Aquaponics

Aquaponics

Simple Aquaponic System

Aquaponics ist a sustainable food production system that combines a traditional aquaculture (raising aquatic animals such as fish, crayfish or (prawns in tanks) with hydroponics (cultivating plants in water) in a symbiotic  environment. In the aquaculture, effluents accumulate in water increasing the toxicity for fish.  This water is run through a hydroponic system where the by-products from the aquaculture are filtered out by plants to be used as vital nutrients  after which the cleansed water recirculates back to the fish tank.

Nitrogen Cycle

Monitoring water quality is an essential component of the aquaponic system.  The nitrogen cycle,  or cycles in general, are difficult concepts for students to visualize. Nitrogen access is a very important part of the aquaponic system because it provides nutrients for the plants.Fish produce waste through fecal production or the excretion of ammonia. ammonia is converted into nitrite which is then converted into nitrate.  Nitrate is a form of nitrogen accessible by plants. Ammonia and nitrite are toxic to fish at low levels.  In a natural system, nitrate is not  usually a  problem but in a closed system such as you do need to monitor the amounts.  Increased levels are needed for plant growth but have to be balanced with levels that fish can safely tolerate

This year the aquaponics team went from a very simple system used for demonstration to a more complex system using a grow bed.  This system uses an ebb and flow design  with a sump.  The emphasis on this project  however is not the aquaponic system  but rather the control systems used to feed fish and monitor temperature and pH.  

Once you decide what you are going to build the next step is shop.   We went to Lowe's to see if  we could all the parts to build our system.  This is an important part of the project.  Whether it is teachers or students it is important for them to be part of the process from design to construction.  As we were buying different PVC parts Fern Edwards asked me how I knew so much about PVC?  I didn't when I started - I knew it was white and used for plumbing.  But after many conversations with Lowe's employees and trial and error I got better.  The hands-on approach really does work!

Once you get your supplies the next step is to  build your design.  The design that was chosen was a 30 gallon tub for fish,  10 gallon tub for plants and another 30 gallon tub for a sump.  Since water runs downhill the fish tank would be highest and drain into the plant tub. A ebb and flow siphon would be designed to drain into the sump.   

The building and maintaining of the automatic siphon has been the most challenging part of the project.  We ended up modifying our original design but still find it has to be tweaked on a daily basis.  One other problem we have had to deal  with is fish getting stuck in the bulkhead  that allows water to leave the fish tank and move to the plant tank.  This will dramatically impede flow.  Another problem that affected the autosiphon was clay pebbles slipping under the outer wall of the siphon and building up so that it didn't drain properly.  Still researching different way to do it. It will work fine for awhile but them the ebb and flow slows down.

The next step once the aquaponic unit is working is to start building the control system.

Greenbelt Corridor, Denton Texas

Thursday, 6/24/2013  Field Trip

GBC: Green Belt Corridor

This morning the RET Team went on a field trip to the Greenbelt Corridor (GBC) north of Denton, Texas. Dr. Acevedo and Dr. Franco discussed this unique forest and highlighted the weather and soil station used for TEO data.  Teachers were able to see how a wireless sensor network was used in the field.

Dr. Acevedo

Dr. Franco

Elm Fork of the Trinity River

 This wilderness area has numerous hiking, biking and horse trails.  This area is mostly a floodplain of the Elm Fork of the Trinity River and is considered a research forest. The history of the Greenbelt is interesting. UNT, City of Denton, and the Texas Parks and Wildlife collaborated  to form the TEO (Texas Environmental Observation) which would provide near-real time data on environmental parameters along the  GBC.  This area is located between Lake Ray Roberts and Lewisville Lake.  There are 1500 acres of land which have been protected since 1980 when the area became a state park..  This area was used for agriculture but was slowly abandoned due to inundation of water during flood events. According to the USGS (1960) 70% of the land used was pasture land and 30% crop land

Bottom Land Hardwoods

The GBC has patches of bottomland hardwoods that date back to the 1950's when Lake Lewisville.  The original dam was build in 1927 (Garza Little Elm), Lewisville Lake Dam was built and the state park in 1980.  Forest succession  was influenced by flooding and seed banks from the old forest and trees left or planted by farmers.  The dominant trees found along the riparian area are Elm, Hackberry, Mulberry, and Green Ash.   Cottonwoods are also found in this area with some estimated to be 70 - 80 years old. A recent bird survey recorded 5500 birds from 91 species during the breeding season in 2009/20010.

