
lb/acre•d
1
<=
50d
2
<= 100d
> 5 ft
3
> 100d
>2 ft
Depth to
Groundwaterc, ft
> 5 ft
Notes
De-minimus loading rate is indistinguishable
from common agronomic conditions. Good
distribution is important.
Good distribution more important.
Use Eqs. 7-2 and 7-4 in design. Good
distribution very important. See Chapter 10
for monitoring recommendations.
Note: Both BOD loading and depth to groundwater apply.
Hydraulic Loading
• Try to match typical irrigation rates.
• Higher rates in “shoulder months” are
OK if designed properly.
• Supplemental low salinity water is
desirable during periods of low
process/rinse water flows.
Salinity Risk Categories
(concentration based guidelines, based on Tulare Lake Basin Plan)
Risk
Category
Process/Rinse Water FDSa (mg/L)
1
< local irr.b
2
< local irr.+ 320 AND
< 640 mg/L
3
>local irr.+320 OR
>640 mg/L,
but not excessive for crops grown
a.
FDS is used as a reasonable basis for comparison.
b.
“Local irr.” refers to the upper end of the range of TDS concentrations of
local irrigation wells near the process/rinse water reuse area.
Salinity Compliance Approaches
• Category Guidelines
• Site Specific Factors and Permit
Requirements
• BPTC (source control, switch to K)
• Average Annual Deep Percolate Salinity
(Cd)
Other Constituents
• Solids: TSS, SM (odors, vectors – good
distribution uniformity important)
• Specific ions – sodium, chloride, boron,
etc. (soil and crop effects)
• Acidity (high rainfall areas)
• THMs (from using bleach, chlorine gas)
Using Loading Rates in Design
• Identify likely limiting design
parameters.
• Perform initial loading rate and land
area needs calculations.
• Consider desired risk category.
• Iterative process; consider options for
site, crops, pretreatment, distribution.
Chapter 8
Source Control
Sources of Waste Constituents
• Filtration backwash from supply water
treatment
• Water softener regenerant
• Boiler blowdown
• Flume or other transport water
• Storage and processing solutions
• Cleanup and sanitation water
Waste Minimization
• Source reduction and recycling
• Critical for salt control
• Strategies (most to least favorable):
- Eliminate
- Reduce
- Recycle
- Treat at the source
- Treat at end of the pipe
Waste Minimization Approach
• Planning
• Assessment
• Feasibility Analysis
• Implementation
Assessment
• Compile and evaluate facility data
– Source water chemistry and volume
– Chemical usage data
– Individual waste stream characteristics
– Total effluent characteristics
– Energy use
– Permit requirements
Assessment
• May need to collect additional data to
characterize discrete waste streams
• Data provides basis for identifying
waste minimization options
• Consider facility operations holistically
when looking for options
Typical Options
• Product substitution
• Housekeeping changes
• Process modifications
• Operational changes
• Recycling/reuse
Feasibility Analysis
• Technical and economic evaluation
• Consider:
– Impact of change on product
– Ease of implementation and maintenance
– Regulatory requirements
– Capital and ongoing O&M costs
– Risks
Develop Action Plan
• Describe:
– Production activities and associated waste
streams
– Options that were considered
– Feasibility analysis results
– Rationale for selected option(s)
– Schedule for implementation
Implementation
• Install equipment, initiate procedural
changes
• Monitor and record results
• Reevaluate program annually
– Did the changes “stick”?
– Are goals being met?
– Are additional changes needed?
– Communicate successes to staff
Pretreatment for
Land Application
• Solids removal
• Constituent removal
– Screening
– Salinity
– Centrifuging
– BOD
– Gravity settling
– Nitrogen
– Dissolved air
floatation
– Filtration
Salinity Reduction Options
• Last resort – try source reduction first
• Membrane systems
– Reverse osmosis or nanofiltration
– Expensive
– Residual brine to manage
• Evaporation
– Residual brine to manage
BOD Pretreatment
• Could be needed if BOD load exceeds
agronomic capacity
• Non-soluble BOD screened out
• Soluble BOD treatment
– Membranes
– Aerobic systems
– Anaerobic systems
Nitrogen Pretreatment
• Could be needed if nitrogen load
exceeds agronomic capacity
• Biologic treatment
– Expensive
– Inconsistent loading can cause upsets
– Used for municipal wastewater treatment
Chapter 9
Distribution Systems
Distribution Systems Components
• Collection
• Pretreatment
• Storage
• Transmission
• Field Distribution
• Tailwater/return Flow System
Storage Considerations
• Odors/aeration
• Lining
• Equalization
• Blending
• Pumping
Transmission Considerations
• Cleaning and flushing pipelines and ditches
• Accommodate supplemental water
• Prevent and monitor for leaks
Results of an undetected leak 
Field Distribution Systems
• Surface
• Sprinkler
– periodic move
– mechanical move
– solid set
• Drip
See Tables 9-2 and 9-3 for
considerations.
