[ Hongjie Water ] Wastewater Reuse Reverse Osmosis Chemical Dosing Technology Solution

[ Hongjie Water ] Wastewater Reuse Reverse Osmosis Chemical Dosing Technology Solution

The treatment process of recycled water is as follows: first, it is filtered by the medium-speed filter unit, and then the filtered water is oxidized by ozone. Finally, the total dissolved solids in the water are removed by the double membrane method of "self-cleaning filter + ultrafiltration + security filter + reverse osmosis".
In this project, the water volume entering the ultrafiltration unit is 800m3/h, and 300m3/h of ultrafiltration water enters the reverse osmosis unit. The RO water production volume is 225m3/h. The other part of the ultrafiltration water is about 450m3/h. It enters the ultrafiltration product pool for other purposes (providing water source for the expansion of the reverse osmosis unit) or used for discharge water dilution and discharge. The backwash water of the medium-speed filter, self-cleaning filter, and ultrafiltration unit is pumped to the horizontal flow oil separator. The reverse osmosis concentrated water volume is 75m3/h, and the COD concentration is 160mg/L. It is sent to the ozone contact pool. The ozone oxidation removal rate is 40%. The COD of the concentrated water after oxidation is reduced to 96mg/L, and then mixed with the BAF standard drainage 350m3/h for discharge.
1. Antiscalant:
Add according to the water supply of the reverse osmosis system. The concentration of the agent is related to the conductivity, iron content, calcium hardness, total hardness, pH, recovery rate and operating temperature of the reverse osmosis system. On-site personnel conduct regular verification and set the best control range according to the water quality of the reverse osmosis water supply.
· Dosing point: water supply pipeline before the security filter; · Liquid configuration: The scale inhibitor adopts PC-1611T model, directly using pure liquid, or using RO pure water to make a 10% solution. 2.5ppm PC-1611T (1.5-3.0ppm) is added at the initial stage of commissioning, and the pH of the reverse osmosis water supply should be controlled not to exceed 8.0.
2. Bactericide
For the pretreatment system, add oxidizing bactericide bleaching water: add continuously to control the residual chlorine at the outlet of the ultrafiltration water tank to 0.3ppm. However, before entering the RO membrane system, the residual chlorine must be removed by adding a reducing agent to control the reverse osmosis water ORP <200 Mv and the residual chlorine <0.05ppm, otherwise it may cause membrane damage.
For RO membranes, fast-reacting non-oxidizing bactericides can be used as microbial control agents in water pretreatment systems or reverse osmosis membrane systems to prevent bacterial contamination. The fungicide used is N7320. There are two methods for adding N7320: A. Online addition of N7320 fungicide without stopping the system: · Add 80-120 ppm according to the water supply of the RO system. · Dosing point: on the water supply pipeline before the security filter; · Dosing times: depending on the number of bacteria in the RO system water supply or seasonal changes, it is estimated that 1-2 times a week will be added, and each time will be added continuously for 1-2 hours. · Dosing method: use a metering pump to add continuously. · Liquid configuration: pure liquid can be added without dilution. B. Addition of N7320 fungicide in the shutdown state: If the RO system can be shut down for 1 hour, it is recommended to use the cleaning system's cleaning tank and other equipment to sterilize the RO system to save the cost of adding the agent. The method is as follows: · According to the amount of water retained in the cleaning tank, 200ppm of N7320 fungicide is directly added to the cleaning tank, that is, 0.2 kg of N7320 fungicide is added per ton of water. ·After the 200ppm N7320 solution is mixed evenly, start the pump to circulate for 40-50 minutes.
3.
Before the reducing agent enters the RO membrane system, the residual chlorine must be removed by adding the reducing agent, and the reverse osmosis inlet ORP <200mV and the residual chlorine <0.05ppm are controlled, otherwise the membrane will be damaged. It is estimated that the amount of reducing agent required for reverse osmosis is 1.5-2.5ppm. During operation, the dosage should be controlled and adjusted according to the test results of ORP and chlorine.
The reducing agent uses N780, and the dosage is calculated according to the situation of this system. Control: The addition of reducing agent determines the start and stop of the dosing pump and the size of the dosing amount according to the ORP of the RO inlet water. Make the residual chlorine in the RO inlet water less than 0.05PPM.
Dosing point: ultrafiltration pool outlet pipeline, after the residual chlorine sampling point, before the scale inhibitor dosing point.

Shenzhen Hongjie Water Technology Co., Ltd. is a high-tech enterprise specializing in product research and development, production, sales, engineering design, installation and commissioning, technical consulting, and supporting material sales in the field of industrial water treatment and drinking water treatment. Main products: pure water equipment, ultrapure water equipment, reverse osmosis equipment, GMP purified water equipment, EDI deionized water equipment, domestic sewage equipment, industrial wastewater equipment, softened water equipment, and reclaimed water reuse equipment. It is an environmentally friendly high-tech manufacturer that integrates the design, manufacture, installation, commissioning and maintenance of water treatment equipment.