ScorePP Dissemination Workshop
(2-3 February 2010)
Comparison of technological treatment options
Middlesex University, Danish Technical University, University of Ljubljana,
ENVICAT, Anjou Recherche.
Overall objectives
To address the technologies available for
eliminating the discharge of priority
pollutants to receiving waters as a result
of different activities and to carry out a
comparative analysis to assess the most
appropriate and feasible reduction
technologies
Treatment options considered in ScorePP
• Stormwater BMPs
• Greywater treatment and reuse systems for household
wastewater
• Industrial wastewater treatment
• Municipal wastewater treatments
• Sludge disposal
• Assessment of the feasibility of the different treatment
options for PPs
Stormwater
Best Management Practices
Stormwater BMPs
•
Stormwater control systems
close to the source
•
Control water quantity &
quality
•
Provide social amenity
•
Infiltration/detention followed
by discharge at a controlled
rate
•
Used individually, in a
treatment train or in
combination with conventional
piped systems
•
Structural and non-structural
•
•
•
•
•
•
•
•
•
•
•
•
Constructed wetlands
Detention basin
Retention pond
Lagoon
Green roof
Settlement tank
Filter strips
Swales
Infiltration basins
Soakaways
Porous asphalt
Porous paving
Fundamental unit
Physical processes Chemical processes Biological processes
Adsorption, Settling,
Filtration, Volatilisation
Flocculation,
Precipitation, Photolysis
BMP characteristics which influence
removal processes:
dry & wet area/volumes; retention & drain
down times; surface exposure times;
hydraulic/flow attenuation; vegetative, algal &
microbial components; presence of sorption
sites/nature and pore sizes of substrate;
existence of aerobic/anaerobic conditions
Plant/algal uptake,
Microbial degradation
Pollutant behaviour:
Susceptibility of a particular
pollutant to the
identified processes
Identification of the potential pollutant
removal efficiency within a specific BMP
Order of preference for the use of BMPs to remove
Pb and Benzo (a) pyrene
Comparison of theoretical ranking with
measured data: Organic PPs in SSF CW
Priority pollutant
Matamoros et al., (2007)
Removal efficiency
(%)
Ranked data
Score PP
methodology
Ranked data
Pentachlorobenzene
>99
2
1
Endosulphan
>99
2
2.5
Lindane
>99
2
5
Pentachlorophenol
94
4
2.5
Chlorpyrifos
83
5
4
Alachlor
80
6
7
Simazine
25
7
6
Diuron
0
8
8
Summary of the ability of stormwater BMPs to
remove PPs
•
In the absence of field data, enables end-users to evaluate BMPs from the
perspective of the removal of non-standard pollutants of concern;
demonstrates critical discrimination across BMPs although infiltration basins
and sub-surface flow constructed wetlands consistently rank most highly for
the removal of priority pollutants
•
BMP order of preference for the removal of PPs compares well with field
data available to date but more field data required to refine and calibrate this
approach
•
Provides input to development of emission control strategies (e.g. ScorePP)
•
Does not take into consideration the suitability of different options for specific
geographical locations, e.g. potential for groundwater contamination due to
infiltration in unsuitable soil type.
Household Greywater
Treatment and Reuse Systems
Household greywater
•
GREYWATER =
•
Previous research has concentrated on conventional water quality monitoring
parameters (e.g. BOD, TSS, nutrients, and pathogens).
•
Increasing support for decentralised WWT – increasing pressures on water
supplies, improved potential for recycling, water savings etc.
•
Difficult to draw conclusions about the efficiency of the various treatment options
(individually or in a train) for PS/PHS in greywater
–
–
–
BATHROOM (sinks, baths and showers)
KITCHEN (sinks, dishwashers)
LAUNDRY (sinks, washing machines)
NO TOILET WASTE
The majority of removal efficiency studies relate to treatment of combined wastewater
Greywater treatment is highly site-specific, wide range of treatment trains, many still in development or
pilot stage
Lack of data on micropollutant treatment efficiency. Only 1 greywater study reporting both inlet and
outlet concentrations of PS/PHS.