Deliah Johnson standing beside a ancient cottonwood

One of the research areas was in soil moisture across the floodplain. An East to West transect across the floodplain,. using wireless sensors,  measure soil moisture, air temperature, rain, wind speed and direction  solar radiation, soil water tension and humidity. The purpose of these sensors was to compare soil water dynamics between four different soil sites:  river levee, meander levee,, poorly drained clay soil under grass and scattered tree vegetation and poorly drained clay soil under a Ceder Elm forest.This data has be archived and is available from the TEO.

Hiking to the weather station 

Weather Station

Wireless sensor instruments

Summer RET 2013

RET is a summer research program for teachers with the electrical engineering department at the University of North Texas.  This program involves teachers from around the Dallas-Ft. Worth area and assigns them a team that includes graduate students and UNT faculty.  This project is supported by a grant  monies from NSF.

This is an excellent program that challenges teachers, provides hands-on research experience and collaboration.  This experience is then taken back to the classroom through the development of a lesson and student activity.  The activity is designed to engage students and  demonstrate the importance of the engineering field.  

The program provides teachers with faculty seminars and training that allow them to experiment and design on their own with feedback from UNT  graduates and faculty.

Dr. Wan provided training on microcontrolers

Dr. Wan received a very prestigious grant from  IEEE.  The following information was taken from an article posted by the University of North Texas, Denton, Texas  Her lecture described the need for controlling systems, how it works and how it affects our daily lives. The following article was taken from the UNT website.

IEEE Control Systems Society Funding to Support K-12 Teacher Outreach Program

April 2013
Denton, Texas
by: UNT College of Engineering

The IEEE Control Systems Society (CSS) has awarded funding that will allow a control engineering track to be added to a program at the University of North Texas (UNT) aimed at helping area teachers bring research into their classrooms.

This funded IEEE CSS outreach project is a collaborative effort between the departments of Electrical Engineering (EE, College of Engineering)  and Biological Sciences (Biology, College of Arts and Sciences), with Yan Wan (EE) as principal investigator (PI), and Miguel Acevedo (EE), Shengli Fu (EE), Ruthanne Thompson (Biology) and David Hoeinghaus (Biology) as Co-PIs. The new award supports the outreach program to K-12 Teachers in control engineering in partnership with the National Science Foundation funded Research Experiences for Teachers in Sensor Networks (NSF RET) program. 

According to Wan, an increasing need exists for the development of high-performance decision-making algorithms to manage complex systems, including but not limited to environmental, biological, economic, and infrastructure-type systems. “Over the years, increasing number of algorithm developers, researchers in interdisciplinary areas, and practitioners in application-specific domains have realized the important role of control engineering, as providing invaluable concepts and tools to address various decision-making tasks in these broad applications,” she said.

Wan, who is the instructor of the undergraduate/graduate courses on control systems at UNT and a researcher in the same field, sees the need for instructing students while they are in the early stages of their education about the value and interdisciplinary asset of control engineering. To this end, an effective approach is to provide trainings to K-12 educators and help them integrate the basics of control into their teaching plans, she said.

The control engineering track will “guide the teachers to practice control concepts through many interactive activities, as well as multiple hands-on projects on the control of environmental systems,” Wan said.

IEEE CSS outreach program is an international award program that has supported outreach activities in many countries. For more information, please visit the IEEE CSS fund's webpage.

Dr. Wan will work with the Aquaponics Team to develop a control system that can could be used to  monitor water levels, pH, temperature and dissolved oxygen. The engineering of control systems affects our everyday 

Nick Tompson provides training on Arduino

The training students received was on working with the Arduino microcontoller.  This system was chosen because it is open source, there is a huge community available for support and it is relatively inexpensive.   The software and code are free  on the internet.  This allows for creativity of design.

Dr. Fu discussed WSN systems and how the work.

Dr. Fu, Sengli, will work this year with the River modeling team and help them expand on research done last summer to monitor water quality.   His talk discussed how a wireless system works and the benefits and restrictions of using this type of system.

Dr. Acevedo discussed the use of sensor at UNT's TEO side

The TEO (Texas Environmental Observatory) site  was set up by the Environmental Department of UNT.  Its goal was to collect environmental data using wireless sensor networks.  Sensors have been set up the "Greenbelt above Denton, Texas.  Weather data, soil moisture, temperature , ozone and water quality data  It provides an important source of local environmental data that is accessible to UNT faculty and students but also the general public.


These are just a few of the faculty involved with the RET program.  I will discuss other equally important faculty, graduate students and teachers in following posts.