Heyne's Wholesale Nursery

Summary

Traditional approach

Cleaner production initiatives

Benefits

Benefits recommended and still being considered

Alternatives pursued since study completion

Where to find additional information

May 1999

Heyne's Wholesale Nursery

Summary

Heyne's Wholesale Nursery has a water management strategy involving a range of water efficiency measures which, when fully implemented will substantially reduce consumption. The installation of more efficient sprinklers and the future introduction of a new evaporation monitoring system will potentially reduce water consumption by approximately 30% resulting in an annual saving of approximately $21,000. Further savings of $30,000 are expected when water is sourced from the nearby Kaurna Park wetlands.

Business Profile
Heyne's Nursery Pty Ltd was one of the first nurseries to be established in SA and for 126 years has played a prominent role in the development of the State's nursery industry. Heyne's wholesale plant production nursery has 32 employees and grows a broad range of plants in containers largely for the landscaping industry and garden centres.

Financial assistance provided
Irritech Consultants and the Institute of Hor ticultural Development, in Victoria, jointly carried out the consultancy study with a grant of $11,800 provided by the EPA's Cleaner Industries Demonstration Scheme.

Measures implemented
Irrigation management efficiency and a feasibility of water recycling.

Cleaner production motivators
Optimising water usage because of increasing water costs and expansion of the business, improvement in production efficiency and minimisation of environmental impacts.

Plant sales area

Traditional approach

Water consumption for June 93-May 94 was 89,503 kL with a total water cost of $78,762.

Waste Management
Gereration of waste stream
The waste stream is generated by irrigating container-grown nursery stock. Most of the waste came from the areas watered by overhead sprinklers (approx 60%) which have lower irrigation efficiency than areas watered by drip irrigation.

Waste stream, waste volume
Approx 40% of applied water ends up as excess irrigation water. For this particular operation that translates to an annual volume of wastewater of 36,000 kL at a cost of $32,000 per annum.

Disposal methods
Wastewater from irrigation discharges to stormwater drainage through an irrigation channel and eventually flows into the ocean. This method does not incur any financial costs but the wastewater contains fertiliser salts, salts from the source water, organic matter and residues of chemicals used in the production process (eg herbicides).

Cleaner production initiatives

Benefits recommended and implemented
Waste Management Strategy

• The original watering system has been semi-automated with solenoid valves and a 32 station Micro Master Controller, which allows for variables such as pot size, plant species, peak weather conditions and the presence of customers. The controller boxes installed throughout the nursery allow operators to monitor a particular section and determine whether a half or full watering cycle is required.
• The introduction of a semi-automated irrigation controller system at a cost of $47,000 and attention to hand watering achieved a reduction of 9,000 kL, during the 1994-95 season at a saving of approximately $9,000.

Evaporimeter

Irrigation Management Improvements

The study identified two initiatives to improve water use efficiency and reduce wastewater.

Efficient Sprinklers

• The existing sprinkler was tested and an alternative was recommended. The acceptable industry sprinkler distribution uniformity norm is at least 75%. A new lower application rate sprinkler, the Antelco Roto Rain, has increased water distribution uniformity from 67% to 87%. This has a projected reduction of 15,000 kL per annum at a saving of approximately $13,000.
• Water is not always dispersed directly to the pots (influence of wind), so placing less sensitive plants around the sprinklers has enabled more plants to be grown with the same amount of water.
• Selected segregation and grouping of different plant varieties according to water requirements has led to more efficient water usage.

Irrigation management

• Irrigation management has the potential to further reduce water use by using evaporation sensors that allow watering according to the weather. The evaporation-based weather sensors will, when installed, establish:
  • the frequency of watering in dripper areas
  • the run time per day in sprinkler areas.

