GRAY WATER REUSE IN SUSTAINABLE URBAN AGRICULTURE

Transcription

1 GRAY WATER REUSE IN SUSTAINABLE URBAN AGRICULTURE AQUAPONICS: A SUSTAINABLE FOOD PRODUCTION SYSTEM Maryam Shafahi, Mechanical Engineering Department California State Polytechnic University, Pomona

2 WHAT IS AQUAPONICS?

3 WHAT IS AQUAPONICS? A SUSTAINABLE AGRICULTURE PRACTICE HYBRID OF AQUACULTURE AND HYDROPONICS IDEAL FOR SMALL SPACES 1

4 HOW DOES IT WORK? 2

5 WHY AQUAPONICS? -Water conservation -Zero Nitrogen discharge -No fertilizers -Closed-loop cycle

6 WATER SCARCITY UNLESS WE CHANGE OUR WAYS BY 2025, TWO-THIRDS OF THE WORLD POPULATION WILL FACE WATER SCARCITY. THE GLOBAL POPULATION TRIPLED IN THE 20 TH CENTURY BUT WATER CONSUMPTION WENT UP 7 FOLD.

7 OUR SURFACE WATERS ARE POLLUTED 40% OF US RIVERS AND STREAMS ARE TOO DANGEROUS FOR FISHING, SWIMMING OR DRINKING AS ARE 46% OF THE LAKES DUE TO MASSIVE TOXIC RUNOFF FROM INDUSTRIAL FARMS, INTENSIVE LIVESTOCK OPERATIONS AND THE MORE THAN ONE BILLION POUNDS OF INDUSTRIAL WEED KILLER THROUGHOUT THE COUNTRY EVERY YEAR. THE MISSISSIPPI RIVER CARRIES AN ESTIMATED 1.5 MILLION METRIC TONS OF NITROGEN POLLUTION INTO THE GULF OF MEXICO EVERY YEAR. THE US GOVERNMENT REFUSES TO BAN THE HERBICIDE ATRAZINE, AN ENDOCRINE DISRUPTER BANNED IN MANY COUNTRIES AROUND THE WORLD AND WIDELY LINKED TO CANCER.

8 WATER AND AGRICULTURE IN CALIFORNIA More than 80% of state water is used in agriculture

9 NITRATE RUN-OFF CONTAMINATED GROUNDWATER TULARE LAKE BASIN AND MONTEREY COUNTY MORE THAN 90 MG/L NITRATE CALIFORNIA DEPARTMENT OF PUBLIC HEALTH MAXIMUM CONTAMINATED LEVEL 45 MG/L 2.5 MILLION PEOPLE

10 AQUAPONICS HISTORY AZTEC CULTIVATED AGRICULTURAL ISLANDS KNOWN AS CHINAMPAS. LONG BEFORE THE TERM AQUAPONICS WAS COINED, THE AZTEC INDIANS RAISED PLANTS ON RAFTS ON THE SURFACE OF A LAKE IN APPROXIMATELY 1,000 AD

11 Primary Components Hydroponic Systems Nutrient Film Technique Floating Raft Reciprocating Gravel

12 Primary Components Filtration Mechanical Ex. Sand beds, filter flosses and settling chambers Biological Ex. Rotating biological contractors, expandable media, fluidized bed filters

13 System Considerations Fish Selection High tolerance of fluctuating water conditions Tilapia, perch, bass and catfish Plant Selection Aquatic vs. terrestrial plants Low vs. high nutritional requirements Lettuce, herbs, watercress and tomatoes

14 System Considerations Water Conditions Balancing Act ph requirements Nitrifying Bacteria Hydroponic Plants Freshwater fish

15 IMPORTANT AQUAPONIC FACTORS SYSTEM FACTORS o DISSOLVED OXYGEN o PH o HARDNESS o ALKALINITY o TEMPERATURES (69-86 F) Bacteria Factors o o o o Ammonia Nitrite Nitrate Levels Bacteria

16 Bacteria Nitrosomonas bacteria oxidizes ammonia which then becomes nitrites Nitrobacter bacteria converts nitrites into nitrates 1

17 Dissolved Oxygen (DO) is needed for fish, bacteria and plants this can be achieved through aeration o should be higher than 5 mg/l fish come to surface to get oxygen at 1 mg/l less DO at higher temperatures 3

18 SYSTEM DESIGN AND IMPLEMENTATION o o o o WHY MECHANICAL ENGINEERS? HEAT TRANSFER, THERMAL DESIGN FLUID DYNAMICS SOLAR PANEL DESIGN/CONSTRUCTION CONTROLS/MEASUREMENTS 3

19 Is Aquaponics using 90% less water compared to soil farming?

20 IS AQUAPONICS SCALABLE? Is Aquaponics Scalable?

21 HOW WE STARTED?

22 AQUAPONICS IN CAL POLY POMONA

23 AQUAPONICS IN CAL POLY POMONA 120 FT 2 GROWING BED, 250 PLANTS, 950 GALLONS OF WATER OVERALL

24 Aquaponics annual average Aquaponics average excluding Summer Compared with CA average 128 liters/kg 106 liters/kg (+ 11%)- (-25%)

25 EVAPORATION: 80-90% OF WATER LOSS Ave Temperature, Rel Humidity, Evaporation Rate vs Time Temperature (F) and Relative Humidity (%) Ave Temp (F) Ave RH (%) Evaporation per hour Ave (Gh) /24 9/3 9/13 9/23 10/3 Time 10/13 10/23 11/2 11/12

26 SERVICE TO THE COMMUNITY ME 499 S (AQUAPONICS ENGINEERING) CLASS LOPEZ ELEMENTARY SCHOOL, POMONA SCHOOL DISTRICT

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29 NEXT STEPS

30 WI-FI CONNECTED DATALOGGERS NITROGEN (AMMONIA, NITRITE, NITRATE) SENSORS/LOGGERS ENERGY EFFICIENCY OF THE SYSTEM GRAY WATER UNIT

31 SUMMARY AQUAPONICS IS A WATER EFFICIENT ENVIRONMENTALLY FRIENDLY FOOD PRODUCTION SYSTEM. ITS WATER EFFICIENCY CAN GROW UP TO 25% COMPARED TO AVERAGE CALIFORNIA WATER USAGE FOR LETTUCE THE RESULTS OF ANNUAL MEASUREMENT ON THIS PILOT PLANT CAN BE USED TO EVALUATE THE SCALABILITY OF AQUAPONICS AS AN ALTERNATIVE AGRICULTURE SYSTEM FOR THE FUTURE.

32 REFERENCES NITROGEN SOURCES AND LOADING TO GROUNDWATER, CENTER FOR WATERSHED SCIENCES UNIVERSITY OF CALIFORNIA, DAVIS, TECHNICAL REPORT 2, BLIDARIU F., GROZEA A., INCREASING THE ECONOMICAL EFFICIENCY AND SUSTAINABILITY OF INDOOR FISH FARMING BY MEANS OF AQUAPONICS - REVIEW, ANIMAL SCIENCE AND BIOTECHNOLOGIES, 2011, 44 (2)

33 QUESTIONS?