Information reviewed
Priority
substance
properties
Priority
substance
sources
Greywater
Pre-treatment
systems
Priority
substance
presence
Recycling
systems
Priority substance
concentrations/
loads
Electricity
Chemical
consumption consumption
Removal
Operational
efficiencies
risks
Health risks Risks to the
connections environment
Cost-benefit
analysis
Water
savings
Nutrient
recycling
Operational
costs
Installation
costs
RBC, Nordhavnsgården, Copenhagen
A0
A2
A3
A4
A6
A1
A7
A5
Primary settling tank
Multi-stage Rotating Biological
Contactor
Secondary settling
tank
Sandfilter
UV-filter
Service water tank
•Proportional potable water use volumes and wastewater volumes based on Danish water use statistics
(DANVA, 2007; Kjellerup and Hansen, 1994; Nordhavnsgården monitoring data).
GW treatment and reuse scenarios
Scenario
Treatment type
Source of treated greywater
Reuse of treated greywater
A
No treatment
-
-
B
Indoor – RBC
Bathroom
Toilet
C
Indoor – RBC
Bathroom
Toilet + Irrigation
D
Indoor – RBC
Bathroom
Toilet + Laundry
E
Indoor – RBC
Bathroom + Laundry
Toilet
F
Indoor – RBC
Bathroom + Laundry
Toilet + Laundry
G
Indoor – RBC
Bathroom + Laundry
Toilet + Irrigation
H
Indoor – RBC
Bathroom + Laundry
Toilet + Laundry + Irrigation
I
Indoor – RBC
Bathroom + Laundry + Kitchen
Toilet + Laundry
J
Indoor – RBC
Bathroom + Laundry + Kitchen
Toilet + Irrigation
K
Indoor – RBC
Bathroom + Laundry + Kitchen
Toilet + Laundry + Irrigation
L
Outdoor – reedbed
Bathroom
Groundwater recharge
M
Outdoor – reedbed
Bathroom + Laundry
Groundwater recharge
Example of a treatment and reuse scenario
Scenario K
Irrigation
0 l p-1 d-1
Daily
potable
water use
85 l p-1 d-1
Bathroom
43 l p-1 d-1
Laundry
17 l p-1 d-1
Greywater
Treatment
Plant
85 l p-1 d-1
Potable H2O saving = 51 l p-1 d-1 (43 %)
WWTP influent reduction = 20 %
Laundry
17 l p-1 d-1
Sludge
Toilet
27 l p-1 d-1
Kitchen
25 l p-1 d-1
Toilet
0 l p-1 d-1
Irrigation
7 l p-1 d-1
Municipal
Wastewater
Treatment Plant
61 l p-1 d-1
Surplus
33 l p-1 d-1
Greywater pollutant dynamics (cadmium)
Irrigation
0 µg p-1 d-1
Irrigation
Bathroom
3.039 µg p-1 d-1
Potable
water
[A]
Laundry
4.65 µg p-1 d-1
Kitchen
1.58 µg p-1 d-1
Toilet
0 µg p-1 d-1
p-1
d-1
Potable H2O saving = 27 l
(23 %)
WWTP influent reduction = 11 %
Greywater
Treatment
Plant
3.039 µg p-1 d-1
Sludge
2.735 µg p-1 d-1
Laundry
0 µg p-1 d-1
[B]
[C]
No decrease
in load to
WWTP unless
Municipal
sludge is
Wastewater
removed
Treatment Plant
20.229 µg p-1 d-1
[D]
Toilet
11.155 µg p-1 d-1
Surplus
0.109 µg p-1 d-1
Decrease in
[F]
WWTP Cd
influent
loading of
2.74 µg p-1 d-1
[E]
Potential Cd
removal
efficiency of
13.5 %
Summary of Greywater Treatment scenarios
•
Domestic greywater is a significant source of micropollutants to the urban water cycle
but there is a lack of knowledge about micropollutant presence and fate in greywater
•
Wide range of potential greywater treatment trains and reuse options; combined with
the variable pollutant characteristics makes modelling difficult.
