Eutrophication control in Eutrophication control in lakes and and reservoirs reservoirs lakes using simultaneous simultaneous dynamic dynamic using optimization approaches approaches optimization Maria Soledad Diaz Soledad Diaz Maria Planta Piloto de Ingeniería Química (PLAPIQUI) Universidad Nacional del Sur – CONICET Bahía Blanca, ARGENTINA
Outline � Motivation Motivation � � Objective Objective � � Biological Biological and and biochemical biochemical determinations determinations � � Global Global sensitivity sensitivity analysis analysis � � Dynamic Dynamic parameter parameter estimation estimation problem problem � � Optimal � Optimal control control problem problem � Simultaneous Simultaneous approach approach for for dynamic dynamic optimization optimization � � Discussion Discussion of of results results � � Conclusions Conclusions �
Motivation � Eutrophication as natural process of aging of water body Eutrophication as natural process of aging of water body � � Water Water bodies bodies increasingly increasingly eutrophic eutrophic due due to to anthropogenic anthropogenic � inputs of of nutrients nutrients inputs � Application of restoration strategies requires systematic study, Application of restoration strategies requires systematic study, � modeling and optimization of eutrophication processes modeling and optimization of eutrophication processes
Cultural Eutrophication � Main anthropogenic Main anthropogenic source source of`nutrients of`nutrients: : Agricultural Agricultural activities activities � (fertilization fertilization) ) ( � Main Main point point source source: : discharge discharge of of agricultural agricultural, industrial , industrial and and � urban wastewater wastewater urban � Over enrichment of nutrients (mainly P and N) � Over enrichment of nutrients (mainly P and N) � Increase in the production levels and biomass � Increase in the production levels and biomass � Very strong development of phytoplankton community � Very strong development of phytoplankton community � � Decrease in water depth caused by sediment accumulation Decrease in water depth caused by sediment accumulation
Objective � Development � Development of of ecological ecological water water quality quality (eutrophication) (eutrophication) model model � Analysis � Analysis of of the the trophic trophic state state of of a a water water body body through through its its composition composition and and abundance of abundance of plankton plankton � Global � Global sensitivity sensitivity analysis analysis and and determination determination of of sensitivity sensitivity indices indices � Parameter Parameter estimation estimation based based on on available available data: data: � � Model Model validation validation � � Study Study of of the the effect effect of of nutrients nutrients concentration concentration and and environmental environmental parameters parameters � on plankton plankton population population dynamics dynamics on � Determination Determination of of optimal optimal bio bio- -restoration restoration policies policies �
Trophic classification of water bodies Oligotrophic Oligotrophic [nutrients nutrients] ] < [ < < Productivity Productivity < Mesotrophic Mesotrophic Eutrophic Eutrophic > [ [nutrients nutrients] ] > > Productivity Productivity > Hipereutrophic Hipereutrophic
Trophic classification of water bodies OLIGOTROPHIC MESOTROPHIC EUTROPHIC HYPEREUTROPHIC OLIGOTROPHIC MESOTROPHIC EUTROPHIC HYPEREUTROPHIC Inorganic Inorganic phosporus phosporus 1- -10 10 10- -20 20 20- -100 100 >100 1 10 20 >100 -1 1 ) (µ µgl gl - ) ( Inorganic Inorganic nitrogen nitrogen <150 150- -300 300 >300 <150 150 >300 -1 1 ) (µ µg gl l - ) ( Phytoplankton Phytoplankton 2000 2000- -5000 5000 >5000 2000 2000 >5000 -1 1 ) (cellml - ) (cellml Superficial Superficial chlorophyll a chlorophyll a 1- -2 2 2- -5 5 5- -50 50 >50 1 2 5 >50 gl - -1 1 ) ( (µ µgl ) Depth of Secchi Depth of Secchi disk disk 5- -10 10 3- -5 5 1- -3 3 <1 5 3 1 <1 (m) (m)
Paso de las Piedras Reservoir Sauce Grande River Latitude: 38º 25´ S Longitude: 61º 38´ W Station 2 Provincial Route 51 Argentina Station 4 Wetland El Divisorio Stream Station 1 20 m Station 3 Dam Sauce Grande River
