Can sludge be incinerated?
Bio-solids like municipal sludge, industrial sludge and fine solids can be incinerated with the advantage of eliminating the sludge. Energy from the incineration process can be recovered as green energy source.
What is a sludge age?
The sludge age is the amount of time, in days, that solids or bacteria are under aeration. Sludge age is used to maintain the proper amount of activated sludge in the aeration tanks.
What is sludge age in wastewater treatment?
Sludge age (Mean Cell Residence Time): Units: days The sludge age or Mean Cell Residence Time (MCRT) may be defined as the mass of solids (MLSS) in the plant at any time divided by the mass of new solids made each day. The higher the F/M loading the shorter the sludge age and vice versa.
Why is sludge age important?
The sludge age is the most fundamental and important parameter in the design, operation and control of biological nutrient removal (BNR) activated sludge (AS) systems. The easiest and most practical way to control sludge age is with hydraulic control by wasting a defined proportion of the reactor volume daily.
Can sludge be burned?
If sludge is sent to an incinerator, most of it is burned up, but there is a part that will not burn. This part, called ash, usually is taken to a landfill. Some of the chemicals in sludge go into the air when sludge is burned, and some people are worried that burning sludge will cause air pollution.
What is a sewage sludge incinerator?
A sewage sludge incinerator (SSI) is an incinerator or combustion device that is used to burn dewatered sewage sludge. SSI units are typically located at wastewater treatment facilities are of one of two types: multiple hearth furnace (MHF) and fluidized bed (FBI) incinerator.
What is a good sludge age?
three to fifteen days
Optimum MLSS concentrations should be determined experimentally for each plant. – A sludge volume index of about 100 and a sludge age of three to fifteen days are normal for most plants.
How is MLSS calculated?
MLSS consists mostly of microorganisms and non-biodegradable suspended matter. The total weight of MLSS within an aeration tank can be calculated by multiplying the concentration of MLSS (kg/m3) in the aeration tank by the tank volume (m3).
What can we do with sludge?
Once treated, sewage sludge is then dried and added to a landfill, applied to agricultural cropland as fertilizer, or bagged with other materials and marketed as “biosolid compost” for use in agriculture and landscaping.
What are incinerators used for?
Incinerator, container for burning refuse, or plant designed for large-scale refuse combustion.
Is it necessary to incinerate sewage sludge?
Depending on their calorific value of the sludge being incinerated, pre-drying of the sludge and pre-heating of the combustion air may be necessary. Landfill or agricultural use of wastewater sludge is not always a feasible solution. The better the wastewater treatment process, the more noxious, or dirtier is the sludge.
What should the temperature be for the incineration of sludge?
Temperatures of 760 to 820°C (1400 to 1508°F) are required for complete combustion of organic solids. In the incineration of sludge, the organic solids are converted to the oxidized end products, primarily carbon dioxide, water vapor, and ash.
How is activated sludge removed from wastewater treatment?
In the activated sludge treatment process, the removal of suspended solids from wastewater is usually through gravity separation in a clarifier. The activated sludge (excess biomass or cell mass) removed from the secondary treatment process. For most treatment plants, this will be a portion of the Return Activated Sludge (RAS) flow stream.
When is the best time to use activated sludge?
For conventional activated sludge, a sludge age of 3-10 days is typical. For extended aeration activated sludge, older sludge ages of 15-30 days are common. F/M ratio and sludge age are inversely related (1 divided by the sludge age approximates the F/M ratio).