Hibiscus rosa-sinensis is a biodegradable material that has remained untested for flocculating properties. The objective of this study is to examine the efficiency of coagulation-flocculation processes for the removal of color, iron (Fe 3?), suspended solids, turbidity and ammonia nitrogen(NH 3-N), from landfill leachate using 4,000 mg/L alum in conjunction with H. rosa-sinensis leaf extract (HBaqs). Hydroxyl (O-H) and (carboxyl) C=O functional groups along the HBaqs chain help to indulge flocculating efficiency of HBaqs via bridging. The experiments confirm the positive coagulation properties of HBaqs. The Fe 3? removal rate using 4,000 mg/L alum as sole coagulant was approximately 60 %, and increased to 100 % when 4,000 mg/L alum was mixed with 500 mg/L HBaqs. By mixing, 4,000 mg/L alum with 100-500 mg/L HBaqs, 72 % of SS was removed as compared with only 45 % reduction using 4,000 mg/L alum as sole coagulant.

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Until now, the development of aerobic granules sludge (AGS) has been extensively reported using sequencing batch reactor (SBR) with reactor height/diameter (H/D) ratio of over 10. This is because the formation process of aerobic granules itself is depending upon the flowing trajectory inside reactor indulge by reactor height and superficial air velocity (SUAV). Thus, this study aims to determine effect of reactor H/D ratio on performance of AGS develop in two SBRS with equal working volume and organic loading rate (OLR). The two SBRs namely as SBR1 and SBR2 had a difference in reactor H/D ratio of 11.3 and 4.4, respectively. At an aeration rate of 4 L/min,  SUAV for SBR1 was two time higher than in SBR2, which were 1.33 cm/s and 0.7 cm/s, respectively. Thus, the SBR2 configuration condition seems unfavorable for development of compact aerobic granules. However, it was found that aerobic granules can be developed in both SBRs at an OLR as low as 0.12 kg CODs/m3 d and up to 0.49 kg CODs/m3 d. Mature aerobic granules were successfully developed after 49 and 89 days of formation, for Batch1 AGS and Batch2 AGS, respectively. At stable conditions, the highest CODs removal and SS effluent for Batch1 AGS and Batch2 AGS were more than 80% and below 26 mg/L, respectively. While effluent performance in both reactors was high, analysis on SVI30 indicated that SBR1 produced more sludge than SBR2. Compare to SBR1, at similar settling time of 15 min, SBR2 provide a short settling distance for biomass which was preferable in case of system breakdown due to shock OLR.

Biokinetic parameters help to describe the rate of substrate utilization and biomass production or growth by microbial action, which is important to the design process and performance optimization of wastewater treatment. Although studies of the biokinetic parameters of aerobic granular sludge (AGS) systems have been increasing lately, the significance for each value in terms of maximum specific growth rate (μmax), substrate concentration at one-half of the maximum specific growth rate (KS), and cell yield (Y) in relation to the applied operating conditions are rarely discussed. Therefore, this study investigates the relationship and significance between the above-stated biokinetic parameters with organic loading rate (OLR) and reactor height/diameter (H/D) ratio from five different batches of AGS treated sewage, using the independent t-test. The biokinetic parameters are summarized as biomass production (Y and μmax ) and relied upon the relative increase in the OLR and reactor H/D ratios. Additionally, aerobic granules developed in reactors with a high H/D ratio have a shorter setup time and are more active in contrast with low H/D ratio reactors.