Method for treating aqueous wastes containing at least 1% proteinaceous matter

A method for treating aqueous wastes containing at least 1% proteinaceous matter with at least 0.20% by weight of cationic water-soluble polyamines. Preferred polyamines include ethylene dichloride-ammonia, quaternary ethylene dichloride-ammonia and dimethylamine-epichlorohydrin-ammonia polymer.

BACKGROUND 
FIELD OF THE INVENTION 
This invention relates to a process for treating rendering plant type 
wastes. The term "rendering plant" is used to refer to those industrial 
facilities which are engaged in the killing and/or processing of animals, 
fish, poultry, dairy products and the like. 
Various types of proteinaceous refuse are produced in rendering plants. 
Rendering plant effluent streams thus contain varying amounts of 
non-recovered proteinaceous matter diluted with wash water. 
Within the present state of the art, diverse coagulation methods are 
available for removing proteinaceous and other matter from the rendering 
plant effluents. These methods include steam coagulation and lignin 
treatments. Alternatively, conventional coagulation chemicals are applied 
in low dosages to flocculate, coagulate and precipitate rendering plant 
wastes. 
However, these prior methods have very significant drawbacks especially 
when it is desirable to reuse the high protein precipitant. Lignin 
treatment, for example, has very unfavorable stoichiometry which results 
in a product containing 30 or more percent lignin. The introduction of 
these large amounts of lignin interferes with the economics and the 
overall efficiency of the utilization of the precipitant as feed. Steam 
coagulation and pH adjustment are similarly impractical as the sole 
treatment method due to unfavorable cost effectiveness. Finally, the use 
of low dosages of polyelectrolytes (5-100 range based on weight) to 
coagulate rendering plant wastes has been found to be effective only where 
the effluents contain concentrations of proteinaceous matter significantly 
below 1%. 
Where rendering plant effluents contain 1% or more proteinaceous matter, 
the traditional treatment methods have been found to be especially 
ineffective. The usual dosages of polyelectrolytes, for example, have been 
found to be almost totally ineffective in treating these high protein 
level effluents. I have now discovered that certain polyelectrolytes at 
heretofore unprecedented concentrations will surprisingly and efficiently 
flocculate, agglomerate and precipitate rendering plant effluents 
containing greater than 1% by weight proteinaceous matter. 
OBJECTS 
It is therefore a prime object of the invention to provide a method for 
treating rendering plant effluents containing greater than 1% by weight 
proteinaceous matter whereby the proteinaceous matter may be separated 
from the water. 
It is a further object of the invention to provide a practical method 
whereby the proteinaceous matter may be recovered from rendering plant 
effluents containing high concentrations of proteinaceous matter. 
Another object of my invention is to provide a practical method for 
treating blood and blood plant wastes and for recovering proteinaceous 
matter therefrom. 
Other objects will appear hereinafter. 
THE INVENTION 
The invention entails a method for treating aqueous wastes containing at 
least 1% by weight of proteinaceous matter which comprises: 
A. adding at least 0.02% by weight based on dry proteinaceous matter of a 
water-soluble polyamine to the aqueous wastes; 
B. dispersing said polyamine within the aqueous wastes; 
C. allowing the aqueous wastes to stand for a sufficient period of time to 
allow the flocs and proteinaceous matter to coagulate and settle thereby 
producing a precipitate of proteinaceous matter; and, 
D. recovering the precipitate of proteinaceous matter. 
The treatment of my invention will be useful when handling any aqueous 
wastes containing greater than 1% by weight proteinaceous matter. However, 
my invention is especially important for the treatment of blood and blood 
serum since these materials are very difficult to coagulate. Blood plant 
effluents usually include raw blood which probably contains about 25% 
protein solids and blood serum which probably contains about 15% protein 
solids. 
When treating raw blood, it may be necessary to either dilute the blood or 
to dilute the water-soluble polyamine in order to obtain water:protein 
solids ratios of 7:1 or greater. When treating blood serum, it may not be 
necessary to dilute with water. 
