Treatment and Disposal of Sewage Sludge in the Mid‐1990s

Abstract

The paper reviews the current methods of sludge technology, and compares them with those discussed by Ashton in 1904. The paper also plots the development of some of the current technology over the last century, particularly those methods of treatment which were mentioned by Ashton but were not in existence at the time. The 1990s have been a most interesting era, and have probably seen more changes in sludge technology than any other decade this century. The most significant impact will be due to the cessation of the sea disposal route which, at the beginning of the 1990s, was used for about 30% of the total sludge production in England and Wales and approximately 76% of the total sludge produced in Scotland.

The physico‐chemical characteristics of thermophilic aerobic sludges

“…The biological treatment of sewage has always generated waste sludge and with the full implementation of the Urban Wastewater Treatment Directive, the amounts of sludge requiring treatment and disposal will increase appreciably 1. The various surveys which have been made provide slightly differing values but the figure will be around the value quoted by Hudson2 of 1 746 000 dry tonnes by 1999. Treating and processing these large amounts of sludge will be expensive and considerable efforts are being made to derive process streams which will minimise these costs.…”

Speciation of selenium and organotin compounds in sewage sludge applied to land

“…From the law on waste recovery and disposal in 1975 to the European guideline about wastes in 1991, priority has been given to waste recovery and recycling (Degrémont, 1989). The most common methods of sludge disposal are agricultural land application, land reclamation, landfilling, ocean dumping or incineration (Hudson, 1995;Coconnier, 1995). With increasing pressure to ban all sludge dumping at sea and the prohibitive costs of landfilling and incineration, there is a an increasing tendency to dispose of sludge on land (40% in 1988 to 60% in 1992) (Perrin and Impens, 1995).…”

A Mini-Review of Urban Wastewater Treatment in Greece: History, Development and Future Challenges

“…In the late 1980s, manufacturers who had successfully applied sludge thermal drying technologies in chemical and food industries, transferred existing technologies to sewage sludge [25]. The first such applications are reported in Avonmouth and Countess Wear in England [26], while by 1993 Membrane Biological Reactors (MBR) systems had been reported for use in sanitary application in Europe [27].…”