. 2007, 25(0708): 34-39.
A two-stage coagulation and adsorption process with charcoal absorbent was used to process laboratory wastewater, where heavy metal, sulfide, volatile phenols, aniline and degree of turbidity were analyzed. The results show that the two-stage coagulation by using copperas and PAC as flocculants to treat the wastewater can effectively reduce the content of heavy metal and sulfide. When PAC was used as the flocculant at the second stage of coagulation, the clearance of Cr6+ was better than that at the first stage of coagulation, reaching up to 90%. Moreover, the charcoal absorbent wiped off the volatile pHenols, sulfide and silver best, with clearance being 98%, 70% and 95.4%, respectively. All of the pollutants' concentrations can meet the national standard, and the turbidity of the sewage and the chroma are improved effectively. With the temperature, stir, aeration and pH in an adjusted range, the clearance of all contaminations can reach a value above 90%. Therefore the method of two-stage coagulation and adsorption of activated carbon is effective in processing laboratory wastewater, removing poisonous and deleterious matter from wastewater, and reducing the harm of the laboratory wastewater to the environment, with rapidity, low-cost and easiness.
