GIDA stands for Gestione Impianti Depurazione Acque. It is a mixed public-private joint-stock company with a turnover of about 17 million euros per year, made up of 66 employees coordinated by a General Manager. In turn, the Management reports to a Board of Directors consisting of 9 members, 5 of whom are public and 4 private. The work activity takes place in a continuous cycle 365 days a year, to guarantee efficiency and environmental safety.

It is not strange even if quite unusual on the Italian scene. In any case, it is a positive and virtuous aspect of the company, which deals with both civil and industrial drains making all those who produce them, citizens and companies, co-responsible. Today, we talk more and more often about public-private synergies, we can say that GIDA has been ahead of its time. The mixed solution emerged naturally, so to speak, when the Merli Law (1976) imposed a path to make wastewater purification mandatory: the Municipality of Prato (as majority shareholder) and the Unione Industriale Pratese were in fact the subjects called into question and the only ones who had and could activate the necessary resources. In 2004 Consiag was added to them, so today the shareholding structure is composed as follows: Municipality of Prato (46.92%); Unione Industriale Pratese (45.08%); Consiag (8%). In the "About Us" section of our website you will find out more about the company's history, mission and governance.

GIDA's activity consists in the purification of wastewater deriving from residential buildings and production activities of the Municipalities of Prato, Montemurlo, Vaiano, Vernio and Cantagallo. Purified water is reintroduced almost entirely into Bisenzio and Ombrone rivers, while a portion of water is further treated in order to make it reusable for local companies, especially dyeing and finishing plants, which can use it through the industrial aqueduct network. In addition to this, GIDA also carries out the treatment of non-hazardous liquid waste within the Calice purification plant, thanks to a specific platform. GIDA is therefore active on several fronts: those who want to know more in detail about the various activities can consult them in the "What we do" section on our website.

Not exactly. In all the plants the core activity is the purification of urban wastewater which is also the only activity carried out as for Vaiano, Vernio and Cantagallo plants. In the two plants of the Municipalities of Prato and Montemurlo, other activities are also carried out. In fact, the Baciacavallo (Poggio a Caiano) plant also carries out the treatment of sludge originating from the purification activity. In Calice plant (Prato) exclusively non-hazardous liquid waste such as septic tanks and leachates deriving from landfills of municipal solid waste are also treated through a special process line. An activity, the latter, which helps to close the circle of the treatment of waste produced by the community. Thanks to the spread of our plants throughout the territory, starting from the Val di Bisenzio to the Prato plain, a total purification service is guaranteed. Further details about our activity can be found on our website.

To size our business we still have to start from numbers but it can be useful to compare them with those that refer to other entities. For example:
the wastewater of the catchment area covered by GIDA is equal to 45 million cubic meters per year, corresponding to what Brasimone and Suviana reservoirs, put together, contain. The work carried out by GIDA ensures that this enormous mass of water is introduced into the waterways, and then ends up in the sea, already purified as required by law.
The 75 kilometers of industrial aqueduct network are tantamount to more than 4 times the distance between Prato and Pistoia
the nearly 4.5 million cubic meters per year of recycled water distributed to companies by the industrial aqueduct is equivalent to twice the annual consumption of drinking water in the municipalities of Vernio and Cantagallo.

Attention: purification does not mean potabilization, or, even less, production of distilled water. Purifying water means making it harmless to the environment, so that it can be returned to waterways without endangering plants, animals and humans. In the water that comes out of our plants, substances are dissolved in concentrations that are not dangerous for the environment: this is the reason for the imperfect clarity. The water purified by GIDA complies with the characteristics provided for by the National Regulations for discharge into surface water (Tab.1 – Tab.2 – Tab.3 Annex 5 Part III D.Lgs.152/06 and subsequent amendments).

The plants managed by GIDA, in principle, are no different from any other purification plant that collects discharges from urban sewerage networks. All purification plants and all urban sewerage networks are in fact equipped with spillways, governed by specific regulations, which are activated in order to guarantee the hydraulic safety of the entire drainage and wastewater treatment system. It is for this reason that in the event of intense meteoric events (for duration or entity), a part of the wastewater is discharged without reaching the purifier. This can happen along the entire sewer network, as ARPAT itself has well described in an article. It is evident that in these circumstances the purified water, whose quality is the usual and regular one ensured by GIDA, mixes with the drained ones, over which GIDA has no control.