•
Sludge management is critical in determining the emission barrier potential
•
WFD PS/PHS not necessarily highest priority in terms of quantity used and/or risks
associated with use
•
Need to employ source control measures for decreasing the Greywater pollutant
contents (e.g. green labeling and procurement, substitution options, information
campaigns, and regulatory controls).
On-site treatment systems for industrial
wastewater
Classification of BAT techniques
Industrial wastewater treatment processes appropriate
for the removal of suspended solids and insoluble liquids
(6 techniques identified as A1 to A6)
• Industrial wastewater treatment processes appropriate
for the removal of inorganic/non-biodegradable/poorly
biodegradable soluble pollutants (15 techniques
identified as B1 to B15)
• Biodegradable soluble pollutants (4 techniques identified
as C1 to C4)
Industrial wastewater treatment database for
individual PPs
•
•
•
•
•
•
•
•
•
•
CAS number
Emission String number
Production process
NOSE-P classification
Production activity
NACE classification
Possibilities for substitution
Applicable treatment processes
BREF code of relevant document
Treatment efficiency and/or achievable emission levels
Extract from Cd database (specific treatment)
Applicable
treatment
processes
Treatment
BREF code
efficiency and
of relevant
achievable
document
emission levels
A2
Large
combustion
plant (BREF
07.06)
Waste water from desulpurisation plant contains
<0.05 mg Cd/l after
treatment
B1 combined with A2 or A3
or A4* .
B10
**.
*** B1
Speciality
+ A2
inorganic
chemicals
(BREF 08.07)
* Cd emission levels <0.01
mg/l.
**
efficient removal of Cd and
its compounds from low
feed concentrations. *** Cd
efficiently removed from
inorganic pigment waste
waters
B1 (co-precipitation at pH 9
with Fe(2+)* .
B1
(using sulphide) more
efficient than hydroxide
precipitation and can be
followed by A2 or A4.
Combinations of
technniques e.g. B1 + A2
followed by A5 and/or B8**
* Achieves Cd emissions in
waste waters of <0.1 mg/l
(B10 can be used for
further clean-up) .
**
Achieves very low metal
levels in final effluent.
Surface
treatment of
metals (BREF
08.06)
Extract from Cd database (generic treatment)
Generic treatment options for Cd
A2
Wastewater
treatment
(BREF 02.03)
B1
ditto
B8
ditto
B9
ditto
Using zeolites as adsorbent
ditto
Cation exchangers (Na)
give good removal of Cd
and compounds at low feed
concentrations
ditto
>99.8% removal when
sufficient sulphate present
to support sulphide
formation; emission levels
<0.01 mg/l from influent of
1 mg/l.
B10
C2
Specific treatment option for electroplating wastewaters
Non-ferrous
Electrodialysis and Reverse
metal
Osmosis widely used for
processing
soluble Cd
(BREF 12.01)
98% removal
Performance dependent on
situation
Nanofiltration achieves
>90% removal
>99.8% removal
Summary of Industrial Wastewater Treatment
• Databases for 25 non-substitutable industrial PPs showing on-site
reductions (removal efficiencies or achievable effluent levels) show
a variability of data availability and a wide range of different
performances.
• Information relating to a specific pollutant is often limited and
therefore generic techniques relating to similar pollutant
characteristics or overall treatment type are also included.
• The scientific principles involved in the treatment processes together
with the equipment and process details are well established.
Municipal wastewater treatment plants
Topics addressed
• Removal of pollutants in conventional and alternative
wastewater treatment plants
• Fate of priority pollutants in different treatment stages in
conventional waste water treatment plants
• Tools to predict the removal and fate of priority pollutants
in WWTP
Example of modelling results for primary treatment
100
STPWIN
FATE
Byrns
% removal per mechanism
80
60
40
``
20
0
f
f
f
f
f
f
nehanCHdrinenedrinCBDD(a)p(b) DT DT(k)drinDEhi)pd)p DT anehanCHdrinenedrinCBDD(a)p(b) DT DT(k)drinDEhi)pd)p DT anehanCHdrinenedrinCBDD(a)p(b) DT DT(k)drinDEhi)pd)p DT
a
D
D
D
D
D
D
D
D
c
c
D
D
l
l
l
H
H
D
b
H
H
D
b
H
H
D
b
l
l
l
b
b
b
h
d lp
d p
d p n h
g ( g ( b p- p- A
b p- p- A
b p- p- A D(g i(cp-D
n h
EnantDie
- p- pb( io-p linsul E antDie
b( io-p linsul E antDie
b olinsu
p
p
p- pr
r
r
o
o
o
o
o
o
d
d
d
flu
flu
flu
en
en
en
% Volatilsation
% Adsorption
% Biodegradation
Literrature
Percentage removal per mechanism during primary wastewater treatment
according to the three tested models
et
hy
le
chne
lo ch
r l
tr beofoor.
