Use of Lightweight Aggregate in Plate Immobilized Biological Process for Removing Carbon and Nitrogen from Wastewater

Immobilization of microbial cells technology combined traditional nitrification and denitrification in one single cell process which had many advantages are high organic carbon and nitrogen removal efficiency, small space occupation and less sludge produced. It also can be improved organic and nitrogen removal efficiency simultaneously from an aerobic activated sludge process. Nowadays, the matrix of immobilized microbial cell can be categorized into two groups: natural and synthetic. The most material for immobilized microbial cell are divides into two categories: Natural and Synthetic. The defect of natural material is easily decomposed by microorganism. Synthetic materials in the process of production applied complex chemicals are adverse impact on the environment. For environment sustainable development, in this study used environmental friendly and lightweight aggregates for the production of microbial cell, and the lightweight aggregates are added to hydraulic conductivity. This research is consisted of two parts: analysis of the material characteristics and operation parameters test with a microbial cell plate. Production conditions test of prepared into flat sheet of plates and dissolution test for the purpose to realize the stability of the material. The operational aspect will focus on investigating nitrification, denitrification and total nitrogen removal efficiency under different operating conditions such as carbon vs nitrogen ratio (SCOD/N) and hydraulic retention time (HRT). The microbial cell plate is formed in pressure 3000 kg/cm² and holding over 30 seconds. The dissolution test shown that the microbial cell plate elute COD over 250 mg/L, conductivity over 8.5 mS/cm and pH over 12.61 after the first day. However, the elute concentration of COD, conductivity and turbidity are found to be stable after five days of test, pH remained over 12 after 20 days of elution. The SCOD/N mode shown that is an impact of the total nitrogen removal efficiency. Nitrification removal efficiency was increased from 58% to 63% and TN removal efficiency increased from 41% to 53% when SCOD/N was adjusted from 4 to 12. In conclusion, the optimum operating conditions is SCOD/N of 12, HRT of 12 hr., which resulted in 94% SCOD removal efficiency, 65% nitrification, and 60% TN removal efficiency.