WASTEWATER TURBINING BEFORE AND AFTER TREATMENT :
AN OPTIMAL USE OF EXISTING INFRASTRUCTURES Vincent Denis MHyLab 1354 Montcherand Switzerland vincent.denis@mhylab.com
17/06/2008
1
Wastewater turbining before treatment • Town at high altitude • Pretreatment station at the penstock inlet instead of at the wwtp inlet. Pretreatment station
Wastewater treatment plant WWTP
Small hydropower plant 17/06/2008
•Wastewater treatment plant in the valley collecting wastewater from miscellaneous urban areas •Possibility to use the difference in level for turbining purpose 2
Wastewater turbining after treatment •Difference in level between the WWTP outlet and the restitution (lake or water stream).
WWTP
Wastewater treatment plant
•Possibility to use this difference for turbining purpose WWTP
Small hydropower plant 17/06/2008
3
The As Samra WWTP project Necessity of building a new WWTP for Amman city and neighborhoods BOT contract between the Jordan government and Degrémont Suez group. Search for an optimum technical solution allowing a maximum energy recovery within the WWTP.
17/06/2008
4
The Amman city and neighborhoods sewage system New (2005) DN 1500 penstock
Amman City Old DN 1200 siphon pipe
Zarqa Ghazal pumping station Ain pretreatment plant Hashimiyya to As Samra DN 500 pipe
Duleil Wadi Old lagoon WWTP
New As Samra WWTP 17/06/2008
5
As Samra WWTP main characteristics More than 100 m head between Amman and As Samra More than 40 m head between As Samra and the nearest water stream 268'000 m3/day of raw water to be treated => Important hydro potential 17/06/2008
6
Our involvement in the project Pre feasibility and feasibility studies Detailed design
Tender document preparation and bid analysis Workshop inspection (in partnership with
)
On site commissioning test (in partnership with 17/06/2008
) 7
As Samra WWTP process
17/06/2008
8
New Wastewater treatment plant Inlet SHP
Outlet SHP Lagoon wwtp
As Samra WWTP general overview
50,000 m3/day
New wwtp 250,000 m3/day
17/06/2008
9
Inlet small hydropower plant Gross head : 104 m Only DN 1500 pipe can be used for power generation
Average hourly flows at Ain Ghazal 2005-2025 4.60 2005 2007 2009 2011 2013 2015 2017 2019 2021-2025
4.40 4.20 4.00 3.80 3.60 3.40 3.20 3.00
Flow m3/s
Maximal turbine discharge limited by the head losses of the existing penstock => Hn > 70 m
2006 2008 2010 2012 2014 2016 2018 2020 Max turbined flow
2.80 2.60 2.40 2.20 2.00 1.80 1.60
Design maximal discharge = 2.5 m3/s
1.40 1.20 1.00 0.80 0.60 0.40
Surplus flowing through DN 1200 pipe 17/06/2008
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Hour
10
22
23
24
The inlet structure and its power plant Choice of Pelton instead of Francis turbines despite of the low head : •Easy to clean
•Limited risk of clogging •Good flexibility towards inlet discharge variations 17/06/2008
11
The inlet turbines
2 five-nozzle Pelton Z = 104 m Qn = 2 x 1.25 m3/s Hn = 79.3 m @ Qn N = 428.57 rpm Pe = 2 x 830 kW E = 12.5 GWh/year Commissioning : April 2007 Supplyer : Andritz VA Tech
17/06/2008
12
Raw water turbines design constraints Trashes driven by the flow Strong head variation between part and nominal load Penstock's length (> 30 km) Strong H2S concentration 17/06/2008
13
Outlet small hydropower plant Gross head : 42.1 m 2000 m of DN 2000 GRP pipe
As-Samra outlet small hydropower plant Average turbined flows 2007 - 2025 5.00 4.50 4.00 3.50 3.00
Discharge m3/s
No intermediate storage between the WWTP outlet and the small HPP
2.50 2.00 1.50
The whole outlet discharge must flow through the power plant
2007 2011 2015 2019
1.00 0.50
2008 2012 2016 2020
2009 2013 2017 2021-2025
2010 2014 2018
0.00 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
Hour
Design maximal discharge = 4.6 m3/s 17/06/2008
14
22
23
24
The outlet hydropower plant Choice of Francis turbines instead of reverse pumps. No need for a storage (no cyclic operation) Better flexibility towards inlet discharge variations Better mechanical efficiency Choice of two turbines to increase the flexibility
17/06/2008
15
The outlet turbines
2 horizontal Francis turbines Z = 42.1 m Qmax = 2 x 2.3 m3/s Qn = 2 x 2.0 m3/s Hn @ Qmax = 41.6 m @ Qmax N = 1'000 rpm Pe = 2 x 807 kW E = 8.6 GWh/year Supplyer : Andritz VA Tech
17/06/2008
16
Treated water turbines design constraints ď‚&#x; Residual pollutant load ď‚&#x; Residual Cl2 load due to water chlorination
17/06/2008
17
Conclusions The four turbines installed at As Samra will generate 21 GWh/year, 1/3 of the treatment plant yearly consumption. Important ecological dimension as Jordan generates its electricity mainly from oil. This production will allow to avoid the emission of more than 17'000 tons CO2 per year. 17/06/2008
18
For more information Please contact us at : info@mhylab.com www.mhylab.com
17/06/2008
19