CN103183457A

CN103183457A - Method for recovering phosphorus in sewage sludge

Info

Publication number: CN103183457A
Application number: CN 201110446835
Authority: CN
Inventors: 施一飞
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-12-27
Filing date: 2011-12-27
Publication date: 2013-07-03

Abstract

The invention discloses a method for recovering phosphorus in sewage sludge. The method comprises the following steps: digesting a certain amount of the sewage sludge at first so as to allow the phosphorus to be released to a solution from the sewage sludge, wherein a digestion method can be one selected from the group consisting of an ultrasonic method, a heating method and an acid addition method or be a combined method of the heating method and the acid addition method ultrasonic method; and then, recovering the phosphorus resource in supernatant of the sewage sludge having undergone digestion, wherein a recovery method is to recover phosphorus in the supernatant of the sewage sludge through precipitation with a CaCl2 solution or through precipitation with seawater used as a magnesium source. With such a technical scheme, the method provided by the invention has the advantages of a simple process, low energy consumption, economic efficiency and social significance.

Description

A kind of method that reclaims phosphorus in the mud

Technical field

The present invention relates to sewage and reclaim, relate in particular to a kind of method that reclaims phosphorus in the mud.

Background technology

Phosphorus not only has important use in agriculture production and is worth, and in industry, medicine, biology, also playing the part of considerable role, be widely used at everyways such as feed, metal treatment, plating processing, material of construction, flame-retarding fire-extinguishing, petrochemical complex, geological prospectings.Therefore, human very huge to its demand.Yet current all signs show that the product that phosphorus is relevant continues deliverability and can descend, and production cost but constantly rises.Phosphorus in the water body is mainly derived from ight soil, washing composition and some trade effluent, mainly exists with, poly-phosphate and three kinds of forms of organophosphorus.By the phosphoric acid salt of washing composition discharging account for total phosphorus pollution load about.Present nitrogenous phosphorus wastewater treatment method is a lot, but shortcoming is in various degree all arranged, and especially for containing high strength ammonia and phosphatic waste water, general biochemical method treatment effect is not ideal enough, and chemistry such as conventional aluminium, iron, calcium salt dephosphorization.Intermediate processing will produce a large amount of reluctant mud.Since the sixties in 20th century, people begin one's study and use magnesium ammonium phosphate (MAP) precipitator method and remove and reclaim nitrogen phosphorus in the waste water.

MAP precipitator method dephosphorization principle is to NH ₄ ⁺Add Mg in the water ²⁺And PO ₄ ^3-Or HPO ₄ ^3-, make it and NH ₄ ⁺Generate indissoluble double salt MgNH ₄PO ₄6H ₂O (be called for short MAP crystallization), the equation of face as follows, thus remove ammonia nitrogen in the waste water.This method also can be used for Removal of Phosphorus in Wastewater.The main chemical reactions equation is as follows:

Mg ²⁺+PO ₄ ^3-+NH ₄ ⁺+6H ₂O＝MgNH ₄PO ₄·6H ₂O↓

Mg ²⁺+HPO ₄ ^3-+NH ₄ ⁺+6H ₂O＝MgNH ₄PO ₄·6H ₂O↓+H ⁺

2002, United States Patent (USP) trademark office disclosed a kind of method that reclaims element phosphor from the mud that contains water, dirt and element phosphor.MS. investigator such as Sa Fen is melted mud with high temperature earlier, and the weight that adds then in contained element phosphor in the mud is about the 0.5%-3% oxygenant, and is about 75%-400% water in the weight of mud.The above mixture of continuously stirring until the external phase of forming element phosphorus, separates to purify obtaining phosphorus at last from this mixture.

On the whole, above mud phosphorus reclaims technology and has advantages such as phosphorous recovery height, mud decrement, but still has some problems: as 1. the energy consumption generation is expensive; 2. technical process complexity; 3. product is comparatively single; 4. the environmental pollution that may cause.

Summary of the invention

Purpose of the present invention is intended to overcome the deficiencies in the prior art, provides a kind of technology simple, reliable, and the method for phosphorus in the higher recovery mud of the rate of recovery.

Realize that technical scheme of the present invention comprises the steps:

Earlier a certain amount of mud is cleared up earlier, made phosphorus from mud, be discharged in the solution; The method of clearing up can be supersonic method, heating method, add a kind of or heating method of acid system and add two kinds of associatings of acid system; Concrete operations are as follows:

1. supersonic method: add water in mud, stir, and regulate pH to 10-11 with NaOH, ultrasound condition is: the every work of ultrasonic wave 4 seconds intermittently 1 second then, continuous firing 60 minutes;

2. heating method: add water in mud, stir, the temperature of heating remains on 60-90 ℃, and the time of heating is 30 minutes to 60 minutes;

3. add acid system: in mud, add 10%HCl, stir, sustained reaction 2 hours;

4. heat and sour integrated process: add 2-4%HCl in mud, stir, the temperature of heating remains on 60-90 ℃, sustained reaction 2 hours;

