monitor quality (8)

28 Sep 2016

Remediating Paclobutrazol From Irrigation Water Using Activated Carbon

Grant, G.A., Fisher, P., Barrett, J.E., Wilson, C.P. (University of Florida)

Recirculating irrigation water can sometimes have residual agrichemicals present, such as paclobutrazol.  Paclobutrazol is an active ingredient used in plant growth regulators to control plant height.  The objective of this project was to use granular activated carbon filtration (GAC) to remove paclobutrazol using different contact times.  A 0.05 mg·L-1 (50ppb) paclobutrazol solution was passed through a small-scale, 0.50 to 4.75 mm particle size (8x30 mesh) coconut coir GAC system.  A bioassay of broccoli seeds and begonia seedlings were used to show the effect of before and post GAC filtered water.  Paclobutrazol concentration decreased by 90% or 99% with a contact time of 12 seconds or 59 seconds GAC, respectively. Overall, this experiment showed that granular activated carbon has the potential to remediate paclobutrazol from irrigation water to below biologically-active concentrations.

ASHS Abstract 2016 Grant (270 KB)

1 Jun 2016

Minimize Build-up In Your Water Pipes

Fisher, P. (University of Florida) and Raudales, R. (University of Connecticut)

In this case study, stain was observed on the plant foliage and on the walls of the greenhouse.  Iron analysis from the well water was high at 8 ppm.  In the main irrigation pipe there was a build up of brown sludge.  Analysis of the sludge showed that 58% of the reported minerals was iron.  To solve this problem an oxidizer (potassium permanganate) was injected into the water to precipitate the iron (into a solid form).  A filter (glauconite greensand) was used to remove the iron from the water. 

Greenhouse Grower June 2016 (541 KB)

1 May 2016

Pinpoint Toxicity in Your Pond Water

Fisher, P.R. (University of Florida)

A case study for a coastal Florida producer using pond water for irrigation.  The pond water passed through a sand filter and chlorination treatment.  The plants showed pitting and bronzing on the foliage and stunted growth.  This article provides trouble shooting tips and tools used to calculate chlorination dosage.

Greenhouse Grower May 2016 (3754 KB)

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Description of research activities

A national team of scientists is working to encourage use of alternative water resources by the nation’s billion-dollar nursery and floriculture industry has been awarded funds for the first year of an $8.7 million, five year US Department of Agriculture – National Institute of Food and Agriculture –Specialty Crop Research Initiative competitive grant.

The team will develop and apply systems-based solutions to assist grower decision making by providing science-based information to increase use of recycled water.  This award from the NIFA’s Specialty Crop Research Initiative is managed by Project Director Sarah White of Clemson University.  She leads a group of 21 scientists from nine U.S. institutions.

Entitled “Clean WateR3 - Reduce, Remediate, Recycle – Enhancing Alternative Water Resources Availability and Use to Increase Profitability in Specialty Crops”, the Clean WateR3 team will assist the grower decision-making process by providing science-based information on nutrient, pathogen, and pesticide fate in recycled water both before and after treatment, average cost and return-on investment of technologies examined, and model-derived, site specific recommendations for water management.  The trans-disciplinary Clean WateR3 team will develop these systems-based solutions by integrating sociological, economic, modeling, and biological data into a user-friendly decision-support system intended to inform and direct our stakeholders’ water management decision-making process.

The Clean WateR3 grant team is working with a stakeholder group of greenhouse and nursery growers throughout the United States.

For example, at the University of Florida graduate student George Grant is collecting data on removal of paclobutrazol, a highly persistent plant growth regulator chemical, from recirculated water using granular activated carbon (GAC) filters. This is being done in both research greenhouses and in a commercial site. The GAC filters can remove more than 90% of chemical residues, and are proving to be a cost-effective treatment method.