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1 Attachment 1 To Amendment 1 To Work Order Number 6 Proposed Bioassay Protocol for Indian River County Utilities South RO Plant Byproduct Treatment Evaluation Project Description and Understanding The following provides a narrative description of a testing protocol proposed to be conducted on the water treatment byproduct produced at the Indian River County Utilities South Reverse Osmosis Water Treatment Plant. The intent of this testing protocol is to determine if it can be demonstrated that the current treatment process applied to this byproduct is the cause of a random but repeated failures in bioassay testing . The current treatment process injects sodium hypochlorite into the concentrate stream to reduce hydrogen sulfide and following that injects diffused air under pressure to elevate dissolved oxygen in the byproduct stream. There is a possibility that random but repeated bioassay test failures have been caused by any of the following. • Inadequate reduction of hydrogen sulfide . • Excess chlorine remaining after reduction of hydrogen sulfide . • Contaminant introduced into the byproduct stream contained in commercially available sodium hypochlorite . • Contaminant introduced into the byproduct stream through the compressed air system. Should it be demonstrated that the current byproduct treatment process is contributing to previous bioassay test failures , a new treatment system is proposed which involves only aeration of the byproduct stream using a counter current packed tower degasifier. A treatment system of this configuration will remove hydrogen sulfide and elevate dissolved oxygen concentration in the byproduct stream without adding chemicals to the stream which may introduce contaminants to the byproduct . SCOPE OF SERVICES The basis of this proposed testing protocol is to conduct simultaneous bioassay tests on samples of byproduct, one taken prior to application of the current treatment process and the second taken after application of the current treatment process . The samples will be taken such that they represent the same byproduct produced by the reverse osmosis plant through the use of sample points which are approximately 500 feet apart in a pipeline having a velocity of 5 fps . The sample taken after application of the current byproduct treatment process would be subjected to bioassay testing without further treatment . The sample taken prior to application of current byproduct treatment will be stripped of hydrogen sulfide and have dissolved oxygen levels increased by aeration , simulating the proposed byproduct treatment process . This simulated treatment process will consist of a vigorous aeration using an air stone and aquarium grade air pump until all hydrogen sulfide is removed from the byproduct sample . H :\044572009\Scope\Bioassay testing - Amendment Ldoc