A South African-linked innovation, which is able to turn seawater into an alternative water, energy and fertiliser resource, has won the Global Grand Honour Award of Applied Research at the International Water Association’s 2012 Project Innovation Awards.
University of Cape Town civil engineering Professor George Ekama participated in the international team that included researchers and scientists from Hong Kong University of Science and Technology, Hong Kong Airport Authority, Hong Kong Drainage Services Department and Delft University of Technology.
The aim of the project was to integrate the triple water supply (TWS) system, the SANI Process and the urine phosphorous recovery (UPR) system to make use of seawater as an alternative resource.
The TWS, SANI and UPR systems can be applied individually. However, the team found that the integration of the solutions provided the greatest financial and environmental benefits, particularly for islands and coastal cities of developing countries.
The TWS system, which produced yearly savings of 52% freshwater requirements and 30 000 MWh of electricity at the Hong Kong International Airport, integrates freshwater and seawater for an integrated water supply and sanitation system.
The team used the SANI process to introduce a sulphur cycle into the carbon and nitrogen cycles for sewage treatment.
This minimised sludge handling and disposal, leading to a 50% cost reduction, as well as saving about one-third of energy consumption.
The UPR technology, using magnesium ion in seawater, recovered phosphorus from urine in the form of magnesium ammonium phosphate - a valuable phosphorus and nitrogen containing fertiliser - by mixing hydrolysed urine with seawater.