Biosorption-membrane reactor with flat filtering elements: the calculation method

Summary

The results of studying the Don River water purification with the use of biosorption-membrane method in a biosorption-membrane reactor with flat-frame filtering elements are presented. An experimental plant with a capacity of less than 2.7 m³/day with addition of powdered activated carbon was constructed at the Novocherkassk water treatment facilities. The specific flow through the membrane was less than 17.6 l/(m²·h). The experimental results showed the high efficiency of natural water purification in a biosorption-membrane reactor that provided for meeting the requirements of Sanitary Rules and Regulations (SanPiN). The efficiency of COD reduction averaged to 41.2%, color – 57.3%, permanganate value – 33.3%. During the entire experiment no suspended solids were found in permeate. The obtained data were used as a basis for calculating the specific rate of organics oxidation estimated by COD and permanganate value. The maximum values of V_max oxidation rate and K_m Michaelis constant were determined by graphical method of double reciprocal. The permanganate value dependence of the specific organics oxidation rate and COD from temperature was obtained. Temperature constant of Van Hoff’s equation was determined by COD and permanganate value to calculate the specific rate of organic pollutants oxidation during winter (10–11 °С) and summer seasons (20–22 °С). The method of calculating a biosorption-membrane reactor is presented.

Key words

powdery activated carbon , natural water treatment , biosorption membrane reactor , specific oxidation rate , biosorption , membrane filtration

Chlororganic and bromorganic compounds in drinking water:
methods of their removal

Summary

Pilot tests of biosorption membrane technology that allows reducing trihalomethanes concentration in drinking water by both preventing from their formation and by removing them from treated water were carried out. Biosorption membrane pretreatment of the Don River water provides for 1.4–1.5 reduction of toxic chlororganic and bromorganic compounds formation during post chlorination of water. Advanced water treatment in a biosorption membrane reactor ensures reducing the concentration of chlororganic compounds formed during primary chlorination. The average efficiency of reducing chloroform concentration in the biosorption membrane reactor was 45%, that of dichlorobromomethane – 82%, and of chlorodibromomethane – 89%, whereas filters provided for 23% chloroform reduction efficiency and 33% of dichlorobromomethane and chlorodibromomethane reduction efficiency, respectively. Additional treatment of the Don water in the biosorption membrane reactor after physical and chemical pretreatment provided for the post treatment efficiency (organics removal) of 33% for COD, 35% for permanganate value, and 34.3% for color. At the same time the efficiency of organics removal in filters was 19% for COD, 9% for permanganate value, and 10% for color. The highest post treatment efficiency in both cases was reached for turbidity removal. The efficiency of turbidity reduction in the biosorption membrane reactor was 91%, in filters – 58%. The results of long-term studies carried out for two years in the pilot plant with the Don River water showed that the development of biosorption membrane technologies was a promising direction of improving natural water treatment processes, in particular, for preventing from formation of chlororganic and bromorganic compounds during chlorination.

Key words

powdery activated carbon , natural water treatment , trihalomethanes , biosorption membrane technology , chlororganic and bromorganic compounds