Study On Reverse Osmosis Application In The Treatment Of Nitrogen Wastewater

With the rapid development of industry and agriculture, ammonia nitrogen pollution is becoming more widely and its emissions are also growing. The sewage, animal waste, industrial wastes as well as landfill leachate contain a large amount of ammonia and nitrogen, which are the main pollutants leading to the water eutrophication. Therefore, controlling the Ammonia Nitrogen Waste Water in an economical and efficient manner is an important issue for the environmentalists.This paper, in accordance with the characteristics of ammonia nitrogen waste water generated due to the production technology of Nano Zinc oxide, introduces the principles of the treatment with two reverse osmosis concentrate, treated reverse osmosis water recycling back to production processes and ammonia recycling by concentrated solution. This technology, providing an economical, environmentally-friendly and reliable method for ammonia nitrogen waste water, has an important theoretical and practical value. The following achievements have been made through the experimental research:(1) The operating pressure of first reverse osmosis system is within the range of 1.0Mpa～1.4Mpa, the system water and concentrated water pressure is no greater than 0.10Mpa; the operating pressure of the second reverse osmosis system is within the range of 4.8～5.0 Mpa, the system water and concentrated water pressure is no greater than 0.10Mpa; the first reverse osmosis desalination rate is greater than 98% and the second reverse osmosis desalination rate is greater than 99%; The reverse osmosis system is operating in good condition.(2) The pH value of wastewater is below 7. The reverse osmosis system treats the ammonia nitrogen in the most stable manner. The content of ammonia nitrogen wastewater, after the reverse osmosis treatment, is 20mg/L, with the electrical conductivity less than 150μs/cm. It can meet the requirements of production technology of Nano Zinc oxide to recycled water.(3) Pretreatment of reverse osmosis systems with coagulationand medium filtration process can meet the reverse osmosis inlet requirement for SDI<5. Compared with ultrafiltration technology for reverse osmosis pretreatment, the technology with coagulation and sedimentation as well as media filtration can help reduce investment costs and operating costs.(4) Through the engineering design that the amount of daily-treated waste water is 1000 tons, it can be concluded that the operating cost of equipment is 1810 Yuan/day. The depreciation cost of the equipment, with the total investment of RMB 1.5 million Yuan, is 206 Yuan/day provided that its life is 20 years. The economic benefits from wastewater recycling is 2405 Yuan/day and the final economic benefits from the reverse osmosis technology of Nano zinc oxide is 389 Yuan/day, with the annual gain of about RMB 142,000 Yuan.As the result, the water treatment technology, with the core of reverse osmosis water treatment, not only has significant environmental benefits, but also has some economic benefits.