Paso de las Piedras Reservoir Provides drinking drinking water water to to more more than than 450.000 450.000 inhabitants inhabitants Provides from Bah Bahí ía Blanca, Punta Alta a Blanca, Punta Alta and and to to a a petrochemical petrochemical complex complex from
Lake Characteristics 1620 km 2 Area of drainage basin Maximum depth 28 m 328 Hm 3 Perimeter of coastline 60 km Maximum volume 36 km 2 Surface Retention time 4 years Mean depth 8.2 m
Paso de las Piedras Reservoir 0.8 � Eutrophic Eutrophic � 0.6 -1 ) Eutrophication lim it O-Phosphate (mgl O bserved data 0.4 0.2 � Main source of nutrients: Main source of nutrients: � 0.0 agricultural activities activities 0 40 80 120 160 200 240 280 320 360 agricultural Tim e (days) 5 2.5x10 O bserved data -1 ) 5 2.0x10 Total Phytoplankton (mgl E utrophication lim it � High High phytoplankton phytoplankton concentration concentration � 5 1.5x10 during spring spring and and summer summer: : during 5 1.0x10 surface water water blooms blooms surface 4 5.0x10 0.0 0 50 100 150 200 250 300 350 T im e (D ays)
Surface water water blooms blooms Surface � Natural phenomena caused by Natural phenomena caused by � phytoplankton. phytoplankton. � Phytoplankton: microscopic floating � Phytoplankton: microscopic floating algae (first link of the trophic trophic algae (first link of the chain). chain). � In In favorable favorable environmental environmental � conditions they they are are multiplied multiplied and and conditions concentrated in in the the surface surface, , concentrated => fast fast increase increase in in algal algal biomass biomass. . =>
Photosynthesis Photosynthesis - + - + 122 + - 2- H + 42 106 CO CO 2 + 16 NO NO 3 + HPO HPO 4 + 122 H H 2 O + 18 + 18 H 106 2 + 16 2 O 3 Solar radiation radiation Solar C 106 H 263 N 16 P + 138 + 138 O O 2 C 106 H 263 N 16 P 2 algae algae
Problems caused by water blooms For man man For ecosystem ecosystem For For � Reduction of biodiversity Reduction of biodiversity � � Blockage of water Blockage of water- -filters filters � � Anoxic conditions � Anoxic conditions � Unpleasant odor Unpleasant odor and taste and taste � � Shade Shade � � Aesthetics Aesthetics � � Blockage Blockage of of fish fish gills gills � � Presence of potentially toxic Presence of potentially toxic � algae algae
Blockage of water- -filters filters Blockage of water Aulacoseira spp Aulacoseira spp . . Staurastrum spp. Staurastrum spp. Closterium spp. Closterium spp.
Unpleasant odor and taste and taste Unpleasant odor Ceratium hirundinella hirundinella Anabaena circinalis circinalis Ceratium Anabaena
Aesthetics Aesthetics
Toxic Cyanobacteria
Biological determinations Qualitative analysis Qualitative analysis Quantitative analysis Quantitative analysis � Rutner � Plankton � � Plankton net net (30 (30 µ µm) m) Rutner water water sampler sampler � In situ � Observation � � Observation to the optical In situ fixation fixation with with Lugol`s Lugol`s solution solution to the optical microscope of the alive and fixed microscope of the alive and fixed � Phytoplankton � Phytoplankton enumeration in enumeration in samples (formol formol 4%) 4%) samples ( inverted microscope microscope by by Uterm Utermö öhl hl inverted � Determination � method (1958) (1958) Determination based based on on keys keys method � Phytoplankton � Phytoplankton biovolume biovolume � Calculation � Calculation of of mgC mgC. . � Cyanobacteria � Cyanobacteria � Diatoms Diatoms � � Chlorophytes Chlorophytes �
Physico- -chemical chemical determinations determinations Physico � Nitrates Nitrates � Water temperature Water temperature � � � Nitrites � Nitrites � Solar radiation Solar radiation � � Ammonium � Ammonium � pH pH � � Organic � Organic Nitrogen Nitrogen � Dissolved � Dissolved Oxygen Oxygen � Phosphates � Phosphates � Biochemical � Biochemical Demand Demand of Oxygen Oxygen of � Organic � Organic Phosporus Phosporus � Depth of Secchi disk � Depth of Secchi disk � Silice � Silice
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