Constructed wetlands for wastewater treatment.pptx

Comprehensive Efficiency
of Constructed Wetland
Wastewater Treatment
Reporter:安奕

01
Overview
of wastewater
treatment in CWs

Physical process
When water flows through wetlands, the flow rate
slows down, which is conducive to wetland
filtration, deposition, and adsorption of pollutants.
Chemical process
Biological process
Microbial interpretation and transformation of
pollutants, such as nitrification and denitrification.
Mechanism of pollutant removal
Complexation and precipitation of pollutants
adsorbed in wetland pores with other ions in soil
。
Overview of wastewater
treatment in CWs
Evaluation of different
sewage treatment effects
Advantages of
constructed wetlands

treatment in CWs
Development of constructed wetlands in China
01 02
Publications related to the search topic
“Constructed wetland”from WOS and CSCD,
with author address belonged to China.
Annual quantity of constructed wetlands in China
Advantages of

Wastewater treatment plants are still the
main method of wastewater treatment in
China, but the growth rate of wastewater
treatment capacity in constructed wetlands is
significantly higher than that of wastewater
treatment plants. Overall, as the number of
constructed wetlands increases year by year,
their contribution to wastewater treatment
will increase year by year.
treatment in CWs
Advantages of

Characteristics
• SF systems are most commonly used
• The substrates are mainly natural materials such as soil, coarse sand, and grave
treatment in CWs
Advantages of

Advantages and limitations of CWs
Cons
Pros
· less expensive
·natural processes
·simple construction
·cost effectiveness
·process stability
·simple operation and
maintenance
·large area requirement
· may be economical
relative to other options
only where is available
and affordable.
·design criteria have yet
to be developed for every
types of wastewater and
climates.
Advantages of CWs Limitations of CWs
treatment in CWs
Advantages of

02
Evaluation of
different sewage
treatment effects

Domestic sewage
Domestic sewage is the wastewater discharged from
residents' daily lives, mainly from residential buildings and
public buildings, such as residential buildings, offices,
schools, hospitals, shops, public places, and industrial
enterprise toilets. The pollutants contained in domestic
sewage are mainly organic substances (such as proteins,
carbohydrates, fats, urea, ammonia nitrogen, etc.) and a large
number of pathogenic microorganisms (such as parasitic eggs
and intestinal infectious viruses, etc.)
Characteristics of domestic sewage
treatment in CWs
Advantages of

Domestic sewage
·In general, most constructed wetlands have good removal effects
on chemical oxygen demand(COD)、BOD5、NH4
+-N、TP、SS
treatment in CWs
Advantages of

Domestic sewage
·INTRODUCTIONS
The constructed wetland at Sunga was constructed in the year 2005, treating municipal domestic
wastewater.The total area of the constructed wetland is 375 m2 (HF-150 m2, VF-150 m2 and SDB-70 m2)
Figure:Schematic representation and site photo of CW at Sunga
Figure:Performance of constructed wetland at Sunga from August 2006 to August 2007
Case studies: The constructed wetland at Sunga
treatment in CWs
Advantages of

Majed Alsubih’s study evaluates the combination of macrophyte CW-along with
a tubesettler system to remove PhACs. The study concluded that CW could be
successfully used to treat hospital wastewater.[1]
Swine Wastewater
Wang Lisha et al. adopted the research method of field positioning observation
and established a surface flow wetland system of green foxtail algae, aiming to
provide a parameter basis for the ecological treatment of subtropical high load
pig wastewater.[2]
Petroleum-containing Wastewater
In order to study the purification effect of constructed wetland systems on
petroleum-containing wastewater, Xiang Wei et al. constructed four
groups of constructed wetland systems to conduct treatment experiments
in the field environment. [3]
Industrial Wastewaters
Hospital Wastewater
treatment in CWs
Advantages of

Hospital Wastewater
Schematic diagram of constructed wetland setup employed in this
study to evaluate the pharmaceutical removal efficiency.
Operational conditions of Constructed
Wetland setup.
Parameter
Construction type
Post treatment
Macrophyte species
Filter material
Filter bed
Specification
Horizontal Surface Flow
Tube settler
Phragmites australis
Natural River Sand of local origin (mainly quartz)
0.2 m thickness
• A constructed wetland was a built-in outdoor environment
comprising galvanized sheets with the dimension of length
(1.5 m), width (0.65 m), and depth (0.5 m).
• The sand bed was 0.2 m thick, which supported the growth
of phragmites australis.
treatment in CWs
Advantages of

Hospital Wastewater
(a) illustrates the Paracetamol removal efficiency by Wetland concerning time (weeks),
(b) Ketoprofen removal efficiency by Wetland concerning time (weeks),
(c) Ciprofloxacin removal efficiency by Wetland concerning time (weeks).
I = influent, E = Effluent, and CWR = built wetland removal efficiency.
treatment in CWs
Advantages of

Swine Wastewater
Engineering parameters of M． elatinoides constructed wetlands
Design parameters CW1 CW2 CW3 CW4 CW5 CW6
Area/m2
Effective water depth/m
Hydraulic load/m ·
Hydraulic retention time/d
194 194 183 270 319 437
0.4 0.4 0.4 0.6 0.6 0.6
0.14 0.14 0.14 0.1 0.08 0.06
2.9 2.9 2.7 6 7.1 9.7
• The table describes Engineering parameters of constructed wetlands.
• The wastewater flows through a Grade 6 wetland and is discharged into adjacent ditches through the outlet.
• Paddy soil is used as the substrate.
• CW1, CW2, CW3, CW4, CW5, and CW6 represent first, second, third, fourth, fifth, and sixth level wetlands, respectively
treatment in CWs
Advantages of

