Chapter 23 - Treating municipal wastewater (40 pages)

1.Treatment line design: limitations
1.1.Characteristics and variability of the efflue to be treated
1.2.Quality and reliability objectives
1.3.End use of sludge: global optimisation of water and sludge
1.4.Influence of a plant's environment (appearance, odours, noise): compactness
1.5.Construction provisions
1.6.Allowing for sustainable development
1.7.Special case of plant refurbishment
2.Choice of water treatment line technologies
2.1.Selecting processes according to limitations
2.2.Performance of the various treatment lines
2.3.Special case of municipal WW disinfection
2.3.1.Selecting and sizing a disinfection system
2.3.2.Notes on bacteriological count
2.3.3.Special case of helminth eggs
3.Examples of typical water treatment lines
3.1.Gabal El Asfar (Egypt) plant
3.2.Seine upstream plant - Valenton 2 (France)
3.3.Milan south plant (Italy)
3.4.Brno plant (Czech Republic)
3.5.Dalian plant (China)
3.6.Cork plant (Ireland)
3.7.Ayrshire (Scotland) plant
3.8.Güstrow plant (Germany)
3.9.Valence (France) plant
3.10.Grasse (France) plant
3.11.Sempra (Mexico) plant
3.12.Marbella (France) plant

Introduction

This chapter describes the systems used to treat municipal wastewater subject to diverse local constraints and with a view to obtaining the qualities required to allow discharge (per local standards) or even re-use, including the most stringent demands (see indirect re-use as drinking water or as ultra pure water).
The reader is advised to refer to chapters 3 and 4 for a description of the fundamentals relating to the physical-chemical and biological treatment processes applied, as well as to chapters 9 to 15 for a description of the Degrémont technologies (pre-treatment, settling tanks, filters, biological systems, membranes) included in the treatment trains described in this chapter.