FEATURE The foyer of the CBW complex in Melbourne. The new black? Despite their high capital cost and maintenance requirements, blackwater treatment systems are playing a growing role in Australia’s new building stock, improving the water efficiency while also reducing the strain on mains sewer systems. Sean McGowan reports. The construction industry continues vacuum flush toilets have an exceptionally Greywater and blackwater treatment to push the boundaries of design in low water use, as low as 0.5 litres per flush, is therefore normally considered when order to reduce the impact of the built compared to a water saving toilet of 3 to opportunities for the reuse of onsite environment on natural resources. 4.5 litres per flush,” he explains. water are also exhausted. Yet whatever downsides may exist are often countered And though energy efficiency in “Tapware is now available which uses by the weighting ESD assessment tools commercial buildings receives more just 1.7 litres per minute, against 6 litres such as Green Star place on water savings attention, water efficiency is also moving per minute, which is typical of a 5 star and waste reductions, around which along at a rapid rate, as technology plays WELS-rated fitting.” modern-day BWT systems are designed. a greater role in the water protocol of reduce, reuse and recycle. We believe that where INSIDE BLacKwaTER Like any major piece of kit, blackwater a good level of water treatment (BWT) systems or plants Onsite wastewater treatment systems in treatment infrastructure is (BWTPs) are not suitable in every buildings typically treat either waste from application, and bring with them a series available, as is the case baths, showers, hand basins, kitchenettes of significant potential downsides. This in many major Australian and other wastewater streams, known as is why professionals such as Roger Kluske, cities, this technology greywater, or all sewage including toilet M.AIRAH, associate and sustainability should not be a first choice and urinal waste, known as blackwater. consultant at Umow Lai, believe ’ This treatment is achieved by a adherence to the water protocol Once water consumption has been combination of chemical, physical or remains the most efficient method optimised, designers should turn their biological processes to successfully treat of water management. attention to areas of harvest and/or reuse the wastewater to a suitable standard for “Of course Umow Lai has designed says Kluske, which typically includes reuse in a range of non-drinking water BWT plants for our clients,” Kluske says. rainwater and stormwater collection. applications, including for flushing “However, we believe that where a good toilets, garden irrigation and in heat- “In some circumstances, it may also be level of water treatment infrastructure rejection systems. worth examining greywater capture and is available, as is the case in many major reuse, but designers should be aware of Although the treatment processes of Australian cities, this technology should regulations around its storage.” greywater and blackwater can be similar, not be a first choice.” greywater treatment systems can require Naturally, the capture and reuse of Rather, he says, opportunities for a duplicate sanitary plumbing system and rainwater and stormwater is the easier, reductions in potable water use should may also suffer from a lack of water, with cheaper and less energy-intensive option, first be exhausted through the use of larger quantities of blackwater due largely and is now considered standard for all but innovative fittings and fixtures. to toilet and urinal flushing. the rarest building designs. Greywater “There are great advancements in water reuse without treatment is also possible According to sustainability consultant saving fittings and fixtures. For example, for some purposes. Nicki Colls, a greywater system is most 22 EcOLIBRIUm • MARCH 2011 Designed by architect Denton Corker Marshall, the new Sydney Water HQ at Parramatta aims to reduce water use by 75 per cent and waste water to sewer by up to 90 per cent compared with an equivalent commercial office building. It is the first government building in New South Wales to incorporate a blackwater treatment plant. The BWT plant collects and treats waste water from cooling towers, showers, sinks, basins, toilets, urinals as well as rainwater, for re-use for irrigation, toilet flushing, fire system testing and cooling towers. The building has achieved 5 star Green Star Office Design and As-Built Rating. Picture: Nicholas Lee. FEATURE “The INDUSTRIAL water such cooling systems require, AIR-VOLUTION particularly on very hot days. According to Norman Disney & Young associate Ben Castle, the Corner has begun” Burke and William (CBW) complex in