HJ 579-2010Technical specifications for membrane separation process in wastewater treatment (English PDF)

4.1 Influent water quality requirements

4.1.1 When designing the membrane system, the water inlet requirements should be met and the appropriate membrane elements should be selected.

4.1.2 Internal pressure type hollow fiber microfiltration and ultrafiltration system water inlet, water quality requirements can refer to Table 1.

Table 1 Internal pressure type hollow fiber microfiltration, ultrafiltration system water reference value

Membrane Material Reference Turbidity/NTU SS/(mg/L) Mineral Oil Content/(mg/L) Polyvinylidene fluoride (PVDF) <=20 <=30 <=3 Polyethylene (PE) 100 000 Removal of suspended particles, bacteria, partial viruses and large-scale colloids Drinking water to turbid, water reuse, nanofiltration or reverse osmosis System pretreatment Ultrafiltration (UF) 0.002~0.1 10 000~100 000 Removal of colloids, proteins, microorganisms and macromolecular organics Drinking water purification, reclaimed water, nanofiltration or reverse osmosis System pretreatment Nanofiltration (NF) 0.001 ~ 0.003.200 ~ 1 000 Removal of multivalent ions, partial monovalent ions, and Molecular weight of.200 to 1 000 Daltons Body Remove the hardness, color and radioactive radium of well water, Partial removal of soluble salts. Process material concentration, etc.

Reverse osmosis (RO) 0.000 4~0.000 6 >100 to remove soluble salts and molecular weight greater than

100 Daltons Organics Seawater and brackish water desalination, boiler feed water, industry Pure water preparation, wastewater treatment and special separation

5.1 General provisions

5.1.1 In order to prevent membrane degradation and membrane clogging, suspended solids, sharp particles, sparingly soluble salts, microorganisms, oxidants, organic Pretreatment of pollutants such as substances and greases.

5.1.2 The depth of pretreatment shall be determined according to the membrane material, the structure of the membrane module, the quality of the raw water, the quality requirements of the produced water and the recovery rate.

5.1.3 Inlet water temperature range. When the pH is 2~10, the operating temperature is 5~45°C; when the pH value is greater than 10, the operating temperature should be less than 35 ° C.

5.2 Pretreatment of microfiltration and ultrafiltration systems

5.2.1 Removal of suspended particulate matter and colloids in the influent can be carried out by a coagulation-precipitation-filtration process. Can be added to help increase membrane flux, and a flocculant compatible with the membrane material.

5.2.2 Fine mesh and disc filters should be installed before microfiltration and ultrafiltration systems. Disk filter filtration accuracy before internal pressure membrane system it should be less than 100 µm; before the external pressure membrane system, the filter efficiency of the disc filter should be less than 300 µm.

5.2.3 When the influent mineral oil exceeds the value of Table 1 or the animal and vegetable oil exceeds 50 mg/L, the degreasing process should be increased.

5.3 Pretreatment of nanofiltration and reverse osmosis systems

5.3.1 To prevent chemical oxidative damage of the membrane, the activated carbon may be adsorbed or a reducing agent (such as sodium hydrogen sulfite) may be added to the influent water to remove residual chlorine or Other oxidants, control residual chlorine content of 0.1 mg/L or less.

5.3.2 To prevent the colloid, slime and particle fouling formed by the corrosion of iron and aluminum, it is possible to use double anesthesia with anthracite and quartz sand as the filter medium.

The filter is removed.

5.3.3 To prevent microbial contamination, the influent can be sterilized by physical or chemical methods.

5.3.4 Control scale formation, acid addition can effectively control carbonate scale; add scale inhibitor or strong acid cation resin to soften, can effectively control sulfuric acid Salt scaling.

5.3.5 Microfiltration or ultrafiltration can remove all suspended solids, colloidal particles and some organic matter, and the effluent reaches the silt density index (SDI)<=3.

Turbidity <= 1 NTU, can effectively prevent colloid and particulate contamination and block membrane components.

6.1 General requirements

6.1.1 The membrane separation process wastewater treatment process should be selected based on the raw water quantity, water quality and water production requirements, and recovery rate. Design data See Appendix B for a lookup.

6.1.2 When using a contact filtration process to treat low turbidity wastewater, the dosing point should be 1.0 m away from the filter inlet.

6.1.3 When the activated carbon adsorption process is adopted, the fungicide should be added at the inlet of the activated carbon filter.

6.1.4 Reducing agent and/or scale inhibitor should be added before the security (filtration accuracy less than or equal to 5 µm) filter. Security filter Install the pressure gauge.

6.1.5 In order to prevent the corrosion of pipelines and equipment caused by acidification and chlorination in pretreatment, PVC should be used on the low pressure side of nanofiltration and reverse osmosis systems.

For pipes and fittings, stainless steel pipes and fittings should be used on the high pressure side.

6.1.6 Membrane separation system Concentrated water should be discharged after treatment.

6.1.7 The ratio of pressure vessel arrangement of the first-stage multi-stage nanofiltration and reverse osmosis system should be 2.1 or 3.2 or 4.2.1 or proportionally increase.

