Water & Wastewater Treatment Magazine
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The SMART-Plant project involves seven material recovery techniques which can be applied to existing wastewater treat- ment plants, each of which is being dem- onstrated through a pilot system which is either fully operational or about to launch at a live sewage treatment site. ● SMART Tech 1 is cellulose recovery, through upstream dynamic • ne-screen and post-processing of cellulosic sludge. Cellulose is a key ingredient of toilet paper, so is present in large quantities in sewage; the cellulose recovered can be used to make bioplastics and construc- tion materials such as asphalt. Suitable for cellulose harvesting at medium or large wastewater treatment plants, the process works using a • ne dynamic sieve called a Salsnes Filter, which separates cellulosic sludge from raw sewage; the cellulose is then re• ned and cleaned by post-processing. It is being demonstrated at Geestmerambacht in the Netherlands (pictured above). ● SMART Tech 2a is the mainstream anaerobic treatment of sewage with secondary biogas recovery, using a polyurethane-based anaerobic bio• lter. This process allows for the recovery of biogas from small and medium sized wastewater treatment works which have irregular organic-load peaks, and would not therefore be considered suitable for anaerobic digestion. It works using a bio- • lter with an innovative polymeric-based immobilisation matrix, which is applied in the activated sludge process. As well as biogas recovery, which can be used to generate energy, the technology results in high COD and TSS removal so the treated e‰ uent can be reused in agriculture. It is being demonstrated at Karmiel in Israel. ● SMART Tech 2b is a novel type of bio- logical nutrient removal known as SCEP- PHAR (Short-cut Enhanced Phosphorus and PHA Recovery), which is being applied to the mainstream sewage treat- ment process. It allows for the enhanced recovery of phosphorus and the chemi- cal PHA, which can be used to make bioplastics. The system works via two sequencing batch reactors (SBRs) one for heterotrophic bacterial growth and one for the growth of autotrophic nitri• ers; there is also an interchange vessel and a chemical system for the recovery of P as struvite. The pilot-scale system is being demonstrated at Manresa in Spain. ● SMART Tech 3 is the tertiary recovery of nitrogen and phosphorus based on ion exchange. This process, applied to secondary treated e‰ uent, results in the extraction of nutrients which can be used in agricultural fertiliser. It uses two di' er- ent ion exchange media, with the process optimised to the ideal regeneration cycle to keep the media working. The system has been developed by UK project partner Cran• eld University, and is being dem- onstrated at Cran• eld's own wastewater treatment plant. ● SMART Tech 4a is a novel con• gura- tion of sludge treatment known as SCENA which allows for enhanced biological phosphorus removal in combination with conventional AD and biogas recovery. In the SCENA (Short-cut Enhanced Nutrient Abatement) set-up, nitrogen is removed through the processes of nitritation/ denitritation, and enhanced P removal is achieved through the alternation of anaerobic and aerobic conditions. The output is P-rich sludge and VFA. It is be- ing demonstrated at Carbonera in Italy. ● SMART Tech 4b is the same SCENA con• guration but used in combination with enhanced AD, which uses thermal hydrolysis pre-treatment. This allows for even greater recovery of P-rich sludge. This is being demonstrated at Psyttalia in Greece (pictured, above le– ). ● SMART Tech 5 is the same SCEPPHAR technology used in 2b but applied to the sidestream sludge treatment process. It enables the integration of conventional biogas recovery from sewage sludge with energy-e˜ cient nitrogen removal from sludge reject water and the recovery of PHA and phosphorus in the form of stru- vite. It is being demonstrated at Carbon- era in Italy. www.wwtonline.co.uk | WWT | AUGUST 2017 | 19 ™ THE PROCESSES ™ DOWNSTREAM TECHNOLOGIES The resources that are extracted by the seven main SMART technologies (whether they are cellulose, nutrients, PHA or VFA) are then able to be transformed into marketable products by two 'Downstream SMART Techs'. The fi rst of these (developed by Brunel University in London) uses cellulosic and PHA materials to make biocomposite plastic which can be used in industry, construction or for consumer goods. The second (at Manresa in Spain) consists of dynamic composting which allows the cellulosic and P-rich sludges to be formed into commercial fertiliser or to be enabled to be used as fuel at biomass plants.