The First Zero-Impact Olive Mill to Produce Energy

Giovanni Cassese's designed a system built by Pieralisi that might just be the first completely environmentally sustainable olive mill.

Oct. 17, 2016
By Ylenia Granitto

Recent News

Harvest just started in Italy and while olive mills are work­ing almost at full capac­ity we met the cre­ator of an inno­v­a­tive method of pro­duc­tion that not only has zero envi­ron­men­tal impact but also pro­duces elec­tric and ther­mal energy. 

This sys­tem has reached the high­est level of inno­va­tion for the dis­posal of waste­water,” said Giovanni Cassese, who gained expe­ri­ence in the fam­ily mill at Villa Castelli, in the province of Brindisi, in Apulia. A very sim­ple agri-food process became a zero-impact prac­tice to pro­duce high-qual­ity extra vir­gin olive oil and gen­er­ate power.”

Cassese con­ceived adjust­ments to the mode of oper­a­tion of a mill and sub­mit­ted them to the milling tech­nol­ogy com­pany Pieralisi, which imple­mented the new setup in a plant that can be con­sid­ered the first com­pletely envi­ron­men­tally sus­tain­able olive mill.

As we know, even the most inno­v­a­tive three-phase sys­tem involves a water con­sump­tion that ranges from 70 to 110 per­cent, while the two-phase sys­tem gen­er­ates very reduced water con­sump­tion but the waste needs to be fur­ther processed to be reusable in some way or digested,” he explained. After extrac­tion with our mill which employs the DMF (multi-func­tional decanter) tech­nol­ogy, we obtain extra vir­gin olive oil and two byprod­ucts or, as I call them, dif­fer­en­ti­ated pro­duc­tions’ — the vir­gin olive pomace with humid­ity con­tent around 55 per­cent, that is very well suited to the extrac­tion of olive pit, and the olive pâté.”
See Also: A Centrifugal Force: Gennaro Pieralisi
He pointed out that the real inno­va­tion is the use of this prod­uct in a plant for anaer­o­bic diges­tion in the same site of the mill that allows to exploit all the resul­tants of a high-effi­ciency cogeneration.” 

The olive pâté is a cream that com­pared the de-stoned olive pomace has no lignin and a rel­a­tively high con­tent of polyphe­nols. These two qual­i­ties make it suit­able to be stored for a long period, with­out caus­ing odor, and it is sub­se­quently digested. The result of diges­tion, in a plant adapted to work mate­r­ial with rel­a­tively high solid sub­stance (EUCOmpact tech­nol­ogy), is bio­gas of 60 per­cent methane with a con­sid­er­able aver­age yield of about 150 cubic meters per ton of olive pâté.

Got a few minutes?
Try this week's crossword.

We con­sume 200,000 kilo­watts per year to pro­duce the olive pâté and for all the util­i­ties,” Cassese explained. Since the result of cogen­er­a­tion is 765,000 kW, after sub­tract­ing the mill con­sump­tion and the self-con­sump­tion of the plant, we pro­vide to the power grid an amount of elec­tric­ity to cover the annual needs of more than 50 fam­i­lies.” He clar­i­fied that the cal­cu­la­tion refers to house­holds con­sum­ing over 10,000 kWh/year, but esti­mat­ing the aver­age con­sump­tion of Italian fam­i­lies, he can serve more than 100 families. 

Moreover, since the pro­duc­tion of energy oper­ates in cogen­er­a­tion mode, the plant also pro­vides about 800,000kWh of ther­mal energy in the form of heat that can be used within the mill, to help the pro­cess­ing and to main­tain the con­stant tem­per­a­ture of stor­age rooms dur­ing win­ter. While in the sum­mer, thanks to the phys­i­cal prin­ci­ple of tri­gen­er­a­tion, the result­ing heat is trans­formed through a lithium bro­mide absorber into cold water that cools the stor­age rooms.

The result of diges­tion is the diges­tate, that is a for­mi­da­ble fer­til­izer ready to return to the same olive trees that gave us their olives and which in their life­time fixed the CO2 that we re-insert into the atmos­phere through the com­bus­tion of biogas.” 

This new sys­tem pro­vides con­sid­er­able sav­ings. The bio­gas plant built in the imme­di­ate vicin­ity of the mill allows the reset­ting of trans­port costs of the pâté that is pre­served with­out loss of yield and, given the high amount of digestible dry mat­ter, has a decline in weight after diges­tion of around 20 – 25 per­cent. Moreover, the spread­ing can be car­ried out all year at the farmer’s choice accord­ing to the fer­til­iza­tion plan, and it is no longer nec­es­sary to dis­pose of waste­water in the same peri­ods of pro­cess­ing and har­vest, result­ing in sav­ings of 25 per­cent for trans­port costs. 

The use of olive pâté from the DMF tech­nol­ogy gen­er­ates imme­di­ate sav­ings in the man­age­ment expen­di­tures of the mill, with zero con­sump­tion of drink­ing water that would be used to dilute the olive paste in the decanter, the reduc­tion of energy con­sump­tion and the total absence of waste­water result­ing from oil extraction.

According to Cassese, this is at the moment the best extrac­tion sys­tem with regard to water and energy con­ser­va­tion, and envi­ron­men­tal protection.”

Related News

Feedback / Suggestions