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Riccardo GoriEnvironmental and sanitary engineering
Reserach groupUniversity of Florence
FIU – Italy WORKSHOPWATER AND ENVIRONMENTAL GLOBAL
CHALLENGES:INTERNATIONAL WATER INFRASTRUCTURES
AND SECURITYFIU- MMC OE 112 May 25, 2017
– Professors and researchers
Claudio Lubello ([email protected]), Piero Sirini
([email protected]), Riccardo Gori ([email protected]) and
Giulio Munz ([email protected])
- PhD Students, Post_Doc, Fellows and Collaborators
Cecilia Caretti, Giuseppe Cocchi, Tommaso Lotti,
Alberto Mannucci, Sara Sguanci, Laura Palli
Giacomo Bellandi, Francesco Spennati,
Cecilia Polizzi, Iacopo Ducci
Who?
DEPARTMENT OF CIVIL ANDENVIRONMENTAL ENGINEERING HOW?
Florence WWTP (UNALAB joint labCuoiodepur WWTP
(CER2CO joint lab)
School of Engioneering
Prato WWTPs(GIDA SPA)
10 km
CARBALA PROJECTCarbon Balancing for nutrient removal EU
Exchange projects
Biosur PROJECTRotating Bioreactors for SustainableHydrogen Sulphide RemovalBiocloc PROJECTBIOprocess ControL through Online titrimetry to reduce Carbon footprint in wastewater treatment
DEPARTMENT OF CIVIL ANDENVIRONMENTAL ENGINEERING HOW?
LESSWATT PROJECTInnovative wireless tool for reducing energy consumption and GHGs emission of WRRFs
M.E.TA. PROJECTMatter and Energy from Tannery Sludges
DEPARTMENT OF CIVIL ANDENVIRONMENTAL ENGINEERING HOW?
PRIN project "Emerging contaminants in air, soil, and water: from source to the marine environment"
PRIN project "Energy consumption and GreenHouse Gas (GHG) emissions in the wastewater treatment plants: a decision support system for planning and management"
Use of fungi for the removal of recalcitrant compoundsfrom industrial wastewater
Use of fungi for the removal of micropollutants from urban wastewater
Applicability of the Anammox process for swine wastewater treatment
To use this tool for the monitoring and controlof operating conditions in a real plant (Calicewastewater treatment plant);
To construct an innovative tool for monitoringthe biological processes in activated-sludgeplants (continuous online differential titrimetry);1
2
To quantify the improvement of the effluent’squality and the reduction in energy andenvironmental costs.3
Differential because the instrument calls for the use of two identical reactorsthat work under the same operating conditions, similar to those of the oxidationtanks from which they are fed. There are numerous processes responsible forpH variations in activated sludge. To isolate only the contribution of nitrification,the only difference between the two reactors is the fact that one of themincludes an inhibitor of the nitrification process. In this way, the difference in thesoda dosage in the two reactors (one inhibited, the other one not inhibited) isdirectly linked to the nitrification rate.
Online because the tool functions as a process probe.Continuous because the tool is continuously fed with activated sludge takenfrom the oxidation tanks.
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1. CONTROL OF AERATION SYSTEMThe nitrification rate, which is continuously returned by the instrument, makesit possible to calculate the optimal dissolved-oxygen value to be maintained inthe oxidation tank in order to ensure the removal of nitrogen in compliancewith the limits for the discharged water.
2. TIMELY IDENTIFICATION OF INHIBITION PHENOMENAThe trend of the nitrification rate permits the real-time detection of the effectsof any compounds that are toxic or inhibit the nitrification process and thatmay influence the plant.
3. INNOVATIVE PROCEDURE FOR THE CALIBRATION OF THE KINETICPARAMETERS OF THE NITRIFYING BIOMASSThe maximum nitrification rate, measured continuously, permits a more precise calibration of the kinetic parameters of the nitrifying biomass compared to the calibration carried out with conventional batch kinetic tests.
Mass balance of oxygen in gas phaseOxygen transferred to the liquid phase = oxygen removed from the gas phase
The off-gas method is a tecnique developed for monitoring the oxygentransfer efficiency of air diffused aeration systems (Redmon et al., 1983).
OFF-GAS TEST
5. Off-gas analyzer
1. Hood for off-gas collection2. Connection pipe between the hood and the analyzer
3. LDO probe
4. Oxymeter
OFF-GAS TEST
Off-gas analyzer
OFF-GAS TEST
Transfer efficiency in process conditions (OTE, %):
Cs,20: saturation concentration @ 20°Cs,pwT: saturation concentration @ process conditionsβ = 1- (0.01 TDS)/1000α = αSOTE/SOTE
Transfer efficiency in standard conditions in process water (αSOTE, %):
α-factor:
oxygen transfer rate (OTR, KgO2/h):
Aeration efficiency (AE, Kg02/kWh):
AE = OTR/P
OFF-GAS TEST
Air flow rate management was shifted from a DO set-point control to an ammonia-DO cascade control
BEFORE: Air flow rate managed on the basis ofDO set-point
AFTER: Air flow rate managed on the basis of N-NH4
+ in the effluent and DO set-point
IMPROVEMENT OF AIR FLOW RATE CONTROL
DO set-point controlOTE ≈22-30%
ammonia-DO cascadecontrol
OTE ≈24-35%
The new strategy for air flow rate control allowed to reduce theaverage DO concentration in the oxidation tank which in turnallowed to increase the oxygen transfer efficiency
Comparison of OTE between the two different strategies
IMPROVEMENT OF AIR FLOW RATE CONTROL