My invention may also be used, as noted earlier, to treat overall rendering 
plant effluents. These effluents are generally a mix of blood serum, 
condensibles from the rendering operation and wash waters from cleaning 
working surfaces within the plant. Generally, the protein levels in these 
effluents are considerably lower than the levels in either blood or blood 
serum. Accordingly, reduced amounts of the polyamines will be needed. 
A key advantage of my invention is that it offers a practical method for 
recovering protein solids for reuse. Since these protein solids can be 
sold for use as high protein feed or for other purposes, this advantage of 
my invention must be factored into any economic evaluations of my overall 
invention. 
Dosages 
At least 0.20% by weight of the water-soluble polyamines will be needed to 
treat the aqueous wastes containing greater than 1% by weight 
proteinaceous matter. When treating blood serum, at least 0.30% by weight 
of the polyamine will be needed. Preferably 0.45% would be used. 
As noted in example 1, in some cases the threshhold amounts of polyamine 
needed to clarify blood serum will vary significantly. Differences can be 
expected due to contaminents in serum samples and due to varying activity 
between different polyamines. However, in practice, the optimal dosage 
will be determined on a case by case basis. 
The Polyamines 
Generally known water-soluble cationic polyamines will function in the 
coagulation method of my invention. Preferable polyamines include ethylene 
dichloride-ammonia, quaternary ethylene dichloride-ammonia and 
dimethylamine-epichlorohydrin-ammonia polymer. Most preferable among these 
is the dimethylamine-epichlorohydrinammonia polymer. Typical synthesis 
methods for these molecules may be found in the following U.S. Pat. Nos. 
3,372,129 (ethylene dichloride-ammonia), 3,751,474 (ethylene 
dichloride-ammonia) and 3,738,945 (dimethylamine-epichlorohydrin-ammonia).

EXAMPLES 
EXAMPLE 1 
Coagulation studies were performed on rendering plant serum water using 
polyamines with results as shown in Table I. Blood serum for testing was 
produced within the rendering plant as follows: 
1. Blood was placed in a mixing tank and coagulated with steam in a screw 
lift conveyer. 
2. Blood solids were removed in a gross filter for drying. 
3. Gross filtrate was further filtered on a fine mesh vibrating filter and 
more solids removed for drying. 
4. Filtrate from the fine filter constituted the serum water. 
The polyamines were evaluated in jar tests. Jar tests were carried out by 
placing 500 ml of serum water in a liter jar, adding polyamine and 
stirring for about 3 minutes at about 60 rpm. The mixture was further 
stirred for about 3 minutes at about 120 rpm and then the sample was 
allowed to stand for about 6 minutes. Floc size, floc settling rate and 
supernate clarity were evaluated on a scale of 0-10 wherein 5 = control, 
0-5 = poorer than control and 5-10 = better than control. 
EXAMPLE 2 
Coagulation studies using jar tests similar to those described in Example 1 
were carried out on another set of blood serum samples. Dosages and 
results are reported in Table II. 
EVALUATION OF DATA IN EXAMPLES 1 AND 2 
An examination of the data reported in Table I (Example 1) shows good 
flocculation at dosages in excess of 1.2% by weight of polyamine. For 
these test samples, it was found that dosages below 1.2% generally did not 
flocculate the serum water protein solids. 
In Example 2, it was found that polyamine dosages as low as 0.48% by weight 
resulted in good coagulation. Dosages below this amount resulted in little 
or no coagulation. 
The difference in the results reported in these two examples are believed 
to be due to differences in the serum water being clarified. It is 
believed, for example, that in Example 2 the serum water may have been 
allowed to stand for from a number of hours to possibly several days 
before clarification. Also, there is a possibility that different 
contaminants were present in the serum waters tested in the two examples. 
Nevertheless, it will be noted that in all cases the polyamine dosages 
were far in excess of what would normally be utilized to coagulate 
industrial effluents. 
