the landfill leachate treatment by aerobic granules made from synthetic wastewater

Leachate generated in the landfill due to the complex structure and high pollution requires developed physical and chemical and biological treatment methods. Aerobic granular sludge is one of the newest technology of immobilized microbes that has the potential to improve the biological wastewater treatment technology. One of the leachate treatment method which have been highly regarded recently is the leachate treatment by aerobic granules in the SBAR reactor. This study has been done for the purpose of treatment of leachate with aerobic granular. In order to optimize the formation of the granules and use it in the leachate treatment of this experiment, the construction of granules and leachate treatment has been done in two distinct phases: granules production has been done in the SBAR reactor for 28 days with increase loading to 6000 mg per liter and leachate treatment has been done in the same reactor in 24 days to loading 6000 mg per liter. The reactor used in this test is made of Plexiglas and has the dimensions 75 *20*20 cm3 and the volume of 28 liter. To link the upper and lower part of the reactor as well as effective mixing in the reactor an airlift PVC pipe has been used with the height of 50 and diameter of 20 cm. Some holes with the diameter of 2 cm has been created at the bottom of the airlift pipe and aeration is in the middle of airlift pipe and the bottom of reactor to led to rotation confusion and the oxygen transfer well done. For granules cultivation the synthetic wastewater containing glucose has been used as the carbon source, the ammonium chloride as the nitrogen source, the potassium dihydrogen phosphate as the phosphorus source as well as the micronutrients such as magnesium sulfate, ferrous sulfate, calcium chloride, potassium dihydrogen phosphate. At first the granules are made with synthetic wastewater in 6-hour cycles containing 30 minutes feeding, 270 minutes’ aeration, 30 minutes settling, 30 minutes’ wastewater discharge. In this experiment, the temperature has been controlled in the range of 20-23 C and DO in the range of 6-8 ppm and PH in the range of 7.5-8.3. In the next stage, the feasibility of using these granules in the leachate treatment has been tested. The results of the MLSS, SVI, VELOCITY, DIAMETER, COD REMOVAL tests show that the granules produced from synthetic glucose wastewater will be able to purify leachate. Synthetic sewages loading in the 6-hour cycles and the organic loading increases have been done till the formation of granules in 28 days. After each cycle, the parameters mentioned above were examined and the sludge morphology. With the entering of synthetic sewage to the reactor, at first the suspended solids increased and the granules' seeds production reduced. With the consolidation of granules and its sustainability, the leachate is injected to the reactor and is replaced by the artificial sewage. With the arrival of leachate to the reactor, the granules start to disintegrate and thus lead to an increase in the suspended solids of the system. Due to the change of the raw sewage and replacement of leachate instead of synthetic sewage, in some granules collapse happened. The results show that when granules are accustomed to the leachate entering the reactor, increase of bacterial activity lead to the improvement of efficiency of leachate treatment in the system and the efficiency of COD removal reached 90%.