8Ammerman D K. Once the province of communities the south and west,water reuBe is gaining popularity throughout the United States[J].Water Environment&Technology.1998,67--71.
9Lazarova V. Control of nitrification efficiency in a new biofilm reactor[J]. War. Sci. Technol. , 1997, 36 (1): 31.
10Welander U R. Nitrification of landfill leachate using suspended-carrier biofilm technology[J]. War. Res., 1997, 31: 2351.