Maintaining optimum settling rate of activated sludge
US4130481A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 16, 1977 |
| Grant date | Dec 19, 1978 |
| Priority date | — |
| Expiry date | Sep 16, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC02F3/12
- WIPO fieldEnvironmental technology
- WIPO sectorChemistry
Abstract
A completely mixed system for controlling the return rate of activated sludge to the aeration tank in activated sludge sewage treatment system plants is disclosed wherein the return rate of activated sludge is controlled to maintain the density of the activated sludge in the aeration tank at an optimum value, which value will result in the optimum settling rate of the activated sludge in the secondary clarifier. The control system is continuous and requires the use of a computer, which continuously receives various measured quantities necessary to compute the control signal for the returned activated sludge pump. The carbon dioxide respired by the cells in the aeration tank is collected along with the aeration air and a non-dispersive infrared ray analyzer determines the percent of carbon dioxide in the collected gases. This determination is one of the factors entering into the computation of the rate of substrate consumption by the activated sludge. Other measured quantities entering the computer are the rate of air flow entering the diffuser, the density of the activated sludge in the aeration tank, the rate of flow of effluent from the aeration tank and the density of returned a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.