6.2 Microfiltration, ultrafiltration system design

6.2.1 Process design parameters include.

1) The amount of water treated, m3/d;

2) treating water quality;

3) membrane flux, m3/(m2·d);

4) operating pressure, MPa;

5) backwash cycle, h;

6) Each backwash time, min.

6.2.2 Process. The operation mode of microfiltration and ultrafiltration systems can be divided into batch and continuous; the arrangement of components should be one stage.

Install in parallel. The recommended basic process flow is shown in Figure 1.

Intake basin disc filter microfiltration/ultrafiltration water production tank Backwash Concentrated water/backwash water Emission/reuse/depth processing Original sewage collection pool

Figure 1 Basic process flow chart of microfiltration and ultrafiltration system

6.2.3 Basic design calculation

6.2.3.1 The amount of water produced is calculated according to formula (1).

Sm mq CS qo= × × (1) where. qs--stable water production capacity of single membrane element, L/h;

Qo--the initial water production of a single membrane element, L/h;

Cm--assembly coefficient, ranging from 0.90 to 0.96;

Sm - stability factor, ranging from 0.6 to 0.8.

The design temperature is 25 ° C, the actual temperature fluctuation, the formula (2) can be used to correct the calculation of water production.

St s (1 0.0215)

Tq q -= × (2)

6.2.3.2 The number of membrane modules is calculated according to formula (3).

In the formula. Q--design water production, L/h.

Equation (4) calculation. 6.2.3.3 The concentration and volume of the concentrate can be RV ( )= ( )( ) (4) where. rho--concentrated concentration of the concentrate, mg/L;

6.3 nanofiltration,

6.3.1 Process

The first-stage system process. the influent water passes through the nanofiltration or reverse osmosis system to meet the water production requirements. Have a first-level batch rho0--the mass concentration of the feed liquid, mg/L;

V--the volume of the concentrate, L;

V0--the volume of the feed liquid, L;

R--contaminant removal rate.

Reverse osmosis system design 6.3.1.1 Rational, first-class continuous. The basic process flow is recommended as shown in Figure 2 and Figure 3.

Concentrated water

Water tank (pool) inlet water nanofiltration/reverse osmosis water production

Figure 2 First-level batch process basic process flow chart

Water tank (pool) inlet water nanofiltration/reverse osmosis water production Concentrated water

Figure 3 One-stage continuous basic process flow chart

6.3.1.2 One-stage multi-stage system process. When the primary separation water quantity does not meet the recovery rate requirement, a multi-stage series process may be adopted, each stage the effective cross-sectional area is decremented. The recommended basic process flow is shown in Figure 4, Figure 5, and Figure 6.

Concentrated water

Water tank (pool) inlet water nanofiltration/reverse osmosis Product water Nanofiltration/reverse osmosis nanofiltration/reverse osmosis

Figure 4 Basic process flow chart of the first-stage multi-stage circulation system

Water tank (pool) inlet water nanofiltration/reverse osmosis Product water Concentrated water Nanofiltration/reverse osmosis nanofiltration/reverse osmosis

Figure 5 Basic process flow chart of the first-stage multi-stage continuous system

Influent

Concentrated water

Water tank (pool)

Nanofiltration/reverse osmosis Nanofiltration/reverse osmosis Nanofiltration/reverse osmosis Nanofiltration/reverse osmosis Nanofiltration/reverse osmosis Nanofiltration/reverse osmosis Nanofiltration/reverse osmosis Product water One paragraph, two paragraphs and three paragraphs

Figure 6 Basic process flow chart of the first-stage multi-stage system

6.3.1.3 Multi-stage system process flow. When the primary system water production cannot meet the water quality requirements, the primary system water production is sent to another Reverse osmosis system, continue to separate until qualified water is obtained. The recommended basic process flow is shown in Figure 7.

Concentrated water

Concentrated water

Product water

Concentrated water

Level 1 and Level 3

Reverse osmosis water tank (pool) water tank reverse osmosis water tank reverse osmosis water

Figure 7 Basic process flow chart of multi-level system

The arrangement of the membrane modules can be divided into series and parallel.

6.3.2 Basic design calculation

6.3.2.1 Water production per unit membrane element

The water production capacity of a single membrane element at a design temperature of 25 ° C, m3/h. It should be corrected according to the temperature correction factor. It can also be designed at 25 °C.

The water production is increased or decreased by 2.5% per liter, down 1 °C.

6.3.2.2 The number of membrane elements is calculated according to formula (5).

Max 0.8

Where. Qp--design water production, m3/h;

Qmax--the maximum water production capacity of the membrane element, m3/h;

0.8--Design safety factor.

6.3.2.3 The number of pressure vessels (membrane shells) is calculated according to formula (6).

eNN

Where. Nv - the number of pressure vessels;

Ne--design component number;

n--The number of components in each container.

6.3.3 Pipe design

6.3.3.1 For nanofiltration and reverse osmosis systems with a water production of 50 m3/h or more, the design flow of the inlet pipe shall be equal to the inlet of each pressure vessel.

The sum of the flow rates.

