Tarımsal, endüstriyel kaynaklı kirletilmiş bir atıksuyun mor fototrafik bakteriler ile arıtılması

The aim of this thesis is to apply an alternative treatment method to conventional nutrient removal with Rhodobacter sphaeroides (RS) or with a co culture of activated sludge (AS) and R. sphaeroides (RS) to an agricultural and industrial polluted wastewater in excessive conditions. In the first experiment environmental conditions were tested to optimize the nutrient removal capacity of RS. Aerobic dark conditions were favored for COD removal. COD removal efficiency of RS with low and high COD/TN ratios with high COD concentrations were tested and the nitrogen fixing capacity of the culture gave COD removal efficiencies over 93% with low COD/TN ratios. In high COD/TN ratios the highest COD removal efficiency was obtained with a COD/TN ratio of 100/23 as 42%. A synthetic wastewater modeled from Porsuk River containing 1000 mg/L COD was used in evaluation of COD/TN (100/5 100/25) and COD/TP (100/0.5 100/2) ratio experiments. RS removed all the COD in a COD/TN ratio of 100/23 and the total phosphorus removal efficiency was around 54±3%. All the COD was removed in COD/TP ratio experiments. The TN removal efficiencies decreased with increasing COD/TP ratios and were over 82%. TP removal was low and it is understood that RS could not remove phosphate from the wastewater sufficiently. A co culture consisted of AS and RS with a high C/N/P ratio was used for nutrient removal. The co culture (AS/RS) ratio of 1/5 was able to convert all the COD concentrations (100%) and TP and TN removal efficiencies were 72% and 89.5%, respectively. The effects of hydraulic retention times (6 15.9 h) on a continuous activated sludge system with the co culture consisted of AS and RS with a ratio of 1/5 was used for nutrient removal. COD, TN, NO3, NH4, PO4 removal efficiencies were highest at 10.1 h with 80, 76, 86, 67 and 79%, respectively. It has to be considered that the simulated surface water characteristic is very close to domestic wastewater which can be classified as open sewage. Besides, Porsuk River has much lower nutrient concentrations than the chosen sampling point of wastewater which can be treated well to meet the receiving water discharge standards. It can be concluded that using a co--culture (AS/RS) may be used as a natural treatment method.