Table of Contents
A sludge blanket clarifier is a treatment unit combining flocculation and upward flow sedimentation, which is more efficient compared to the conventional sedimentation tank. It has the ability to treat water at a faster rate, resulting in less space requirement.
What is a sludge blanket?
Sludge blankets are high-quality reactors that were created to remove organic matter from our water. The wastewater receives treatment when it’s passing through. The sludge blanket will move up and down through various compartments well the wastewater passes through the reactor.
What is sludge blanket level?
In activated sludge processes, the sludge blanket should never exceed 25% of the sidewall depth of the secondary clarifier. In some texts, a 2-foot blanket is recommended. Whenever this depth is approaching or exceeding this depth, the operator should take precautions.
Why does sludge float?
Denitrification – small nitrogen gas bubbles float the sludge in the clarifier creating floating sludge chunks with small bubbles entrapped. Fats, Oils & Grease – simply put, FOG floats on water. This is often caused by nutrient deficiencies (normally low phosphate) in industrial waters.
How does the activated sludge process work?
The activated sludge process in the treatment of wastewater involves blowing oxygen or air into raw, unsettled sewage. The sewage is bubbled, and sewage liquor is discharged into an activated sludge chamber. Live bacteria settle to the bottom of the tank and dead bacteria float to the top.
How is sludge measured?
To measure the sludge layer: Slowly lower the tube into the septic tank until it touches the bottom of the tank. As the device is slowly pulled out of the water, the check valve closes capturing a liquid/solid profile of the septic tank water. The thickness of the sludge layer can be measured.
How long does the sludge stay in the sludge digesters?
The sludge is vigorously aerated in an open tank for about 20 days.
What are the steps of activated sludge process?
The sludge treatment process involves four steps as described here.Treatment Steps Step 1: Screening and Pumping. Step 2: Grit Removal. Step 3: Primary Settling. Step 4: Aeration / Activated Sludge. Step 5: Secondary Settling. Step 6: Filtration. Step 7: Disinfection. Step 8: Oxygen Uptake.
How does activated sludge appear?
In activated sludge process wastewater containing organic matter is aerated in an aeration basin in which micro-organisms metabolize the suspended and soluble organic matter. A part of this settled biomass, described as activated sludge is returned to the aeration tank and the remaining forms waste or excess sludge.
How do I control bulk sludge?
Control of low F/M bulking is by reducing the aeration basin MLSS concentration and increasing the F/M (manipulating the “M” component). Lowering the MLSS concentration may not be suitable for many plants as this may cause the loss of nitrification and increase waste sludge production.
What is an upflow clarifier?
Compact and relatively economical, upflow clarifiers provide coagulation, flocculation, and sedimentation in a single (usually circular) steel or concrete tank. These clarifiers are termed “upflow” because the water flows up toward the effluent launders as the suspended solids settle.
What is a good sludge age?
The common range for sludge age for a conventional activated sludge plant is between 3 and 15 days. For extended aeration activated sludge plants the range is between about 15 and 30 days. Generally during the winter months, higher sludge ages are required to maintain a sufficient biological mass.
Is provided after activated sludge process?
The combination of wastewater and biological mass is commonly known as mixed liquor. In all activated sludge plants, once the wastewater has received sufficient treatment, excess mixed liquor is discharged into settling tanks and the treated supernatant is run off to undergo further treatment before discharge.
What is clarified sludge?
A clarifier is generally used to remove solid particulates or suspended solids from liquid for clarification and/or thickening. Concentrated impurities, discharged from the bottom of the tank are known as sludge, while the particles that float to the surface of the liquid are called scum.
How does a Pulsator clarifier work?
The Pulsator® is a pulsed sludge blanket clarifier. The sludge formed during flocculation is made up of an expansion mass. Water, that has coagulated beforehand, arrives from the bottom of the device and flows through this sludge blanket to emerge clarified at the top of the settling tank.
What is required to keep the activated sludge suspended?
3. What is required to keep the activated sludge suspended? Explanation: To maintain the aerobic conditions and to keep the activated sludge suspended, a continuous and well-timed supply of oxygen is required. Flocs of bacteria, which are suspended and mixed with wastewater is used for the process.
What is a sludge judge?
Sludge Judge. Measure settled solids in sewage treatment plants, chemical plants, or food processing facilities. Take accurate, noncaustic measurement of settable solids, 5% or less.
What do you mean by sludge?
1 : mud, mire especially : a muddy deposit (as on a riverbed) : ooze. 2 : a muddy or slushy mass, deposit, or sediment: such as. a : precipitated solid matter produced by water and sewage treatment processes.
What causes bulking sludge?
The main cause of sludge bulking is the growth of filamentous bacteria. Filamentous microorganisms grow in long strands that have much greater volume and surface area than conventional floc and are very slow to settle.
What is a solids contact clarifier?
Solids contact clarifiers combine the process of mixing, flocculation and sedimentation in a single tank. Solids Contact Clarifiers are typically used in water softening and color and turbidity removal clarifiers in water treatment plants, and polishing or tertiary clarifiers in waste water treatment plants.
What do you mean by activated sludge?
Activated sludge refers to a flocculent culture of organisms developed in aeration tanks under controlled conditions, according to WEF. Activated sludge is typically brown in color. Activated sludge is also known as waste activated biosolids or waste activated solids.
