High quality compost production
In addition to the plant in Orvieto, Acea Ambiente has three composting facilities located in Aprilia, Sabaudia and Monterotondo Marittimo.
The plant, which is one of the facilities used for the recovery of the organic fraction from separate waste collection in Lazio, will be expanded to allow the recovery of up to 120,000 t/year of organic fraction and to launch a section for anaerobic digestion with recovery of electrical and thermal energy. The plant will also be equipped with an industrial wastewater recovery system. The new section is expected to be operational by December 2019.
The Sabaudia plant has undergone various activities of revamping/ maintenance since 2016, and operations were resumed in August 2018 112. When the liquid waste treatment section is reactivated, as in the past it will be possible to reuse the purified water for industrial uses. The plant has a treatment capacity of 20,000 tonnes of compostable waste per year and 30,000 tonnes of liquid waste per year.
Finally, during the year, the Monterotondo Marittimo plant started work on the construction of a new composting section and a new anaerobic digestion section that will allow recovery of electrical and thermal energy. In its final configuration, the plant will be able to recover up to 70,000 tonnes/year of organic waste fraction, green fraction and sludge.
The aforementioned works, which will transform the Aprilia and Monterotondo Marittimo plants into integrated composting and anaerobic digestion plants, will make it possible to produce biogas and thus generate electricity from a renewable source, in line with the prospect of sustainable growth and to combat climate change.
In 2018 Aquaser, which performs the activity of transporting and disposal of sludge from biological purification and waste deriving from the purification of water, of treatment of waste water and liquid waste, managed, inter alia, about 198,000 t of sludge from purification coming from the water companies of the Group 113, of which about 152,000 tonnes of sludge from Acea Ato 2, Acea Ato 5 and Gesesa.
The dried out and dehydrated sludge coming from these companies were transported to the following end destinations:
- 80.7% to material recovery operations (pretreatments aimed at agricultural use - conditioning, composting);
- 2.5% to recovery of energy (waste-to-energy).
 On 14 April 2018 the Public Prosecutor authorised the resumption of operations by removing the seals from the Aprilia plant, without prejudice to the seizure.
 On 16.08.2018 deliveries were resumed for composting only, while the liquid waste treatment section, also being revamped, is inactive. A review of the AIA (Integrated Environmental Authorisation) is pending.
 The data detailed here for the sake of completeness concerns sludge for which Aquaser has managed the entire supply chain, from loading to transport and final disposal, originating from the following Group companies: Acea Ato 2, Acea Ato 5, Gesesa, Acquedotto del Fiora, Umbra Acque, Publiacqua.