The industrial aqueduct of Prato is an infrastructure of which the district can be proud: at European level there are not many similar examples, especially for extension and for the management of reused water. The citizens know little about it: many do not even pay attention to the yellow hydrants that are seen around in some areas of the city. To sum up: part of the water purified by GIDA, about 4.5 million cubic meters per year, is subjected by the company itself to further treatments, so as to make it usable mainly by the companies of the city which need water for their production cycle (dyeing, finishing, car washes, etc.). The water thus obtained is distributed to the companies through an aqueduct network parallel to the one for drinking water, of about 75 kilometers long, called industrial aqueduct. More details on our website. The function of the industrial aqueduct remains important from an environmental point of view even today that the aquifer has risen: let's not forget the difference between recycled water (which does not have the characteristics to become drinkable) and natural groundwater, which represents a strategic and potentially fundamental source for drinking water production.

In an urbanized and industrialized context such as Prato, the solution of centralized plants guarantees greater purification efficiencies and greater guarantees from an environmental point of view. The solution of the plants at the foot of the factory would involve the construction and punctual control of more than 300 small industrial plants. This would result in a much more complex management and greater impact on the population (think, for example, of the potential territorial spread of bad smells), with fewer guarantees from an environmental point of view and with much higher costs. In addition, the decentralization of purification would create a problem linked to the need to take and transport sludge (the quantity of which would remain unchanged) from numerous points spread throughout the territory, to be treated in special plants, with the consequent environmental problems and impacts. It also remains to be considered that the plants at the foot of the factory would not cover the purification needs deriving from the production of civil wastewater in the community, which would inevitably have to be traced back to further purification plants. A centralized system ensures continuous and competent management by specialized personnel, greater controls and overall a greater guarantee from an environmental point of view.

The Baciacavallo incinerator is authorized for the exclusive disposal of sewage sludge self-produced by the company. Sewage sludge constitutes a "special non-hazardous waste", with specific characteristics that identify it with the CER code (European Waste Catalogue) as 19.08.05 "sludge produced by the treatment of urban waste water". The sludge can be imagined as a "sponge" that absorbs and retains the various pollutants removed from the wastewater during the various phases of sewage purification (primary, secondary and tertiary treatments) and constitutes the main waste deriving from purification. Basically, it is a liquid mixture (97% on average is water), which must be "dehydrated" with specific machines (up to humidity values of about 75%) and then disposed of. The 5 GIDA plants produce about 32,000-34,000 tons of dewatered sludge every year and with the current plant it is possible to dispose of only 75%-80% of production independently. The remaining portion is transported to third-party plants (composting, landfilling or drying) located mostly in Lombardy, Veneto and Tuscany. The solid residues produced by incineration are equal to 10% of the sludge that is treated and the ashes produced are sent to special treatment plants and then become recovery material for other activities (eg road substrates, etc ...).

Incinerators, like everything else, are dangerous if used outside the rules. But this is not the case of GIDA that acts in full compliance with Italian and European standards. We directly control emissions 24 hours a day and are then subject to "surprise" inspections by ARPAT, which reports in public documents on the outcome of its audits. In addition, GIDA data are periodically transmitted to the control bodies and available on the website of the Province of Prato.

Let's be clear: combustion, even the most trivial, almost always produces a certain amount of dioxin. In order to produce zero dioxin, we would have to outlaw practically everything, from domestic boilers to motor vehicles, including the fireplace at home and the barbecue: if one day technology offers us viable alternatives on a large scale, it will be a very good thing, but in the meantime we must resign ourselves to producing – all of us without exception – a certain proportion of dioxin. The key lies precisely in the "certain quota": the law sets very precise limits to emissions. GIDA produces extremely low concentrations of dioxin, 140 times below the legal limit. This fact sheet explains numbers and data well. To explain briefly why GIDA produces minimal amounts of dioxin: sewage sludge contains small amounts of chlorine, a basic element in dioxin molecules; moreover, the combustion that reaches high temperatures (at least 850 ° C) and the subsequent rapid cooling of the fumes, do not allow the formation of dioxins. If in the area of Baciacavallo there is indeed an abnormal concentration of dioxin (something on which we do not have data) GIDA really makes an insignificant contribution. GIDA data are periodically transmitted to the control bodies and available on the website of the Province of Prato.

The transition to a new plant is necessary and recommendable. The current system, although completely safe, requires increasingly frequent and demanding maintenance. The risk is not at all that dangerous situations will arise but that the service will have to be interrupted with the consequent problems of sludge management. The current incinerator is like a car that has exceeded 100,000 km: you can keep it in perfect order in terms of safety and exhausts (and that's what we do), but for this it needs very frequent maintenance. The new car not only requires less maintenance, but also consumes less! In fact, creating a new plant like the one we have identified means seizing the opportunities that new technologies give us; It means having a service that is not only equally safe but also able to transform sludge from a "problem" into a "resource", from residues to be disposed of to material that allows us to recover energy. The choice of the new waste-to-energy plant is therefore sensible and justified, and in any case will not entail any danger, neither before, during nor after the construction of the new plant.

