TY  - BOOK
AU  - Visscher, J. T
AU  - Veenstra, S
TI  - Slow sand filtration  :  manual for caretakers / J. T Visscher and S. Veenstra with illustrations by A. Figee
U1  - B 16.31 VIS -12498   
CY  - The Hague,The  Netherlands, 1985.
KW  - Water - Furification - Sand filtration
KW  - Drinking water
KW  - ENG
ER  -