Moisture level checks in the various sized pots determine optimum watering times. The 80 mm evaporimeter (designed for home gardens) is planned to be used for 300 mm diameter pots and larger which are watered by drip irrigation. As small diameter pots (up to 250 mm) usually dry out daily in peak conditions, a 600 mm evaporimeter is also being trialled. A mechanism is being developed to adjust the run time directly according to the change in the water level reading so that the run time can be varied automatically, on a daily basis.

Benefits from improved irrigation management

Environmental
Water usage and reduction	Efficient irrigation management significantly reduced water wastage by using more efficient sprinklers and installing evaporation-based weather sensors. Water use efficiency is projected to increase from 63% to 83%.
Economic
Productivity	Time previously taken to hand-water plants not adequately watered by sprinklers is now markedly reduced by more efficient and even watering. Even watering and reduction of under and over watering will result in minimal fertiliser loss and therefore provide optimum growing condition for maximum production.
Investment	Semi-automatic irrigation controller system $47,000. Installation of Antelco Roto Rain Sprinklers (completed 1996) $42,500. Install evaporative sensors (projected 1999) $3,120. Integration with wetland (projected 1999) $20,000. Total investment $72,620.
Water cost savings	Semi-automatic irrigation controller system $9,000. Installation of Antelco Roto Rain Sprinklers (completed 1996) $13,000. Install evaporative sensors (projected 1999) $8,000. Integration with wetland (projected 1999) $30,000.
Payback period	Semi-automatic irrigation controller system - 5 years. Installation of Antelco Roto Rain Sprinklers (completed 1996) - 3 months. Install evaporative sensors (projected 1999) - 5 months. Integration with wetland (projected 1999) - 8 months.

Benefits recommended and still being considered

Feasibility of Using Recycled Drainage Water
This study initiative evolved into an investigation into the feasibility of all possible alternate water sources of the nursery. The sources included:

• mains water
• bore water
• recycled runoff water
• desalinated mains or bore water
• 'CAREFREE conditioned' water from the mains or from a bore.

Salinity
Mains water can reach salinity levels close to bore water (1100 EC) at times in summer but is usually manageable at around 600-700 EC. Runoff water has borderline salinity levels (1000 EC) for recycling, so all three sources need dilution with low salinity water before use. A desalination unit could provide low salinity water for mixing to dilute the saline water. Alternatively, if it is confirmed that the CAREFREE unit can condition water to mitigate the harmful effects of salinity, then this could be an alternative to desalination.

Disinfection
Recycled drainage water will need to be disinfected before reuse. Chlorination and ozonisation would not be effective for disinfection of plant pathogens because of high pH and alkalinity, however chlorine dioxide is the preferred treatment. Disinfection by UV light is likely to be only partially effective if recycled water is used because the water has high turbidity and so the UV light penetration will be restricted. The advantage of using recycled water is that the nursery would be able to reduce fertiliser application by approximately 10-15% because of its nutrient load.

Alternatives pursued since study completion

Recent research on the use of "Slow Flow" sand filtration has shown strong prospects for application because it does not use chemicals and is applied online.

Chlorine dioxide treatment will probably be used as a back up treatment until the "Slow Flow" sand filtration method is proven.

The integration of water supply and drainage with the Kaurna Park wetland as shown in the first flow diagram is the preferred water source and is projected for implementation in 1999.

Should the supply from the wetlands not be sufficient, the desalination option will need to be pursued, as shown in the second flow diagram. As Salisbury Council considers the wastewater quality after the desalination treatment to be acceptable for the wetland, it will be directed to the head of the wetland and reused when required. The estimated savings from use of the wetlands, are approximately $30,000 per annum following the wetland treatment process.

Flow diagram of preferred irrigation system

Flow diagram of alternative irrigation system

Kaurna Park Wetland

Where to find additional information

Garry Heyne
Manager
Heyne's Wholesale Nurseries
Corner Waterloo and Bolivar Roads
BURTON SA 5110

Phone: (+61 8) 8280 8088
www.heyne.com.au/WholesaleNursery/

This page was last modified 21-04-2006