Static mixers are machines mounted direct in the pipeline or open channel. static mixers mounted in pipelines Static mixers mounted in pipelines have a very high velocity gradient (1,000 to 30...

by the resin. Should the contrary occur, zero hardness can be obtained by combining the two or when water titrations allow for this (TH = 1.5 to 3 x alkalinity titration), in the same unit, a layer...

be thorough and the abatement level will be noticeably lower than that achieved with an external treatment. The oxidised liquor will still contain high levels of NH4+, above 500 mg · L–1 and more often...

. The crystallised product Aℓ2(SO4)3, 18H2O is available as : powder < 0.5 mm ; 1 to 3 mm grains; 5 to 30 mm beads; in blocks (occasionally). dissolution The crystallised product is usually...

for a complete cold rolling unit. Figure 56. Treatment used in cold rolling units This approach conserves a substantial volume of water, total consumption being reduced to approximately 0.5 m3·t–1...

general Up until the year 2000, the European standard for drinking water was 50 µg · L–1 of As, a target that was within the reach of clarification or carbonate removal treatment in most cases...

(using a US sensor, a piezometric sensor or a bubbler tube). Venturis are most frequently used when major flows are involved; the Parshall Flume (figure 1) venturi is also often selected for flows...

contamination. Clarification will also be required to deliver improved performance on pathogenic organisms and, above all, on parasitical protozoa such as Giardia and Cryptosporidium, with a 0.1 NTU turbidity...

: Therefore, the global corrosion reaction can be written as follows : The Nernst equation for this system is written as follows : where PH2 is the partial pressure of hydrogen gas, set at 1...

ratio varies from a figure of less than 1 in Latin America to 2 certain wastewater in India, for an average of 1.2 in France. Furthermore, we cannot use these global parameters (BOD, COD, suspended...

of water to be cooled between the tower inlet and outlet: DT (°C) = outlet temperature – inlet temperature; the power of the tower : W (kcal/h) = Q x Dt x 1,000; evaporation (quantity of water...

of nuisances (flies, odours…). classification Trickling filters are classified according to the hydraulic and organic loadings applied. Hydraulic loading is expressed in m3 · m–2 · h–1 in relation...

. A properly balanced digestion system will produce 900 to 1,100 L of gas for each kg of OM destroyed. The gas mainly consists of CH4 (60 to 65 % v/v) and of CO2 (35 to 40 %v/v).Other elements may be present...

accept that the grit can be pumped out of the other structures; in particular, when the plant includes straining (1 to 2 mm mesh for instance), grit removal must be carried out upstream to avoid any...

in the open. This will ensure that the organic matter degrades naturally, typically decreasing from 5% to 2% in 2 months, and the heap will find back a normal sand colour. Recommended minimum duration is 1...

levels of sulphates (> 500 mg · L–1) and depending on the value of the SO42–/COD ratio; on certain substrates, difficult to hydrolyse. The tank can also play a secondary role as a pollution flow...

configurations : The Hydrazur filter constructed of coated steel, for high filtration rates; this system is available in a twin column version (figure 6) : layer depth = 0.6 m; 1.4 to 3 m diameters...

Fine drops of hydrocarbons (1 to 20 mm) suspended in water are trapped by the media, using the same mechanisms as for suspended solids (see section filtration), and feed a film that gradually...

biocides that do not result in the formation of trihalomethane…): An amount of 5 g NH3·g–1 free Cℓ2 is often recommended (see chapter oxidation-disinfection). Transporting and storing concentrated...

remain relatively stable. Depending on the type of sludge, heating will render soluble 20 to 40 % of OM and, therefore, result in the production of interstitial liquor containing 3,000 to 6,000 mg · L–1...