Melbourne Zoo's water wisdom - Pump Industry Magazine

By Ethan Jenkins, Communications Advisor at Zoos Victoria

Melbourne Zoo is highly regarded for the vast array of species it hosts and its dedicated conservation efforts, but perhaps less well-known is the work being undertaken behind the scenes to uphold the high sustainability standards it prides itself on, including an onsite water treatment plant and VSDs supporting crucial Aquatic Life Support Systems.

Melbourne Zoo is renowned for its rich biodiversity and is located within the heart of the city. As you wander through the world of wildlife, visitors will notice the diversity of species that call the Zoo home – species that are representative of a diverse range of landscapes, from tropical rainforests to the Australian bush.

Melbourne Zoo is also a botanical garden with complex needs and maintaining a microcosm of the world in the one precinct presents its own set of unique horticultural challenges and requirements. In response to this, the Zoo has some groundbreaking systems in place that are being used to conserve water onsite.

As many endangered animals are vulnerable to climate change and habitat loss, Zoos Victoria is determined to be a world leader in environmental sustainability, recognising the key role sustainable practices play in its mission to fight extinction. Zoos Victoria is committed to reducing water consumption, while maintaining the diverse environments for the more than 200 species that call the Zoo home.

Melbourne Zoo’s Zac Saber, is Sustainability Manager at the 160-year-old cultural location, where a large part of his role is water management. At Melbourne Zoo, 90 per cent of the water used is collected from the Zoo grounds and processed onsite through a water treatment plant. This has considerably decreased the Zoo’s use of potable water when its consumption is not needed.
The water is captured across the entirety of the zoo – from stormwater drains, wastewater, animal exhibits and moats.

“Our ability to utilise recycled water and avoid potable water use has been a huge achievement,” Mr Saber said.

“Recycled water accounts for approximately 50 per cent of our annual usage onsite by having this plant.”

Melbourne Zoo’s Sustainability Manager, Zac Saber. Image credit: Zoos Victoria.

How is recycled water used?

Among the Zoo’s team of Horticulturists, Plant Operators and Water Technicians, one person looking after the complex water needs of Melbourne Zoo is Irrigation Specialist, Giuseppe Greco.

Hailing from Catania, Italy, where his family still operates an organic citrus farm, Mr Greco’s agricultural roots led him to study Science and Technology, where he produced a thesis on biomass and energy. Mr Greco holds an intimate knowledge of the Zoo’s varied landscapes and the science behind effectively managing its most precious resource: water.

“I make sure we efficiently deliver water to maintain our diverse landscapes to keep them happy and healthy,” Mr Greco said.

Mr Greco explained that the Zoo has a very sophisticated network, starting at what he has dubbed its ‘headquarters’: the water treatment plant.

The recycled water captured onsite is delivered with an automated system to the grounds via a complex irrigation network to all the gardens managed by the horticulture team, as well as to various water bodies across the property, including the Asian elephant pools and Pygmy hippopotamus pools.

“We have a reticulation system of approximately 15,000 sprinklers throughout the Zoo, which I utilise to maintain our gardens and tree collections,” Mr Greco said.

“Some of these trees are listed on the City of Melbourne’s Exceptional Tree Register, so we need to ensure we are receptive to the trees’ needs.”

Mr Greco and the team have developed a modelling system with soil probes and other environmental monitoring devices, some attached to the canopies of trees.

“Each area behaves differently, but we know how much water goes through the soil layers. The monitoring system provides us with data on the volumes of water needed in particular areas, allowing us to be efficient in our watering.”

Mr Greco said that a day with a 34°C forecast with some wind means there will be a significant amount of water loss from transpiration in the tree canopy.

Melbourne Zoo’s Irrigation Specialist, Giuseppe Greco. Image credit: Zoos Victoria.

“For example, the 105-plus years old Ficus tree (Ficus Macrophylla) at Carousel Park has a wide canopy and will lose roughly 1,000L of water on a very hot day.”

To counteract these heat events, Mr Greco and the team proactively forecast the climate and prepare soil before time.

“This site is complex to manage because there are so many different landscapes and water requirements. My role is to ensure we have a system that supports both our habitats and animals.”

The Zoo has a whole range of different pumps that are within the variety of the systems in use, the specs of which are dependent on the system they are feeding and the optimal flow rates required for associated life support systems.

Many of the Zoo’s filtration systems are retrofitted into areas that may not have always been water bodies – as is the nature of a constantly changing 160-year-old zoo – so depending on the differing needs, the Zoo will employ submersible or end-suction pumps.

