The research results of this project belong to the technical field of urban water supply engineering.
In response to problems such as difficulty in constant effluent throughput, long chemical cleaning time, and high water consumption rate for physical backwashing, relying on a number of domestic first projects, it has led and promoted the development and application of submerged ultrafiltration membrane water purification process in the urban water supply field. Through 8 years of joint technical research between industry, academia and research, the following innovative results have been achieved:
(1) Key technologies for multi-mode energy-saving and constant throughput water outlet. It has developed a multi-mode energy-saving technology based on siphon self-outflow water, and is the first to use siphon self-outflow water and pump suction water. It is switched or superimposed in real time, making full use of the abundant water head of 2.5m in the entire process of the old water plant, solving the problem of energy-saving operation and flux maintenance at low temperatures. An intelligent regulation method of inlet and outlet water level regulation and joint control of production water pump and regulating valve is proposed, which solves the problem of stable water level and production water flux in the membrane tank.
(2) Circular online chemical cleaning integrated technology. For the first time, maintenance and recovery online chemical cleaning technology was formed, and a cyclic cleaning method in which liquid medicine flows out through the membrane was developed. The coupling effect of liquid medicine immersion and flushing was fully utilized. The technology was innovatively proposed to strengthen the chemical cleaning technology by intermittent physical cleaning, which accelerated the membrane pore surface drug renewal rate, giving full play to the synergistic effect with physical cleaning during the chemical cleaning process, increasing the transmembrane pressure difference reduction value by more than 15%, shortening the cleaning duration from the regular 6 hours to 5 hours. Solve the problem of improving chemical cleaning efficiency.
(3) External reflux enhanced short-term precipitation/submerged membrane short-process integrated technology. It pioneered the sludge reflux sedimentation membrane integrated tank, innovated the centralized reflux/aeration technology of post-settled biological powder carbon and sludge to achieve synergistic effects such as biological oxidation, contact adsorption, enhanced flocculation, and submerged membrane filtration, and solved the problem of intensive micro-polluted raw water. The problem of multi-functional processing. The innovatively shortened the advection sedimentation residence time from the conventional 2 hours to less than 1 hour, and eliminated the sand filter, which reasonably connected the settled water and the membrane inlet water, saving head loss and project investment.
(4) Resource saving backwash integrated technology based on liquid level control. The first technology of incomplete backwashing emptying has reduced water consumption by more than 66%, and saved more than 36,000 m3 per year on a scale of 10,000 tons of water. It is the first optimization technology to stabilize the submerged water level of membrane wires, giving full play to the bubble scrubbing effect, and saving electricity by 1688kW.h per year during the operation of air source equipment. It is the first technology to combine or combine water outlet pump and backwash pump. The backwash pump does not need to be set up separately or only requires small flow superposition, saving equipment investment and maintenance costs.
(5) Quick optimization of key parameters and multi-functional use of pipelines. Based on Hagen-Poseux's Law, project investment and operating costs, an optimal solution model that is convenient, rapid and accurate to judge membrane flux and transmembrane pressure difference is systematically proposed for the first time, solving the problem of determining economic membrane flux. The first multi-functional technology for multiple types of the same pipeline is used to achieve seamless connection of pipelines such as normal filtration, physical cleaning, and chemical cleaning, reducing maintenance workload and saving project investment and land occupation.
According to novelty search and consultation, the overall technology has reached the international advanced level. The results include 8 authorizations and patent applications (2 invention authorizations and 2 acceptances), 12 papers and 1 monograph have been applied in Shandong, Zhejiang, Xinjiang, Jiangsu, Henan, Hebei and other provinces and cities, including the first large-scale submerged ultrafiltration membrane project in China, the first external reflux enhanced precipitation/submerged ultrafiltration membrane integrated tank project in China, the first high-efficiency precipitation/submerged ultrafiltration membrane short-process project in China, the first siphon filter upgrading project in China, and the largest submerged membrane ultra-large project in China, etc., The annual water saving is more than 2.88 million m3 and the annual electricity saving is 470,000 KW.h. The total investment of the project exceeds 4 billion yuan, and the total scale exceeds 1.8 million m3/d, accounting for nearly 80% of the total scale of similar projects in the country. It has effectively improved the industry's submerged ultrafiltration membrane technology level has promoted the development of the domestic submerged membrane industry.