WASTEWATER SLUDGE DEWATERING
Methods for treating wastewater and dewatering a discharge sludge stream are provided. In an exemplary embodiment, a method for treating wastewater includes adding oxygen to a wastewater to produce a treated wastewater, and separating a wastewater sludge stream from the treated wastewater. The wastewater sludge stream is split to produce a recycle sludge stream and a discharge sludge stream, and the recycle sludge stream is added to the wastewater such that the oxygen is added to the recycle sludge stream and the wastewater. A peroxide source is added to the discharge sludge stream, and the discharge sludge stream is dewatered to produce a sludge cake and a sludge liquid portion.
1 . A method of treating wastewater, the method comprising the steps of:
adding oxygen to a wastewater to produce a treated wastewater;
separating a wastewater sludge stream from the treated wastewater;
splitting the wastewater sludge stream to produce a recycle sludge stream and a discharge sludge stream;
adding the recycle sludge stream to the wastewater such that the oxygen is added to the recycle sludge stream and the wastewater;
adding a peroxide source to the discharge sludge stream; and
dewatering the discharge sludge stream to produce a sludge cake and a sludge liquid portion.
2 . The method of claim 1 , further comprising:
adding a flocculant to the discharge sludge stream prior to dewatering the discharge sludge stream.
3 . The method of claim 1 , wherein the peroxide source is added in an amount of from about 10 to about 500,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
4 . The method of claim 1 , wherein the peroxide source is added in an amount of from about 20 to about 100,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
5 . The method of claim 1 , wherein the peroxide source is added in an amount of from about 30 to about 50,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
6 . The method of claim 1 , wherein the peroxide source is added in an amount of from about 50 to about 1,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
7 . The method of claim 1 , wherein the peroxide source is added in an amount of from about 100 to about 500 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
8 . The method of claim 1 , wherein the peroxide source is added in an amount of from about 300 to about 350 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
9 . The method of claim 1 , wherein the peroxide source comprises hydrogen peroxide in an aqueous carrier.
10 . The method of claim 9 , wherein the hydrogen peroxide is present in the peroxide source at a concentration of from about 3 to about 35 weight percent, based on a total weight of the peroxide source.
11 . The method of claim 1 , wherein the peroxide source comprises one or more of a percarbonate, a perborate, urea hydrogen peroxide, calcium peroxide, magnesium peroxide, percarbamide, and combinations thereof.
12 . The method of claim 1 , wherein the peroxide source is added in a quantity such that a total cost of (i) a disposal cost of the sludge cake and (ii) an acquisition cost of the peroxide source is minimized.
13 . The method of claim 1 , further comprising:
mixing the discharge sludge stream after adding the peroxide source and prior to dewatering the discharge sludge stream.
14 . The method of claim 13 , wherein mixing the discharge sludge stream comprises passing the discharge sludge stream through an inline mixer.
15 . A method of dewatering a discharge sludge stream in a wastewater treatment system, the method comprising the steps of:
adding a peroxide source to the discharge sludge stream, wherein the peroxide source provides hydrogen peroxide;
adding a flocculant to the discharge sludge stream; and
dewatering the discharge sludge stream to produce a sludge cake and a sludge liquid portion.
16 . The method of claim 15 , wherein the peroxide source is added in an amount of from about 30 to about 50,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
17 . The method of claim 15 , wherein the peroxide source is added in an amount of from about 50 to about 1,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
18 . A method of dewatering a discharge sludge stream in a wastewater treatment system, the method comprising the steps of:
rupturing a microbial cell membrane with hydrogen peroxide, wherein the discharge sludge stream comprises a plurality of microbial cells, and wherein the microbial cells comprise the microbial cell membrane;
dewatering the discharge sludge stream to produce a sludge cake and a sludge liquid portion.
19 . The method of claim 18 , further comprising:
adding a peroxide source to the discharge sludge stream, wherein the peroxide source provides hydrogen peroxide in an amount of from about 30 to about 50,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.
20 . The method of claim 18 , further comprising:
adding a peroxide source to the discharge sludge stream, wherein the peroxide source provides hydrogen peroxide in an amount of from about 50 to about 1,000 parts H 2 O 2 per million by weight, based on a total weight of the discharge sludge stream.