A Pilot Scale Test On The Fluorescent Whitening Agents Industrial Wastewater Treatment

Fluorescent whitening agents (FWAs) is a kind of organic compound that is used to whiten and brighten substances by the use of optical effects. In China, it is categorized as printing and dyeing assistant and is widely used in textile industry, paper-making, plastics and synthetic detergents manufacturing etc. There is a mass production and sales of fluorescent brightening agents both in China and abroad. However, due to the difficulties in biodegradation of FBA products and in that of substances such as aniline, DSD acid, melamine, etc, which are produced in the productive processes and contained in the waste water, the survival and development of enterprises which are related to the products, is greatly obstructed.Therefore, based on a thorough study of a pilot scale test of the FBAs waste water treatment, which was carried out by Zhengzhou University in cooperation with an FBA manufacturer, this thesis presents the operational results of each section of the treatment process, which adopts a method of combining physic-chemical treatment with biological treatment, and provides analysis and discussion of related questions found in the process of the test.The pilot scale test adopts the "acidulation precipitation and coagulation method +anaerobic treatment+Fenton oxidation modification treatment+oxygen treatment +ozone advanced treatment" technology, with a treatment capacity of 5 cubic meters of water per day. The COD content of the raw water is less than 7100mg per liter, NH3-N about 40mg per liter, and the concentration of Cl- lower than 13,000mg per liter. The results show that the COD content of the treated water is less than 300mg per liter, NH3-N lower than 30mg per liter. Other indexes also meet the local emission standards.The acidulation precipitation and coagulation section of the test is to add coagulant PAM into raw water in an acidic condition for precipitation reaction. Experiments show that in the condition of pH value for 5 and with the amount of PAM added 20mg per liter, the removal rate of COD can amount to 23 percent or above.The anaerobic processing includes a hydrolysis acidification tank and an internal circulation (IC) anaerobic reactor. In the case of good operation, the removal rate of COD in this section can amount to 50 percent, and the NH3-N content in anaerobic effluent can approximately increase to 200mg per liter.In the third section, Fenton is used for oxidation modification to enhance the biodegradability of waste water. Upon research, this technology of "Fenton oxidation modification+A/O technology" can achieve a 50 percent removal rate of COD and 89.7 percent that of NH3-N.The ozone advanced treatment mainly aims at the advanced oxidation of the A/O effluent. In this test, the amount of ozone used is 170mg per liter, and the reaction time is 10 minutes. The results show that the removal rate of COD amounts to 60 percent, and the COD content in discharged water is stably below 300mg per liter, reaching the anticipated goals of the test.