Biochemical Oxygen Demand On-Line Automatic Monitor Develops And Applied

Biochemical Oxygen Demand is a comprehensive index to reflect water pollution levels by organic matter. Meanwhile it is also a main index to research the sewage degradation by means of bio-chemical.Under the condition of the water monitoring. Biochemical Oxygen Demand is an important reference.Furthermore it is the vital data of the sewage disposal and dynamics research.Recently, the Five Days Biochemistry Training Method has a important position at home and abroad.But this method has lots of disadvantages,such as complexity, time-consuming, high requirements to operators, and it cannot reflects the information and the scientific reference. Even if there have some new methods--- Coulometry, BOD test method and Activated Sludge Process in this field, they also have some weakness and cannot satisfy the admeasurements.With the increasingly serious environmental pollution, the system of rapid determination of bio-chemical aerobic quantity is becoming more and more important. Nowadays Microbial sensor method is one kind of Biochemical Oxygen Demand test method, it has lots of advantage --- simple, quick and easy to grasp, precision and accuracy, easy to master and anti-interference automation and so on. It is the core element to Microbial sensor and achieves the on-line automatic monitoring.This experiment is about starch factory's soil, and we get the aerobic microbial strains through separation, screening, domestication and series of other steps, then it is proved a bacillus. We continue to lots of tests---choice, proportioning and making the advanced microbial membrane by many materials mixed the microorganisms. At ordinary temperatures, this method has many advantages, immobilization, no damage, convenience for loading and unloading, easy to preserve, used repeatedly, good mechanical strength, toughness and permeability. Then we use special type O material making microbial membrane and put it on the miniature oxygen electrode to achieve the assembly work. The test shows --- microbial sensor's linear response range, cycle of measurement and life are 2-60mg/L,3-10min and 6 months.In order to get the precision and accuracy results and the effect by diluted times, the tests need this conditions:test temperature, pH value, and buffer solution of the drum pump. All provide the on-line automatic monitoring with the technical assurance.To find the relevance between this instrument measuring results and the Five Days Biochemistry Training Method, we use the comparative tests on standard samples and actual sewage samples and find they have well relevance; this new instrument can satisfy actual measurement requirements.In order to analysis the new instrument operation, they authorize city urban drainage station and pharmaceutical factory to test the new instrument. Under this condition, we use the on-line automatic monitoring instrument to survey the pharmaceutical wastewater and sewage compare with the two dates. Then the result show the error is around±8.0% according to the standard, and it satisfies the needs of practical application.