Chapter 10
Monitoring
Risk Based
Monitoring Approach
What we want
to avoid!
Monitoring Approach –
Process/Rinse Water
Table 10-5. Typical Process/Rinse Water Quality Monitoring Parameters and Frequency
Parameter
pH
EC
Temperature
BOD/COD
TSS
FDS
Objective:
Compliance (C),
Operational (O)
or Both (B)
B
B
B
C
C
C
Risk
Cat.
Typical
Frequency
1
Monthly
2
Weekly
3
Daily or
continuous
1
Monthly
2
Weekly
3
Daily/cont.
all
Process specific
1
2 / year
2
2 / month
3
Weekly
1
2 / year
2
Monthly
3
2 / month
1
2 / year
Comment
Low pH may be used as an indirect indicator of anaerobic
conditions.
The EC is primarily a result of the dissolved inorganic ions in the
sample – measurement can be correlated with FDS and with TDS
when BOD is negligible.
Often not of critical importance
BOD loading rates assigned in WDRs should reflect site
assimilation capacity and need to prevent nuisance odors. COD is
a good proxy for BOD for high frequency characterization.
Higher TSS levels can result in fouling of pipelines and nozzles.
High TSS may not be distributed well with border strip irrigation.
Measurement of the inorganic portion of TDS, without the organic
fraction, is important; FDS, measured by heating a sample to
Monitoring Approach - Soil
Table 10-7. Soil Chemical and Physical Monitoring Parameters
Parameter
Organic matter, CEC, TKN
pH, ECe, NO3-N, NH4-N
Available K, Available P
Extractable Na, Ca, Mg, Cl,
SO4, SAR, ESP
Risk
Category
Frequency
Depths
(feet)
1
Initial
0-2
2,3
5 years
0-1, 2-3, 4-6
1
Annual
0-2
2
Annual
0-1, 2-3, 4-6
3
2 / year
0-1, 2-3, 4-6
1
5 years
0-2
2,3
Annual
0-1, 2-3, 4-6
1
5 years
0-2
2,3
Annual
0-1, 2-3, 4-6
Considerations
Slowly changing basic soil parameters.
Mobile constituents and good indicator
parameters to assess soil fertility and
process water loading capacity.
Low mobility nutrients
Soil salinity and sodicity status
parameters, some mobile
Definitions: Electrical conductivity of saturated paste extract (ECe),Total Kjeldahl Nitrogen (TKN), Nitrate-Nitrogen (NO3-N), Ammonium-Nitrogen (NH4-N),
Calcium (Ca), Magnesium (Mg), Potassium (K), Sodium (Na), Sulfate (SO4), Chloride (Cl), Phosphorus (P), Sodium Absorption Ratio (SAR), ESP (Exchangeable
Sodium Percentage)
Other Monitoring Issues
• Use lysimeters for test plots.
• Consider geophysical surveys for long
term salinity monitoring.
• Crop management and monitoring
(vigor, ash, nutrients)
• Operational adjustments (Table 10-14)
Groundwater Monitoring
Requirements
• Minimum number of wells:
– one upgradient / two downgradient
• Downgradient point of compliance:
– As close to edge of application area as
practicable (within 150 feet)
– Within application area is not appropriate
Groundwater Monitoring
Requirements
• First encountered groundwater
• If groundwater is deep (>100 ft), use
soil monitoring as an early indicator
Compliance vs Operational
• Compliance monitoring is specified by
WDRs for the facility
• Operational monitoring can include
– Compliance monitoring
– Routine inspections
– Soil sampling and other techniques to
obtain early warning of potential impacts
Chapter 11
Research Needs
Organic/N Topics
•
Determine soil aeration under various BOD loading
rates.
•
Evaluate use of soil-gas testing to confirm soil
aeration under various BOD loading rates.
•
Assess the correlation of BOD loading with TDS,
alkalinity, dissolved iron and manganese, and
arsenic in receiving groundwater.
•
Determine the minimum organic loading necessary
to maintain and enhance soil health and fertility.
•
Determine the nitrogen mineralization rates of
organic nitrogen for common process/rinse waters.
Salinity Management
•
Compare the salinity uptake by various cover
crops, considering climate and applied water
quality.
•
Identify best practicable treatment and control
methods to minimize salinity impacts on
groundwater.
•
Determine if crops can be developed to remove
specific ions, such as sodium and chloride.
•
Determine the management approach to long-term
immobilization of salts by chemical precipitation in
the soil mantle.
Salinity Control
•
Identify alternative methods for peeling
fruit to minimize use of caustic.
•
Identify alternative cleaning products
to minimize introduction of sodium.
