Abstract: Infrastructure assets are essential in urban cities; their purpose is to facilitate the public needs. As a result, their conditions and states shall always be monitored to avoid any sudden malfunction. Sewer systems, one of the assets, are an essential part of the underground infrastructure as they transfer sewer medium to designated areas. However, their conditions are subject to deterioration due to ageing. Therefore, it is of great significance to assess the conditions of pipelines to avoid sudden collapses. Current practices of sewer pipeline assessment rely on industrial protocols that consider distinct defects and grades to conclude the limited average or peak score of the assessed assets. This research aims to enhance the evaluation by integrating the Quality Function Deployment (QFD) and the Decision-Making Trial and Evaluation Laboratory (DEMATEL) methods in assessing the condition of sewer pipelines. The methodology shall study the cause and effect relationship of the systems’ defects to deduce the relative influence weights of each defect. Subsequently, the overall grade is calculated by aggregating the WHAT’s and HOW’s of the House of Quality (HOQ) using the computed relative weights. Thus, this study shall enhance the evaluation of the assets to conclude informative rehabilitation and maintenance plans for decision makers.
Abstract: This study is concerned with the development of a micro-hydraulic turbine for power generation installed in sewer pipes. The runner has a circular hollow around the central (rotating) axis so that solid materials included in water can be easily flow through the runner without blocking the turbine. The laboratory experiments are also conducted. The hollow is very effective to make polyester fibers pass through the turbine. The guide vane is useful to heighten the turbine performance. But it is easily blocked by the fibers, making the turbine lose the function.
Abstract: Corrosion of concrete sewer pipes induced by
sulphuric acid attack is a recognised problem worldwide, which is not
only an attribute of countries with hot climate conditions as thought
before. The significance of this problem is by far only realised when
the pipe collapses causing surface flooding and other severe
consequences. To change the existing post-reactive attitude of
managing companies, easy to use and robust models are required to
be developed which currently lack reliable data to be correctly
calibrated. This paper focuses on laboratory experiments of
establishing concrete pipe corrosion rate by submerging samples in to
0.5pH sulphuric acid solution for 56 days under 10ºC, 20ºC and 30ºC
temperature regimes. The result showed that at very early stage of the
corrosion process the samples gained overall mass, at 30ºC the
corrosion progressed quicker than for other temperature regimes,
however with time the corrosion level for 10ºC and 20ºC regimes
tended towards those at 30ºC. Overall, at these conditions the
corrosion rates of 10 mm/year, 13,5 mm/year and 17 mm/year were
observed.
Abstract: Corrosion of concrete sewer pipes induced by sulfuric
acid is an acknowledged problem and a ticking time-bomb to sewer
operators. Whilst the chemical reaction of the corrosion process is
well-understood, the indirect roles of other parameters in the
corrosion process which are found in sewer environment are not
highly reflected on. This paper reports on a field studies undertaken
in Austria and United Kingdom, where the parameters of
temperature, pH, H2S and CO2 were monitored over a period of time.
The study establishes that (i) effluent temperature and pH have
similar daily pattern and peak times, when examined in minutes
scale; (ii) H2S and CO2 have an identical hourly pattern; (iii) H2S
instant or shifted relation to effluent temperature is governed by the
root mean square value of CO2.
Abstract: Concrete sewer pipes are known to suffer from a process of hydrogen sulfide gas induced sulfuric acid corrosion. This leads to premature pipe degradation, performance failure and collapses which in turn may lead to property and health damage. The above work reports on a field study undertaken in working sewer manholes where the parameters of effluent temperature and pH as well as ambient temperature and concentration of hydrogen sulfide were continuously measured over a period of two months. Early results suggest that effluent pH has no direct effect on hydrogen sulfide build up; on average the effluent temperature is 3.5°C greater than the ambient temperature inside the manhole and also it was observed that hydrogen sulfate concentration increases with increasing temperature.