The Relationship Between The Food Chain Of Micro-organisms And The Sludge Reduction In The GCOR System

The management of the organic, inorganic and the microbial population in sludge and biofilm is very important for the proper food chain maintenance and efficiency of a treatment plant. The recent invention of a gravel contact oxidation reactor (GCOR) system in Changchun city in China showed that microbes could be very reliable in activated sludge disposal. The reactor filled with crushed stone globular aggregates as carriers, has been demonstrated capable of reducing the excess sludge effectively in some pilot and small-scale engineering studies. However, the relationship between microbial food chain and the sludge reduction in the GCOR system has not been investigated. This project was instituted to investigate this relationship especially SS, TP, TN, Chemical oxygen demand (COD) and mixed liquor suspended solid (MLSS), and After purification and extraction of DNA, we determine absolute concentrations of these DNA samples by steps of Real-time qPCR. This was to determine whether the control and regulation of the amount of waste sludge, type of microbe, type of sludge and the metabolic products are important in maintaining the efficiency of the GCOR plant especially after its successful launching. The results indicated that the SS in GCOR was only 24.19 mg/L, 31.23 mg/L for the COD, 0.706 mg/L for TN, 4.02 mg/L for TP, and 120 mg/L for MLSS, the number of protozoa was 314 per 100 l, 148 for metazoan, and 295 per 100 l for algae. COD is reduced with a high removal rate of over 87%. The microbial diversity and population difference both in the GCOR carriers indicated that the diverse microbes, a large amount of biomass presenting longer microbial food chains attached on the stone globular aggregates carriers may be the main functions for the excess sludge reduction in GCOR.We found out that there is interplay between the amounts of substrate, the COD and the amount and type of microbes, hence disposers should consider the type of SS and MLSS released to the GCOR and its effect on microbes. This can be helpful in having a sustainable and efficient GCOR system.