DE1767971B2 - METHOD OF DRAINING MUNICIPAL SLURRY - Google Patents

Description

organic nitrogen content of the examples given below;

Solid 1 to 5 ⁰ Z ₀ lent synergistic effects of the listed devices!> -

Protein content of the solids 8 to 30%, not the same substance classes.

35 As can be seen from the statements by F. S t a t h c r

The digested sludge is anaerobically digested fresh results, it is still not possible today, the tannins sludge, often to be clearly characterized chemically with larger proportions of others. Our sludge mixed from biological clarification stages. saying therefore refers to connections nut These sludges have the following characteristic tannin character, which is common to the two Key figures: 40 labeled groups of tanning agents can be calculated.

As a high molecular weight water-soluble polyethylene

Solids content 2.5 to 15% glycols are those suitable in aqueous solution

Loss on ignition of the solid 35 to 75% at 20 ¹ C a viscosity number of at least 10t),

organic nitrogen content of preferably greater than 500. The viscosity solid 0.5 to 3% 45 number results from DIN 53 726, Section 6.1,

Protein content of the solid ... 4 to 18% from the formula

For the further dewatering of the fresh and viscosity number = ( ~ ¹ ) ' _c digested sludge, long and short-term processes ^ ^{? 0} ' are used. For the long-term procedure, use 5 °
Dry beds equipped with drainage floors. Here mean: the short-term methods are mechanical dewatering devices such as sieves, presses, filters, / - the arithmetic mean of the throughput times, centrifuges and the like. the solution

Because of the gel-like nature, the 55, ^ arithmetic mean value of the throughput times

Drainage of the municipal sludge considerable ^ ₅ solvent

Trouble. As a dehydration aid, dissolved substances are used in a

up to now mainly Saize of polyvalent metals, ins- C = concentration =; -

special iron and aluminum salts alone and in solution in ml

Used in combination with calcium hydroxide. The 60

high required additional amounts of these inorganic The throughput times of the tend to gel

Niche dehydration aids can be used in aqueous solutions of polyethylene glycols

Further processing of the dewatered sludge in the capillary viscometer according to O s t w a 1 d under

fold disadvantageous, determined both when using as a turn of a capillary of 0.5 ± 0.01 mm.

Fertilizers as well as incineration. 65 For the measurement, solutions are used that are in 1 ml

The use of organic high molecular weight less than 0.00Od g polyethylene glycol and the same

Contains watering agents alone and in combination with the early 0.02 g NaCl. The sodium chloride

above-mentioned inorganic metal salts and reduces the tendency to gel. In focus

tration range of less than 0.0005 g / ml and in the presence of NaCl, ^{the viscosity number is practically independent of the concentration at 2O 0} C, so that the polyethylene glycols in question for the present process by specifying the viscosity number t. 'are clearly marked.

The quantities of tanning agents and high molecular weight polyethylene glycols to be used can vary within wide limits depending on the type of sludge and the desired drainage effect. Very good drainage effects are generally obtained with the addition of 100 to 1000 g of tanning agent and 5 to 20 g of the high molecular weight polyethylene glycols per m ^{3 of} sludge. In individual cases, smaller or larger amounts are used for sludge dewatering.

The optimum ratio of tanning agent to polyethylene glycol ¹ must be determined from case to case by means of preliminary tests (cf. Example 1, Nos. 5 and 6). In general, the amount of tannin added can be reduced in the case of more digested sludge and that of the polyethylene glycol can be increased.

The most favorable order of the two additional items is also determined on a case-by-case basis (see example 1, Kr. 7 and 8). In most cases, especially with fresh sludge, it is better to use the tanning agent first to add. Only in individual cases, especially with digested sludge, were better effects obtained, if the polyethylene glycol was added to the sludge first.

The temporal succession of the addition of both Dewatering aid is not of critical importance to the present process. the However, the time between the addition of the first and second components must depend on the intensity of the mixing process at least as long

until the component added first is evenly distributed in the sludge. This is going to be very strong turbulence within a few seconds, with weak turbulence only a few minutes. 5 After the uniform distribution of the first component, the sludge can -ι before the addition of the The second component can be kept in rest or in moderate motion for a while, which means that in In individual cases the drainage effect was still lost is improved.