•
Identify alternatives to water softener
and boiler blowdown chemicals.
Groundwater Protection
•
Evaluate the actual nature and extent
of groundwater quality impacts at land
application sites based on existing
groundwater quality monitoring data.
•
Determine the protection from
degradation of TDS afforded by using
potassium in place of sodium in
caustic and water softener
regeneration.
Vadose Zone Monitoring
•
•
•
Assess the correlation between the
thickness of vadose zone and treatment
processes.
Define appropriate operational monitoring
programs for land application sites to
ensure that the systems are functioning as
intended. Establish whether vadose zone
monitoring by lysimeters can provide
representative samples.
Compare intensive soil sampling versus
lysimeters for operational monitoring.
Soil/Site Selection
•
Investigate whether long-term
wastewater application has an effect
on soil buffering capacity.
•
Confirm that soil (and soil solution) is
not adversely affected by wastewater
with a pH in the range of 3 to 10.
Crop Irrigation
• Determine whether the guidelines for
land application of food process rinse
water are applicable to the reuse of
process wastewater for crop irrigation.
Chapter 12
Design Examples
Are we having fun yet?
Steps
• Initial process/rinse water
characterization
• Identify/investigate sites
• Select initial risk category target
• Calculate loading rates of major
constituents, compare with guidelines
• Iterate as necessary; considering
site(s), crops, pretreatment, distribution
Example 1 – N and BOD
Loading Rate = Flow * Concentration * Conversion Factor * Duration
Area Loading Rate (lbs/ac) = Total Loading Rate / Area
Daily Area Loading Rate (lbs/ac*d) = Area Loading Rate / Days
Note: lbs/ac*d means same thing as lbs/ac/d
• Calculate for N
• Calculate for BOD
• Increase site area as needed and available for the
limiting loading rate
Example 1 - Hydraulic
• Get ET factors (CIMIS), other hydraulic data (Table 124).
• Calculate agronomic irrigation rates (monthly, or at
least max and min) using Eq. 7-5.
• Determine needs for supplemental water, additional
land, storage, or EPA Type 1 operation (application in
excess of irrigation need).
Example 1 – Salts and Other
Considerations
• Check FDS concentration against guidelines.
• Select/finalize appropriate distribution system.
• Plan other associated facilities.
Example 2
• Same broad steps as for Example 1:
–
–
–
–
–
Initial process/rinse water characterization
Identify/investigate sites
Select initial risk category target
Calculate loading rates; compare with guidelines
Iterate as necessary; considering site(s), crops,
pretreatment, distribution
• More calculation details:
– N loss
– Aeration capacity
– Monthly water balance
– Average annual percolate salinity
Example 2 – N
Loading Rate = Flow * Concentration * Conversion Factor * Duration
Allowable N Loading
Rate = U / (1-f)
C:N ratio
>8
1.2-8
0.9-1.2
•
•
•
•
Table 7-2. Nitrogen Loss Factor for Varying C:N Ratios
Nitrogen Loss Factor, f
Example
Flooda
Sprinklerb
Food processing wastewater
0.5 - 0.8
0.2 – 0.4
Primary municipal effluent
0.25 - 0.5
0.15 – 0.3
Secondary municipal effluent
0.15 - 0.25
0.1 – 0.25
Calculate allowable N loading.
Compare with planned loading for area identified.
Conversely, can calculate area required.
Increase site area as needed and available for the
limiting loading rate.
• Consider other options (crops, application methods).
Example 2 – BOD
Loading Rate = Flow * Concentration * Conversion Factor * Duration
BODu ~ 1.4 * BOD5; alternatively can use COD as a max
• Apply Eqs. 7-2 and 7-4 to calculate oxygen availability.
• Compare with BODu loading.
• Increase site area as needed and available .
• Consider other options (application methods, cycle
duration).
Example 2 - Hydraulic
• Get ET factors (CIMIS), other hydraulic data (Table 124).
• Calculate irrigation needed using Eq. 7-5 and monthly
water balance.
• Determine needs for supplemental water, additional
land, storage, or EPA Type 1 operation (application in
excess of irrigation need).
• Note annual totals for possible use in other loading
calculations.
Example 2 - Salts
Cd = (Salt Applied – Salt Uptake) / Deep Percolate
• Using FDS, calculate average mineral salinity and
compare with risk category guidelines.
• Using totals from monthly water balance, calculate
average annual Cd.
• Compare with “background” groundwater upper limit.
• Other salinity compliance methods could be more
applicable, depending upon permit and BPTC
considerations.
Example 2 – Other
Considerations
• High TSS  design system to accommodate
– furrows or corrugations instead of border strips
– shorts runs, high flows
• Select/finalize appropriate distribution system
• Check other crop nutrient needs
• Plan other associated facilities
Questions and Answers