Recently, under the joint leadership of Prof. Gao Baoyu, from the School of Environmental Science and Engineering at Shandong University, and Dr. H.K. Shon, from the University of Technology, Sydney (UTS), a joint research project entitled “Titanfloc for innovative water purification and sludge recycling” was the Asia Pacific Regional Winners of the 2012 IWA Project Innovation Awards (PIA). The contributors of this research are H.K. Shon, J.-H. Kim, S. Vigneswaran, Gao Baoyu, J. Kandasamy, Y. Okour, J.B. Kim and Zhao Yanxia.

As the winner for Applied Research Category of the 2012 IWA PIA, they are qualified to participate in the global level competition. The global level competition for the Global Grand Awards will be presented at the IWA World Water Congress in Busan, Republic of Korea in September 2012.

The project “Titanfloc for innovative water purification and sludge recycling” uses titanium salts (e.g., TiCl4 and Ti(SO4)2) instead of more commonly iron (FeCl3) and aluminium (Al2(SO4)3) salts as an alternative coagulant to remove organic matter and nutrients (phosphorus) from wastewater that are not removed in the conventional sewage treatment plants (STPs). The alternative coagulant (TiCl4) successfully removed organic matter to the same extent as Fe and Al salts. The floc size of the settled floc with titanium salt was bigger than that of Fe and Al salts and led to faster and more effective settling. After flocculation with titanium salt, the settled floc was incinerated to produce functional TiO2, which has the same quality as that of commercial TiO2.

TiO2 is the most widely used metal oxide in the applications of pigments, paper, solar cells and environmental purification. In order to meet the demand of a large amount of TiO2, this novel process can significantly contribute to the supply of TiO2. Aquatic toxicity of the Ti-salt flocculation processes was investigated and the results showed a very low acute toxicity effect for the TiCl4 coagulant and TiO2 produced from different sludge. This process could significantly lower the cost of waste disposal in water treatment, protect the environment and public health and yield economically valuable TiO2.

For example approximately 500 kg/day of functional TiO2 can be produced from a medium size STP of 25 million litres per day using the TiCl4 coagulant. The cost of TiO2 is about AUD $20/kg. Thus, an amount of AUD $10,000 can be recovered from this STP. This process will result in an efficient and economically-viable process not only in terms of the removal of organic matter and nutrients, but also sludge reduction and wastewater reuse.

The amount of TiO2 recovered by this process from STPs meets the demand of TiO2 used in all major applications. Therefore, the recycling of Ti-flocculated sludge not only produces TiO2 with a wide range of environmental applications but also solves the problem of sludge disposal from water and wastewater treatment plants. This project was highly rated by the review committees of the IWA, which lead to its award.

The IWA is a global reference point for water professionals, spanning the continuum between research and practice and covering all facets of the water cycle. Through its network of members and experts in research, practice, regulation, industry, consulting and manufacturing, IWA is in a better position than any other organization to help water professionals create innovative, pragmatic and sustainable solutions to challenging global needs.

The PIA is a prestigious global competition which recognizes and celebrates innovation and excellence in water engineering projects around the world in six different project categories - applied research, planning, design, operations/management, small projects and marketing and communications. Established in 2006, the programme runs on a two-year cycle, with entries competing first at the regional level in one of the regional bases, and the Global Awards being delivered at the biennial IWA World Water Congress. The PIA is open to applicants who may be individuals, and companies, organizations, governmental bodies, or any combination of the above, whether or not they are members of IWA.

Written by: Zhao Yanxia

Edited by: Lawrence Phillips, Jing Zizhao

Source: School of Environmental Science and Engineering,www.view.sdu.edu.cn