The treatment system for rural communities with Batch-Activated Sludge Process was improved. The focus was on removal of nitrogen by intermittent aeratyion. Following the experimental results, treated water quality lower than 10 mg/l of BOD and T-N was ensured throughout the year, under the operational conditions of hydraulic retention time in aeration tank longer than 24 h and MLSS higher than 2,500 mg/l. Treated water quality of T-N was less than 5 mg/l within cumulative frequency of 66%. Removal capacity of T-N did not reach its limit under condition less than 0.05 kgN/m3d−1 of influent load. Estimating from the nitrogen removal rate, consumption of alkalinity, characteristics of biomass growth and the amount of nitrogen content in MLSS, 77% of influent nitrogen was denitrified, 18% of that was discharged as treated water and 5% of that was extracted as excess sludge or SS in treated water. Fluctuation patterns of DO and ORP in a cycle by seasonally changed water temperature were effective indices for regulation of operation. A remote monitoring system was helpful to support the management, because it enabled maintenance staff to judge urgency of management from the latest real time data.
Treatment System of Wastewater from Rural Settlements with Batch-Activated Sludge Process
Y. Yuyama, K. Fujino, Y. Miyamoto, R. Oonishi; Treatment System of Wastewater from Rural Settlements with Batch-Activated Sludge Process. Water Sci Technol 1 November 1993; 28 (10): 223–232. doi: https://doi.org/10.2166/wst.1993.0238
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