For a double series of reasons, linked on the one hand to the limits of the current system and on the other, vice versa, to the opportunities that new technologies offer us:
The current system, although completely safe, requires increasingly frequent and demanding maintenance. Every year that passes the interventions are more and more numerous (+ 30%) and expensive. The prolonged interruption of the service would lead to serious problems in the management of sludge, which would also affect the quality of the water discharged
the current plant is undersized: we are unable to treat 20%-25% of our sludge independently and we are therefore forced to mobilize about 400 trucks a year to take them out of the area (not only in Tuscany but also in Lombardy and Veneto)
The new plant, in addition to being dimensionally adequate, which would make the company completely self-sufficient, thanks to the choice of energy recovery technologies will improve the already good environmental performance (-55% in methane consumption). To resume the comparison with the car, it is a bit like changing a car of 25 years ago that with a liter of gasoline made 12 kilometers, and buying one of today that with the same liter makes 20.

The path that led us to the identification of the solution was long and complex and also passed from the verification "in the field" of the performance of various technologies in use as well as in Italy also in France and Switzerland. In the end, it was decided to have a fluidized bed furnace with a capacity of 40,000 tons per year, which will thus also cover production peaks. It is an innovative but already consolidated technology, which is characterized by absolute safety, possibility of energy recovery and management flexibility. This document, extracted from the Design Reference Framework of the Environmental Impact Study attached to the final project to replace the Baciacavallo sludge incinerator, describes in detail the project of the new plant.

The transition to a capacity of 40,000 tons per year compared to the current 35,000 is linked to the desire to make the company self-sufficient from the point of view of sludge management, given that the current plant allows to treat only 75%-80% of the sludge we produce. The production of GIDA sludge in recent years has been about 34,000 tons / year and no significant fluctuations are expected in the coming years, also because the requests for continuous improvement of wastewater quality lead to the production of greater quantities of sludge. The size of 40,000 tons / year, in addition to being a market standard, is necessary as it allows to cover the production peaks that are generally recorded in spring-summer and to have an adequate residual capacity to be able to manage maintenance interventions and any plant downtime. The technique chosen and the design carried out are suitable exclusively for the treatment of sewage sludge and no other material; the potential will be sufficient to satisfy only the internal needs of GIDA.

The answer is: because, in the specific case of GIDA, abandoning combustion would not be a qualitative leap at all, from any point of view. This document, extracted from the Design Reference Framework of the Environmental Impact Study attached to the final project to replace the Baciacavallo sludge incinerator, describes the alternatives evaluated there. The only technically and economically realistic alternative would be the deposit of sludge in landfills: given the annual production of 32,000-34,000 tons of sludge, this would mean more than 1,500 trips per year, even hundreds of kilometers, of as many trucks with trailers. A considerable impact to transport material that for 75% is made up of water! Instead, after treatment, 90% of the original mass is no longer there and 100 trips are enough to dispose of the last residues. Let us not forget that landfill does not mean zero environmental impact: it must be taken into account the production of leachate and the potential risks of pollution to groundwater and subsoil that derive from it. The combustion fully complies with the indications of the European Union and the National Legislation on waste treatment and, carried out with plants such as the one that GIDA will realize, allows to enhance the sludge using it for energy recovery.

No, not at all, performance will actually improve even more, although it makes little sense to talk about improvements when we are already enormously (140 times!) below the limits. To explain briefly what will happen: it being understood that the sewage sludge contains small quantities of chlorine, a basic element in dioxin molecules, and that the combustion of the new furnace will maintain high temperatures (at least 850 ° C) that do not allow the formation of dioxins, further measures have been provided for the specific treatment of any dioxins "reformed" in the fumes at lower temperatures. The concentration of "dioxin-like" substances in the fumes produced by the combustion of GIDA sewage sludge has always been extremely low (100 times lower than the legal limit). This document, extracted from the Design Reference Framework of the Environmental Impact Study attached to the final project to replace the Baciacavallo sludge incinerator, describes in detail the project of the new plant.

