Chapter 20- Reagent storage and feeding (42 pages)

1.General provisions
1.1.Packaging - conditioning
1.2.Location
1.2.1.Reagent preservation
1.2.2.Ease of operation
1.2.3.Nuisances
1.3.Storage area sizing
1.4.Transport - Unloading - Transfer
1.5.Accessibility
1.6.Materials used
1.7.Safety
2.Liquid reagent feeding
3.Powdered reagent storage and feeding
3.1.Storage
3.1.1.Installation rules
3.1.2.Filling the silo
3.1.3.Product flow assisters
3.2.Feeding
3.2.1.Volumetric feeders
3.2.2.Gravimetric feeding
4.Suspension and solution preparation from powdered or granular reagents
4.1.General principles
4.2.Preparing solutions
4.2.1.Sodium chloride
4.2.2.Aluminium sulphate
4.2.3.Ferric chloride
4.3.Lime
4.3.1.Quick lime
4.3.2.Lime water
4.4.Miscellaneous products
4.4.1.Potassium permanganate
4.4.2.Calcium carbonate
4.4.3.Bentonite (clay) - Structuralite (clay)
4.4.4.Ferrous sulphate
5.Gas reagents storage, feeding and dissolution
5.1.Chlorine
5.1.1.Distribution and feeding principles
5.1.2.Chlorine feeding units operating in a vacuum
5.1.3.Detecting and neutralising chlorine leaks
5.1.4.Diagram of a complete system
5.2.Carbon dioxide CO₂
5.2.1.Principle of a CO₂ injection unit
5.2.2.Layout example
5.3.Ammonia NH₃
6.Special applications
6.1.Using «polyelectrolyte» polymers
6.1.1.Preparing polyamines (organic coagulants)
6.1.2.Preparing acrylamide copolymers (organic flocculants)
6.1.3.In-line dilution
6.2.Chlorine dioxide
6.2.1.Chlorine used to oxidise sodium chlorite
6.2.2.Hydrochloric acid action on sodium chlorite
6.2.3.Dispensing chlorine dioxide solutions
6.2.4.Precautions applicable to the use of reagents
6.3.Powdered activated carbon (PAC) (figures 22, 23 and 24)

Introduction

Many chemical products are used in water treatment processes. These chemicals can be:

specific:

coagulants: aluminium, iron salts...
oxidants or disinfectants: chlorine...
flocculants: polyelectrolytes, additives...
adsorbants: activated carbon...

general:

bases: sodium hydroxide, lime...
acids: sulphuric, hydrochloric...

§ 3. Chapter 8 describes the main properties of a large number of reagents.