Research On The Integrated Process Of Pure Oxygen–Ceramic Membrane/Active Bio-filtration Treating Micro-polluted Water

This thesis aims todeal with the seasonally micro-polluted raw water from the lower reaches of the Xijiang River. A pilot-scale test of 36m³ dwas developed to study on improving the effect of active bio-filtration process and ceramic ultrafiltrationprocess with pure oxygen aeration, focusing on the removal efficiencies of NH₃-N, organic matter, iron and manganese ions; ceramic ultrafiltration membrane was also used for treating seriously polluted sludge water; the operational cost of these processes was evaluated.Pure oxygen aeration is able to enhance the efficiencies of active bio-filtrationfor pollutants removal. The results showed that turbidity in effluent was about 0.1 NTU, Fe<0.03 mg L, Mn <0.1mg L; When the concentration of CODMnand NH3-N were respectively 4mg L and 3mg L in raw water, the treated effluent can reach to 1mg Land 0.1mg L with no accumulation of NO₂^--N; the concentration of taste and odor compounds were very low, and there was no peculiar smell in effluent.The ceramic ultrafiltration membrane integrated processescan be significantly enhanced by pure oxygen aeration. With membrane flux of 100 L m²?h and pure oxygen aeration rate of 0.6L min, the trans-membrane pressure was increased by 1.22 k Pa after running 5 days. The particle pollutants can be removed effectively, turbidity in effluent <0.1 NTU, particles number larger than 2 μm<50CNT ml, and the mean concentration of Fe and Mn were 0.019 mg L and 0.035 mg L, respectively. Nevertheless, ceramic membrane had low efficiencies of dissolved pollutants, including NH3-N and DOC. Thus, the combination on ceramic membrane and active bio-filtration can be relatively complemented.The results showed that the pollutants exited in sludge water can be removed by ceramic ultrafiltration membrane. With turbidity of 1530¹7360 NTU, CODMnof 149⁵11mg L, Fe and Mn ions >10mg L in sludge water, the ceramic membrane can make the turbidity in effluent <0.4 NTU, CODMn removal of 99%, 99.11% of Fe and 84.74% of Mn. It was found that 42.97⁶2.79% of NH3-N, 20.90²5.08% of DOC and part of taste and odor compounds were removed in membrane tank, due to its function like a membrane bioreactor.The processes of pure oxygen aeration- active bio-filtration, pure oxygen aeration/ceramic ultrafiltration membrane- active bio-filtration and sludge water treatmentwith ceramic ultrafiltration membrane could increase the operational cost by 0.076, 0.173 and 0.047 RMB/m³. It is suitable for water plants’ upgrading and reconstruction.