The aim of this study was to investigate the biological treatment of synthetic oilfield-produced water in activated sludge in an attempt to remove the organic compounds using endogenous bacteria; we also hope to determine the biokinetic coefficients. The activated sludge was operated with various hydraulic retention times (HRT=20 hours, 12 hours, 8 hours), solid retention times (SRT=25 days, 20 days, 15 days, 10 days), and substrate concentrations (500 mg L -1 to 1,100 mg L -1 ). The endogenous bacterial strains, which were isolated from existing wastewater treatment facilities, were identified as Pseudomonas sp., Enterobacter sp., Bacillus sp1., and Bacillus sp2. It was observed that the highest COD removals were obtained in reactors A (80.7%) and B (82.4%), which had high SRTs (25 days and 20 days) and HRT (20 hours). At shorter SRTs (15 days and 20 days), the concentration of the COD effluent did not comply with the Indonesian regulations for oilfield-produced water quality standards, which means that these SRTs were not recommended as appropriate operational conditions. Furthermore, the results showed that the yield (Y), decay coefficient (kd), maximum specific growth rate (k), and saturation constant (K s ) were 0.533 mg MLVSS mg -1 COD, 0.167 day -1 , 0.985 day -1 , and 255.46 mg COD L -1 , respectively. These biokinetic coefficients (obtained from the Y and K s values) indicated that although the strains of bacteria can grow well in the reactor, they had low affinities to the substrate, which caused the concentration of the COD effluent to be relatively high.

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The purpose of this research is to investigate wastewater treatment with ozone pretreatment and post-treatment integrated with Moving Bed Biofilm Reactor (MBBR). Ozonation as a pre-treatment served to increase the Biochemical Oxygen Demand (BOD)/Chemical Oxygen Demand (COD) ratio while as a post-treatment to remove the remaining organic residues. Ozone doses were 1 mg/min, 4 mg/min, 20 mg/min, and 40 mg/min. In the pre-treatment, ozone produced a BOD/COD value of 0.68. The MBBR process had a COD and color removal efficiency of 68.89% and 67%, respectively. In the MBBR process without ozone pre-treatment, the efficiency of COD and color removal were 79.31% and 64.7%, respectively. The effluent treatment results from MBBR were then processed with ozone and showed the highest COD and color removal results of 76.8% and 99%, respectively. In this study, the processing with ozone as post-treatment was better than the pre-treatment.

Due to their non-toxicity and biodegradability, natural polymeric flocculants have gained popularity in water and wastewater treatment in recent years. Because of its broad availability, renewability, sustainability, and surface modification potential, cellulose, the most common polymer on the planet, is regarded as one of the foundation polymers for flocculant production and modification. The following article consists of a review of the latest developments regarding biopolymers, in particular, cellulose as a natural flocculant. One of the plants that can be developed in Indonesia is Boehmeria nivea, or what is known as Ramie, which contains cellulose that is still not utilized optimally. There is a method of isolation of alpha-cellulose derived from Boehmeria nivea and its application as a flocculant in synthetic wastewater presented in this paper. The alpha-cellulose of Boehmeria nivea was used as a flocculant in jar testing using kaolin suspension (5 g/L). The study shows that adding alpha-cellulose as an aid to PAC slightly increased the turbidity removal efficiency, and further modification of alpha-cellulose by cationic grafts into cationic cellulose is needed.

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Biosurfactants, also known as biological surface-active agents, are a group of surface-active agents, which are produced by a variety of microorganisms. Biosurfactants possess the characteristic property of lowering surface tension, increase the solubility of poorly soluble compound, low toxicity, non-allergenic, and biodegradable. Growing public awareness about the environmentally friendly health care and associated product has stimulated the search for eco-friendly compounds in laundry detergents. In this research, the application of biosurfactants in the formulation of a washing detergent was investigated. Variation of biosurfactants and its mixture with sodium tripolyphosphate as a builder and sodium sulfate as filler was applied to wash cotton fabric which was contaminated with known amounts of stain (chocolate milk). The effects of various bio-detergent formulations, including the ratio of biosurfactants and builder, was examined. The formulation presented in this study was also compared with some standard detergent for the stains removal efficiency. The results showed that the rhamnolipid biosurfactants have a promising as a substitute for its synthetic counterpart. Based on the colorfastness to wash, color strength (K/S), and color difference (∆E) value, rhamnolipid based bio-detergent have similar washing effectiveness compared to the synthetic detergent. Research result also found that Na-bicarbonate and Na-citrate have the potential as a substitute for phosphate-based detergent builder.