What is BS EN 14702‑3 ‒ Settling properties of sludges about?
BS EN 14702‑3 is the third part of an international multi-series standard that covers the characterization of sludges.
BS EN 14702‑3 specifies a method for determining the zone settling velocity (ZSV) and the compression point for determining the settling properties of sludges.
BS EN 14702‑3 gives test methods that are based on one of two basic approaches. The first approach uses the volume of the sludge occupied after a fixed period of settlement. The second approach uses the subsidence velocity of the solid/liquid interface of the sludge at its initial concentration calculated from the straight-line portion of the resulting curve.
BS EN 14702 is applicable to sludge and sludge suspensions from:
- Stormwater handling
- Urban wastewater collecting systems
- Urban wastewater treatment plants
- Plants treating industrial wastewater similar to urban wastewater (as defined in Directive 91/271/EEC)
- Water supply treatment plants
Note: BS EN 14702‑3 is also applicable to sludge and sludge suspensions of other origins.
Who is BS EN 14702‑3‒ Settling properties of sludges for?
BS EN 14702 on settling properties of sludges is useful for entities dealing with:
- Wastewater collecting systems
- Wastewater treatment plants
- Plants treating industrial wastewater
- Water supply treatment plants
Why should you use BS EN 14702‑3‒ Settling properties of sludges?
In wastewater treatment plants, sludge thickening occurs in the lower layers of clarifiers and in separate thickening tanks. Due to wide variation in sludge settling properties, design criteria for these processes are mostly based on batch thickening tests. A number of parameters have been developed to obtain a quantitative measure of the settleability of sludge.
BS EN 14702‑3 characterizes a test that can be easily performed and has widespread use in routine process control for sludge quality comparison in settling tanks. It gives you the procedure for the use of indexes for sizing/optimizing decanters and static thickeners and talks about the care with which they should be handled. It also tells you about the influence upon indexes, by laboratory artefacts, i.e., channelling and bridging effects, turbulences caused by filling, shallow depth by partial support through the solids from the bottom to the vessel, the impact of stirring on sludge.
BS EN 14702‑3 provides you with the measures for determining the settling properties of sludges, that can help you evaluate the impact of sludge chemical conditioning on the size and design of the thickener or on the process productivity. This is further helpful for you as a decanter/thickener well-sized will can enable sludge treatment as the lowest cost for its volume reduction.
