our plant in tortona represents the evolution and technical and management optimization of traditional composting plants. Anaerobic digestion applied to the treatment of the organic fraction of sorted waste is, in fact, a process that helps limit environmental impact and optimizes management and recovery processes through the production of biogas, which is used for the production of electrical and thermal energy.

Anaerobic digestion plantTORTONA (Alessandria)

the tortona plant, in a strategic position within the Milan-turin-Genoa industrial triangle, is made up of two distinct areas arranged in series.

In the first, anaerobic biodigestion takes place. This is where the bio-masses delivered undergo a biochemical type conversion that pro-duces biogas and a stabilized residue resulting from the digested sludge. in the second, already in operation since 1995 and today undergoing revamping, the digested matter is transformed into com-post, a stabilized product to be used as an organic soil conditioner in agriculture and for environmental rehabilitation.The Tortona plant is extremely modern in every respect thanks to its use of the best technology existing on the market today and due to

the maximum reduction of environmental impact resulting from the new establishment under construction. For this reason, the tortona site is part of a major research and development project financed by the Ministry of Economic Development within the “industria 2015” project.

overall the plant allows for the treatment of 33,000 t/year of oFMSW from separate waste collection, 7,000 t/year of lignocellulose fraction, and the equivalent of 2,000 t/year of sewage sludge, that can be adapted with the oFMSW to up to 10,000 t/year.

Plant characteristics and purpose

oFmSw RecepTIon pRe-TReATmenT AnAeRoBIc DIgeSTIon

gASomeTeR

DehYDRATIon

solid

liquid

BIogAS cogeneRATIon unIT

eLecTRIcITY

digestate

compoSTIng In AeRATeD DYnAmIc

wInDRowS

quALITY compoST

biogas purification

puRIFIcATIon pLAnT

puRIFIeD wATeR

TheRmAL DRYIng oF The DIgeSTATe

TheRmAL eneRgY

Project data: input & outputYear �����������������������������������������������������������������������1995 aerobic compostingYear �����������������������������������������������������������������������2015 implementation of aerobic composting and anaerobic digestion technology used ....................................................wet anaerobic digestion and aerobic composting in dynamic windrows type of waste treated .............................................oFMSW and lignocellulose fractionplant capacity ........................................................42,000 t/yearDaily plant capacity ...............................................115 t/daybiogas power fed to the engine .............................2.4 MWnominal electrical power .........................................1 MWElectricity produced ................................................8,400,000 kWh/year Equivalent households potentially served ................more than 2,500thermal power recovered .......................................1 MWQuality compost produced .....................................15,000 t/year

RECEIPT AND MECHANICAL PRE-TREATMENT:

- pre-treatment, aimed at the elimination of the heavy and non-putrescible substances is a step of primary importance for the progress of the subsequent bio-stabilization process. After separating the incompat-ible impurities through the treatment cycle and dilu-tion of the organic material, the biomass is sent to the fermentation phase.

ANAEROBIC DIGESTION:

A� DIGESTER- The substrate is first heated and brought to a tem-

perature of 38° C and then sent to the digester, which is fed several times a day and in which the anaerobic biochemical process by methanogenic bacteria de-velops. the material is mixed continuously through vertical agitators that prevent sedimentation, ensure homogenization, and maintain the pH and tempera-ture of the substrate inside the digester.

- the biogas produced in this phase is sent to a gas-ometer and then a cogeneration plant while the diges-tate is sent to the post-fermentation tank and then the dehydration stage.

B� COGENERATION PLANT- the energy exploitation of biogas is through com-

bustion in a cogeneration engine. the thermal ener-gy produced is used inside the plant and is possibly even available for the public network.

C� DEHYDRATION Of THE RESIDuE fROM fERMENTATION AND DRYING

- the substrate coming out of post-fermentation is treated in centrifuges in order to separate the liquid phase from the solid phase. the separated liquid phase is recirculated to pre-treatment while the ex-cess water is sent to the cooperative purifier. The solid phase, on the other hand, is sent to the drying section through a medium temperature belt able to use the heat produced by the cogeneration unit. the dried sludge is then sent to the aerobic composting phase after mixing with the structuring matrices.

AEROBIC COMPOSTING:

- The final section of treatment is aerobic composting, which creates a quality compost that can be used as an organic soil conditioner in agriculture or for envi-ronmental rehabilitation.

Description of the process

Flow chart

1�

2�

3�

1� 2� 3�

Eboli (SA)

lA SpEziA (Sp)

bolzAno (bz)

FuSinA (VE)

bAri (bA)

MontAlE (pt)

AlbAirAtE (Mi)

tortonA (Al)

CupEllo (CH)

SASSAri

©2015 – Laduner Ambiente Spavia Innsbruck 33, 39100 Bolzano ITALYTel. +39 0471 949 800Fax +39 0471 949805info@ladurner.itwww.ladurnerambiente.it

The Ladurner Ambiente SpA industrial group offers 360 degree solutions in the environmental field and in the production of renewable energy. It is involved in the design, construction and management of municipal solid waste treatment plants, RDF-SSF production plants, waste-to-energy incinerators and anaerobic digestion and composting plants. Through its various divisions, Ladurner is also involved in designing plants for the production of renewable energy from liquid and solid waste and from agricultural biomass, designing plants and machinery for the treatment of municipal and industrial wastewater and the reclamation of contaminated sites. Its continuous research for innovative technologies has made the group one of the major operators in the Italian waste and wastewater industry today, maintaining an active approach to the various topics and transforming waste into a resource for the future.