6.3.3.2 The flow rate of the water producing branch pipe and the main pipe should be less than or equal to 1.0 m/s.

6.3.3.3 The water produced in each section should be directly input into the production tank. If each section of water production pipe should be connected in parallel to a main pipe, it should be installed on each section of water production pipe.

Install a check valve.

6.3.4 Dosing system, a liquid tank with a thermometer should be set up to prepare a solution of a certain concentration. Dosing method should be measured Pump delivery can also be done using a ejector mounted on the inlet pipe.

6.3.5 Automatic control systems and instruments

6.3.5.1 The monitoring items of the automatic control system shall include.

1) Inlet pressure, MPa;

2) Influent conductivity, µS/cm;

3) Water production flow rate, m3/h;

4) water conductivity, µS/cm;

5) Concentrated water flow, m3/h;

6) Concentrated water pressure, MPa.

6.3.5.2 The inlet pipe shall be provided with a residual chlorine monitor and operated in conjunction with the reducing agent dosing device.

6.3.5.3 The high pressure pump inlet shall be provided with a low pressure protection switch; the high pressure pump outlet shall be provided with a high pressure protection switch.

6.3.5.4 When adding acid to adjust the pH value of the influent water, the pH upper and lower limit cut-off switches should be set; if the inlet water is equipped with heating measures, it should be set.

High temperature cut-off switch.

6.4 Treatment of membrane separation concentrated water

6.4.1 Technical requirements for concentrated water treatment

The membrane separation concentrated water produced by the sewage treatment process can be incorporated into the sewage biochemical treatment system; it can also be combined with chemical cleaning wastewater, medium filter and live the charcoal filter backwashing wastewater is collected and processed.

6.4.2 The basic process flow for concentrated water treatment is shown in Figure 8.

Membrane separation

Chemical cleaning water Filter backwash Regulating tank reaction tank sedimentation tank hydrolysis acidification tank contact oxidation tank Sludge pool Pressure filter mud cake Sedimentation tank Reaction cell Discharge

Figure 8 Basic process flow chart for concentrated water treatment

6.4.3 Concentrated water treatment discharges shall comply with national or local wastewater discharge standards.

7.1 Microfiltration, ultrafiltration system installation and commissioning

7.1.1 Microfiltration, ultrafiltration system installation

It should be installed according to the design requirements.

7.1.2 Microfiltration, ultrafiltration system debugging

7.1.2.1 When the system is started, the concentrated water discharge pipe valve and the production pipe valve should be opened, and the protection liquid in the membrane module should be rinsed with tap water until the rinse water is free of foam.

7.1.2.2 Inlet pressure is 0.1-0.4 MPa, and working temperature is 15-35 °C.

7.1.2.3 The commissioning project shall include.

1) Inlet pressure, MPa;

2) Influent flow rate, m3/h;

3) Water production flow rate, m3/h;

4) Concentrated water flow, m3/h;

5) Concentrated water pressure, MPa.

7.1.2.4 For every 30 minutes of continuous operation, the system should be backwashed once, and the backwashing time should be 30 s.

7.2 Nanofiltration and reverse osmosis membrane system installation and commissioning

7.2.1 Nanofiltration, reverse osmosis system installation

7.2.1.1 The main frame of the equipment and the installation of the water pump shall comply with the provisions of GB/T 19249 and HJ/T 270.

7.2.1.2 Pipe installation shall comply with the provisions of GB 50235 and HG 20520.

7.2.1.3 The installation of instruments and meters shall comply with the provisions of GB/T 985.1 and GB/T 1804.

7.2.1.4 Both ends of the pressure vessel shall be provided with a space not less than 1.2 times the length of the membrane element. The equipment should be installed indoors.

7.2.1.5 The installation of the electric control cabinet shall comply with the provisions of GB/T 3797.

7.2.2 Debugging of nanofiltration and reverse osmosis systems

7.2.2.1 Prior to the start of the membrane system, the pretreatment equipment and piping should be thoroughly flushed to remove impurities and dirt.

7.2.2.2 Membrane system Inlet pipe valves and concentrate pipe regulating valves shall be fully open. Use low pressure, low flow qualified pre-treatment water to drive away the membrane system the internal air, the flushing pressure is 0.2-0.4 MPa, the phi100 mm pressure vessel flushing flow is 0.6-3.0 m3/h, phi200 mm pressure capacity the flushing flow rate is 2.4 to 12.0 m3/h.

7.2.2.3 The low-pressure rinsing time of the membrane element with protective liquid shall be not less than 30 min, and the low-pressure rinsing time of the dry membrane element shall be not less than 6 h. in During the rinsing process, check the leak point and tighten immediately.

7.2.2.4 When the high pressure pump is started for the first time, the inlet valve must be adjusted to close to the fully closed state, and the large inlet valve should be slowly opened to slowly close the small concentrated water discharge.

The pipe valve adjusts the flow rate of the concentrated water and the inlet pressure of the system until the system water flow reaches the designed value. The boost rate should be less than 0.07 MPa per second.

7.2.2.5 The system is continuously operated for 24 to 48 hours, and the operating param...