Organizing and Managing the Implementation of Large Diameter Tapping and Plugging Technology for a Major Sanitary Improvement Project in Ho Chi Minh City, Vietnam

Abstract

This paper will discuss the organization, management and implementation of tapping and plugging technology on large diameter reinforced concrete cylinder pipe. The configuration of a 78 inch, 60 inch and 48 inch Triple STOPPLE ® on concrete cylinder pipe was one of the largest operations of this type performed at that time in the Asia Pacific Region. The procedure facilitated the installation of a new under water crossing of an important water supply line as part of a major Peoples Committee of Ho Chi Minh City, Vietnam environmental sanitation and public improvement program. The program consisted of installation of storm and sewage collector systems as well as dredging of canals to alleviate flooding and to promote natural tidal flushing of estuaries for this major Asian city experiencing rapid growth. The demands related to the particular location, the client’s unfamiliarity with the technology and types of pipes presented challenges in planning, organizing, designing and managing field operations. Ho Chi Minh City Sanitation Project The Ho Chi Minh City, Vietnam sanitation project is financed by credits provided by the World Bank and is administered by a World Bank Project Management Unit (PMU) staffed by CDM. The project was designed to serve as a transformational urban project in the city center by turning an open sewer into an important development asset by reducing wastewater pollution and the occurrence of flooding in the area surrounding the Nhieu Loc-Thi Nghe (NLTN) basin in the central business districts of the city. The project comprises a hydraulically integrated system with 40 miles of combined primary and secondary sewers and 168 miles of tertiary sewers. The effluents drain into a 5 mile long interceptor which runs under the NLTN canal. This interceptor flows into a pumping station which discharges into a temporary point in the middle of the Saigon River. In the future the effluents will be taken into a wastewater treatment plant. The Project also finances dredging, transportation and safe disposal of more than 1.30 million cubic yards of sludge from the canal along with improvements to 11 miles of canal embankments. When completed, the project will bring direct benefits of reduced flooding and safe wastewater disposal to over 240,000 households. Relocation of 78 Inch Water Transmission Line Needed to Complete Project In order to complete the final section of the interceptor under the canal there was a need to relocate a 78 inch diameter water main that crosses under the canal. This is the only water supply pipe for about 4 million people. The existing water main is a 50 year old pre-stressed concrete pipe for which there is no alternative water supply. Any failure to successfully carrying out the temporary bypass and relocation of the main would result in the interruption of service to such a large number of city residents that it would have had serious social consequences. Due to the City's extreme concern about any failure, it proposed a direct contract with the Saigon Water Corporation (SAWACO) for the relocation of the water main. SAWACO is an independent state-owned enterprise under the Ho Chi Minh City People's Committee that is considered to be a legally and financially autonomous State Owned Enterprise operating as a commercial entity. In view of SAWACO experience, qualifications and unique know-how, it was felt to