Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/86284
SECTION RESEARCH EDR life-cycle costs equals MF/RO - report There is very little difference in life-cycle costs for desalination of reused water between reverse osmosis (RO) with microfiltration (MF) pretreatment and electrodialysis reversal (EDR). This is the prime conclusion of a new report from the WateReuse Association in the USA, A Full-Scale Performance and Cost Comparison Between Electrodialysis Reversal and Microfiltration/Reverse Osmosis (www.watereuse.org/product/08-17-1), which concludes that utilities will need to determine if there are any additional plant-specific factors that could impact the process costs. Authored by principal investigator and project manager, R Shane Trussell of Trussell Technologies, this report documents and compares the actual lifecycle costs and process performance of the two most common membrane processes used for removing salt from recycled water. The need to reduce the salinity of recycled water is becoming more widespread, says the report, as wastewaters have become more saline and recycled water consumers have started demanding a higher quality product. Recently, the regulatory community in the US has indicated the need to desalinate recycled water, and the California State Water Board has drafted a document (Policy for Water Quality Control for Recycled Water) that requires agencies to prepare basin- specific salt and nutrient management plans by 2014. MF/RO and EDR have both been successfully applied to desalting in water reuse, but a full comparison of the actual lifecycle costs of existing full-scale systems has never been documented. Direct reuse could reduce flood risks says researcher Use of direct potable reuse (DPR) of wastewater could have saved the Australian city of Brisbane from severe flooding in 2011 and mitigated recent flood risks in the state of New South Wales, according to an environmental engineer at the University of New South Wales. Dr Stuart Khan of the Water Research Queensland alone, DPR would be the equivalent of immediately constructing a new 425 million m3 cost of construction or having to relocate a single home or farm, says Khan. Khan's research shows that this added reservoir, without the Centre said on 12 April 2012 that DPR could free up millions of cubic metres of water from reservoirs around Australia, giving cities a greater buffer to capture rainwater and control major flooding events. With DPR, highly treated wastewater is introduced directly to drinking water treatment plants, without re-entering the natural environment along the way. In Saudi Arabia's Saline Water Conversion Corporation (SWCC) signed a memorandum of understanding on 25 March 2012 with Dow Chemical Co to jointly pursue development of desalination technologies. At a signing at the Saline Water Desalination Research Institute (SWDRI) in Jubail, the two sides agreed to start 'virtual' storage space would represent a 30% increase on the volume currently reserved for flood mitigation in this region. Khan points out that this type of water recycling also has several environmental benefits compared with indirect potable reuse. "DPR can mean a reduced need for pumping water, reduced operational costs, reduced energy consumption and a lower carbon footprint," says Khan. SWCC and Dow to pursue joint R&D program initiatives to share local and global practices and insights, while researching desalination practices and technologies. Among those at the ceremony were Dr Abdul Rahman bin Mohammed Al Ibrahim, SWCC governor; Groom Bereberah, executive vice president of Dow; and Dr Ibrahim Altesan, general director of SWDRI. | 42 | Desalination & Water Reuse | May-June 2012 MIT improving condensation surfaces at nanoscale Nanoscale surface patterning can be used on condensation surfaces to provide an increase in heat transfer, according to new research just pub- lished by a group at Massachusetts Institute of Technology (MIT). Condensation, which is crucial to the operation of thermal power and desalination plants, has been studied for many years, but the MIT research has examined the effect of changes to the condensing surface at the nano level. This can dramatically affect how long drops take to form, how soon they fall and how much energy is given off to the heat exchanger. The paper, Effect of Droplet Morphology on Growth Dynamics and Heat Transfer during Condensation on Superhydrophobic Nanostructured Surfaces is authored by Nenad Miljkovic, Ryan Enright and Evelyn N Wang and was published on 31 January 2012 in the journal ACS Nano by the American Chemical Society. Solar still trial at Almagordo Indiana-based Suns River is nearing completion of a commercial-sized solar still at the Brackish Groundwater National Desalination Research Facility in Almogordo, New Mexico, USA, following the issue of a patent on its process, US #8,088,257 on 3 January 2012. Suns River chairman and CEO Hill Kemp told D&WR that the company expected to start up the installation in early March 2012. Kemp first announced the process in a paper (IDAWC/DB09-346) to the Dubai congress of the International Desalination Association in 2009. "We have made some further refinements but our breakthrough is alterations to the classic solar still which zoom its productivity by a factor of 3 - 5 times," said Kemp. "In much of the desalination market, our economics are better than reverse osmosis, especially when logistics costs are included."