What is a rotating biological contactor?
Along with the online lesson, read Chapter 7: Rotating Biological Contactors in your textbook Operation of Wastewater Treatment Plants Volume I . The rotating biological contactor (RBC) is a fixed film biological secondary treatment device. The basic process is similar to that occurring in the trickling filter.
How difficult is it to operate a biological contactor treatment plant?
Between the roller chain, the sprockets, and the chain casing. Rotating biological contactor treatment plants are not difficult to operate and produces a good excellent provided the operator properly regularly performs which basic duties?
What maintenance is required for a rotating biological contactor (RBC)?
• Routine maintenance of in particular six RBC structures: media, shaft, reactor basin, drive assembly system, orifice/weir, lines and valves and underdrains is necessary to ensure the proper functioning of a rotating biological contactor.
Which items should be checked when inspecting rotating biological contactor equipped?
Which items should be checked when inspecting rotating biological contactor equipped? Till the motors to determine if they are running hot. Fill the outer housing of the shaft bearing to see if it is running hot. Inspect the belts for proper tension.
How does a rotating biological contactor work?
In the Rotating Biological Contactor, wastewater is purified using microorganism membranes which are attached to disks. The disks slowly rotate with approximately 40% of surface area submerged in the wastewater.
Is the rotating biological contactor aerobic or anaerobic?
aerobicRotating biological contactors (RBC) are a conventional aerobic biological wastewater treatment unit.
When using a rotating biological contactor which two conditions are required for effective operation?
When using a rotating biological contactor (RBC), which two conditions are required for effective operation? A. The rotating drum(s) must be 50 percent submerged and rotate at a speed greater than 2 rpms.
How do aerated lagoons work?
Aerated lagoons are common in small communities. These systems use aerators to mix the contents of the pond and add oxygen to the wastewater. They are sometimes referred to as partial-mix or complete-mix lagoons depending on the extent of aeration.
How does oxidation pond work?
Oxidation ponds, also called lagoons or stabilization ponds, are large, shallow ponds designed to treat wastewater through the interaction of sunlight, bacteria, and algae. Algae grow using energy from the sun and carbon dioxide and inorganic compounds released by bacteria in water.
Who described the use of contactors in wastewater treatment?
Who described the use of contactors in wastewater treatment? Explanation: Ware and Pescod in 1989 described the use of contactors. The full scale aerobic/anaerobic rotating biological contactors are used to remove or treat the brewery wastewaters. More than 85% of COD was removed in the aerobic stage.
What adjustment to RBC operation allows better control of the oxygen supply?
What adjustment to RBC operation allows better control of the oxygen supply? Changing the rotational speed of the discs.
What is the method of treatment used when the TSS in the sample is high?
What is the method of treatment used when the TSS in the sample is high? Explanation: High rate solid contact clarifier is used to treat samples with very high TSS. The other methods namely ultrafiltration and pressure sand filter cannot treat samples with very high TSS. This is because the filters will get clogged.
Why is the sludge aerated?
Why is the sludge aerated? Explanation: An activated-sludge reactor is a system in which pre-treated sewage (i.e. having passed through primary treatment) is aerated to promote the growth of bacteria (cells) that gradually consume the organics in the sewage.
What are the different method of aeration in treatment of aerated lagoon?
There are many methods for aerating a lagoon or basin:Motor-driven submerged or floating jet aerators.Motor-driven floating surface aerators.Motor-driven fixed-in-place surface aerators.Injection of compressed air through submerged diffusers.
How is wastewater aerated?
How is Wastewater Aerated? Aeration is an activated sludge process. It pumps air into a tank, promoting microbial growth in wastewater. Bacteria that forms the activated sludge, after settling in a separate settling tank, recirculates back to the aeration basin.
How does anaerobic lagoon work?
An anaerobic lagoon is a deep earthen basin with sufficient volume to permit sedimentation of settlable solids, to digest retained sludge, and to anaerobically reduce some of the soluble organic substrate. Raw wastewater enters near the bottom of the pond and mixes with the active microbial mass in the sludge blanket.
What is a RBC contactor?
A rotating biological contacto r is a type of secondary (Biological) treatment process.
What is the media used in wastewater treatment?
Commonly used plastics for the media are polyethylene, PVC and expanded polystyrene. The shaft is aligned with the flow of wastewater so that the discs rotate at right angles to the flow, with several packs usually combined to make up a treatment train. About 40% of the disc area is immersed in the wastewater.
What is secondary clarifier?
Secondary clarifiers following RBCs are identical in design to conventional humus tanks, as used downstream of trickling filters. Sludge is generally removed daily, or pumped automatically to the primary settlement tank for co-settlement. Regular sludge removal reduces the risk of anaerobic conditions from developing within the sludge, ...
How many modules are needed for carbon conversion?
Most design of RBC systems will include a minimum of 4 or 5 modules in series to obtain nitrification of waste water.
When was the first RBC installed?
The first RBC was installed in West Germany in 1959, later it was introduced in the United States and Canada. In the United States, rotating biological contactors are used for industries producing wastewaters high in biochemical oxygen demand (BOD) (e.g., petroleum industry and dairy industry).
