INTERNATIONAL CONGRESS ON RECENT ADVANCES IN SCIENCES AND TECHNOLOGY - Kuala Lumpur - Malaysia (2019-02-20)

A Sustainable method for design a novel separate sewer system

The combined sewer systems makes up about 70% of sewer systems in the UK and Europe. However, an environmental regulations limit the use of combined sewer system in many developed and developing countries and separate sewer systems are currently used in all new developments. The main challenge, in the UK, most other European, and other countries, is install the traditional separate systems in narrow streets, which are more common in such as these countries. These streets are occupied by a complex network of infrastructure services, and find a space in which to place two sets of pipes is therefore challenging. This research design a novel method for separate sewer systems, allows to use one trench to set both sanitary pipe and storm pipe. The system included a new design for manhole shape, use for stormwater flow and foul flow without mixing. The novel design for manhole, combining the conventional separate sewer system into one structure. The new shape for the manhole is discussed in this paper, the structural behavior tested and compared with the structural performance of the conventional manhole. A physical model was built in the laboratory to test structural performance, the results used to validate the FE model which was then upgraded to a full scale FE model. The manhole shape is cylindrical and has two chambers which are arranged coaxially. The external one is used as the storm manhole, the internal one used as the sanitary manhole. The base of the storm chamber is at the level of the bottom of the inlet storm pipe, while the sanitary chamber extends to the same level as the bottom of the inlet sanitary pipe. The displacement of the new manhole using reinforced and non-reinforced concrete, is shown in Figure 1 under three categories of applied loads: weight of manhole, HS20, HS25 and Double HS25 through a one wheel traffic load applied on the cover of the sewage chamber. These results were compared with performance of the conventional manhole under the same series of applied load. Table 1. presents the comaprison between displacment of the new manhole and conventional manhole. Figure 1. Displacement of the non-reinforced new manhole under a one wheel applied load on the one cover of the sewage chamber. Table 1. Summary of the displacement of the new manhole and conventional manhole under different applied loads and type of material. Manhole Material of manhole The maximum displacement of soil below the centerline of manhole Weight load HS20 load HS25 load Double HS25 load The new manhole Non-reinforced concrete 1.63 2.61 2.73 3.83 Reinforced concrete 2.12 3.14 3.26 4.38 The conventional manhole Non-reinforced concrete 1.39 3.97 4.35 7.74 Reinforced concrete 1.57 4.22 4.60 8.02 The conventional manhole has less displacement under light and medium loads and aproximatlly the same displacement under heavy loads, compared with the displacement of the new manhole under the same loads. It also experiences higher displacement under over-loads in comparison to the new manhole. The conventional manhole has less displacement compared to the new manhole under the weight effects and small loads (HS10 and HS15). The displacement of the new manhole is significantly less than the displacement of the conventional manhole when a one-wheel load applied. Keywords: 3 D finite elements, separate sewer system, structural performance.
Mrs. Massara Abbas, Mr. Alaa Abbas, Mrs. Felicite Ruddock, Professor Rafid Alkhaddar, Professor Robert Andoh, Dr. Glynn Rothwell