Table I 
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SERUM WATER CLARIFICATION 
DOSAGE FLOC SUPERNATE 
TRIAL 
TREATMENT CHEMICAL 
(% BY WEIGHT)* 
FLOC SIZE 
SETTLING RATE 
CLARITY REMARKS 
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1 Dimethylamine-Epichlorohydrin 
0.75 5 5 5 Nothing 
Ammonia Polymer 
2 Dimethylamine-Epichlorohydrin 
1.2 5 5 5 
Ammonia Polymer 
3 Dimethylamine-Epichlorohydrin 
1.2 5 5 5 
Ammonia Polymer 
4 Dimethylamine-Epichlorohydrin 
3.0 7 6 6 Good floc 
Ammonia Polymer 
5 Dimethyl-Epichlorohydrin 
3.75 8 8 8 
Ammonia Polymer 
6 Dimethylamine-Epichlorohydrin 
6.0 8 8 8 Good floc, 
good settling 
Ammonia Polymer 
7 Dimethylamine-Epichlorohydrin 
1.2 8 9 8 
Ammonia Polymer 
8 Dimethylamine-Epichlorohydrin 
6.75 8 9 8 
Ammonia Polymer 
9 Alum 1.0 8 6 6 Good floc 
10 Alum 2.5 8 6 6 
11 Alum 2.5 8 6 6 
12 Dimethylamine-Epichlorohydrin 
3.0/1.0 7 7 7 
Ammonia Polymer/Alum 
13 Dimethylamine-Epichlorohydrin 
0.75/0.5 Nothing 
Ammonia Polymer/Alum 
14 Dimethylamine-Epichlorohydrin 
0.75/1.0 
Ammonia Polymer/Alum 
15 Dimethylamine-Epichlorohydrin 
0.75/2.0 Fine pin 
point floc 
Ammonia Polymer/Alum 
16 Dimethylamine-Epichlorohydrin 
0.75/5.0 Good floc, 
good clarity 
Ammonia Polymer/Alum 
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*Based on dry solids 
TABLE II 
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SERUM WATER CLARIFICATION 
Dosage 
Trial 
Treatment Chemical (% By Weight)* 
pH Remarks 
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1 Dimethylamine-Epichlorohydrin-Ammonia Polymer 
0.48 7.0 
Good floc, supernate clarity, 
fast 
settling, % solids 46% 
2 Dimethylamine-Epichlorohydrin-Ammonia Polymer 
0.30 7.0 
Nothing 
3 Dimethylamine-Epichlorohydrin-Ammonia Polymer 
0.60 7.0 
Very good floc settling time 
and 
compaction 
4 Dimethylamine-Epichlorohydrin-Ammonia Polymer/ 
0.48 4.0 
Good heavy floc, good settling 
time, 
Hydrochloric Acid highly colored supernate 
5 Dimethylamine-Epichlorohydrin-Ammonia 
0.48/0.012 
7.0 
Good coagulation, small floc, 
good - Polymer/Bentonite 
Clay settling, fair 
supernate 
clarity 
6 Dimethylamine-Epichlorohydrin-Ammonia Polymer/Silica 
0.48/0.012 
7.0 
Very good floc, fast settling 
time, 
good compaction 
7 Dimethylamine-Epichlorohydrin-Ammonia Polymer 
0.48 7.0 
Good floc and settling 
8 Ethylene Dichloride-Ammonia Polymer 
0.20 7.0 
Pinpoint floc, very slow 
settling 
9 Ethylene Dichloride-Ammonia Polymer 
0.20 4.0 
Pinpoint floc, poor settling 
10 Ethylene Dichloride-Ammonia Polymer 
0.25 7.0 
Nothing 
11 Ethylene Dichloride-Ammonia Polymer 
0.50 7.0 
Good floc, supernate clarity, 
fast settling time 
12 Ethylene Dichloride-Ammonia Polymer 
0.50 7.0 
Very good floc, settling, and 
compaction 
13 Ethylene Dichloride-Ammonia Quaternary Polymer 
0.30 7.0 
Very poor 
14 Ethylene Dichloride-Ammonia Quaternary Polymer/Silica 
0.30/0.012 
7.0 
Very poor 
15 Ethylene Dichloride-Ammonia Polymer/Acid/ 
0.20/acid/0.48 
4.0 
Good floc, slow settling 
Dimethylamine-Epichlorohydrin-Ammonia Polymer 
16 Acrylamide-Formaldehyde-Dimethylamine Mannich Product 
0.012 7.0 
No coagulation 
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*Based on dry solids