Enhanced membrane fouling control through self-forming dynamic membrane and sponge-wrapped membrane: A novel membrane bioreactor.

Membrane technology offers a wide variety of advantages in wastewater treatment, but fouling impedes its widespread applications. Hence, in this study, a novel method was tried to control membrane fouling by combining the self-forming dynamic membrane (SFDM) with a sponge-wrapped membrane bioreactor. The configuration is termed a "Novel-membrane bioreactor" (Novel-MBR). To compare the performance of Novel-MBR, a conventional membrane bioreactor (CMBR) was operated under similar operating conditions. CMBR and Novel-MBR were run consequently for 60 and 150 days, respectively. The Novel-MBR was composed of SFDMs in two compartments before a sponge-wrapped membrane in the membrane compartment. In Novel-MBR, the formation times for SFDMs on coarse (125 µm) and fine (37 µm) pore cloth filers were 43 and 13 min, respectively. The CMBR experienced more frequent fouling; the maximum fouling rate was 5.83 kPa/day. In CMBR, the membrane fouling due to cake layer resistance (6.92 × 1012 m-1 ) was high, and that alone contributed to 84% of fouling. In Novel-MBR, the fouling rate was 0.0266 kPa/day, and the cake layer resistance was 0.329 × 1012 m-1 . Also, the Novel-MBR experienced 21 times less reversible fouling and 36 times less irreversible fouling resistance than the CMBR. In Novel-MBR, the formed SFDM and the sponge wrapped on the membrane helped to reduce both reversible and irreversible fouling. With the modification tried in the present study, the Novel-MBR experienced less fouling, and the maximum transmembrane pressure at the end of 150 days of operation was 4 kPa. PRACTITIONER POINTS: CMBR experienced frequent fouling, and the maximum fouling rate was 5.83 kPa/day. Cake layer resistance was dominant in CMBR and contributed to 84% of fouling. The fouling rate of Novel-MBR at the end of the operation was 0.0266 kPa/day. Novel-MBR is expected to perform for ≈3380 days to reach the maximum TMP of 35 kPa.

Performance evaluation of membrane bioreactor coupled with self-forming dynamic membrane.

In the present study, Conventional Membrane Bioreactor (C-MBR) and Modified Membrane Bioreactor (M-MBR) were run consequently to compare the fouling reduction through incorporated modification. M-MBR was developed by introducing a Self-forming dynamic membrane (SFDM) formed on a nylon cloth filter ahead of a flat sheet membrane. The coarse cloth filter and fine cloth filter had a pore size of 125 µm and 37 µm, respectively and it took 45 min and 12 min to form a dynamic membrane on them. The C-MBR experienced frequent fouling with cake layer resistance (RC) as the dominant one which contributed to 83.98% of total resistance (RT). Whereas in M-MBR the cake layer resistance (67.86% of RT) and pore blocking resistance (RP) (1.31% of RT) was less compared to C-MBR. The formed SFDM on nylon cloth filters led to the reduced RC and RP in M-MBR. Therefore, the operation of M-MBR was prolonged, which took 150 days to reach 8.6 KPa (0.057 KPa/day). Eventually, it was concluded that the modification made in this study significantly reduced the fouling.

Use of naturalized coagulants in removing laundry waste surfactant using various unit processes in lab-scale.

This lab-scale experiment is aimed at demonstrating a treatment system for purification and reuse of laundry rinsing water generated from households. The main objective of the study is to compare the efficiencies of various natural coagulants in removing laundry waste surfactants and other major pollutants from the laundry rinsing water. The treatment system consists of Coagulation-Flocculation, Sand filtration and Granular Activated Carbon (GAC) adsorption. Four experiments were conducted in batch process by varying the coagulants (Nirmali seed and Pectin extracted from pith of Orange peel). Coagulants have been selected due to their local availability at affordable cost and technical feasibility. From the study it is concluded that laundry rinsing water polluted with high turbidity and anionic surfactant treated with Nirmali seeds as coagulant at a retention time of 24 h gives the best results. The treatment system where Orange peel pectin is used as coagulant at a retention time of 24 h is found to be the most efficient one based on the weighted factor. Hence the treatment of laundry rinsing water by aforesaid combination results in better water quality.