An investigation for a method for measuring microbial degradation for oxochlorates in waste water sludge

Abstract: The oxochlorates, such as ClO4-, ClO3- and ClO2- are toxic compounds and therefore they must be removed from effluents. In general they are synthetic compounds from industries and naturally also presents in Chilean caliche. Salts of these compounds are used in many purposes for examples, NH4 ClO4 uses as a solid propellant in rocket, explosive and fireworks. It is difficult to removing this salt from environmental pollutions because it is soluble in water. Today, bioremediation process which is most used method to removing these toxic compounds in wastewater treatment from industries. There are many species which have capability to using perchlorate and/or chlorate as a sole electron acceptor in respiration pathway under anaerobic conditions, for examples, Ideonella dechloratans, strain GR-1, CKB and perc1ace. However, besides a perchlorate and chlorate, nitrate can also be used as an electron acceptor by PRB. The using of nitrate instead ammonia is saving both cost and energy, but nitrate may be interfere with the chlorate reduction. The reduction of (per) chlorate is catalyzed by two enzymes, (per)chlorate reductase and chlorite dismutase(Cld). Chlorite dismutase (Cld) is a heme based enzyme and has an important function in the pathway of reduction of (per)chlorate, which converted chlorite into oxygen and chloride (ClO2 -            Cl-+O2).   The main object of this work was to investigate and develop a method to measuring the potential effect of nitrate on chlorate reduction in activated sludge from the paper and mill industry. The result of this work is that no effect of nitrate concentration on chlorate reduction from the sludge was found.