Presentation on the Gotland demonstration case for the EU's project NextGen.

1. 1
Circular solutions for
Water
#7 Gotland
Sweden
Relevant data
Relevant sectors
Tourist
industry
Municipal
sector
Water
sector
Lead partners
Storsudred testbed area: 14 000 ha
Habitants during winter: 900
Habitants during summer : 1800
Tourists per year: 300 000

2. 2
1. Objectives of the NextGen solutions
• Rainwater harvesting using automatic
floodgates to replenish aquifers and
monitoring of aquifer levels
• Decentralized membrane treatment of raw
wastewater to reduce volumes treated at the
central WWTP
• Climate efficient wastewater reuse
powered by solar energy to overcome
carbon footprint drawbacks
• Optimized membrane filtration for
producing drinkable water from challenging
surface water
• Storage of water in subsurface dams
Water

3. 3
Technology Evidence Base (TEB)
Gotland
1. Objectives of the NextGen solutions
Positioning of demo case within the CE

4. 4
T 1.2.1. Decentralised membrane treatment
powered by solar energy
2. New NextGen solutions
PRE-FILTRATION
COAGULATION AND
ULTRAFILTRATION
UV
SEDIMENTATION
SCREEN
DISC FILTER
ULTRAFILTRATION
REVERSE OSMOSIS
UASB
Annamox
PRECIPITATION
CHLORINATION
UV
PRECIPITATION
Treatment in the WTP  drinking water
Decentralised membrane treatment  regenerated water
Sewage
water
Recovered
water
Sewage
concentrate
to external
WWTP
Solar energy
Circular
water
systems

5. 5
T 1.2.1. Drainage ditches with IoT for flow and water levels control
2. New NextGen solutions

6. 6
T 1.2.1. Controlled nautral ponds dams for storage
2. New NextGen solutions
Keep the surface level during the summer
by an autmatic flood gate
Inflow, ditch, hatch
Burgsvik village
Lake
Reclaimed
waste
water
25 000 m3
Damed lake will store
100 000 m3
To pilot WTP for production of
60 000 m3 drinking water
quality
Water balance established but
the automatic floodgate is
foreseen to have delays of 9 –
12 months before testing the
system (summer 2021).

7. 7
T 1.2.1. Groundwater dams for subsurface water storage
2. New NextGen solutions

8. 8
3. Specific KPIs (actual vs expected)
Case
study
Topic Objectives
Specific Key Performance Indicator
(KPI)
Starting
value
Expected
value
#7
Gotland
(SE)
Wastewater
treatment
and reuse
To treat the wastewater by a
decentralized membrane treatment
to obtain regenerated water for being
stored in the controlled neutral ponds
dams and, after another treatment, to
be used as potable water
Water yield of Water yield of the system [%
of regenerated water produced] water
produced]
0
10 %
80, 95, 75
Water quality - Removal yield [%] of the
following parameters (outlet vs inlet):
conductivity, COD, ammonia,
Rainwater
harvesting
Rainwater harvesting and storage in
surface dams & lake.
Collection capacity [m3/year] 100 000
Drainage
ditches with
IoT
Flow and water levels measuring and
control
Flow and water levels measured and
controlled
Every 10-30 min
Aquifer
storage
Rainwater and lake water used in the
water treatment plant for obtaining
drinking water
Pilot capacity [m3/year]
100 000
80, 10, 50, 80,
10, 99
Water quality - Removal yield [%] of the
following parameters (outlet vs inlet):
metals, conductivity, color, COD, some
anions and E.coli.
Energy
Use of solar panels to minimize
electricity consumption during
wastewater reuse (summer)
Electricity consumption [kWh/m3
regenerated water]
3

9. 9
4. Results
T 1.2.1. Decentralised membrane treatment of sewage powered by
solar energy
Off-site tests
Water quality Water recovery yield
Energy consumption
Parameter Removal (%)
NH4
+ 90%
COD 88%
Conductivity 99%
TSS (No filter) 0%
TSS (20 𝜇-filter) 40%
TSS (30 𝜇-filter) 23%
TSS (150 𝜇-filter) 6%
Parameter Value
Concentration Factor (CF) for the UF 10-25
Concentration Factor (CF) for the RO 7.3
Global CF 4.5 – 5.8
Water recovery 78 – 83%
Off-site tests finalized. Pilot under construction. Pilot operation: March 2021

10. 10
4. Results
T 1.2.1. Drainage ditches with IoT for flow and water levels control
1 300 000 m3 / year
flows out to the sea
Rain per day
Ground water level
IoT for establishment of water balance since 2019.

11. 11
4. Results
T 1.2.1. Controlled neutral ponds dams for storage
Water quality
Inflow and outflow of water to lake Mjölhatteträsk plotted with precipitation data. IoT-sensors
installed at MY3 and MY1.
Water quantity
Automatic floodgate and membrane filtration spring 2021

12. 12
4. Results
T 1.2.1. Groundwater dams for subsurface water storage
• Detailed investigation will finalized in
November 2020
• If positive: Large scale capacity test in
January 2021
2
2

13. 13
5. Lessons learned
• When it comes to on-site evaluation at an far-away island of a number parameters,
including communication with land-owners, pandemic out-breaks is a hinder for rapid
achievements
• Even by use of novel technologies and innovative methods, it is hard to predict
overburdens (e.g. clay versus sand).
• Unforeseen challengers is time-consuming but will result in new ideas and solutions
that are interesting, fun and pushes the development forward .
(Maybe not a very new lesson learned but confirms your experiences).

14. 14
Thank you!
staffan.filipsson@ivl.se
www.ivl.se
xtGen - Community of Practice
14
anna.serra@eurecat.org
sandra.cases@eurecat.org