PRODUCT DETAILS : CONVENTIONAL ETP SYSTEM
DESCRIPTION:
The proposed Effluent Treatment Plant, quoted by us, will be consisting of two (2) sections, as described above, for treating the raw waste water in question and to produce treated waste water, suitable for discharging into the main drain/sewer System.
Unit operations of various sections of the proposed plant have been enumerated below for your ready reference:-
Physico-chemical treatment section
- Raw waste water will be collected in the underground Equalization Cum neutralization tank for holding raw waste water equivalent to minimum 12 hours requirement of the treatment plant. This is required for maintaining steady flow of waste water into the treatment plant as well as maintaining more or less uniform characteristics of the raw waste water for treatment in the Effluent treatment plant. Since production of waste water will be erratic, the minimum holding time of 12 hours requirement of the plant is essential for proper operation of the Effluent
- treatment plant. Since the influent water is highly alkaline in nature, spent Sulphuric acid is required to be dosed to bring down the pH from ~11 to ~7 with the help of acid dosing pump.
- Neutralised raw waste water will be drawn by means of raw waste water transfer pump set for feeding the same to the subsequent treatment plant.
- Lime solution and Ferrous Sulphate / PAC solution will be dosed at the inlet of the flash Mixer in order to remove of colour, BOD and COD content of the raw waste water to some extent by means of coagulation. Ferrous Sulphate / PAC solution and Lime solution will be dosed at the inlet of the flash mixer through gravity.
- Polyelectrolyte solution will be dosed in the raw waste water for the purpose of removal of colour and will also act as flocculant for the flocculation of coagulated mass for the purpose of removal of suspended impurities expeditiously. Polyelectrolyte solution will be dosed in the flash mixer by means of Simplex type metering pump set.
- Raw waste water will be taken from the equalisation cum neutralisation chamber into the flash mixer wherein Ferrous Sulphate solution / PAC solution, Lime solution and polyelectrolyte solution will be dosed. Intimate mixing of chemicals with the raw waste water will be facilitated in this reaction chamber and for this purpose, electrically driven slow speed agitator will be provided.
- The resultant waste water along with chemical solution will then gravitate to the primary settling tank for the purpose of removal of suspended impurities and chemical sludge thereby rendering the settled water more or less clear in nature.
Biological Treatment Section
- Settled water from Primary clarifier will then be fed into the Aeration Unit for the purpose of removal of BOD of the influent waste water. There will be one (1) no. of Aeration Unit and we have incorporated diffusers with PVC air distribution bed for this unit.
Aeration unit will be of RCC construction where-in diffusers will be provided for administering oxygen into the waste water for bio-degradation through rotary twin lobe type air blower.
The aerated water will next be fed into the clarifier by gravity for the purpose of removal of biological sludge, produced in the aeration tank. The clarifier is provided with a central drive arrangement. Along with a sludge scraper blades positioned on the floor of the clarifier slowly sweeps settled sludge into a central sludge hopper. From the clarifier hopper, settled sludge is carried by gravity to a sludge catch pit on the aeration tank periphery and an air ejector is used to recycle back sludge to the aeration tank from the sludge pit. A second air ejector is used to transfer excess sludge to the sludge drying beds. Clear water is collected in the water storage tank.
- Sludge slurry of primary settling tank and clarifier will be fed into the sludge drying beds through sludge pit. There will be three (4) nos. of sludge drying beds, each bed measuring sludge drying beds will be of masonry construction and will be incorporating RCC construction filtrate sump to hold clear filtrate that will be produced from the sludge drying beds. Out of 4 nos. of sludge drying beds, while 3 nos. of beds will be in operation at a time, the another one (1) bed will remain under cleaning operation and/or stand-by unit.
Sludge slurry, obtainable from the settling tanks, will be fed into these sludge-drying beds. Solid mass of the sludge slurry will be retained on the top of the media of the drying beds and clear filtrate, from the bottom, will either be disposed-off or returned back into the Equalization tank, as the case may be.
- Treated and settled water, obtainable from the settling tank, will be collected in the treated wastewater reservoir.