the phase i and ii of the integrated wastewater treatment project at the salk lake charhan industrial park, qinghai, for which lehigh is responsible for the engineering, procurement and construction (epc), have been successfully delivered recently. it makes lehigh the first in china to successfully apply the patented microbial agent for efficient removal of nitrogen to the treatment of industrial wastewater on the qinghai plateau. the engineering operation shows that the product can remarkably remove pollutant factors including organic matter and ammonia nitrogen from the wastewater and the processed water outperforms the designed indicators in every aspect. the eco-friendly technology will serve the economic development of cities along the belt and road, improve the ecological environment in areas with high altitude and extremely cold climate and enjoy broad application prospects.
the key technology for the integrated wastewater treatment project at the salk lake charhan industrial park is the microbial agent for efficient removal of nitrogen and its application technology independently developed by lehigh. so far, most of the microbial agents for the removal of nitrogen used to treat wastewater in china are imported.
to break the foreign technological monopoly, lehigh's r&d team has spent eight years making technological breakthroughs, experimented over and over, screened and cultivated more than 1,000 microorganisms in light of the characteristics of organic high-ammonia-nitrogen-content wastewater, and selected and bred dozens of nitrification and denitrification strains highly capable of nitrogen removal. through multiple small- and medium-sized experiments and scale-up experiments, lehigh has eventually commanded the technology for massive cultivation of microbial strains capable of nitrogen removal and applied for several national patents. the technology has been maturely applied to the treatment of industrial wastewater in the coal chemical industry and the fine chemical industry across china at a low cost and has produced better results than national standards in every technical aspect.
“the biochemical treatment of high-ammonia-nitrogen-content wastewater faces several challenges in high-altitude areas in west china,” said the head of the lehigh environmental protection institute. the project is located in charhan where the winter is long and freezing, the day-night temperature difference exceeds 20℃, and the oxygen content in the air is only 70% of that in plains, seriously affecting the normal operation of the microbial system for wastewater treatment, especially the efficient biological nitrogen removal from high-ammonia-nitrogen-content wastewater.
the project team used advanced oxygen supply facilities, optimized the designed parameters, improved the system’s own heat quantity and added external heat sources and solved problems with oxygen deficiency and the low temperature in high-altitude areas. meanwhile, targeted microbial agents for nitrogen removal are cultivated in light of the characteristics of industrial wastewater in the industrial park to remove nitrogen efficiently from the wastewater.
charhan is severely short of fresh water, with only the average annual rainfall of 35mm while the average annual evaporation is 3,566mm. the wastewater treatment facility uses the country-leading, world advanced biochemical treatment technology for high-ammonia-nitrogen-content wastewater, is non-hazardous and pollution free, and takes into full consideration of local climate and other natural conditions. after optimization, most of the reclaimed water processed by it can be re-used by companies in the industrial park to reduce the wastewater discharge and save water, meeting the state requirements of energy conservation and emission reduction.
charhan industrial park is located in golmud city, qinghai, with the altitude of nearly 3,000 meters, and houses several chemical companies including the potash plant of qinghai salt lake industry group company limited and its phase i & ii projects, and salk lake metal magnesium integration project. the integrated wastewater treatment project undertaken by lehigh is divided into three stages and its construction started in 2013. the phase i & ii projects have been completed and delivered and the phase iii project is being designed. after completion, the whole project is expected to handle 1,800 m3 of industrial wastewater per hour.
