AWWA ACE56154

The water treatment industry is constantly faced with the difficult task of balancing the chemical and microbial risks associated with drinking water contaminants. For example, higher doses of free chlorine may make water safer from the microbial perspective by inactivating more pathogens, but the chemical safety of the water will be compromised due to the increased production of disinfection byproducts (DBPs), which are suspected human carcinogens. Many water utilities will soon be forced to modify their treatment process to comply with new federal and state regulations. Biological filtration is a process already proven to reduce finished water levels of DBPs and other chemical contaminants, and the recent experimental results of this research team indicates an enhanced ability of biofilters to remove particles, including Cryptosporidium oocysts. Based on the advantages of biological filters in terms of both chemical and microbial safety, it is foreseeable that many utilities may soon wish to switch to biological filtration. Proper filter backwashing is essential to maintaining the performance of any granular media filter, and backwashing is even more important to biological filters due to the behavior of the biofilm on the media. It is also essential for maintaining enhanced organic and pathogen removals. Distinctions between conventional and biological filters are made based on experimental evidence and explained with a microscopic force model approach that includes hydration forces and Born repulsion. Includes 34 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/16/2002

Number of Pages:

20

File Size:

1 file , 320 KB