SU947088A1 - Method for treating effluent precipitates - Google Patents

Description

() METHOD FOR TREATMENT OF WASTEWATER DRAINS

one

The invention relates to the treatment of sludge formed at biochemical wastewater treatment plants.

There is a method of treating sewage sludge, including anaerobic digestion of a mixture of sludge from primary sedimentation tanks and compacted excess activated sludge, washing the fermented sediment mixture with water, followed by compaction of the washed mixture, reagent treatment and dewatering | lj.

The disadvantages of this method are the need to pre-compact excess activated sludge and its subsequent digestion, which increases the volume of methane tanks and impairs their operation; high consumption of wash water and significant removal of contaminants from the wash water, the return of which to the head of the facilities significantly increases the load on the aeration tanks.

The closest to the technical essence and the achieved result to the proposed method is the treatment of sewage sludge, including mixing the primary sedimentation tanks fermented under anaerobic conditions with excess active sludge and subsequent compaction of the mixture 2j.

The disadvantage of this method is the high humidity of the precipitate mixture due to the low biofloculating capacity of the activated sludge, as well as the need for additional measures to prevent the rotting of the precipitation mixture.

The purpose of the invention is to prevent the activated sludge from rotting and reducing the moisture of the compacted sludge.

The goal is achieved by the fact that excess activated sludge is subjected to preliminary aerobic stabilization, it is mixed with an anaerobically fermented sediment of primary sedimentation tanks, and the resulting mixture is purged with air just before compaction.

Excessive activated sludge is preliminarily subjected to aerobic stabilization in the mode of displacement for 0 days. The resulting mixture of fermented ice and aerobic stabilized sludge is purged with air for 0 hours.

The method is carried out as follows.

The sediment from the primary settling tanks is subjected to anaerobic digestion in the digesters and mixed with excess activated sludge that has undergone aerobic stabilization within 0.5 to 3 seconds in sectional stabilizers-displacers. The duration of aerobic stabilization is determined by the minimum value of the filtration resistivity; the fermented sludge is mixed with aerobic stability; activated activated sludge is produced in the latter. a stabilizer section designed for a residence time of a precipitation mixture of 0.5-3 hours, which is determined by the minimum value of the resistivity of the filter cake. The resulting precipitate mixture is directed to compaction, conditioning and dewatering.

Aerobic stabilization consists in biochemical oxidation of easily rotting exo- and endogenous active sludge substrates. As a result, non-decaying activated sludge is formed, which has not lost its biological activity, which leads to an improvement in its biofloculating ability, i.e. the ability to adsorb coloid particles of fermented sludge on the surface of slam slabs.

present in the sediment in large quantities and impeding its dehydration.

Improving the biofloculating capacity of the activated sludge leads to an increase in the efficiency of compaction of the sediment mixture, i.e. to a decrease in the moisture of the compacted sludge and a significant decrease in the contaminants in the silt water from the compactor, also to a decrease in

0 resistivity of sediment filtration, which significantly reduces the cost of air conditioning and increases the capacity of the dewatering equipment or load

5 on silt sites.

The mixture of aerobic stabilized active sludge with fermented sludge is carried out with aeration of the mixture with air for 0.5-3 hours. The aeration of the mixture should ensure the most complete use of the bioflocking ability of the activated sludge. The duration of aeration depends on the specific characteristics of the precipitation.

5 and is determined by the minimum value of the filtration resistivity.

A decrease or increase in the duration of aeration leads to a decrease in the efficiency of compaction; in the first case, due to insufficient use of the biofloculating ability of activated sludge, in the second, due to the fragmentation of the cotton of active sludge during prolonged aeration and the release of suspended and colloidal particles adsorbed on them.

Data indicating the advantage of the proposed method in comparison with the known, are given in the table.

"- N

oooCsl

00

rf - oh o4 D

exe tsi m es cm see um see

oo eg

WCD

oo

Il 1L -

see

(M cm t-

Lf

-00g oo

tsl

gf | eeil -se cho

see cvi cm

Se vD o o o

G-3- o with g

LA

cm-cm 1L -I- il

about

about

about

see see

oh oh

-3o

t-00 about

vO

SP

oo

D

cm - t - cm

cm

- cm

t-cm

s2

and

qm

fflО

s:

cct

Wow

ao

with about

five

and

0)

Z u

l :: s; S

0) act ta) a

silt

ha

Claims (3)

Claim 1. The method of treatment of sewage sludge, including anaerobic digestion of sludge of primary sedimentation tanks, mixing it with excess activated sludge and compaction, characterized in that, with the aim of pre- - to prevent decay of activated sludge and reduced humidity of compacted sludge, excess activated sludge is preliminarily subjected to aerobic stabilization, the mixture of fermented sludge and aerobnostabilized activated sludge is subjected to air purging before compaction. 2. The method of pop. 1, characterized in that aerobic stabilization of activated sludge is carried out in the displacement mode for 0.5 ~ 3 days. 3. The method according to PP. 1 and 2, characterized in that the air is purged with a mixture of fermented sludge and aerobnostabilized activated sludge: they are carried out for 0, 5–3 hours.