Starting from 1997 increasing importance was assigned to the automation of the plant, as a result from those years a centralised infromatic system monitored and elaborated in real-time all plant techniocal data, from machine energy consumption to the discharge flow rate, all main process parameters, the weather condistions and odorous emissions, with the aim to have a better control on the environmental impact.
Among digital archives there were memorised years of managing data which allow everyone to verify the efficiency and the functioning of wastewater treatment systems.
Besides the automation of the monitoring system, manual controls continued to be pacticed by operators, main controlled parameters among treatment stages (entrance, homogenisation output, primary sedimentation output, first biological stage output, second biological stage output, final discharge), were:
•Liquid Dissolved Oxygen (LDO)
•Oxidation Reduction Potential (ORP)
•Thickeners and sedimentation tanks sludge level and concentration
•Microscopic and biological analysis of biomass
| PARAMETER|| METRICS||MOST FREQUENT VALUES ||AVERAGE VALUES ||LEGAL VALUES |
| pH|| ||6,5-8,5|| 7,25||5,5 - 9,5|
| COD|| mg/l|| 120 - 160|| 150||160 |
| SUSPENDED SOLIDS || mg/l|| 20 - 30 || 25 || 35 |
| N-NH4+|| mg N-NH4+/l|| 0,5 - 10 || 6 ||15 |
| N-NO3-|| mg N-NO3-/l|| 8 - 18||12 || 20|
| SULPHIDES|| mg S=/l|| 0||0||1 |
| SULPHATES|| mg SO4=/l|| 1.300 - 1.600||1.500 || 1.700|
| CHLORIDES|| mg Cl-/l||2.200 - 2.800||2.500||3.800 |
Whole plant analysis (excluded the single user discharge) were carried-out by the internal laboratory where worked n.4 technicians, which controlled the sludge quality as well as the chemicals one and they also characterised the tanker load. Between 1993 and 1994 the plant suffered relevant disfunction and Public authority in some cases intervened to stop the industrial activity because of the overcoming of discharge law limits. Beside this, in order to safeguard the environemnt and operators health, orders bannings were produced, also on the grounds of public demonstrations against unpleasant odours.
From 1997 to 2001 the process consolidated its treatment performances ensuring an overall abatement of pollutants of more than 98,5% (as COD reduction) and acquiring higher quality level for air emissions which permitted to gain also the Public Authority recognition. Some chemical such as sodium hydroxide, lime, and hydrogen peroxide have been using since those years with the only target to improve the environmental quality. Not only these chemicals are dosed within the plant but also along the sewerage system and the air treatment systems.