ic s n rm
hl im ze
o a n
te roe zine
te n tra atr th e
tr a ch az yl
ac ph l in .
hl th ori e
o
d
ch en roalene
e
lo do lin th e
rf s d y
en u a l.
vi lphne
np a
hn
oc
ty HCos
m an lph TCH
et th en B
hy ra o
le ce ls
chne ne
lo ch
r l
tr beofoor.
ic s n rm
hl im ze
o a n
te roe zine
te n tra atr th e
tr a ch az yl
ac ph l in .
hl th ori e
o
d
ch en roalene
e
lo do lin th e
rf s d y
en u a l.
vi lphne
np a
hn
oc
ty HCos
m an lph TCH
et th en B
hy ra o
le ce ls
chne ne
lo ch
r l
tr beofoor.
ic s n rm
hl im ze
o a n
te roe zine
te n tra atr th e
tr a ch az yl
ac ph l in .
hl th ori e
o
d
ch en roalene
e
lo do lin th e
rf s d y
en u a l.
vi lphne
np a
hn
oc
ty HCos
an lph T H
th enCB
ra o
ce ls
ne
m
% removal per mechanism
Example of modelling results for secondary
treatment
120
STPWIN
% Volatilsation
Byrns
% Adsorption
% Biodegradation
FATE
100
80
60
40
``
20
0
Literrature
Percentage removal per mechanism during secondary wastewater treatment
according to the three tested models for pollutants with log Kow < 4.5
Summary of municipal wastewater treatment
•
•
•
Experimental data exists for 14 of the priority substances originally identified
in the WFD
The removal and fate of an additional 19 priority substances has been
predicted using a combination of models (Byrns; FATE; STPWIN)
Overall, the data collected on 33 priority pollutants can be summarised as:
– 19 pollutants presented a removal efficiency higher than 80% (benzene,
naphthalene, tetrachloroethylene, chlorfenvinphos, 1,2,4-trichlorobenzene,
pentachlorophenol, endrin, p-p-DDT, fluoranthene, nonylphenols,
hexachlorobenzene, 4-para-nonylphenol, benzo(b)fluoranthene, aldrin,
benzo(g,h,i)perylene, o-p-DDT, DDE, DEHP and PBDE),
– 12 PPs exhibited removal efficiencies between 50 and 80% (methylene chloride,
chloroform, trichloroethylene, carbon tetrachloride, lindane, α-endosulphan,
HCH, octylphenols, anthracene, dieldrin, DDD and benzo(a)pyrene)
– 2 PPs (simazine and atrazine) demonstrated removal efficiencies lower than
40%.
PP behaviour in wastewater sludges
and evaluation of sludge disposal options
Sludge production and treatment
WW treatment systems producing sludge
•
Municipal wastewater treatment
–
•
Industrial wastewater treatment
–
•
e.g. Sedimentation tanks, Coagulation/flocculation, membrane filtration systems
Stormwater treatment systems
–
•
e.g. Anaerobic digestion (focus in ScorePP), membrane bioreactors
e.g. Sedimentation tank, detention ponds/basins (dry ponds), retention ponds/basins
(wet ponds), constructed wetlands
Greywater treatment systems
–
e.g. multi-stage rotating bioreactors, membrane bioreactors, soil filter systems – normal
removal process leads to a build-up of sludge/sediment.
