Sewer rehabilitation using epoxy resin injection

Over the years many systems or methods of rehabilitating sewers have claimed to be the next generation and the answer to the prayers of city, water and municipality engineers the world over, and yet many of these promises have not been fulfilled. The claims from manufacturers cannot always be accepted and therefore independent testing organisations such as IKT (Institute for Underground Infrastructure) of Germany plays a big role in helping engineers choose the best method of repair in a given situation.

Since its establishment in 1994 the organisation of IKT has been based on a neutral, independent, non-profit research, testing and consulting institution. It seeks to find answers to questions relating to the construction or repair of underground pipes and infrastructure networks for gas, water and wastewater. As an independent and reliable partner for utility companies, sewer system operators, water associations and related industry, IKT offers highly specialised cutting edge research and testing of technologies in a practical and application-orientated manner by means of ‘product tests’.

The objective of IKT product tests is to provide network operators with reliable and independent information on the strength and weaknesses of products and methods in different wastewater technologies. The tests are made together with network operators who follow the whole procedures over several meetings. An essential aspect of IKT product tests is the practical product-quality evaluation, such as under construction or operating conditions. The focus of the examinations is not only to ensure the compliance with individual standards or bodies of rules and regulations. It is also to ensure the reliable fulfilment of network operator requirements during construction; the operation and the service life under expected conditions such as load, groundwater, earth pressure, volume of traffic or high-pressure cleaning, is also the focus of attention. The result is that the network operators are provided with independent, clear, practice-related, and technically well-founded information concerning the strengths and weaknesses as well as areas of application and limits of the tested products. The network operators are quickly and comprehensively informed on product quality with an understandable evaluation scheme and a test seal. At the end of any IKT product test the tested products and methods are all assessed with marks from very good to poor.

The results of IKT product tests that have been completed to date have clearly shown the need for evaluation of the different available wastewater technologies, products and methods in comparative quality tests in order to provide information to network owners on the most suitable method for a particular situation.

In June 2004, IKT conducted testing of 13 methods of repairs for lateral connections ranging from inliner, top hats and robotic methods. Only one manufacturer was awarded the rating of good from all those who participated. That company was KA-TE System AG, now KA-TE PMO AG, utilising its worldwide patented – Shield Repair System – which injects epoxy resin through small openings behind the shield.

Using a balloon inflated by the robot into the lateral means that it follows the natural angle of entry from the lateral into the main sewer, whatever the angle. This method allows more than one repair to be carried out in the same pipe length during a single travel. The shield has a minimal effect on the flow of the sewer and can be removed and re-used after the resin has cured.

The repaired area is precise and exact, making it cost effective and efficient, according to the company. The results from the test can be downloaded free from the website (www. ikt.de).

In July 2009, IKT followed up on the previous tests with Repair Methods in Main Sewers and once again KA-TE PMO AG achieved the best test results from the 14 systems tested. The repair this time was made not by the Shield Repair System, although this could have been used, but by manual filling.

The use of epoxy resin injection as a form of sewer repair is nothing new. There are more than 170 KA-TE PMO systems in operation worldwide; it has proven over the last 20 years to give the city and water engineers peace of mind when choosing this over other systems said the company. The likes of epoxy resin from Epoxonic and Congresive have been tested and shown to have no effect, even on drinking water. Repairs using epoxy resin are durable and robust, extending the life of the sewer infrastructure without any contamination.

>> This article is presented with permission of Trenchless International magazine <<
(www.trenchlessinternational.com)