INITIAL STUDY FOR STRUVITE FORMING FROM NUTRIENTS IN WASTE WATER WITH PRECIPITATION PROCESS USING AIR CATHODE ELECTROCOAGULATION

• Main Author: Said Baashen, Mellyana
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/71880
• Institution: Institut Teknologi Bandung

Nitrogen and phosphorus are important elements in life, but their continued excessive release to the environment can cause eutrophication in natural water systems. The formation of Magnesium Ammonium Phosphate Hexahydrate (MAP) (MgNH4PO4·6H2O or struvite) can be a solution related to nutrients removal and recovery. Struvite formation can occur in the process of precipitation using an electrocoagulation reactor. Air Cathode Electrocoagulation (ACEC) is one method of electrocoagulation that does not require additional external energy to support the struvite precipitation process. In this study, the nutrients removal and recovery in waste water were carried out by recirculating 1 liter of artificial waste water into the reactor for 24 hours in recirculation discharge variations that is 1, 2, 3, 4, and 5 ml/min. Then the reactor operation is carried out with optimum recirculation discharge and initial pH variations of waste water 4, 7, 8, and 9. Optimum nutrients removal and recovery are obtained at a recirculation discharge of 2 ml/min (with a nitrogen removal rate of 22.95 mg/hr, phosphate removal rate of 18.58 mg/hr, and struvite formation rate of 49.87 mg/hr) and initial pH of waste water 8 (nitrogen removal rate of 24.21 mg/hr, phosphate removal rate of 35.25 mg/hr and struvite formation rate of 89.96 mg/hr). Struvite characteristics were analyzed using SEM-EDS and XRD tests. Based on the SEM-EDS test, the morphology of the sediment analyzed was in the form of irregularly shaped crystals accompanied by a sharp surface, whereas based on the EDS spectrum it was seen that the elements contained in the sediment were C (31.05%), O (46.01% ), Mg (10.16%), and P (12.78%). From the SEM-EDS test results also can be analyzed the ratio of Mg:P is 0.795 which is quite close to the value of Mg:P = 1:1 which is a theoretical mole ratio of struvite-forming elements (Mg:NH4:PO4 = 1:1:1 ). The XRD results also show that there are similarities in the specific peak of the test sample with struvite.