It is not technically possible to eliminate the production of sludge in the wastewater purification process. There are techniques (enzymatic biolysis, alternating cycles, cannibal processes, ozonolysis, thermolysis, phytodepuration), many of which are still in an experimental state, which would allow to reduce the amount of final waste to be disposed of, but this would still remain in a quantity equal to about 60%-70% of the current one. The possible adoption of these techniques would come up against management, energy or dimensional problems, guaranteeing, in the end, reductions realistically not exceeding 30-40%. Let's think about perhaps the most emblematic example, phytodepuration: if hypothetically it were used to manage the volumes of wastewater produced in Prato, tanks of 400 hectares (twice the entire area of Cascine di Tavola) would be needed for a depth of 100 meters. All this to minimize and not eliminate the production of sludge: unthinkable. This does not mean that GIDA does not look with interest at new purification systems: always in the field of phytodepuration, we are carrying out an experimental project that could allow us to use this technique for the refinement of a limited part of the water we treat.

Yes, it is definitely the best solution. Otherwise, the dewatered sludge would have to be transported to other combustion plants, causing the same transport problem as if it went to landfill. Given the annual production of 32,000-34,000 tons of sludge, this would mean 1,500 trips per year, even hundreds of kilometers, of as many trucks with trailers. In any case, it is appropriate for GIDA and for the city to be self-sufficient in treating its sludge. This allows you to free yourself from problems that we could run into due to the scarce availability of external systems, as well as from possible economic burdens due to market fluctuations. In addition, sending the sludge outside would lose the possibility of recovering energy. In the end, managing the sludge we produce autonomously ensures maximum control over the environment and safety, as well as a better service over time.

Bad smell does not directly imply danger. There are potentially lethal gases that are completely odorless (think of simple carbon monoxide) and totally harmless bad smells, so generalizing is definitely wrong. The current incinerator is completely "innocent" compared to bad smells, as will be the future waste-to-energy plant: high temperatures in fact involve a complete degradation of all potentially odorous substances. Purification plants, on the other hand, can sometimes generate bad smells, inherent in the "treated raw materials" (sewage water) and in the treatment processes themselves, with consequent inconvenience for those who live and work next to our plants. In any case, these are molecules that are released from the microbial degradation of the biodegradable materials we treat and that in general are not associated with problems of toxicological impact. And even when it comes to substances that in high concentrations could be toxic (ammonia, for example, or hydrogen sulfide) it must be taken into account that when these produce odors perceptible by humans we are still far – by several orders of magnitude – from their level of danger. However, GIDA is aware that bad smells, although harmless to health, are unpleasant for the population and over the years has made improvements to limit their development. Among the investments of the Business Plan there is also the construction of covers for purification tanks.

GIDA uses maximum transparency with respect to its work. Society has always welcomed citizens who had questions to ask, provided answers, given the maximum willingness to verify the doubts raised. And not only on days when they are open to the public but also at any other time. GIDA has adopted this line not only out of duty and ethical choice, but also out of direct interest. Interest in any responsibilities and, above all, in the possible consequences on the health of the people who attend the company on a daily basis, i.e. workers, technicians and administrators. GIDA must not and does not want to operate incorrectly and has no interest in doing so.

GIDA is completely certain of the correctness of its work and of the total compliance with the rules of what it does. The alarms are explained on the one hand by the right attention of citizens and public health institutions and on the other, perhaps, by positions sometimes prejudicially hostile. To date, no scientifically based study based on real measurements has shown a correlation between GIDA activity, environmental pollution and diseases. To understand each other better:
"Scientifically based study" means respectful of consolidated procedures ranging from the methods of identification and collection of samples to the investigation techniques as well as (very important) the documentation and motivation of each of these steps. It is not known, for example, whether the study on so-called "dioxin chickens" has all these characteristics.
"study based on real measurements" means that work such as the Ispra study on hexachlorobenzene-HCB (on a theoretical basis and not based on field tests) should be taken as scientific contributions and not as demonstrations of actual reality. With regard to this topic, there are two interesting press releases published in the recent past by ARPAT (Press Release "ARPAT controls of atmospheric emissions from the incinerator of Baciacavallo (Prato)" of 27 March 2013 and News n. 115 - Monday 03 June 2013).

GIDA is an EMAS and ISO 14001 certified company, testifying to the absolute regularity and conformity of its environmental performance. In particular, it should be noted that all emissions to the chimney of the sewage sludge disposal plant are constantly monitored and certified by Arpat and comply with the legal limits, with a very large margin, for the various parameters analyzed, including dioxins and metals. With regard to dust, the law requires emission control: also in this regard GIDA is an order of magnitude below the legal limit (1.5 milligrams per cubic meter while the limit is 10 milligrams per cubic meter). It should be noted that any combustion phenomenon produces dust, from vehicle fuels to boilers.