TABLE OF CONTENTS Upflow anaerobic filter (Figure A.9 ).
Unavoidable annual real losses.
Upflow anaerobic sludge blanket.
Unsatisfactory CSOs ( combined sewer overflows).
An adaptation of the activated sludge process that can achieve the nitrification, denitrification and biological phosphorus removal. The four stage process involves an anaerobic zone followed by one or two anoxic zones and finally an aerobic zone ( see Figure U.1). The aerobic zone is used for BOD removal and nitrification. The return activated sludge from the sedimentation tank is fed back to the first anoxic zone. Recycles occur within the process in order to achieve denitrification in the anoxic zones. The first zone is required in order to obtain biological phosphorus removal. The percentage removal can be in excess of 95% for nitrogen and 90% for phosphates.
Unsatisfactory Intermittent Discharges.
An acronym occasionally used erroneously to mean UK Environment Agency . There is no such body as the UK Environment Agency. The Environment Agency is responsible for England and Wales only, Scotland and Northern Ireland have their own agencies.
A wire shaped green alga found in a variety of fresh waters, polluted or unpolluted, and on trickling filters.
Either the theoretical oxygen demand or the ultimate biochemical oxygen demand, the maximum value of the BOD test, ordinarily reached...
