Brick making from 100 percent of incinerated sewage sludge ash is deve
loped. There are already 8 full scale plants in Japan. All of them emp
loy high pressure molding of incinerated sewage sludge ash and firing
at about 1000 degrees C. The end products are widely accepted for publ
ic works such as flooring of plazas or pedestrian walk ways. Early in
the history of the development, overall quality of the sewage brick wa
s not competitive. They were subject to get moss growth on the surface
because of its high moisture content, or whitening because of leachin
g of Calcium Carbonate. The problems were solved by increasing the tem
perature of the firing process and by chemical coating. The manufactur
ing cost of one sewage brick is around two dollars and the retail pric
e is one dollar. (C) 1997 IAWQ. Published by Elsevier Science Ltd.