Specialist Group on Use of Macrophytes in Water Pollution ... - IWA

Rovigo Province Landfill Site Leachates Treatment – Villadose , Rovigo
Ecogest Srl, the company which manage the waste cycle in the Rovigo province, has realised
a natural treatment system for solving their high expenses in transporting the leachates
produced in their landfill site to a delocalized WWTP; for the difficult nature of this kind of
wastewater the adopted design is also quite complex. The CWs system is a multistage plant
which will be able to treat from 10 to 40 m 3 /d and it‘s composed by: a peat filter, a 2 stages
vertical submerged flow CW, an horizontal submerged flow CW, a Free Water System and
finally a storage pond. The final effluent can be pumped back to the landfill for capping
irrigation or discharged in a small ditch. The total area of the treatment plant is about 5800
m 2 . The total cost for the CWT is about 1,2M €. Considering that at the moment the cost for
the leachates treatment in a near WWTP is above 30 €/m3, the total investment will be paid
back in a maximum of 3 years of operation at full capacity.
Villesse-Gorizia Highway – stormwater treatment by delocalised CW systems
Within the elaboration of the Detail Plan for the highway connection in Villesse-Gorizia,
natural treatment technologies have been adopted as appropriate methods to minimize the
highway runoff impact, to set environmental mitigation zones and to improve infrastructure‘s
landscaped insertion. The adopted design takes into account the underground water high
vulnerability; in general terms the treatment train (in total nearly 60 CWs for approximately
17 Kms of highway) consists in a ―off-line‖ scheme as following: 1) rough screening by a
mechanical grid, primary physical treatment by a first flush sedimentation tank, followed
from a high performance degreaser (Coalescence filter); 2) a subsurface horizontal flow
constructed wetland; 3) a Wet Pond, that receives effluents from the previous sections
together with the second flush, assuring therefore also to this last amount of lightly polluted
water a certain degree of treatment; 4) a final vegetated retention area, which acts like an
infiltration area for groundwater recharge and at the same time like a high efficiency
evapotranspiration sector. Only in five cases the vegetated retention area was not requested
because it was possible to discharge in a significant water-body, the Isonzo river; in two of
this cases, the choice was an on-line treatment, constituted by a sand-removal tank, a
degreaser and a submerged flow constructed wetland specially designed for stormwater
events.
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IWA <strong>Specialist</strong> <strong>Group</strong> on Use of Macrophytes in Water Pollution Control: Newsletter No. 35 29