OKKIE (Shanghai) Environmental Protection Technology Co., LTDis a company focusing onlow oxygen biological treatment on wastewater(DO at end of aerobic zone is lower than 0.5mg/l), with 25 years and hundreds of successful projects. We are the witness and participant to introduce European low-oxygen technology into China and creator of Chinese unique low-oxygen technology which is first generation Chinese low-oxygen biological enhanced nitrogen and phosphorous removal A2O process(in short PTA2O). PTA2O is able to fill the blank of this area in China with its revolutionary and leading innovation and more advanced compared to European ones. In the future, we will create a new sewage industry chain international alliance cooperation community which can be widely participated worldwide(connecting all the industries related to energizing wastewater and sustainable recycling of wastewater).