Sludge treatment options
•
Thickening, dewatering (centrifugal, pressure based, electrokinetic),
stabilisation, conditioning, thermal reduction, sludge pasteurisation, aerobic
digestion, anaerobic digestion (mesophilic and thermophilic), drying,
composting, storage.
30
Summary of sludge treatment
• Primarily designed to reduce volume, odour and
pathogenic risk prior to disposal/reuse
• Guideline limits will become increasingly stringent for
sludges being disposed of by agricultural land
application, landfilling or incineration.
• Reuse options encouraged where feasible e.g. sewage
sludge in building materials, metal recovery from
electroplating sludge, exploitable by-products.
• The sustainability of many reuse options need careful
examination
Assessment of the feasibility of treatment options.
Priority Pollutant Focus
Feasibility assessment has concentrated on 12 PPs.
•
•
•
•
•
Benzene
Benzo(a)pyrene
Cadmium
Chlorpyrifos
DEHP (Di-(2-ethylhexyl)phthalate)
• Diuron
•
•
•
•
•
EDC (ethylene dichloride)
Lead
Mercury
Nonylphenol
PBDE
(pentabromodimethylether)
Agreed criteria for treatment techniques
Screening Criteria
Indicators
Benchmarks
Technical feasibility
Extent to which
appropriate technology
exists
Level of establishment or
development
Technical efficiency
Effectiveness of treatment Potential or actual ability
technology
of treatment technology to
remove target PP
Financial considerations
Costs associated with
treatment option
Investment costs and
operational/maintenance
costs
Environmental impact
Level of impact on
receiving water quality
Average annual dilution
required for receiving
water to achieve EQS
Scored matrices – Lead example
Treatment type
Pre-Environmental Release
Treatment
* = Insufficient data available
** = Data not calculable as
percentage removal efficiency
*** = data not calculable as a
dilution rate
- = Incalculable total score due
to data gaps
Treatment option
Criteria
Tech.
Feas.
Tech.
Effic.
Financ.
Cons.
Env.
Imp.
Total
score
B1 + A2 + A4
1
**
1
3
-
B1 + A2
1
**
1
3
-
A4
1
*
1
*
-
A4 + B8
1
1
1-2
***
-
A2
1
**
1
2
-
A4 + B1 + A2 + B10
1
**
1*
2
-
2
3
*
3
-
Retention pond
1
3
1
1
6
Infiltration trench
1
3
2
1
7
Infiltration basin
1
2
1
1
5
Porous paving
1
3
2
1
7
Filter strip
1
3
3
1
8
Swale
1
3
1-3
1
6-8
Porous asphalt
1
3
2-3
1
7-8
Settlement tank
1
3
1-2
1
6-7
Industrial treatments
Municipal wastewater treatment
WWTP
Post-Environmental Release
Treatment
Stormwater BMP treatments
Summary of treatment feasibility approach
• A treatment feasibility approach has been developed
despite the existence of data gaps and the problems
associated with non-comparability of inconsistent units
• Scoring protocols have been allocated according to the
available data but may not be suitable for all situations
e.g. the relevance of the local context
• Some parameters (e.g. pollutant removal efficiencies;
dilution ratios) may be oversimplifications in representing
specific criteria.
Application to substance flow analysis (SFA)
approach
Treatment barrier database
Treatment Barrier Database
Information on a
selected treatment
Assessment of the
potential treatments
38
Conclusions
• A unit process based approach applied to stormwater treatment by
BMPs enables removal of PHS/PS to be assessed.
• Greywater treatment and reuse can make a valuable contribution to
potable water savings and WWTP flow reductions but quality
improvements are strongly dependent on sludge management
• The existing BAT techniques together with developing treatment
options demonstrate taht a comprehensive range of efficient options
are available for the industrial control of PPs in process waters.
Conclusions (continued)
• A combination of experimental and modelling data provides relevant
information regarding the removal of PHS/PS in conventional
WWTPs.
• Sludge treatment needs serious future consideration as it is
becoming increasingly unacceptable to practice current disposal
routes for contaminated sludges.
• A treatment feasibility approach has been developed and provides
the basis for a multi-criteria analysis.