WASTEWATER TREATMENT & REUSE
SLUDGE
DEWATERING
IMPROVEMENT
AT
KUNSHAN
CITY WWTP
JianBang WWTP has replaced powder flocculants with
Kemira EPAM.
By Kemira
Figure 1: Jar Test
32
EverythingAboutWater | September 2014
Figure 2: Actual Performance 26 m3/h
www.eawater.com/eMagazine
Keywords: Sludge Dewatering, Flocculants, Polymer
WWTP of JianGong LuJia is one of the five
WWTPs that belong to JiangBang Group.
JianBang Group is a wholly-owned subsidiary of
BeiKong Water Group which is located in LuJia
Town, KunShan city. It treats mostly domestic
sewage and partial industrial sewage by using
MBR process. Three units of belt press are the
sludge concentration and dewatering devices
with the capacity of 30 cubic meters per hour per
unit.
www.kemira.com
link emulsion polymer - SuperFloc SD2085.
With special molecular structure, the sludge
dewatering performance improved because the
cross link structure is more resistant to shearing.
Cross link type of polymer has advantage over
normal powder flocculent for belt press filter.
RMB/
day
RMB/
year
Depreciation charge of extra
109.59
unit
40,000
Technical Issues
Energy savings
100
36,500
When temperature drops, normally sludge
dewatering performance decreases and chemical
consumption increases. Many researches find out
that this is just because of extracellular polymeric
substances (EPS).
Savings by sludge reduction
166
60,590
Total savings
357.59
137,090
LuJiang WWTP was experiencing the same
issues caused by EPS. Nevertheless, extra sludge
from MBR system makes the sludge dewatering
even harder. Several trials with different powder
flocculants failed. Sludge water content was more
than 80% and maximum capacity of each unit
could only reach 18 cubic meters per hour.
Kemira Application
After onsite technical survey, Kemira’s expert
recommended high performance and cross
Items
Chemical treatment cost only increased very little.
Annual net savings now is about 123,950 RMB.
Now JianBang WWTP has replaced powder
flocculants with Kemira EPAM. It has become a
show case in the whole JianBang Group.
Chemical Cost
RMB/Day
RMB/Year
Original Treatment
384
140,160
Kemira EPAM
420
153,300
Savings
-36
-13,140
Table 2: Chemical Cost Comparison
Table 1: Cost Savings
Return on Investment
Direct Benefits:
 Efficiency Improvement: Capacity of the
belt press increased from 18 m3/h to 26
m3/h per unit. It improved by about +44%.
Because of that, one extra unit of belt press
filter was saved.
 Performance Improvement: Water content
of sludge cake decreased from 82% to
consistent 80% which meets the national
Figure 3: Sludge Cake, +20% Dry Solids
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discharge standard. Total daily discharged
sludge was reduced about 2 tons.
About the Contributor
Kemira provides application know-how and
combinations of chemicals for water-intensive industries.
They focus on pulp & paper, oil & gas, and mining and
water treatment. They enable municipal and industrial
customers to improve their water treatment efficiency
by providing expertise and chemicals for raw and waste
water management.
To know more about the contributor, you can write to
us. Your feedback is welcome and should be sent at:
[email protected]. Published letters in each issue
will get a one-year complimentary subscription of
EverythingAboutWater Magazine.
Figure 4:Sludge Cake Thickness, ~ 1cm
September 2014 | EverythingAboutWater
33