• Journal of Korean Society of Water and Wastewater
• /
• v.24 no.2
• /
• pp.195-202
• /
• 2010

The evaluation of organic matters and nutrients removal was investigated for the synthetic wastewater and the high strength of dairy wastewater. Two different systems were performed for this research. System A composing of a single RBC with tapered aeration was fed with the synthetic wastewater for 74 days with 173L/day of influent, 200% of internal return and 100% of sludge return for the period 1 and 2. The feed conditions were maintained 346L/day of influent, 50% of internal return and sludge return for the period 3. The dairy wastewater was introduced to evaluate treatment efficiency for system B composing of dual RBCs and tapered aeration tanks for 50 days of experimental run time, in which hydraulic rates were maintained at the constant ratios of 346L/day, 50% of internal return and 50% of sludge return. The spiral string media made of nylon fibre was attached by Bacillus sp. in RBC for both systems. The specific area of string media was $1.4m^2$/m and biomass was maintained at the concentrations of 23g/m. The synthetic wastewater was supplied by 1,800mg/L of glucose, 500mg/L of $NH_4Cl$, and 500mg/L of $KH_2PO_4$ to system A. The dairy wastewater was supplied to system B from dairy production plant. The average influent concentrations were 1,334mg/L of BOD, 2,014mg/L of CODcr, 160mg/L of T-N, and 12mg/L of T-P in system A. The average influent concentrations of parameters were 1,006 mg/L for BOD, 1,875mg/L for $COD_{cr}$, 51.6mg/L for T-N and 8.9mg/L for T-P in system B. Results indicated that removal efficiencies of BOD and $COD_{cr}$ were more than 90% however, the removal efficiency of T-N was 87%, and that of T-P was 82% for system A. Removal efficiencies were 98.5% of BOD, 91.3% of nitrogen and 89% of phosphorus for system B. The removal efficiencies of organic matters, T-N and T-P were higher in system B than in system A. The effluent quality issued by the stringent national legislations for the discharge of the high strength of dairy products wastewater can be improved using sequential RBCsand tapered aeration reactors rather than a single RBC and tapered aeration reactors with Bacillus sp.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.6
• /
• pp.1733-1738
• /
• 2008

The treatment efficiency of rotating biological contactors (RBCs) for the high strength of dairy wastewater was investigated. Two different systems were conducted composing of a single RBC with tapered aeration reactors for the system A and a sequential RBCs following tapered aeration reactors for the system B. Experiments using dairy wastewater were conducted for 50 days period of time, in which hydraulic rates were maintained at the constant ratios of 346L per day and variable BOD concentrations were at the range from 1,358mg/L to 829mg/L, the $COD_{cr}$, concentration of the range were from 2,384mg/L to 1,329mg/L, the range of T-N concentrations was from 66mg/L to 38mg/L, and 50% of internal recycle and 50% of sludge return were performed. Results indicated that the removal efficiencies of the system B were higher than those of the system A. The removal efficiencies of system A for the BOD, $COD_{cr}$, T-N and T-P were 97.8%, 96.7%, 87.2% and 82%, respectively. The removal efficiencies of system B for the BOD, $COD_{cr}$, T-N and T-P were as of 98.5%, 98.5%, 91.3% and 89%.

• Journal of Korean Society of Water and Wastewater
• /
• v.13 no.2
• /
• pp.55-65
• /
• 1999

AF(anaerobic filter)/BAF(biological aerated filter) system and UASB(upflow anaerobic sludge blanket)/BAF system, of which system effluents were recirculated to the anaerobic reactors in each system, were operated in order to investigate the performance in simultaneous removal of organics and nitrogen in high-strength dairy wastewater. Advanced anaerobic treatment processes of AF and UASB were evaluated on applicability as pre-denitrification reactors, and BAF was also evaluated on the performance in oxidizing the remaining organics and ammonia nitrogen. At system HRTs of 4.0 to 4.5 days and recirculation ratios of one to three, the AF/BAF system could achieve more than 99% of organics removals and 64 to 78% of total nitrogen removals depending upon the recirculation ratio. Although the UASB/BAF system also showed more than 99% of organics removals, total nitrogen removals in the UASB/BAF system were 53 to 66% which are lower than those in the AF/BAF system at the corresponding recirculation ratios. Optimum recirculation ratios considering simultaneous removal of organics and nitrogen and cost-effectiveness, were in the range of two to three. The upflow AF packed with crossflow module media, as a primary treatment of the anaerobic reactor/BAF system, showed better performances in denitrification, SS removals, and gas production than the UASB. Higher loading rate of suspended solids from the UASB increased the backwashing times in the following BAF. Especially, at a recirculation ratio of three in the UASB/BAF system, the increase in head loss due to clogging in the BAF caused frequent backwashing, at least once d day. The BAF showed the high nitrification efficiency of average 99.2% and organics removals more than 90% at organics loading rate less than $1.4KgCOD/m^3/d$ and $COD/NH_3-N$ ratio less than 6.4. It was proved that the simplified anaerobic reactor/BAF system could maximize the organics removal and achieve high nitrogen removal efficiencies through recirculation of system effluents to the anaerobic reactor. The AF/BAF system can, especially, be a cost effective and competitive alternative for the simultaneous removal of organics ana nitrogen from wastewaters.