Analysis of the filtrate quality from discontinously operated rapid filters
author:
MICHAŁ ZIELINA
ORCID ID:
0000-0001-7710-8982
No:
06/2021 Instal p. 34-38
DOI:
10.36119/15.2021.6.4
There are reports in the literature suggesting the possibility of a deterioration of the filtrate quality after interrupting
the operation of a rapid filter for several hours and restarting it without prior backwash. The theoretical reasons for
this phenomenon are analysed in this paper. The results of experimental research at one of Krakow’s filter stations
are presented. The filters were taken out of operation for a few hours twice. The first time, shortly after backwash,
when the bed was still slightly colmated, and the second time, after a longer period of time, when the bed was
already largely filled with sludge. The tests showed a complete lack of deterioration of the filtrate quality after the
first removal of the filter from service. The second time, a slight deterioration in turbidity removal efficiency was
observed for a short period of time compared to the efficiency before the filter was taken out of service. At the same
time, large and sustained decreases in the removal efficiency of total particle number and suspended solids
concentration were observed. This phenomenon was caused by smaller decreases in the removal efficiency of finer particles and larger, longer lasting decreases in the removal efficiency of coarser particles. The observations showed a possibility of safe disconnection of filters with a small degree of collimation and a risk of disconnection of filters at
a later stage of their exploitation.
Keywords:
About Authors:
Dr hab. inż. Michał Zielina, prof. PK, https://orcid.org/0000-0001-7710-8982 – Politechnika Krakowska, Wydział Inżynierii Środowiska
i Energetyki, ul. Warszawska 24, 31-155 Kraków. Corresponding Author: michal.zielina@pk.edu.pl