Innovative Bottom Ash Technology Secures Reference Project 

The signing of the contracts between Hitachi Zosen Inova AG (Switzerland) and ZVHo at the end of May signaled the start of the retrofitting and revamp work at KVA Horgen. The cooperation between the Swiss technology firm and the Horgen district waste treatment association is aimed at securing the operation of the plant through to 2030. New technologies for bottom ash discharge and a new combustion concept will be used for the first time, and the project will thus involve pioneering work for both companies.

Hitachi Zosen Inova AG (HZI) has been commissioned by the Horgen district waste treatment association (ZVHo) to upgrade the Horgen waste incineration plant (KVA) for further operation through to 2030. “With this project, we are taking on a pioneering role in waste treatment,” said Romano Wild, Director at ZVHo. HZI CEO Franz-Josef Mengede added: “Our client will receive state-of-the-art incineration and flue gas treatment technologies. We are delighted to have a further reference plant close to our head office.”
Economic benefits thanks to efficient technologies While slag from incineration was previously quenched and discharged in wet form, KVA Horgen will instead feature dry bottom ash discharge. The aim is to process the bottom ash at ZAV Recycling AG in Hinwil, to increase the recovery of valuable mineral and metal materials, and thus deliver a sustainable environmental benefit. Thanks to HZI’s technologies, the bottom ash discharge will not only be dry, it will also be completely dust-free.

In addition to the modernisation of the existing boiler and flue gas treatment system, a new incineration system will be installed at the plant, this marking the first time that this innovative system has been retrofitted for industrial application. This will reduce the long-term maintenance costs while at the same time increasing energy efficiency. The furnace developed by HZI produces less CO, raw NOx, and fly ash. The combination of the new dry scrubbing flue gas treatment system Xerosorp+ and a heat exchanger to recover thermal energy will enhance the economic efficiency of KVA Horgen.

The Xerosorp+ process developed by Hitachi Zosen Inova ensures exceptionally low emissions of harmful substances, and delivers decisive energy savings since the treatment system functions without the energy-intensive reheating usually used prior to the catalyst. A new heat exchanger also means much more energy can be recovered from the flue gases. This new process thus makes a two-fold contribution to ensuring that the treatment of our daily waste is as environmentally friendly as possible. At the same time, the requirements of the Swiss Ordinance of Air Pollution Control are met within the smallest possible building volume. The order volume totals more than CHF 13 million. The retrofitting work will commence in April 2015, and will be completed in good time for the start of the heating period in the fall of 2015.