START-UP AND OPERATION OF AN ACTIVATED SLUDGE REACTOR WITH EXTERNAL CLARIFIER
A reactor system was designed and fabricated to facilitate treatment of municipal wastewater. Carbon oxidation and nitrification was accomplished in an aerated, completely mixed vessel simulating the activated sludge process. This system was enhanced with an external clarifier to achieve waste activated sludge recycle, providing more efficient treatment and sludge age control. Four reactors were operated in parallel at varying solids retention times (SRTs). The four SRTs were maintained at 2, 5, 10 and 20 days by wasting a calculated volume of the reactor contents each day. Various parameters were measured during start-up and operation of this system to define treatment efficiency. Initial MLSS concentrations were 3000, 2200, 1300, and 900 mg/L for the 20, 10, 5 and 2 day SRTs, respectively. Influent total COD levels ranged from 175 to 275 mg/L. The SVI values were below 80 mL/g for the first 6 days of operation but increased to values as high as 1500 mL/g denoting poor settling. A subsequent increase in the effluent suspended solids accompanied the poor settling. The influent wastewater strength then increased significantly resulting in a drastic increase in solids concentration for all four reactors. A corresponding decrease in SVI and effluent suspended solids was noted. The additional substrate supported growth of more bacteria, enhanced bioflocculation, improved settlability, and subsequently decreased effluent suspended solids. Ultimately, steady state was achieved in all reactors.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
Document Type: Research Article
Publication date: 2000-01-01
More about this publication?
- Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.
WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
- Subscribe to this Title
- Membership Information
- About WEF Proceedings
- WEFTEC Conference Information
- Learn about the many other WEF member benefits and join today
- Ingenta Connect is not responsible for the content or availability of external websites