Denitrification

Environmental concerns about the release of greenhouse gases to the atmosphere, and issues of global warming and climatic change regularly feature in the media. What is often not referred to in these stories is the role of wastewater treatment. Biological processes could have a major effect on the composition of the atmosphere. Recent studies reveal […]

Nitrification and Denitrification

Sewage is made up of carbonaceous waste and a small amount of nitrogen waste. Nitrogen is a found in proteins and in ammonia, an important compound in sewage.

Bulking In The Activated Sludge Process

Bulking can be said to have occurred in activated sludge plants when the sludge does not settle easily and has an excessive volume. This can lead to carry over from the final effluent clarifies.

Anaerobic Digester Performance

A question often posed by operators of anaerobic digesters is “what should I be looking for?”. This is often in the context of process plant with a myriad of expensive instrumentation and computer control.

What is the FM Ratio

One of the most fundamental control parameters for the activated sludge process is the relationship between the load (i.e. kg/day as opposed to mg/l) of BOD (or bacterial ‘food’) entering the aeration plant, and the ‘mass’ of bacteria in the aeration tank available to treat the incoming BOD.

Denitrification

Environmental concerns about the release of greenhouse gases to the atmosphere, and issues of global warming and climatic change regularly feature in the media. What is often not referred to in these stories is the role of wastewater treatment.

Dosing Syphons

At all rates of flow to the treatment works rotary distributors must be fed at rates sufficient to ensure that the jets of sewage will rotate the arms. If the flow to the distributors is too low they might stand still and dribble.

Reed Bed Design Factors

Reed beds are a tertiary treatment with the process aim of removal of suspended and dissolved matter beyond that which the conventional secondary sewage treatment process provide. They remove 60 – 80% solids from the secondary effluent.

How Activated Sludge Works

The Activated Sludge (AS) process was developed as an alternative to biological filters, and is particularly useful for large populations where land is at a premium. More recent research however, has shown that the process can be operated in many different modes, making it a more flexible process than biological filtration.

Loading of conventional biological filters

The rate at which sewage can be treated on a biological filter will depend on the nature of the sewage and the required effluent quality. Loading rates are best measured in terms of organic loading, kg of BOD per cubic metre per day, often abbreviated to kg/m3/d.