EN 14701-4-2010 pdf download.Characterization of sludges – Filtration properties – Part 4:Determination of the drainability of flocculated sludges.
This EN 14701-4 specifies a method for the determination of drainability of flocculated sludges. It is applicable to sludge and sludge suspensions from:
a) storm water handling,
b) urban wastewater collecting systems;
c) urban wastewater treatment plants:
d) treating industrial wastewater similar to urban wastewater (as defined in Directive 9112711EEC); e) water supply treatment plants.
This method is also applicable to sludge suspensions from other origin.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
EN 872. Water quality — Determination of suspended solids — Method by filtration through glass fibre filters
EN 12832:1999, Characterization of sludges — Utilization and disposal of sludges — Vocabulaiy
EN 12880, Characterization of sludges — Determination of dry residue and water content
CENITR 14742, Characterization of sludges — Laboratory chemical conditioning procedure
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 12832:1999 and the following apply.
drainability
ability of treated sludge to separate from sludge liquor by gravity filtration
3.2
flocculation
coagulation by means of inorganic or organic flocculants (polyelectrolytes)
4 Sludge conditioning
For flocculation, the sludge shall be sampled already flocculated or mixed with flocculard in repeatable and quantified conditions according to CEN/TR 14742 for a laboratory preparation.
EN 14701-4:2010 (E)
5 Principle
A given volume of flocculated sludge is poured in a filter cell equipped with a known filtering medium, the mass of filtrate collected is recorded versus time and the corresponding wet and dry mass of the sludge retained on the filtering medium and the undissolved solids remaining in the filtrate are measured.
6 Apparatus
Ordinary laboratory apparatus and the following (see informative Annex A):
6.1 Transparent tube (e.g. glass, polyethylene) of 150 mm diameter and of about 200 mm height, supported by a system composed of a filtering medium tightened In a device equipped with an appropriate sealing ioint.
6.2 Filtering medium whose characteristics shall be the same as that used in the full scale drainage device and in comparative tests.
6.3 Filtrate draining device fixed under the filtering medium.
6.4 Beaker for the filtrate collection.
6.5 Weighing balance with an accuracy of at least 0,1 g connected to a computer to continuously record the cumulative mass of filtrate collected over time. The software shall be able to record data every 0,5 s.
6.6 Apparatus for the determination of dry solids content of the sludge retained on the filtering medium.
6.7 Apparatus for the determination of suspended solids in the filtrate.
NOTE To allow a correct interpretation of data, the comparison of flocculation conditions shouki be made with the
same test equipment.
7 Procedure
a) Prepare the balance and the software to recoid the mass of filtrate as soon as the first drops of filtrate are collected.
b) Measure the water content of the flocculated sludge.
c) Gently pour (without shaking) (1 ± 0,2)1 of flocculated sludge (record the exact mass) in the centre of the cell for the sludge to recover the whole surface of the filtering medium.
d) Record the cumulative mass of filtrate collected over time every 0.5 s at least during the first 30 s.
e) Stop the test when the mass of filtrate to initial mass of sludge ratio is constant to within 0,1 g or after 10 mm.
f) Measure the concentration of suspended solids in the filtrate (see EN 872) and the wet and dry mass of the sludge retained on the filter medium (see EN 12880).
g) Repeat steps a) to 1) for at least twice if repeatability measurements are needed.
Record the following data obtained for each test:
a) Adimensional mass of filtrate recovered at t = 30 s, t = 90 s and at the end of the test:
b) Time necessary to collect a volume of filtrate corresponding to 50 % of the water content of the sludge;
c) Dryness of the cake retained on the filtering medium;
d) Dry mass of suspended so’ids per unit volume of filtrate.
NOTE The optimal operating conditions of the drainage process are those for which the drainage is the fastest to remove the maximal drainable quantity of water, the mass of wet and dry solids retained on the filter medium is the highest, and the mass of suspended solids in the filtrate is the lowest
9 Test report
The test report shall contain at least the following information:
a) Reference to this document:
b) Identification of the sludge (origin, type, identification, concentration, method of sampling and storage);
c) Identification of the flocculation conditions and preparation;
d) Characteristics of sludge and filtering medium (initial mass and water content of sludge, reference and supplier of the filtering medium):
e) Adimensional mass recovered versus time with at least the volume of filtrate collected at t = 30 s, at , 90 s and at the end of the test:
f) Time, in seconds (s), corresponding to the collection of 50 % of the initial water content of the sludge;
g) Dry mass of the suspended solids per unit volume of filtrate (in milligrams per litre (mg/I));
h) Dryness (mass fraction in percent (%)) of sludge cake retained on the filtering medium:
i) Any detail not specified in this document or which are optional and any other factor which may have affected the results.EN 14701-4-2010 pdf download.
EN 14701-4-2010 pdf download
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