Guidelines for Membrane Technology in Sewage Works

Introduction

Sanitation coverage in Japan reached 73.3% of the total population by the end of the fiscal year 2009, thanks to steady progress in the implementation of sewage systems. Sewage works still face many problems, however, such as how to improve the water quality in a closed water area, how to construct a sound water circulation system, and how to systematically reconstruct aging facilities. Membrane technology is expected to be a critical solution for such problems in the future, and Japan is a world leader in terms of the accumulation of the art and know-how of this technology. Aiming to achieve efficient, sophisticated, sewage facilities, our progress with regard to the application of membrane technology is therefore expected. To encourage broader use of membrane technology through its application, mainly, in medium- to large-scale sewage treatment plants for which demand for reconstruction will increase in the future, it is necessary to improve the conditions required for introduction of membrane technology by local governments. To set technical guidelines, in June 2008, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) launched “Sewage Technical Meeting on Membrane Technology,” which was responsible for the above tasks, and as a result of which, the “Guidelines for Introducing Membrane Technology in Sewage Works: The 1st Edition” was issued in May 2009. Subsequently, the MLIT assessed the classification of the designed effluent water quality according to its suitability for membrane bioreactors (MBR), the recycled nitrification/denitrification process that separates activated sludge with a membrane, or the same process with added coagulant. At the same time, the MLIT launched the “Advance of Japan Ultimate Membrane bioreactor technology Project (A-JUMP)” in fiscal year 2009 to promote the full-fledged penetration of MBR as a foundation of membrane technology for sewage treatment, and implemented “Demonstration of MBR Introduced When Reconstructing Existing Sewage Treatment Facilities” and “Demonstration of MBR Introduced to Satellite Treatment Facilities,” which demonstrated the applicability, high performance, and energy saving capability of MBR. The former, in particular, achieved excellent results in energy saving, with approximately 40% lower energy consumption compared to the conventional process. In addition, other organizations began promoting the R&D and demonstration of membrane technology for application in the water business; for example, the New Energy and Industrial Technology Development Organization (NEDO), an independent government agency, launched a water-saving, environment-conscious water recycling project in fiscal year 2009. This technology is expected to achieve higher performance, including increased energy savings. To reflect the achievements of such demonstration and R&D projects, as well as the latest findings both in Japan and overseas, this document was revised by the Sewage Technical Meeting on Membrane Technology. The revised document contains a significant amount of maintenance management and cost information based on such results and findings, and also describes the overseas trends toward standardization, which is useful information for Japanese companies planning to enter into the water business overseas in the future. MBR has been increasingly used at large-sized treatment plants worldwide, and movement toward standardization has also been accelerating in various countries. Therefore, we consider that MBR will become a core technology for use when reconstructing, upgrading, or enhancing medium- to large-scale treatment plants also in Japan. We hope that readers use these guidelines to deepen their knowledge on membrane technology.