EURASIAN WATER CONFERENCE 3 rd ASEM Seminar on Urban Water Management Urban solutions for global challenges September 2018 Budapest

Transcription

1 EURASIAN WATER CONFERENCE 3 rd ASEM Seminar on Urban Water Management Urban solutions for global challenges September 2018 Budapest

2 ECO FRIENDLY TECHNOLOGIES FOR THE CONVERSION OF THE POLLUTED GROUNDWATER INTO DRINKING WATER, IN THE CONTEXT OF WATER SCARCITY Authors: Sorin Claudiu ULINICI, Grigore VLAD, Attila TOKOS S.C. ICPE Bistrita S.A., Parcului Str., no 7, , Bistrita, ROMANIA

3 Water- a valuable and a strategically natural resource The European Union water legislation: Water Framework Directive: Directive 2000/60/EC of the European Parliament- promotes a strategy based on protection of water resources on the long term Groundwater Directive (2006/118/EC)- sets groundwater quality standards and introduces measures to prevent or limit the input of pollutants into the groundwater Drinking Water Directive (98/83/EC) - applied to all distribution systems serving more 50 peoples drinking water from tankers drinking water in bottles or containers water used in the food- processing industry Directive 2008/105/EC- on the water quality standards Directive 2009/90/EC - establishes technical specifications for chemical analysis necessary for monitoring the quality of water deposits

4 Raw Water Quality- specific problems Surface raw water- major pollutants: - Non- biodegradable organic matter (surfactants, cosmetics, plasticizers, chlorinated solvents and dioxine, etc.) - Water-soluble inorganic pollutants, such as acids, salts and toxic metals - Bacteria, viruses, protozoa and parasitic worms Groundwater- major pollutants: - Non- biodegradable organic matter (pesticides, insecticides, volatile organic compounds, etc.) - Water-soluble inorganic pollutants, such as toxic metals (arsenium, copper, iron, manganese), fluoride, etc. - Nitrogen compounds: ammonium, nitrates and nitrite - Bacteria and viruses

5 Flash Case Study: Timis County, Romania In rural area, from a number of 275,281 inhabitants, 176,050 inhabitants are not connected to a drinking water network because of poor chemical quality of raw groundwater resources, polluted especially with ammonium, As, Fe, Mn!

6 Target pollutants from Groundwater Reduction by direct oxidation for Fe 2+, Mn 2+ si As from treated water and retention of oxidant compounds on filtration bed Oxidation and nonselective elimination of eventually organic pollutants, including residue of organophosphorus compounds and pesticides What we expect from a WTPs? Pollutants: -organic substances hardly oxidable -nitrogen compounds: ammonium, nitrites, nitrates -ionic metals: Fe 2+, Mn 2+, As -microbiological contamination Degradation of nitrogen compounds (ammonium, nitrites, nitrates) from treated water, by biofiltration processes Efficient disinfection Avoiding the possibility of appearance of secondary reaction toxic compounds (trihalomethanes) is removed In the treatment process the chemicals are used in minimum percent and are mostly used oxidation compounds generated in situ for treating water (ozone, electrochemical oxidation). Implementation in a compact treatment system Automatic operation. Remote monitoring of treatment processes

7 Combined Processes : Advanced Oxidation & Bio Filtration AOP- Advanced Oxidation Processes Mineralisation. OH + Pollutants CO 2 + H 2 O + inorganic ions Bio Filtration A. Physical processes: -Filtration - Adsoption B. Biochemical processes: -Nitrification - Denitrification - Annamox

8 Advanced Oxidation Processes How could we achieve AOP s? Cold plasma O 3 in aqueous media O 3 /UV H 2 O 2 /O 3 H 2 O 2 /UV H 2 O 2 /O 3 /UV Heterogeneous photocatalysis O 3 -Granular Activated Carbon (GAC) Heterogeneous ozone catalysis

9 Advanced Oxidation Processes- used alone or in combinations Direct ozonation (decomposition of ozone in aqueos media) 3O 3 + OH + H + 2OH o + 4O 2 Electrochemical treatment using pulsatory DC based on the existing dissolved chlorides (1) 2Cl - Cl 2 + 2e - (2) Cl 2 + H 2 O HClO + HCl (3) HClO ClO - + H + (4) H 2 O OH ads + H + + e - -anodic oxidation Catalytic ozonation or/and GAC adsorption O 3 GAC GACox + o OH [1] [1] M. Sui, J. Liu, L. Sheng, Appl. Catal. B: Environ. 106 (2011),

10 Biofiltration NITRIFICATION and DENITRIFICATION biological processes used for ammonium removal from drinking water Nitrification is the biological oxidation of ammonia or ammonium to nitrite followed by the oxidation of the nitrite to nitrate. 2 NH O 2 2NO 2 + 2H 2 O + 2H + 2 NO 2 + O 2 2 NO 3 Dentrification is a biological process in wihch the nitrare is reduce to nitrogen gas (N 2 ). 2 NO e + 12 H + N H 2 O ANAMMOX Biological process for ammonium removal from water Anaerobic ammonium oxidation (Anammox) is a significant component of the biogeochemical nitrogen cycle. The overall reaction : NH NO 2 - Anammox bacteria N H 2 O

11 Automated Water Treatment Plant - P&ID

12 Local Area Water Treatment and Distribution Network Raw water sources: sparsely distributed water wells with different quality Compact WTPs: special designed for the water quality provided by the adiacent water wells. Include also water storage facilities. Automation: The processes are automatically adjusted using the online quality sensors.

13 SCADA Network The Compact WTPs and the water distribution network are continuously monitored by a centralised SCADA dispatch The SCADA communications are done over a secure VPN network. The VPN network must be flexible enough to support various types of transmission media according to the on-site possibilities.

14 Implementation of technology in the area

15 Pollutants removal grade Current no. Location Water treated flow [m 3 /h] Concentration of targeted water pollutant [mg/l] Category Raw water Treated water Maximum allowed concentration Efficiency of removal 1 Nasaud, ROMANIA 10 Ammonium 1.10 < % 2 Ibanesti, ROMANIA 20 Nitrates % 3 Ghilad, ROMANIA 15 Manganese 0.14 < % Iron % Ammonium 0.40 < % 4 Gad, ROMANIA 10 Iron % 5 Pordeanu, ROMANIA 6 Remetea Mica, ROMANIA Ammonium 0.90 < % 15 Arsenium % Ammonium % 15 Ammonium % 7 Cruset, ROMANIA 20 Ammonium % 8 Hemeius, ROMANIA 25 Ammonium % Manganese % 9 Rediu, ROMANIA 40 Nitrates % 10 Goiesti, ROMANIA 15 Ammonium %

16 CONCLUSIONS Combined use of Advanced Oxidation Processes and Bio filtration allows the efficient removal of a large classes of pollutants (organic compounds, nitrogen compounds, metal ions). The flexibility of the technology allows it to be dimensioned according to the quality of the raw water source so as to obtain maximum efficiency at minimum investment and operating costs. Technologies alredy implemented are environmentally friendly, involving the use of non-pollutant reaction agent (ozone), produced at the application site. The SCADA automated control and dispatching system enables the control of an entire network of compact WTPs in order to optimize energy consumption and to increase redundancy. Following the implementation of these technologies in 10 locations, we have reduced the metal ions concentrations (Fe > 93%, Mn > 91%, As- 84%) and the nitrogen compounds (ammonium > 82%, nitrates -66% 92%), the treated water being drinkable. The examples presented clearly reveal the operational efficiency of implementing such processes and how a non-compliant raw water source can be exploited using compact WTPs particularly designed considering the particular target pollutants.

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