The Wild Sea Precinct

Mr Saber and his team also manage Aquatic Life Support Systems within the Zoo’s Wild Sea Precinct.

Wild Sea showcases Victoria’s coastal environment and the marine life that calls it home. These species include Australian and long-nosed fur seals, little penguins, fiddler rays, seahorses and other fish species. With an unmissable conservation focus, the area highlights the threats to Victoria’s coastal areas and underscores what people can do to help protect them.

New Zealand Fur-seal. Image credit: Zoos Victoria

An extensive web of 24-hour life support systems maintain the quality of numerous bodies of water for the animals of Wild Sea. These life support systems are comprised of pumps, chillers, UV Sterilisers, Ozone Generators and filters that process around 1.5 million litres of water several times a day.

Wild Sea is also reusing water onsite with its backwash recovery system. Water that goes through backwash is sterilised through sand filters and injected with ozone.

Once the water is cleaned, it goes into saltwater distribution before filling up the seals and penguins’ systems. One backwash of the systems that services the seals and penguins uses approximately 30,000L of water that is then able to be reused.

Wild Sea pumps in play

Many of the systems in use at the Wild Sea Precinct will have corrosion resistant pumps as saltwater and ozone often eats away at various components. This also prevents any trace metals entering the water as some of these systems have fish and elasmobranchs in them that could be sensitive to any corrosion by-products.

The Wild Seas systems are designed with multiple circulation pumps so ideally the Zoo doesn’t lose the entire Life Support System if one pump was to fail. Similarly, the Zoo’s stormwater plant has multiple pumps for the filtration stages, as this is particularly beneficial for systems that are running submersible pumps as failures are less likely to be identified early.

Even with such sensitive and critical systems, the Zoo’s commitment to sustainability is never far off. Most of the circulation and filtration at Wild Sea was designed with VSDs to achieve flow-rates rather than throttling valves – this allows many of the automation processes to be controlled from the Programmable Logic Controller, aids in longevity of pumps, and is beneficial to our energy consumption for the precinct.

While VSDs were less involved in the overall design of the Zoo’s stormwater treatment plant, the pressure pumps and any booster pumps that are built into the system do use VSDs for the same reasons, and would likely be a consideration for any future replacements.

While water circulation and filtration are significant power consumers onsite, Melbourne Zoo strives for best practice in this space wherever possible – it aids the Zoo in aiming for its sustainability targets, but also makes the most sense from an asset management point of view.

Felix the pygmy hippo. Image credit: Zoos Victoria.

Pressures of the job

The biggest complications faced by the team at the Zoo are critical failures and more often than not, systems are run with multiple pumps either in a Duty-Standby arrangement or they are designed in such a way that a pump failure does not mean the entire plant is down.

Due to the large demand for recycled water at the Zoo, any plant failures must be dealt with quickly to avoid impacting operations and most importantly animal welfare.

Most of the pumps in use onsite have relatively low maintenance requirements – with occasional greasing and more of a focus on monitoring and inspecting. In spite of this, there are also a handful of critical spares the team would need onsite to keep them out of trouble. The team is equipped to handle ornamental water bodies stopping for a period of time, but there’s no room for complete life support failure.

“Problem solving any plant failures can take precedence over what was planned for the day. Addressing a burst pipe is far more time sensitive than responding to an email!” Mr Saber said.

“Most of our systems are automated with a Programmable Logic Controller (PLC) and Human Machine Interface (HMI) system – from the Wild Seas Life Support Systems through to our organics processing and HotRot Machine, there’s a lot of technology that we use daily.

“It also helps a lot to have remote access to identify faults. On a big day, I might walk ten kilometres around the Zoo between all of the plant rooms, so having the tools to remotely check if something is running is very useful.”

Many of the upgrades the Zoo has undergone have actually been through software and programming changes. The team didn’t always have the ability to adjust the speeds of some filtration pumps through the PLC systems, and these changes have allowed for slight tweaks resulting in better water quality parameters for the Zoo’s exhibit inhabitants.

Zoos Victoria’s sustainability commitment reflects its identity as an ecologically mindful conservation organisation.

“We do a lot of work in conservation, but also recognise that our power, waste and water will have an impact on the planet. By reducing that footprint, we are better equipped to fight extinction and reduce habitat loss,” Mr Saber said.

“You can’t campaign for the conservation of endangered species if you aren’t practising it in your own backyard.”