Solwa2

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.

Leachate: the problem

Leachate: the treatmentThe 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.

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

Leachate yield

• 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)

PRODUZIONE DI PERCOLATOdiscarica di PONTE SAN NICOLO', lotti B e C

-2.0004.0006.0008.00010.00012.000

1997 1999 2001 2003 2005 2007 2009 2011anno

mc

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.

SOLWASOLWA (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.

The project: solar still plantAIM:

•In-situ leachate treatment (DGR 264/13)•Extract the water and discharge into surface water bodies•Using solutions of high environmental value

First testsThe leachate was treated with the solar still, with a water extraction of around 50% The RESULTS:

Chemical Compound Leachate Treated leachate (50% dewatering)

Water extract

pH 7,37 9,09 8,76Suspended solids (mg/l) 23 386 1BOD5 (mg/l) 150 300 1COD5 (mg/l) 485 1058 5Arsenic (mg/l) 0,0081 0,0123 0,0005Cadmium (mg/l) 0,001 0,001 0,001Chrome total (mg/l) 0,03 0,4 0,01Chrome VI (mg/l) 0,01 0,01 0,01Iron (mg/l) 2,4 0,2 0,1Manganese (mg/l) 0,54 0,01 0,01Mercury (mg/l) 0,0005 0,0005 0,0005Nickel (mg/l) 0,15 0,41 0,02Lead (mg/l) 0,01 0,01 0,01Copper (mg/l) 0,22 1,16 0,01Zinc (mg/l) 1,05 0,15 0,05Chlorides (mg/l) 874 1387 0,3Fluorides (mg/l) 0,54 0,67 0,05Ammonia nitrogen (as NH4) (mg/l) 482 35,3 853Nitrous (as N) (mg/l) 0,01 0,01 0,01Nitric (as N) (mg/l) 0,2 0,2 0,2Hydrocarbon total (μg/l) 100 760 80Conductivity (μs/cm) 7200 10200 4410

The project: landfill plant

The exctracted water has high ammonia

concentration

Ammonia stripping

Dewater leachate has a ratio C/N = 10

Phytodepuration to treat the concentrate Water

discharge into surface

water bodies

River Discharge

Scrubber

River Discharge

SOLAR STILLS

LEACHATE TANK

Constructed wetland

Leachate

Solar radiation Water + ammonia

Dewater Leachate

Conclusions:

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);

The chemical analysis carried out show that the solar stills are capable of extracting an aqueous solution containing ammonia (NH4) with high concentrations (853 mg / liter)

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.

It appears that the solar stills are able to concentrate the leachate at least 50%, balancing the ratio C / N = 10

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.

Thanks for the attention