Marine sewage treatment equipment

Marine sewage treatment equipmentRaw water is filtered through fine filters, granular activated carbon filters, compressed activated carbon filters, etc., and then pressurized by a pump. A reverse osmosis membrane (RO membrane) with a pore size of 1/10000 μ m (equivalent to 1/6000 the size of Escherichia coli and 1/300 the size of a virus) is used to separate high concentration water into extremely low concentration water (i.e. purified water) and higher concentration water. Low concentration water is used, while high concentration water is discharged or resources are reused. At the same time, industrial pollutants, heavy metals, bacteria, viruses, and other impurities mixed into the water are all isolated to achieve the physical and chemical indicators and hygiene standards specified for drinking, producing water that is clean to pure. It is the choice for the human body to replenish water in a timely manner, with a cleanliness of almost 99%. So people call this type of water production machine a reverse osmosis purified water machine. Of course, there are also some higher purity pure water manufacturing technologies (such as EDI, polishing mixed bed, etc.) that are not suitable for drinking water production.

Pure water equipment, in simple terms, refers to equipment used for producing pure water. And purified water is widely used in various fields such as daily drinking, chemical industry, animal husbandry, planting, food, beverages, etc.

The application of membrane separation technology in reverse osmosis water purification equipment can effectively remove charged ions, inorganic substances, colloidal particles, bacteria, and organic substances from water. It is equipment used in high-purity water preparation, desalination of brackish water, and wastewater treatment processes. Widely used in fields such as electronics, pharmaceuticals, food, textiles, chemicals, and power generation.

Reverse osmosis, also known as reverse osmosis, is a membrane separation operation that uses pressure difference as a driving force to separate solvents from a solution. Apply pressure to the liquid on one side of the membrane, and when the pressure exceeds its osmotic pressure, the solvent will undergo reverse osmosis in the direction of natural osmosis. Thus, the solvent that permeates through the low-pressure side of the membrane, namely the permeate, is obtained; The concentrated solution is obtained on the high-pressure side, namely the concentrated solution. If reverse osmosis is used to treat seawater, fresh water is obtained on the low-pressure side of the membrane, and brine is obtained on the high-pressure side.

During reverse osmosis, the permeation rate of the solvent, i.e. the flow energy N, is:

N=Kh(Δp－Δπ)

In the formula, Kh is the hydraulic permeability coefficient, which slightly increases with increasing temperature; Δ p is the static pressure difference on both sides of the membrane; Δ π is the osmotic pressure difference between the solutions on both sides of the membrane. The osmotic pressure π of a dilute solution is:

π=iCRT

In the formula, i represents the number of ions generated by ionization of solute molecules; C is the molar concentration of solute; R is the molar gas constant; T is jue for temperature.

Reverse osmosis typically uses asymmetric membranes and composite membranes. The equipment used for reverse osmosis is mainly hollow fiber or roll type membrane separation equipment.

Reverse osmosis membranes can intercept various inorganic ions, colloidal substances, and macromolecular solutes in water, thereby obtaining purified water. It can also be used for pre concentration of macromolecular organic solutions. Due to its simple process and low energy consumption, reverse osmosis has developed rapidly in the past 20 years. It has been widely used in desalination of seawater and brackish water (see brine), softening of boiler water, and wastewater treatment, and combined with ion exchange to produce high-purity water. Its application scope is expanding and it has begun to be used in the concentration of dairy products, fruit juice, as well as the separation and concentration of biochemical and biological agents.

Equipment shutdown protection

Due to fluctuations in production, reverse osmosis water purification equipment inevitably needs to be shut down frequently. Protective measures must be taken during short-term or long-term shutdowns. Improper treatment can lead to a decrease in membrane performance that cannot be restored.

Short term storage is suitable for systems that have been shut down for less than 15 days, and low-pressure flushing can be used every 1-3 days to protect reverse osmosis water purification equipment. Practice has found that when the water temperature is above 20 ℃, the water in reverse osmosis water purification equipment will become smelly and spoiled after being stored for 3 days, and a large number of bacteria will multiply. Therefore, it is recommended to perform low-pressure flushing every 2 days or 1 day when the water temperature is above 20 ℃, and every 3 days when the water temperature is below 20 ℃. After each flushing, all inlet and outlet valves on the reverse osmosis device of the water purification equipment should be closed.

Long term shutdown protection is applicable to systems that have been shut down for more than 15 days. At this time, protective liquid (disinfectant) must be filled into the reverse osmosis device of the water purification equipment for protection. The commonly used formula for fungicides (composite film) is formaldehyde 10 (mass fraction), isothiazolinone 20mg/L, and sodium bisulfite 1 (mass fraction).

Marine sewage treatment equipment

chemical cleaning

Under normal operating conditions, reverse osmosis membranes may also be contaminated by inorganic scale, colloids, microorganisms, metal oxides, and other substances. The deposition of these substances on the membrane surface can cause a decrease in the output or desalination rate of the reverse osmosis device, an increase in pressure difference, and even irreversible damage to the membrane. Therefore, in order to restore good permeability and desalination performance, chemical cleaning of the membrane is necessary.

Generally, cleaning should be done once every 3 to 12 months. If cleaning is necessary every month, it indicates that the pre-treatment system should be improved and the operating parameters adjusted. If cleaning is required once every 1-3 months, it is difficult to determine whether the pre-treatment system needs to be improved, as it is necessary to improve the operational level of the equipment.

processing system

The reverse osmosis system is the core component of the entire pure water system, and only through reverse osmosis can the standard of pure water be achieved. The reverse osmosis system mainly adopts membrane filtration technology. Then water molecules can pass through the reverse osmosis membrane. Other ions such as calcium, magnesium, and sodium are discharged together with the wastewater. Below are the components of this system.

1. Precision filter

Mainly filters large particle molecules in water.

2. Special high-pressure pump

Provide strong power for reverse osmosis water purification equipment.

3. Reverse osmosis membrane

The reverse osmosis membrane adopts membrane filtration technology. Let water molecules pass through other ions that cannot achieve the purpose of purifying water.