INNOKANIS - INNOVATIVE INSPECTION METHODS FOR OPTIMISATION OF SELECTIVE SEWER OPERATION STRATEGIES

In Austria sewer systems have been nearly fully implemented in the last decades. Thus operation and maintenance of the valuable infrastructure (ca. 100.000 km of public sewers) is of prior interest. Regular inspection of the underground assets is necessary. Condition assessment is derived from either eye-view by personnel directly or indirect by CCTV inspection in most of the cases. CCTV-inspection provides exact structural and partly operational information, if carried through quality assured whereas cost intensive. General aim of this research project is to develop a qualitative high standing and cost efficient alternative resp. Supplement to conventional CCTV inspection for sewers. That means it should provide the operators with all relevant information for optimising operation and maintenance for water pollution control as it should reduce costs significantly. This is especially needed in rural areas with small number of inhabitants related to the length of the systems. Preliminary investigations with Manhole-Zoom-Cameras resulted in estimations of costs for sewer inspection of ca. 0,3 €/m. Conventional CCTV-Inspection ranges from ca. 1 to 2 €/m. In the pre-study the inspected lengths per day with the Manhole-Zoom-Camera ranged from 2.000 – 3.000 m/d. This result underlies that with this method a fast impression of the condition of the sewers could be gained. Using the fast inspection method for an overview the conventional one can be applied for detailed condition assessment (e.g. for rehabilitation measures), and costs will be minimised. Investigations with the Manhole-Zoom-Camera into proactive sewer cleaning have resulted in a good assessment of sediment rates and prediction of sediment loads. Sewer operators are able to plan appropriate cleaning activities according to the inspection results. Additional information by acoustic inspection should help to transform the optical estimation into automatic calculation of sediment rates. Especially for small and medium sewer utilities there is a need for simple and cost-efficient methods to change from fixed to flexible cleaning intervals. Furthermore „Make or Buy“ decisions depend strongly on the intervals as these influence the length of sewers to be cleaned each year. The combination of Manhole-Zoom-Camera and acoustic inspection into one device will be an innovative and powerful instrument for sewer inspection. The challenge for that goal is to develop both technologies and improve the recognition capacities for structural and operational sewer conditions. Apart from conventional analog methods (e.g. like sewer mirror) all data transfer will be implemented fully digital from onsite inspection into office systems. At the end of the project every sewer operator should have the possibility to carry out a cost-efficient and meaningful inspection of his sewer system with the combined technology. This should help the utilities especially in times of severe financial restrictions to fulfil the legal and environmental obligations. The fully integration into a management software should provide the inspection results as basis for integrated sewer operation and maintenance decisions.