Then, to reclaiming through phosphor resource in the supernatant liquid of clearing up back mud; The method that reclaims can be with CaCl ₂Solution precipitation reclaims the phosphorus of mud upper strata in the stillness of night, perhaps is the phosphorus in the magnesium source precipitation recovery mud supernatant liquor with the seawater; Concrete operations are as follows:

1. CaCl ₂Solution deposit: get the supernatant liquid behind the sludge digestion, add proper C aCl ₂Solution, and stir with agitator, adjusting pH is 10-11, reacts after 5-10 minute, stops to stir, and leaves standstill;

2. the magnesium source precipitator method: get the supernatant liquid behind the sludge digestion, add an amount of seawater and ammonium solution, stir with agitator, adjusting pH is 10-11, reacts after 15-20 minute, stops to stir, and leaves standstill;

The temperature of the phosphorus in the above-mentioned recovery mud supernatant liquor is 10-35 ℃.

The frequency that above-mentioned agitator stirs is 100-120rpm.

Advantage of the present invention is:

(1) ultrasonication, the method that heats, adds the associating of acid and hot acid are discharged in the solution phosphorus from mud, carry out the recovery of phosphorus again from solution, and technology is simple relatively, and it is low to consume energy.

(2) the present invention adopts the calcium phosphate precipitation method to reclaim phosphorus, with CaCl ₂For the calcium source generates calcium phosphate, reclaim for the mode of magnesium source generation magnesium ammonium phosphate realizes the phosphorus precipitation in the solution with the seawater, because seawater is a kind of extremely cheap and inexhaustible resources for coastal cities, can save the cost of precipitation reagent, therefore have certain economic benefits and social effect.

(3) to reclaim the product that phosphorus finally obtains be calcium phosphate or magnesium ammonium phosphate to the calcium phosphate precipitation method, can be used as fertilizer utilization, realizes the recirculation of phosphor resource.

Description of drawings

Fig. 1 is process flow sheet of the present invention.

Embodiment

Below in conjunction with example the present invention is further elaborated, as shown in Figure 1.

As one embodiment of the present of invention, earlier with adding water in a certain amount of mud, stir, and regulate pH to 10 with NaOH, ultrasound condition is: work 4s intermittently 1 second, continuous firing 60 minutes;

Then, get the supernatant liquid behind the sludge digestion, add proper C aCl ₂Solution, and stir with agitator, regulating pH is 10, react after 5-10 minute, stops stirring, leaves standstill;

The temperature of the phosphorus in the above-mentioned recovery mud supernatant liquor is 25 ℃.

The frequency that above-mentioned agitator stirs is 120rpm.

The rate of recovery of phosphorus can reach 80% in the mud.

As an alternative embodiment of the invention,, stir reaction 2h earlier with adding 10%HCl in a certain amount of mud; Then, get the supernatant liquid behind the sludge digestion, add an amount of seawater and ammonium solution, stir with agitator, regulating pH is 10, react after 15 minutes, stops stirring, leaves standstill;

The temperature of the phosphorus in the above-mentioned recovery mud supernatant liquor is 10 ℃.

The frequency that above-mentioned agitator stirs is 100rpm.

The rate of recovery of phosphorus can reach 75% in the mud.

As an alternative embodiment of the invention, earlier with adding 2%HCl in a certain amount of mud, stir, the temperature of heating remains on 90 ℃, reaction 2h;

Then, get the supernatant liquid behind the sludge digestion, add proper C aCl ₂Solution, and stir with agitator, regulating pH is 11, react after 5 minutes, stops stirring, leaves standstill;

The temperature of the phosphorus in the above-mentioned recovery mud supernatant liquor is 35 ℃.

The frequency that above-mentioned agitator stirs is 100rpm.

The rate of recovery of phosphorus can reach 82% in the mud.

The above, it only is preferred embodiment of the present invention, be not that the present invention is done any pro forma restriction, any technical solution of the present invention content that do not break away from,, all still belong in the scope of technical solution of the present invention any simple modification, equivalent variations and modification that above embodiment does according to technical spirit of the present invention.

Claims

1. method that reclaims phosphorus in the mud, it is characterized in that it comprises the steps: earlier a certain amount of mud to be cleared up earlier, make phosphorus from mud, be discharged in the solution, the method of clearing up can be supersonic method, heating method, add a kind of or heating method of acid system and add two kinds of associatings of acid system that concrete operations are as follows:

3. add acid system: in mud, add 10%HCl, stir, sustained reaction 2 hours;

1. CaCl ₂Solution deposit: get the supernatant liquid behind the sludge digestion, add proper C aCl ₂Solution, and stir with agitator, adjusting pH is 10-11, reacts after 5 to 10 minutes, stops to stir, and leaves standstill;

2. the magnesium source precipitator method: get the supernatant liquid behind the sludge digestion, add an amount of seawater and ammonium solution, stir with agitator, adjusting pH is 10-11, reacts after 15-20 minute, stops to stir, and leaves standstill.

2. the method for phosphorus in the recovery mud as claimed in claim 1, it is characterized in that: the temperature of the phosphorus in the described recovery mud supernatant liquor is 10-35 ℃.

3. the method for phosphorus in the recovery mud as claimed in claim 1 is characterized in that: the frequency that described agitator stirs is 100-120rpm.