Example 1 suction tests

Experimental device: porcelain suction slide 125 mm diameter; Feeding bottle; Water jet pump; Vacuum meter and Vacuum regulator; Filter paper Schwarzband No. 589 from Schleicher & Schüll.

Carrying out the experiment: In each case 0.5 l of sludge was filtered off under a constant vacuum and the amount of filtrate obtained was measured after 1 minute. The final vacuum 10 to 15 torr, held constant during the experiment was achieved 10 seconds after switching on f.er pump.

After the addition of the two dewatering aids, the sludge was stirred with a glass rod for 10 seconds each time and then poured into the suction filter.
Test material ·. Fresh and digested sludge from a municipal sewage treatment plant with the following data:

Fresh sludge

Solid content 114 g / l

Loss on ignition of the solid ... 78 ⁰ Z ₀ N content (org.) Of the solid 3.3%

Digested sludge

60 g / l 55- / 0

Test results

No.

Product addition:
g effective
Substance / m ³

Filtration rate ml / min with fresh sludge | with digested sludge

J
2
3
4th
5
6th
7th
8th
9
10

a) -

b) =

c) =

without addition

Tanigan CLS a)

Polyethylene glycol I b)

Polyethylene glycol lic)

Tanigan CLS 4- polyethylene glycol I.
Tanigan CLS + polyethylene glycol I.
Tanigan CLS + polyethylene glycol II
Polyethylene Glycol I + Tanigan CLS.

Turmeric d)

Turmeric + polyethylene glycol I

Synthetic auxiliary device from the company Farbenfabriken Bayer AG with 35% active substance.
Viscosity number 1100.
Viscosity number 200.

230
20th
20th

115+ 10
115 + 20
115 + 10
10 + 115

1200
600 + 10

45
130

70
240
300
175
288

37
215

25th

30th

180

115

315

320

244

326

28

297

d) = vegetable tanning agent, available as a powder.

, Example 2
Dry bed trial

Experimental set-up: You need a plastic bucket with a volume of 101 and a perforated bottom, 3 mm Hole diameter. The bottom of the bucket is 40 mm thick with coarse gravel, 2 to 4 mm 0, and i.'on top in 40 mm layer thickness with fine gravel (sand),

0.2 to 1.0 mm 0, coated. The water drained from the bucket is in a graduated vessel caught.

Carrying out the experiment: In each case 5 l of sludge were stirred for 15 seconds after the addition of the reagents and then into the test device described, the sieve bottom of which was previously rinsed with fresh water, given. The resulting filtrate was then

amount determined per time unit. After the main amount of water had run off through the drainage system, the Buckets filled with mud were left to dry at about 20 ° C. From the cake were one hour after the start of the drainage attempt and then at further intervals vertically to Samples were taken from the sand layer and the water content was determined.

Test material: fresh and digested sludge from a municipal sewage treatment plant with the following data:

Fresh sludge

Solids content 48 g / l

Loss on ignition of the solid ... 85%
N content (org.) Of solid 3,9 ° / ₀
specific weight of the
ίο sludge 1022 g / l 1036 g / l

Digested sludge from fresh and activated sludge

g / l 48 ° / ₀ 1.5%

I. Drainage rate

product

Addition: g active substance / m ³

lot 30 ' of you with - fresh mud 1830 after 1' y 1900 60 ' 500 725 1835 1900 540 780 3700 1950 500 725 3890 1910 2900 3180 1830 4100 33C3 3500 3885 4180 510 727 1912 3270 3480 4140

with digested sludge according to Γ I 5 'I 30' I 60 '

without addition

Polyethylene glycol I a) ..

Tanigan supra LH b)

Tanigan supra LH + polyethylene glycol I.

Tanigan supra LH + polyethylene glycol I.

