Chapter 5. Water analysis and treatability (78 pages)

1.General
2.Sampling
2.1.Water sampling
2.2.Sludge sampling
2.3.Sample identification, transport and preservation
3.Analysis
3.1.On site analysis
3.2.Laboratory methods with summary table
3.2.1.Preliminary concentration
3.2.2.Taste evaluation
3.2.3.Gravimetry
3.2.4.Volumetry
3.2.5.Nephelometry
3.2.6.Amperometry
3.2.7.Ionometry
3.2.8.Spectrophotometry
3.2.9.Fluorescence
3.2.10.Chromatography
3.2.11.Polarography
3.2.12.Mass spectrometry (MS)
3.2.13.Measuring radioactivity
3.2.14.Combined techniques
3.3.Microbiological analysis
3.3.1.Principle for the sanitary control
3.3.2.Bacteriological analysis
3.3.3.Virological analysis
3.3.4.Parasitological analysis
3.3.5.Molecular biology techniques
3.3.6.Algology
4.Consumption and Production Waters examination
4.1.Treatability tests
4.1.1.Study of natural sedimentation and desludging
4.1.2.Study of water coagulation and flocculation
4.1.3.Decarbonatation test using lime
4.1.4.Determination of oxidants demand
4.1.5.Degassing-aeration test
4.1.6.Physical-chemical iron removal test
4.2.Measuring global parameters
4.2.1.Fouling index FI or SDI (Sludge Density Index)
4.2.2.Particle count
4.2.3.Marble test
4.3.Lightly mineralised water
5.Wastewater examination
5.1.Specific analysis
5.1.1.Biological oxygen demand (BOD)
5.1.2.Chemical oxygen demand (COD)
5.1.3.Suspended solids
5.1.4.Volume of settleable matter
5.1.5.Hydrocarbons
5.1.6.Nitrogen
5.1.7.Phosphorus
5.1.8.Sulphur
5.1.9.Total Alkalinity (M-alk.)
5.1.10.Heavy metals
5.1.11.Toxicity
5.1.12.Mohlman index
5.2.Treatability tests
5.2.1.Oxygen consumption measurements: respirometry
5.2.2.Nitrification test
5.2.3.Denitrification test
5.2.4.Bench test
6.Sludge examination
6.1.Suspended solids (SS) in liquid sludge
6.1.1.The centrifugation method
6.1.2.Filtration method
6.2.Total solids content = dry matter (DM)
6.2.1.Total solids content at 105 ºC
6.2.2.Total solids content at 175-185 ºC
6.2.3.Total solids content at 550 ºC and volatile solids (VS)
6.2.4.Dry solids at 900 ºC
6.3.Quick method used to determine M-alk. and volatile fatty acids (VFA) in liquid sludge
6.3.1.M-alk. measurement
6.3.2.VFA measurement
6.4.Measuring fats and oils
6.5.Heavy metals
6.6.Filtrability test
6.6.1.Büchner vacuum filterability test
6.6.2.Pressurised filtration test
6.6.3.Determination of the compressibility coefficient
6.7.Determination of the limit dry solids content
6.8.CST (Capillary Suction Time) test
6.9.Drainability tests
6.9.1.Büchner drainability test
6.9.2.Drainability test with GDD - GDE6 - GDE8 screens
6.9.3.Industrial tests
6.10.The dry solids content approach of an industrial centrifuge
6.10.1.Test principle
6.10.2.Apparatus
6.10.3.Operating method
6.10.4.Interpretation of results
7.Granular and powdered materials examination
7.1.Material properties
7.1.1.Filtering matter granulometry
7.1.2.Flakiness index
7.1.3.Friability
7.1.4.Acid Loss (see NF X 45.401)
7.1.5.Density
7.1.6.Humidity
7.2.Analysis of the adsorbent capacity of a carbon
7.2.1.Granulometry of an powdered activated carbon (PAC)
7.2.2.Adsorption isotherm = Freundlich isotherm
7.2.3.Carbon ash
7.2.4.Iodine index
7.2.5.Dechlorination capacity
7.3.Specific analysis applicable to resins
7.3.1.Granulometry
7.3.2.Resin capacities
7.3.3.Resin pollution
8.Pilot testing

Introduction

Analysis is an essential requirement at every stages, from plant's design to operation:

water analysis carried out on water supply sources or on raw wastewater;
water analysis performed during plant commissioning to control performances;
routine water analysis performed during plant operation to verify consistent compliance with the relevant standard...

This field is undergoing rapid changes as the result of:

the emergence of new technologies and increasingly fast analytical protocols that produce improved performance;
research work that demonstrates the validity and possibility to measure very small amounts of various compounds:

table 26 in chapter 2 illustrates the apogee reached in this field; this table shows how the electronics industry requires water with ever lower metal concentrations that are now being quantified in ppt (parts per trillion) or 1 mg per 1,000 m³. One can currently check that these levels are met;
EEC standards on drinking water require each pesticide to be eliminated down to 0.1 mg.L-1...

A few concepts detailed below are used to establish the validity of an analytical protocol:

accuracy is the difference between the actual value and the mean of the measured results. Accuracy depends on systematic errors (interference, sampling, calibrating);
reliability is judged based on repeatability (same operating conditions and same operator) and on reproducibility (same operating conditions achieved with different operators). The standard deviation is the statistical expression of these differences. «Interlaboratory» analysis are used to evaluate a given protocol accuracy and reliability. Aliquots from an identical sample are analysed by different operators and/or different laboratories;
sensitivity is the statistical deviation for a given parameter measurement
the detection limit is the minimum concentration that can be detected with a 95 % confidence probability. For all spectro-metric measurements, the detection limit applicable to an element is the concentration that corresponds to twice the signal resulting from the machine background noise.

More sophisticated statistical methods can be used to evaluate systematic errors and as a result to select a more appropriate analytical or sampling procedure (locations and frequencies)...