SOLWA (SOLAR WATER)METHOD FOR THE LANDFILL LEACHATE DEHYDRATION THROUGH SOLAR ENERGY – TESTING IN PONTE SAN NICOLÒ LANDFILL (Padua-Italy)

1. SOLWA (SOLAR WATER)
METHOD FOR THE LANDFILL LEACHATE DEHYDRATION
THROUGH SOLAR ENERGY –
TESTING IN PONTE SAN NICOLÒ LANDFILL (Padua-Italy)
Authors:
Franceschetti P.
Moretto A.
Atzori A.

2. Leachate: the problem

3. Leachate: the treatment
The leachate treatment must comply with:
•limited cost management/maintenance;
•simplicity of treatment and maintenance;
•autonomous systems to be placed directly on the landfill;
•durable equipment for operational and post-operational;
•high environmental protection;
•use of renewable energy.

4. Ponte San Nicolò (PD) landfill
• Waste disposal from 1989 still 1999, closed in the 2002
• Total volume = 791.000 m3 equal to 812.247 ton of solid wastes
• Equipped with biogas recovery plant since 2003, has produced 1,264,000
kWh (year 2012)
• Installed in 2010 1 MWp photovoltaic plant on 2ha of coverage, lot C,
which produces 1,163,000 kWh / year (year 2012)
Landfill high vocation experimental and innovative research, with
lots B + C property of the Bacino Padova 2

5. Leachate yield
PRODUZIONE DI PERCOLATO
discarica di PONTE SAN NICOLO', lotti B e C
mc
12.000
10.000
8.000
6.000
4.000
2.000
1997
1999
2001
2003
2005
anno
2007
2009
2011
• Lots B + C have a surface area of 134,000 m2
• Capping with 30 cm of clay material + 80 cm of soil
mixed
• Average yield of leachate of about 7600 m3/year
• Leachate collection wells with pneumatic suction
pumps
• storage in several leachate tanks and sent to waste
water treatment plant with tankers (1-2 trips / week)

6. The solar still
Solar stills use in the treatment of solutions containing water,
advantages:
•the absence of external sources of supply;
•low maintenance;
•ease of management, without the need for trained personnel;
•reduced cost and limited to the initial investment.

7. SOLWA (SOLar Water)
The advantages of solar still SOLWA to the treatment of landfill leachate:
•Continuous flow operation;
•Maintenance close to zero;
•Air recirculation with lack of external odor;
•Increased capacity of treatment;
•Extraction of 50% of the initial water from the leachate.

8. The project: solar still plant
AIM:
•In-situ leachate treatment
(DGR 264/13)
•Extract the water and
discharge into surface water
bodies
•Using solutions of high
environmental value

9. First tests
The leachate was treated with the solar still, with a water extraction of
around 50%
The RESULTS:
Chemical Compound
pH
Suspended solids (mg/l)
BOD5 (mg/l)
COD5 (mg/l)
Arsenic (mg/l)
Cadmium (mg/l)
Chrome total (mg/l)
Chrome VI (mg/l)
Iron (mg/l)
Manganese (mg/l)
Mercury (mg/l)
Nickel (mg/l)
Lead (mg/l)
Copper (mg/l)
Zinc (mg/l)
Chlorides (mg/l)
Fluorides (mg/l)
Ammonia nitrogen (as NH4) (mg/l)
Nitrous (as N) (mg/l)
Nitric (as N) (mg/l)
Hydrocarbon total (μg/l)
Conductivity (μs/cm)
Leachate
7,37
23
150
485
0,0081
0,001
0,03
0,01
2,4
0,54
0,0005
0,15
0,01
0,22
1,05
874
0,54
482
0,01
0,2
100
7200
Treated leachate (50%
dewatering)
9,09
386
300
1058
0,0123
0,001
0,4
0,01
0,2
0,01
0,0005
0,41
0,01
1,16
0,15
1387
0,67
35,3
0,01
0,2
760
10200
Water
extract
8,76
1
1
5
0,0005
0,001
0,01
0,01
0,1
0,01
0,0005
0,02
0,01
0,01
0,05
0,3
0,05
853
0,01
0,2
80
4410

10. The project: landfill plant
Solar radiation
Water +
ammonia
Leachate
Dewater leachate
has a ratio C/N = 10
Dewater Leachate
River Discharge
Constructed wetland
Ammonia stripping
River Discharge
LEACHATE TANK
Scrubber
Phytodepuration to
treat the concentrate
The exctracted water
has high ammonia
concentration
SOLAR STILLS
Water
discharge
into surface
water bodies

11. Conclusions:
The chemical analysis carried out show that the solar stills are capable of extracting an
aqueous solution containing ammonia (NH 4) with high concentrations (853 mg / liter)
The change in the system with solar stills allows to:
1.Halving the volume to be treated, concentrating the ammonia in 50% of water extracted;
2.Ability to extract pure ammonium salts for commercial use (agricultural use);
It appears that the solar stills are able to concentrate the leachate at least 50%, balancing
the ratio C / N = 10
1. Possibility of realizing a conctructed wetland system capable of blocking the various
pollutants;
2. Discharge into surface water body without using any chemical compound or complex
plant.

12. Conclusions:
The SOLWA solar stills have demonstrated, for the first time, as the
technology of solar still is applicable to the treatment of landfill leachate,
with the following advantages observed:
1.no emission of odour or other volatile compounds in the atmosphere;
2.good capacity for removal of water from the leachate;
3.use of renewable energy sources;
4.possibility of application of the system on site (landfill);
5.low maintenance and operational specialization;
6.reducing the cost of handling, transportation and disposal of leachate;
7.project highly eco-friendly.

13. Thanks for the attention