Chestnuts c)

Chestnuts -j- polyethylene glycol I

20 800

180 +

360 +

1200 10 + 660
46 ^ 680
660

2750

2950

435

2900

3000

3310

603

3270

1640
1700
1650

3660

3750
1655
3682

a) = polyethylene glycol I, viscosity number 1100.

b) - synthetic full tanning agent from the company Farbenfabriken

Bayer AG with 96% active substance.

c) = vegetable tanning agent, available as a powder.

II. Air drying

product

Addition: g active substance / m ³

Fresh sludge IStd. 24 hours 72 hours Digested sludge 24 hours Water content 92.52
92.38
92.48 82.42
82.29
82.33 68.00
67.90
68.02 in ° / o after 83.06
83.30
82.11 76.00 66.12 52.10 1 H. 74.07 74.00
92.45
74.90 64.06
82.37
64.20 51.09
68.10
50.97 93.32
93.35
92.28 70.66
82.00
71.92 83.00 80.30
92.26
82.40

Hours.

without addition

Polyethylene glycol I.

Tanigan supra LH

Tanigan supra LH + polyethylene glycol I

Tanigan supra LH + polyethylene glycol I.

Chestnuts

Polyethylene glycol I + chestnuts

20 800

180 +

360 +

1200 10 + 69.66 69.91 68.03

61.50

57.55 67.91 58.83

Example 3 Spin test

Test device: solid bowl screw extractor, 680 mm 0.1500 rpm, centrifugal number 850.

Carrying out the experiment: A 1% solution of the synthetic was put into the inflow line before the centrifuge Tanigan CLS tanning agent and a 0.2% solution of polyethylene glycol directly into the centrifuge given.

Test material: digested sludge with the following key figures:

Solids content 68 g / l

Loss on ignition of the solid 61%

N content (org.) Of the solid 2%

Protein content of the solid 16%

Test results

Product addition:
g effective
Substance / m ³

Solid content in g / l
in the drop I in the filtrate

1 without addition

2 Tanigan CLS (35% WS)

3 polyethylene glycol a)

4 Tanigan CLS "+ polyethylene glycol.

a) = polyethylene glycol, V ^: viscosity number 1100.

to 800

20th
+ 10

38.5
about 38
38.6
37.3

25.4
about 25
23.0
4.1

Claims (1)

Calcium hydroxide has so far only led to satisfactory results in individual cases. Claim: The invention therefore relates to a method for dewatering municipal sludge under Process for draining municipal 5 addition of drainage aids that thereby Sludge with the addition of dewatering aids is characterized in that the sludge is remedied, characterized. that known per se vegetable and / or aromatic, synthetic tannins and highly vegetable tannins that are known per se in the sludge are added one after the other and / or aromatic, synthetic kular polyethylene glycols as Entwasserungsh.lfs tannins and high molecular weight polyethylene glycols io medium added, with the second component added as a drainage aid, adding only when the first component is the same second component only adds when it is moderately distributed in the sludge. the first component evenly in the sludge The characteristic property of tannins is distributed is known then that they alone or m 15 combined application are capable of animal Converting skin into leather. Of the compounds known today as tanning agents, the vegetable and aromatic synthetic tanning agents are by far the best yc- It is common to choose the 20 different proportions. A more detailed characterization of these two from domestic and industrial sewage there are groups of tanning agents in the monodes municipal wastewater initially through sediments »tanning chemistry and tanning technology. thickening. The Akademieverlag Berlin, 1967, which occurs in this clarification stage, for the flan sludge are either directly used as fresh sludge on pages 247 to 267 and for the aroma or after a putrefaction process alone or mixed 25 see synthetic tannins b. 35J to 36; with excess sludge from biological cleaning. Other compounds mentioned in this work - dewatered. The fresh sludge can show tanning properties as a result Key figures are characterized: ned application with high molecular weight Polyathylcn- Glycols still have certain effects, but in some cases ..: i Solids content 3 to 18 ° / ₀ 30 this compared to the claimed tanning agent Glow of the solid .... 50 to 90 °; ₀ classes strongly. These effects come from the