Melbourne is a prime example of where FRANK SEELEY AM a BWT system has been used for this purpose. “We designed these buildings to incorporate a 100 kL-per-day BWT plant, treating sewage from two office buildings atop a common podium,” Castle explains. “Here, recycled water is supplied for toilet flushing and cooling tower use. A 5 star Design rating has been achieved under the Green Star Office Design rating system.” The WRAMS (water reclamation and management scheme) system at Sydney INDUSTRIAL COMMERCIAL Olympic Park takes the technology to a district scale, providing up to 7ML of recycled wastewater daily to multiple buildings linked to the system across the The award-winning Climate Wizard has set a new benchmark in air conditioning, site, as well as to the surrounding suburbs delivering cooling performance that can rival refrigerated systems, but using up to of Rhodes and Newington. In doing so, 80 per cent less energy. it achieves even greater efficiencies than stand-alone systems. Climate Wizard uses the natural process of evaporation to cool, but employs revolutionary technology that cools without adding moisture to the air. It can be used on its EcONOmicS AND own (stand-alone) or in conjunction with existing or new OTHER MOTivaTIONS refrigerated systems. Although any building design that The 1 Bligh St building being constructed by Grocon in Sydney reduces mains water demand and reduces Braemar evaporative coolers have been employs blackwater treatment. the stress on the civic sewer system should Australia’s number one choice for be applauded in the same manner as commercial and heavy industrial cooling attractive within multi-residential common method being membrane those that reduce electrical grid demand, buildings, given the large, constant bioreactors (MBR), although a variety for more than 40 years. For reliable, low the economics of such design decisions supply of bathroom wastewater and maintenance cooling with even lower of other established techniques exist. remain at opposite ends of the ledger. high non-potable water demands. running costs, year after year, Braemar An MBR system, for instance, is used “Blackwater treatment plants are coolers are the proven performers. “In contrast, rainwater reuse systems are at the Vancouver Convention Centre in expensive to design and construct, more often considered when there is a British Columbia, Canada to treat the on top of the ongoing maintenance smaller, less reliable source of greywater building’s sewage, providing 80 per cent requirement,” says Castle. “With water and large, non-potable water demands, of the water needs for toilet flushing in being so inexpensive, there is no payback such as commercial office buildings,” Colls the building and supplemental water for on investment if it is looked at purely Natur arth says, adding that sites with a small footprint irrigating its 24,280 sq m living roof. from the perspective of the potable water al air conditioning that is out of this world, but won’t cost the e and consequently less potential to capture reduction.” After primary treatment, tertiary and reuse rainwater are those that typically AWARDS INDUSTRIAL & COMMERCIAL APPLICATIONS consider onsite recycling of wastewater to treatment disinfects the resulting water, The capital cost of a BWT system reduce potable water demand. and can include one or several techniques depends on its size, design, method 2009 GreenPlumbers Energy Efficient Product of the Year • Data centres • Community halls including flocculation, filtration, UV of treatment and local regulatory 2010 Airconditioning, Refrigeration & Building Services Trade Expo • Warehouses • Leisure centres To achieve a suitable standard of recycled irradiation, chlorination, ozonation, requirements, but Castle says to expect (ARBS) HVAC Product Excellence Award water from such systems, Colls says three • Supermarkets and retail stores • Sporting stadiums electro-dialysis and reverse osmosis. an initial outlay of at least $500,000 2010 Southern Adelaide Innovation Award for Innovation in an stages of treatment are typically employed. for a large office building project. Environmental Product • Food processing plants • Manufacturing faculties This water can then be used for a range 2010 Gold GAIA Award at the Big 5 International Show, Dubai • Schools • Offices Primary treatment uses physical of purposes, including heating and However, Colls reports in her paper, Black separation to remove larger cooling systems, which is often an and Greywater Reuse: The Real Results, contaminants, either via filters, screens, attractive option where buildings have presented at AIRAH’s Achieving the centrifuges or settling. A secondary very high cooling demand. Green Dream conference last year, that treatment