Who made the first GRP RBC?
In the UK, the first GRP RBC's - manufactured by KEE Process Ltd. originally known as KLARGESTER - go back to 1955. KLARGESTER GRP RBC from 1955. A properly designed RBC produced a very high quality final effluent.
What is biofilm in wastewater?
Biofilms, which are biological growths that become attached to the discs, assimilate the organic materials (measured as BOD5) in the wastewater. Aeration is provided by the rotating action, which exposes the media to the air after contacting them with the wastewater, facilitating the degradation of the pollutants being removed.
What is each contactor called?
Each individual contactor is called a stage and the group is known as a train. Most RBC systems consist of two or more trains with three or more stages in each. One major advantage of the RBC system is the level of nitrification that can be achieved if sufficient stages are provided.
How does a RBC work?
In operation, a media, consisting of a series of circular disks mounted side by side on a common shaft is rotated through the wastewater flow. The shaft continually rotates at 1 to 2 rpm, and a layer of biological growth 2 to 4 mm thick is soon established on the wetted surface of each disk. The organisms in the slime remove organic matter from the wastewater for aerobic decomposition. Typically, a single contactor is not sufficient to achieve the desired level of treatment, so a group of contactors are used in series. Each individual contactor is called a stage and the group is known as a train. There are many more advantages to using RBCs than disadvantages.
How many stages of BOD removal in RBC?
For combined BOD 5 and NH 3 -N removal, a minimum of four stages is recommended per flow path. Whenever multiple process trains are employed with three or more shafts in a row; the flow path should be introduced perpendicular to the shafts, and the wastewater should be distributed evenly across the face of the RBCs.
What is the purpose of a RBC?
The purpose of an RBC is to remove soluble food from the water. Soluble food is often referred to as soluble BOD. For this reason, the RBC must be preceded by primary settling. The surface of the disk is covered with a biological slime similar to that on the media of a trickling filter.
What are the observations of the RBC?
If the unit is covered, observations are usually limited to that portion of the media that can be viewed through the access door.
What is hydraulic loading on a RBC?
Hydraulic loading rate on an RBC is based on the media surface area in square feet or in square meters. The media surface area must be specified by the manufacturer. Hydraulic loading on an RBC can range from 1 to 3 gpd/ft 2.
What is the BOD of wastewater?
The Biochemical Oxygen Demand, or BOD, is the amount of dissolved oxygen which is used up by these microbes and is roughly equivalent to the amount of "food" (organic matter) found in the wastewater. The more "food" that is present in the water, the more DO will be used up by the bacteria and the greater the BOD reading will be.#N#A major disadvantage of the BOD test is that results are not available for 5 days. Nevertheless, BOD tests are an integral part of the wastewater operator's repertoire. Wastewater treatment plants use BOD as an estimate of the waste load in the influent water. They can also test BOD of the effluent to determine the plant's efficiency, to control plant processes, and to determine the effects of discharges on receiving waters.
How does a sewage treatment train work?
The shaft is aligned with the flow of sewage so that the discs rotate at right angles to the flow, with several rotors usually combined to make up a treatment train. About 40% of the disc area is immersed in the sewage. The biological growth that becomes attached to the discs assimilates the organic materials in the wastewater.
What is the RBC process?
In addition, the RBC process can treat effluents and process wastewater from dairies, bakeries, food processors, pulp and paper mills, and other biodegradable industrial discharges.
What is organic loading?
Organic loading is the primary design parameter for the RBC process. This is generally expressed as the organic loading per unit of media surface area per unit of time, or in units of pounds BOD5 per thousand square feet per day. Wastewater temperatures above 55°F have a minimal effect on organic removal and nitrification rates; however, below 55°F, manufacturers shall be contacted to obtain the various correction factors that must be utilized to determine the needed additional media surface area. In determining design-loading rates on RBCs, the following parameters should be utilized:
Why is RBC process used?
The RBC process may be used where the wastewater is suitable for biological treatment. The RBC process can be used in many modes to accomplish varied degrees of carbonaceous and/or nitrogenous oxygen demand reductions. The process is simpler to operate than activated sludge because recycling of effluent or sludge is not required.
What is a RBC?
Rotating Biological Contactors (RBCs) are used in the treatment of wastewater as a secondary treatment process. The RBC process involves allowing wastewater to come in contact with a biological medium in order to remove contaminants in sewage before discharge of the treated wastewater to the environment, usually a river.
Can municipal wastewater be used in RBC?
Pretreatment. Raw municipal wastewater shall not be applied to an RBC system. Primary settling tanks are required for effective removal of grit, debris, and excessive oil or grease prior to the RBC process. In some cases, fine screens (0.03-0.06 inches) may be considered.
What is an operator?
As an operator, you are responsible to your employer for maintaining an economical and efficient operating facility. TRUE. An operator has an obligation to the great numbers of people who rely on down stream water supplies and are totally dependent on the operator's competence and trust worthiness for their welfare.
What is the function of wastewater treatment plant?
TRUE. One of the primary functions of a treatment plant is the removal of solids from wastewater. TRUE.