The following P&ID shows a temperature control process. (a) Interpret the instru
ID: 2079447 • Letter: T
Question
The following P&ID shows a temperature control process. (a) Interpret the instrument tags, (2) indicate the control loop(s), (3) how the tank liquid temperature is controlled?
(for control engineering Class)
1) The PFD of a conventional wastewater treatment process is given below. From the figure describe how the process generally works. Conventional Wastewater Treatment Process First Sedimentation Tank Garbage Disposal Garbage Disposal Tertiary Treatment Water Treatment Tertiary Sedimentation Tank Secondary Sedimentation TankExplanation / Answer
The process is described below:
First waste water is passed through a series of screens that filters out the large garbage particles and other large particles and these garbages are taken out and the filtered water is taken to the Grit Chamber.
Grit chambers are narrow and they are designed in such a way so that it slows down the speed of flowing water which helps sand, sand like particles, egg shells etc. to settle out of the water. These settled out garbages are taken for disposal and the remaining water is send to the next stage of processing.
Sedimentation tank is a very important component in modern wastewater management, It allows suspended particles to settle out of water as water passes through it very slowly. Layer of accumulated solid, called sludge, is accumulated at the bottom of the first sedimentation tank and it is removed periodically.
Biological treatment involves wide vareity of of microorganisms, such as Bacteria to decompose biodegradable organic matter present in the wastewater into simpler substances. From the blower room, air, containing these microorganisms are flowed through the waste water.
Secondary sedimentaion tank is employed to remove these simpler wastes that are produced due to Biological treatment of the wastewater.
The goal of tertiary sedimentation tank is to remove unwanted elements such as SS, COD (solid and colloidal), phosphorus and specific compounds (pesticides, metals, detergents, and so on). It is designed to improve the quality of purified water so that it can be discharged into the natural environment or re-used.
Final stage of water treatment involves UV disinfection and sand filtration to remove the remaining unwanted substances out of the water.