SU1590447A1 - Method of treating lignin-containing sediments of waste water - Google Patents

Abstract

The invention relates to the treatment of sludge formed during chemical wastewater treatment of cellulose sulphate production. The aim of the invention is to intensify the dewatering process and reduce the residual moisture of the lignin sludge due to the treatment of the precipitate with polyacrylamide, compaction by flotation, the introduction of an auxiliary filter material - lignoprotein sludge 1 g of dry matter of the original sediment. 1 hp f-ly, 1 tab.

Description

The invention relates to the pulp and paper industry, preferably to a method for treating sludge produced during chemical treatment of wastewater. Cellulose sulphate production.

The purpose of the invention is to intensify the dewatering process and reduce the residual moisture of lignin-containing sewage sludge.

Polyacrylamide is introduced into the lignin-containing sediment in the form of a 1% solution at the rate of 15-20 mg per 1 g of dry matter of the sediment and is subjected to compaction by flotation. Into the compacted lignin-containing sediment (concentration of 30-50 g / l), a lignin-protein precipitate is added as an auxiliary filtering material in an amount of 0.3-2.0 g / g of dry matter of the initial sediment. The resulting mixture is stirred, subjected to mechanical dehydration and heat dried.

Lignoprotein sediment is a waste of the acid inversion process of the prehydrolyzate with the addition of biomass of excess activated sludge. In the process of acid inversion, the ligno-protein precipitate undergoes a long acid-temperature treatment and, after separation from the inverted prehydrolyzate, has good filterability.

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Lignoprotein precipitate added to lignin containing sediments. Sulphate-cellulose production wastewater as an auxiliary filtering material contributes to the intensification of the dewatering process and a decrease in the residual moisture of sediments.

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Example 1, (i.p.min.trc): the precipitate is introduced in an amount of 0.3 g / g of dry matter of the initial lignin-containing sewage sludge. Polynacrylamide at the rate of 15 mg per 1 g of dry sludge is added to the lignin-containing sediment obtained during chemical wastewater treatment and compacted by flotation.

In a 500 ml beaker, 207 g of the compacted lignin-containing sediment suspension (concentration 12.0 g / l) and 63 g of the lignin-protein precipitate suspension (concentration 41.8 g / l) are weighed. The resulting composition is stirred, the amount of wine transferred to the filter process and subjected to mechanical dehydration at a pressure of 0.4 MPa. The filtration time is set according to the breakthrough of air through a layer of sludge on filter cloth VI and a pressure drop on the pressure gauge. The dehydrated precipitate is removed / from the filter cloth and dried in a drying oven at 105 ° C, the residual moisture content of the cake is 7.4, the filtration time is 1100 s.

Example 2 Treatment of lignin-containing sewage sludge is carried out in the same way as in Example 1 with an amount of added ligno-protein sludge of 0.5 g / g of dry matter of lignin-containing sewage sludge, i.e. The amount of injected lignoprotein sludge (concentration | p1 is 41.8 g / l) is 90 ml, and the suspension of compacted sewage sludge is 180 ivin (concentration 42.0 g / l).

The residual moisture of the sludge after dehydration is 72.8%, the filtration time is 875 s.

PRI me R 3. The treatment of lignin-containing sewage sludge is carried out as in Example 1, with an amount of lignin-protein sediment to be injected at 1.0 g / g of dry matter of sewage sludge, i.e. to 135 g of the suspension of compacted lignin-containing sediment with a concentration of 42.0 g / l are added, 50 liters of 135 g of the suspension of the ligno-protein precipitate with a concentration of 41.8 g / l.

The residual moisture of the sludge after levitating is 69.5%, and the time is 710 s;

PRI me R 4. Treatment of lignin-containing sewage sludge is propagated as in Example 1 with

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In addition, the added lignin protein precipitate is 2 g / g dry lignin-containing sediment, i.e. to 90 g of suspension (concentration 42.0 g / l), 180 g of suspension of lignin-protein precipitate (concentration 41.8 g / l) are added.

The residual moisture of the sludge after dehydration is 65.3, the filtration time is 580 s.

Comparison data of the proposed method with the known are given in the table.

As can be seen from the table, the use of a lignoprotein sludge as an auxiliary puffing material, which is a waste of the acid inversion process of a prehydrogenate with active sludge, helps to reduce the residual moisture of the sediments after dehydration, improves its transportation and reduces the heat consumption at the drying stage. Reducing the filtration time of lignin-containing sediments increases the productivity of the dewatering equipment.

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Claims (2)

1. A method for treating lignin soder- sewage sludge, including 5 1S90i "it76 the introduction of polyacrylamide, sealing material using ligninpronium (by subsidies, the introduction of auxiliary-they sediment is a waste of the process of cybic filtering material and fur-lot inversion of the prehydrolyzate with dehydration with post-sludge. thermal drying, characterized by 2. The method of pop. 1, which is also distinguished by the fact that, in order to intensify the process and that the ligno-proteosification of the dewatering process, the willow sediment is injected reduction of residual moisture, 2.0 g / g of dry matter of the original as an auxiliary filter sediment.