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Domestic wastewater contributes about 40% as the source of water bodies pollutants in Indonesia, causing the spread of pathogens and bioaccumulation effects on the environment. The purpose of this study was to analyze the characteristics of household wastewater in Jakarta and Depok in terms of quantity and quality. The average wastewater quantity estimation results from laundry, bathroom, kitchen, and closet were 49 ± 18, 79.1 ± 5, 24.5 ± 12, and 29.9 ± 3 liters/person/day. The qualitative analysis results stated that blackwater tends to have higher concentration on conductivity 1606-2046 μs/cm, TDS 709-1007 mg/L, ammonia 78-167 mg/L, total nitrogen 511-836 mg/L, total phosphorus 16.6-21.3 mg/L, phosphate 33-46.8 mg/L, potassium 32.5-47.9 mg/L, and fecal coliform 430,000-1.600,000 MPN/100 mL compared to other sources. Meanwhile, laundry greywater tends to have higher concentration on COD 559-1991.6 mg/L, MBAS 0.3-0.31 mg/L, aluminum 1.65-5.09 mg/L, sodium 7.5-61.4 mg/L, and silica 17.7-23.2 mg/L compared to other sources. Statistical results show that some parameters have significant difference in average concentration between each source so that these parameters can be considered as source tracer. The high pollutant concentration and quantity leads to high estimation of pollutant load on the river, as water bodies receiver, in Jakarta and Depok, especially on organic and nutrient load.

Indonesia currently has a waste generation problem arising from the fact that sixty percent of the waste it produces is organic waste (OW). The scope for anaerobic digestion (AD) of OW has not yet been optimized, with many reactors not functioning properly. The purpose of this study is to determine the suitability of food waste with an organic loading rate (OLR) of 8-14 kgVS/m 3 day to produce the highest volatile solids destruction (VSD) and methane. A semi-continuous pilotscale dry AD of 0.5 m 3 was run for 134 days in mesophilic conditions. The results showed that the feedstock was suitable for dry AD due to the high total solids (TS) (23.2-27.1%) and organic content (volatile solids of 90-95% TS). Meanwhile, the optimum OLR was 10 kgVS/m 3 day with a VSD of 92.2% and a methane yield of 127 LCH4/grVSday. In addition, OLR 10 kgVS/m 3 day had the highest stability, as shown by the pH value of 6.52 and ammonia concentration of 848 mg/l. The VSD values fell with respect to the OLRs of 12 kgVS/m 3 day and OLR 14 kgVS/m 3 day, to 90.42% and 86.73%, respectively.

No abstract

One-step chlorination (OSC) is a common method, generally implemented as the last step of wastewater treatment plants (WWTPs) and water treatment plants (WTPs). Improving disinfection efficiency is necessary to increase pathogen and organic matter removal. Two-step chlorination (TSC) has been studied as a new method of chlorination. This study aimed to compare OSC and TSC efficiency for coliform and organic matter removal. Chlorination was performed in a batch system and at laboratory scale using calcium hypochlorite. Samples were collected from WWTP effluent in an industrial estate located in Indonesia. The samples underwent the adsorption process beforehand. Chlorine dosage at 10-110 mg/L, at a 10-200-second time interval, and with a dosage ratio of 3:1-7:1 were evaluated. Results showed that the optimum dose for OSC is 80 mg/L. The optimum condition for TSC is a 50-second time interval and a 5:1 dosage ratio between the two steps. With the same total dose as in OSC, TSC improved efficiency for COD, BOD, and coliform removal up to 12%, 35%, and 0.39-log reduction, respectively (p < 0.05). Moreover, trihalomethane (THM) formation was reduced up to 13% by using the TSC method. However, an increasing ammonia concentration occurred because of the OSC and TSC processes (p < 0.05).