Optimization of an integrated sponge--granular activated carbon fluidized bed bioreactor as pretreatment to microfiltration in wastewater reuse

A specific integrated fluidized bed bioreactor (iFBBR) was optimized in terms of organic loading rate (OLR), hydraulic retention time (HRT) and frequency of new sustainable flocculant (NSBF) addition for primary treated sewage effluent (PTSE) treatment. It was observed that iFBBR achieved the best performance with the operating conditions of 4 times/day NSBF addition, HRT of 90 min and OLR of 8.64 kg COD/day m(3). The removal efficiencies were found to be more than 93% of dissolved organic carbon (DOC), 61% of total nitrogen (T-N) and 60% of total phosphorus (T-P). iFBBR as pretreatment of submerged microfiltration (SMF) is successful in increasing the critical flux and reducing the membrane fouling. NSBF-iFBBR-SMF hybrid system led to very high organic removal efficiency with an average DOC removal of 97% from synthetic PTSE.

Evaluation of an integrated sponge--granular activated carbon fluidized bed bioreactor for treating primary treated sewage effluent

An integrated fluidized bed bioreactor (iFBBR) was designed to incorporate an aerobic sponge FBBR (ASB-FBBR) into an anoxic granular activated carbon FBBR (GAC-FBBR). This iFBBR was operated with and without adding a new starch based flocculant (NSBF) to treat synthetic primary treated sewage effluent (PTSE). The NSBF contains starch based cationic flocculants and trace nutrients. The results indicate that the iFBBR with NSBF addition could remove more than 93% dissolved organic carbon (DOC), 61% total nitrogen (T-N) and 60% total phosphorus (T-P) at just a very short hydraulic retention time of 50 min. The optimum frequency of adding NSBF to the iFFBR is four times per day. As a pretreatment to microfiltration, the iFFBR could increase 5L/m(2)h of critical flux thus reducing the membrane fouling. In addition, better microbial activity was also observed with high DO consumption (>66%) and specific oxygen uptake rate (>35 mg O(2)/g VSS h).

Intra-aortic balloon assistance in cardiogenic shock after myocardial infarction or cardiac surgery

Sixty-eight patients were referred for consideration of intra-aortic balloon assistance, 55 of whom were accepted. Thirty-one patients were in cardiogenic shock after myocardial infarction and the remaining 24 were cardiac surgical patients. Twenty-three of the myocardial infarct group were established on IABA and all 24 of the cardiac surgical patients. Of the 23 patients with cardiogenic shock after myocardial infarction, 19 showed initial haemodynamic improvement on intra-aortic balloon assistance and 5 (22%) survived to leave hospital. Of the 24 cardiac surgical patients, 15 could not be withdrawn from total cardiopulmonary bypass. With intra-aortic balloon assistance, 11 (73%) could be withdrawn from cardiopulmonary bypass and 5 (33%) were hospital and long-term survivors. The remaining 9 surgical patients were in cardiogenic shock in the early postoperative phase, though 5 showed initial haemodynamic improvement there was only one hospital survivor in this group. Intra-aortic balloon assistance was, therefore, of most value in patients dependent on cardiopulmonary bypass. The survival in patients with cardiogenic shock after myocardial infarction was marginally improved.