Swine Wastewater
• The contribution of plant absorption to N and P is not significantly different.
• The contribution of sediment adsorption to TP removal is significantly higher than that to TN removal.
• Constructed wetland has a good treatment effect on swine wastewater, with an average pollutant removal rate of over 90%.
Contaminant mass balance
Project
input
kg
output
kg
absorption
g/(m2 · d)
absorption
rate %
plant absorption
g/(m2 · d)
ratio
%
sediment adsorption
g/(m2 · d)
ratio
%
others
%
TN 3917.5 114.86 9.92 97.1 1.89 19.1 1.96 19.8 61.1
TP 391.12 32.87 0.94 91.6 0.19 20.2 0.58 61.7 18.1
2978.09 76.31 7.57 97.4 —— —— —— —— ——
COD 7766.69 781.75 18.22 89.9 —— —— —— —— ——
−
treatment in CWs
Advantages of

Stormwater runoff
Treatment effect
Constructed wetlands
can significantly improve
the quality of urban and
rural runoff, especially in
terms of nitrogen and
phosphorus removal.
The concentration of pollutants in urban road surface
rainwater runoff is high and varies widely, especially
the concentration of COD and SS in initial runoff is
much higher than that in typical domestic sewage
Characteristics of rainwater runoff
treatment in CWs
Advantages of

Stormwater Runoff
·Introductions
Zonglvquan CW is located in Chongqing province
, a typical urban residential area runoff treatment
constructed wetland, which is a composite treatment
system combining HSSF and SWF.
Figure:Schematic representation of Zonglvquan CWs
Zonglvquan constructed wetland has a good
removal effect when operating under no impact
load, and also has a good control effect on the
concentration of runoff pollutants under rainfall
impact load.
Case studies: Zonglvquan constructed wetland
treatment in CWs
Advantages of

Secondary effluent
Nowadays, people are increasingly using constructed wetlands for tertiary treatment of
urban sewage. After advanced treatment of secondary effluent from constructed wetlands,
the final effluent can meet the requirements of toilet flushing, irrigation, and road
flushing.
treatment in CWs
Advantages of

Secondary effluent
(A)The core structure of the IVCW,
(B)The flow chart of treatment process by IVCW in
Beijing Olympic Forest Park
(C , D)The sightseeing of the IVCW
The main objective of the CW in
the Olympic Forest Park, an IVCW,
was to purify water from the
WWTPand recycle lake water as
well,tail water from the WWTP was
used as the water sources for the
dragon-shaped water system in the
Beijing Olympic Forest Park, and
the CW was mainly for the
improvement and maintenance of
water quality.
The CW in Beijing Olympic Forest Park
Case studies:
treatment in CWs
Advantages of

03
Advantages of

Treatment of ECs
In recent years, emerging contaminants (ECs), such as
pharmaceuticals and personal care products (PPCPs) and
endocrine disrupting chemicals (EDCs), have increasingly
gained attention.
CWs are considered to be reasonable options for treating ECs
due to its lower cost, easy operation and less maintenance
requirements.(Wu et al., 2015b, Liu et al., 2016)
treatment in CWs
Advantages of

Treatment of ECs
treatment in CWs
Advantages of

Treatment of ECs
>80%
60%-80%
40%-60%
0-40%
<0
Contribution of removal=(C -C )/C
inlet outlet RL
Combined
pretreatment
Pretreatment
+Reed beds
ECs
Pretreatment Reed
Beds
Total
removal
EQ Aer Sed PP Out
BPA >99.9% >99.9% >99.9%
ACT 82.2% 92.8% 91.4%
GFZ 80.3% 97.2% 94.0%
DEET 93.9% 98.0% 93.1%
CF 73.7% 89.4% 80.3%
SA 76.2% 82.6% 77.2%
DCF 79.2% 99.4% 91.8%
CA 94.9% 99.8% 99.9%
SMZ >99.9% 99.1% 99.9%
RL: raw landfill leachate; EO:equalization tank; Aer: aeration lagoon;
Sed: sedimentation tank; RB: reed bed; PP: polishing pond; 0ut: outlet.
The overall removal of PPCPs and EDCs in the hybrid CW system were greater
than 77.2% (Left Table ). In particular, several compounds, such as BPA, CA,
and SMZ, exhibited excellent removal efficiencies (>99.9%).[4]
treatment in CWs
Advantages of

Economic, social, environmental triple effect
Economic effect：The economic functions of CWs include not only direct utilization
values such as providing economic products of wetlands to humans, but also indirect
utilization values such as maintaining hydrological cycles and purifying the
environment.
Social effect：The rich landscape elements and species diversity of constructed
wetlands make them rich in social functions such as tourism, education, and
scientific research.
Environmental effect：Constructed wetlands can degrade sewage, purify water
quality, regulate climate,and provide habitat for species.
treatment in CWs
Advantages of

Outlook
As a new process of sewage treatment with
low cost, simple operation and adjustable
treatment unit, wetland construction can
reduce the cost of sewage classification
treatment, which has broad application
prospects.
Further research should effectively judge
the effect of substrate, microorganism and
plant on removing pollutants, so as to
strengthen the removal efficiency of
constructed wetland and further expand the
application range of constructed wetland.
treatment in CWs
Advantages of

Constructed wetlands for wastewater treatment.pptx

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