In this study, the performances of GAC adsorption and GAC bioadsorption in terms of dissolved organic carbon (DOC) removal were investigated with synthetic biologically treated sewage effluent (BTSE), synthetic primary treated sewage effluent (PTSE), real BTSE and real PTSE. The main aims of this study are to verify and compare the efficiency of DOC removal by GAC (adsorption) and acclimatized GAC (bioadsorption). The results indicated that the performance of bioadsorption was significantly better than that of adsorption in all cases, showing the practical use of biological granular activated carbon (BGAC) in filtration process. The most significance was observed at a real PTSE with a GAC dose of 5g/L, having 54% and 96% of DOC removal by adsorption and bioadsorption, respectively. In addition, it was found that GAC adsorption equilibrium was successfully predicted by a hybrid Langmuir-Freundlich model whilst integrated linear driving force approximation (LDFA)+hybrid isotherm model could describe well the adsorption kinetics. Both adsorption isotherm and kinetic coefficients determined by these models will be useful to model the adsorption/bioadsorption process in DOC removal of BGAC filtration system.

A novel sponge-submerged membrane bioreactor (SSMBR) to treat a high strength wastewater for water reclamation was developed in this study. The performance of this system was evaluated using two kinds of polyester-urethane sponges (coarse sponge with higher density S28-30/45R and fine sponge with lower density S16-18/80R) with sponge volume fraction of 10% and bioreactor MLSS of 10 g/L. The results indicated the addition of sponge in SMBR could increase sustainable flux (2 times for S28-30/45R and 1.4 times for S16-18/80R) and lower TMP development, thus significantly reduce membrane fouling. S28-30/45R gave rise in attached growth biomass and the removal efficiencies of DOC, COD and PO4-P whilst S16-18/80R had better performance in removing NH4-N. Although the SSMBR performed well for most of the trials, the superior recycled water quality was achieved when adding S28-30/45R and S16-18/80R together in SMBR with the ratio of 2:1 and without any pH adjustment during the operation.

This study focuses on comparing the performance of submerged membrane bioreactor (SMBR) and submerged membrane adsorption bioreactor (SMABR) over a period of 20 days at a hydraulic retention time (HRT) of 3.1h. The effects of PAC on critical flux and membrane fouling were also investigated. The SMABR exhibited better results in terms of mixed liquor suspended solids (MLSS) growth, DOC removal (over 96%), COD removal (over 95%), transmembrane pressure (TMP) and oxygen uptake rate. Nearly 100% of bacteria and 100% of total coliforms were removed in both systems. The addition of PAC could maintain the critical flux at a lower TMP value (7.5 kPa), while irreversible fouling caused by PAC occurred when the filtration flux exceeded critical flux.

Sponges not only can reduce membrane fouling by means of mechanical cleaning and maintain a balance of suspended-attached microorganisms in submerged membrane bioreactor (SMBR), but also can enhance dissolved organic matter and nutrient removal. This study investigated the performance of three different sizes of sponge (S 28-30 /45R, S 28-30 /60R and S 28-30 /90R) associated with continuous aerated SMBR. A laboratory-scale single stage sponge-SMBR showed high performance for removing dissolved organic matter (>96%) and PO 4 -P (>98.8), while coarse sponges such as S 28-30 /45R, S 28-30 /60R could achieve more than 99% removal of NH 4 -N. When three-size sponges (S 28-30 /45R, S 28-30 /60R and S 28-30 /90R) were mixed at a ratio of 1:1:1 and in conjunction with two kinds of membranes (0.1 µm hollow fiber and 2 µm nonwoven), the sponge SMBR system has proved its generic merits of superior treated effluent quality and less membrane fouling. The NH 4 -N and PO 4 -P removal were found excellent, which were more than 99.8% and over 99% respectively. Molecular weight distribution also indicated that major fractions of organic matter could be successfully removed by sponge SMBR.

Membrane fouling has been regarded as one of the biggest challenges to widespread application of membrane bioreactor (MBR). This study focuses on minimizing the membrane fouling and improving the performance of submerged membrane bioreactor (SMBR) by porous sponge addition. The effects of sponge addition on sustainable flux and membrane fouling were investigated. Acclimatized sponge could significantly increase the suspended growth in SMBR with biomass of 16.7 g/L(sponge). With sponge volume fraction of 10%, SSMBR could enhance sustainable flux up to 50 L/m 2 .h compared with sustainable flux of SMBR (only 25 L/m 2 .h). SSMBR also exhibited excellent results in terms of DOC removal (over 95%), COD removal (over 97%), lower transmembrane pressure development and oxygen uptake rate. Over 89% of NH 4-N and 98% of PO 4-P were removed when SSMBR was operated with a MLSS concentration of 15 g/L.