The wastewater treatment plant of Iraklion receives and treats urban wastewater from the greater Iraklion town complex (“Iraklion”, “Nea Alikarnassos” and “Gazi”). The total incoming load (annual average) is 11.20 kg BOD/day. The total incoming flow is 32,960 m³/day. The average daily allowance in winter time is 30,530 m³/day, while 47,089 m³/day in the summer.
The reclamation facility of Iraklion includes the biological unit of the city, a large complex of central separating conduits, secondary drains and also pumping stations built below ground level. The pumping station is equipped with submersible pumps capable of safely guiding the course of the reclaimed water. The pipeline is 3.855 meters long and the undersea pipeline is 12 meters and stays within a radius of 1 km from the coast with diffusion through diffusers. There are also two biological reactors for the wastewater treatment (anoxic and aerobic 2 x 2,009 m³ = 4,018 m³).
The reclaimed water is used to irrigate cultivated areas with grapes, mainly raisins and currants, as well as grapes for wine production and table grapes. The reclaimed water is used to a lesser extent for the irrigation of olive trees in the settlement of ‘Profitis Elias’, located at the southwest of the city of Iraklion.
Nutrient removal - Filtration-flocculation unit
Pesticide removal
Desinfection - microfiltration, Ultraviolet disinfection (UV) with open type channel
Suspended solids removal
Other
In 2012, the wastewater treatment plant was initially designed for 170.000 population equivalents (pe). The capacity will increase to 257.000 pe by 2032. The daily water in summer and sewage effluent was calculated for the year 2012 at 33,000 m³ and estimated for the year 2032 at 52,700 m³. The effluent from the tertiary treatment the irrigation of agricultural land counts 9,500 m3/day.
The extent of the agricultural land which is benefitted from the treated wastewater is 570 ha. Of all the crops, 62.61% is irrigated with reclaimed water. Additional irrigation sources are water stored in reservoirs (17.92%), well water (11.75%) and water from drilling (7.71%).
The cost of reclaimed water is below 0.5 euro/m3.
Roditakis, A. (2018). Urban underwater management. The case of the Wastewater Treatment Plant in Heraklion, Crete. Evaluation of the reuse of treated wastewater for irrigation. https://doi.org/10.13140/RG.2.2.20473.11369
