This research was conducted essentially to treat fresh peat water using a series of adsorbents. Initially, the characterization of peat water was determined and five parameters, including pH, colour, COD, turbidity, and iron ion exhibited values that exceeded the water standard limit. There were two factors influencing the adsorption capacity such as pH, and adsorbent dosages that were observed in the batch study. The results obtained indicated that the majority of the adsorbents were very efficient in removing colour, COD, turbidity at pH range 2-4 and Fe at pH range 6-8. The optimum dosage of cationic surfactant modified zeolite (CSMZ) was found around 2 g while granular activated carbon (GAC) was exhibited at 2.5 g. In column study, serial sequence of CSMZ, GAC, and limestone showed that the optimal reduction on the 48 hours treatment were found pH = 7.78, colour = 12 TCU, turbidity = 0.23 NTU, COD = 0 mg/L, and Fe= 0.11 mg/L. Freundlich isotherm model was obtained for the best description on the adsorption mechanisms of all adsorbents.

The effectiveness of bentonite using chitosan as a coagulant for raw water treatment was assessed in this study. The possible link between Alzheimer's disease with conventional aluminium based coagulants, has become an issue in water treatment. A method for treating water, using a natural approach as an alternate to achieve enhanced coagulation, might help to reduce risk to health, and be more environmentally friendly. One method for removing turbidity from raw water is by the adding of a primary coagulant (e.g., a natural polymer of chitosan) and a coagulant aid (e.g., natural clay of bentonite) to the raw water. A series of batch coagulation tests were conducted by jar test to obtain the optimum dosage, pH, ratio of coagulant aid and primary coagulant, and the efficiency time for the jar test, by evaluating the standard parameters, such as turbidity, pH, colour, aluminium, and chlorine. In terms of these parameters, chitosan:bentonite showed the best result, with a ratio of 30:70 in an optimal concentration of 1,000 mg/l with 0.15 g chitosan plus 0.35 g bentonite. The coagulants performed with an optimal pH of 5, with 30 min of mixing time during flocculation. However, the optimal pH condition during the jar test showed an improvement in the water alkalinity results, from pH 5 to 6.8. Coagulation with bentonite-chitosan successfully removed the turbidity with a highest efficiency of 98%. After water treatment in the optimal condition, results showed a great water quality standard, with 1.38 NTU, 10 TCU, 0.01 mg/l amount of chlorine and aluminium, and a pH of 6.8. However, data only showed slight differences of efficiency, between natural and conventional coagulants. In terms of the sludge volume index (SVI), the ratio of alum to bentonite-chitosan was found to be 3:1 which indicated that less sludge was produced by the natural coagulant. In a cost comparison between these coagulants, based on a rough estimation, bentonite-chitosan is nearly 10 times more expensive than the alum coagulant. However, with mass production and commercial availability, in the long run the price of chitosan could be reduced tremendously.

Dye wastewater sample contains moderate concentration of chemical oxygen demand (COD), ammonia (NH₃) and color. This work evaluates the removal of COD, ammonia and color in dye wastewater using granular activated carbon (GAC) and zeolite in the column studies. Different surface loading rates, height of adsorbent and empty bed contact time were used to investigate the efficiency of the adsorption process. The maximum removal efficiency was found at the surface loading rate of 2.84 mL/cm².min and bed height of 10 cm. Due to the characteristics of GAC and zeolite, a sequence of combination with both adsorbents produces a better removal of contaminants. The best removal of the contaminants among the all adsorption treatment was found using GAC (bottom layer) and zeolite (upper layer) in 6.35 cm diameter column with 59.46% removal of COD, 60.82% removal of ammonia and 58.4% removal of color. For the adsorption with zeolite as the bottom layer and GAC as the upper layer, the data fitted well with the Langmuir model. While for the adsorption with zeolite as the upper layer and GAC as the bottom layer, the data fitted well for both Langmuir and Freundlich isotherms.

The study of the interrelationship between groundwater and surface water is crucial in groundwater basin research. As an effective tracer in groundwater basin research, environmental isotopes can reveal the interrelationship between river water and groundwater. A research of groundwater and river water alongside river of Bandung area and its surrounding has been carried out. This research was conducted by taking some samples of shallow groundwater, deep groundwater and river water (Citarum, Cikapundung, Cikeruh and Citarik). The objective of this research is to determine groundwater recharge area and to investigate the inter-relationship between groundwater and river water. Based on isotopes ? ²H vs. ? ¹⁸O results, there were a mixing process at three location of shallow groundwater with river water. However, the result of isotope ¹⁴C does not show interrelationship, either by shallow groundwater or river water. From iso-age contour lines, it could be concluded that the dynamic patterns of deep groundwater show movement derived from the North and the South mountain to the North-West direction. The actual velocity in the area was around 0.25-3 m/year that can be estimated from iso-ages lines contour.