Description of Process:

The treatment process shall comprise the following stages:
Physical treatment 			: Coarse bar-screening
Equalization tank 			: Flow equalization with air mixing
Biological treatment 			: Moving Bed Bio Reactor
Final sedimentation 			: Final settling tank 
Disinfectants 				: Chlorine Dosing/UV sterilizer
Sludge disposal 			        : Dewatering

Process Description:

The Contractor shall design the Sewage Treatment Plant to receive continuous sewage inflow within the plant room allocated on the site plan. The ease of maintenance and operation is of utmost importance in the design of Sewage Treatment Plant.

Performance Criteria of the Plant:

Raw sewage will be brought into the Sewage Treatment Plant. The Contractor shall receive sewage from this point to the treatment plant for treatment process.
The treatment plant shall be designed to treat the following basic characteristic expected in the raw sewage.
Description 					       APT
Peak hour Flow factor				2.5
Minimum Influent 				BOD concentration 250-350 ppm
Minimum Influent 				chemical oxygen demand 600‐800 ppm
Minimum Influent 				suspended solids 200-300 ppm
Oil & Grease 					           50 ppm, 

Process Description:

The Sewage Treatment Plant is designed to receive continuous sewage inflow within the plant room allocated on the site plan. The ease of maintenance and operation is of utmost importance in the design of Sewage Treatment Plant.

Inlet Screen Chamber:

Raw sewage shall flow into the inlet screen chamber by gravity. Large solids particles shall be intercepted by a fine step screen. A manual screen shall be installed.

Oil & Grease Separator Chamber:

Raw sewage shall flow into oil & Grease separator after screen chamber by gravity. Where oil shall be in floated form over top layer while the sewage shall flow through baffle valve from the bottom of chamber. In this process, utmost oil shall be removed.

Equalization Tank:

The equalization tank is designed to provide a minimum storage as per technical designed data. Where the aeration is introduce through coarse bubble diffuser. In this stage the sewage shall equalize properly.

MBBR Tank:

Sewage Pumped from Equalization Tank flows to MBBR Reactor.  The proposed biological process is the MBBR (Moving Bed Bio Reactor) system, which utilizes attached growth grown on Biomass Carriers. The technology will be installed in a biological reactor. The reactor will be divided into two aerobic stages; each stage will be filled with biomass carriers. Aeration will be achieved by coarse bubble diffusers, installed at the reactor bottom in the required pattern. Unique airlift hydraulics will assure mixing of biomass carriers. A media retention screen will be installed at outlet of each stage in order to maintain the carriers inside the reactor,
Whereas mixed liquor may flow unobstructed. The media retention screens are continuously cleaned by the mixing flow of water, air bubbles and biomass carriers.
 
Philosophy of Biological Treatment

 MBBR filter is having with diffused aeration system, and urea and DAP are dosed to develop the bio culture. MBBR (Moving Bed Bio Reactor) bio media are being designed to achieve high surface area per given volume resulting in high specific mass transfer. The structure aids uniform growth of biological film. Micro-organism growth on the bio film convert the dissolved and ‘unsettle able’ colloidal impurities into a settle able biomass. An adequate flow of air is fundamental importance to the successful operation of a mbbr filter to provide efficient treatment and to provide odors. The most common application of oxygen transfer is in the biological treatment of waste water. Because of low solubility of oxygen and the consequent low rate of oxygen transfer, sufficient oxygen to meet the requirements of aerobic waste treatment does not enter water through normal surface air water interfaces. To transfer the large quantities of oxygen that are needed, additional interfaces must be formed. Either air or oxygen can be introduced into liquid.  By aeration, volatile organic compounds are to be removed. Air stripping of VOCs occurs when air is temporarily entrained in wastewater or is introduced purposefully to achieve a treatment objective. When gas is introduced into a wastewater, VOCs are transferred from the waste water to the gas. The force governing the transfer phases are the same as described.

The waste water from the primary clarifier come to by gravity in to an aeration tank where it will be mix with living organisms also  called MLSS (Mixed Liquor Suspended Solids) in presence of air & air shall be introduced through submerged air diffusers (MLSS in aeration tank shall be maintained 3000-4000 mg/l).  The aeration system shall be designed in a way so as to achieve complete mixing of organisms with waste water. From the aeration tank this mixed liquor passes into the secondary clarifier through the use of baffles the liquid in the clarifier tank is maintained in quiescent condition which allows the solids to settle the bottom for collection. The accumulating solids known as “sludge” shall be constantly pumped back in to the aeration tank by sludge recirculation pump. This return sludge undergoes further digestion in the aeration tank & also provides the active organism needed to digest the incoming raw effluent. 



Air Blower

These can be high speed roots blower is causes transfer of oxygen from the atmosphere into the water. In this system the air is diffused into the aeration tank through diffusers located over the full floor area of the reactor.  The air is supplied through air blower.  This diffusion of air also causes full mixing of the tank contents. 

Diffuser Performance 

The efficiency of oxygen  transfer depends  upon the type and porosity of the  diffuser,  the size  of the bubbles produced, the depth  of  submergence, and  other  factors, such as oxygen concentration  in  the tank.  While coarse bubble diffusion systems  and  aerator systems  have oxygen transfer rates that  are  comparable, the  fine bubble diffusion systems offer  oxygen  transfer rates which are nearly twice that of the coarse bubble and surface aerator rates. This higher efficiency is achieved at the cost of a higher initial investment. 

Secondary Clarifier Tank:

The sewage become in a colloidal form, where the biomass and suspended particles which is in colloidal form settled down in the form of sludge and collected hopper bottom of clarifier. The clear water flow upwards and collected into the break tank. 

Tertiary Treatment:

The clear water pumped into the Multi Dual Media filter from break tank, where the remaining suspended particles trapped down and all organic compounds adsorbed through Activated Carbon Filter.  Finally treated water is introduce with Chlorination for disinfectants and to reduce Colleen level and.

Sludge Dewatering:

The treated wastewater will flow from the Clarifier to a sludge sump for solid-liquid separation. Excess sludge generated from SST shall be withdrawn to Sludge holding Sump. The sludge from sludge sump transferred directly through sludge pump into Filter Press/SDB. The Dried solid sludge is manually removed and liquid sludge forwarded to recycle.

DELIVERY SCHEDULE 
Delivery Period will start from date of receipt of Technically & Commercially clear Purchase Order 
Drawings will be provided for approval within a week after receipt of request from you and you will Provide drawing approval within 1 week. 
In case you have any comments/observations or any change required on Drawing submitted for approval, please get back to us within 7 days else we will presume that drawings are in order and shall be released for production. Any delay in approval of drawings by you beyond one week or any time taken to redo the drawings after approval until re¬-approval, the delivery will be extended accordingly. 
Delivery starting on Ex¬ works basis 	: 	10-12 weeks	

Rs. 5000/Head/ Day (8 hours) will be charged for supervision for Erection & Commission and all accommodation (Lodging & Boarding) will be extra or  in client scope
 Though erection and commissioning is performed by client and client request from us to be present in time commissioning. is payable.
STANDARD TERMS AND CONDITIONS
SPECIFICATIONS 
Specifications, dimensions, design, description, shades of paint etc are not binding on us in minute details and are subject to reasonable alteration / change without notice. 
INSPECTION 
If necessary, the goods will be offered for inspection at our works/our supplier’s works. The date of inspection will be intimated about one week in advance. If inspection is not carried out on the date mentioned, we shall be free to dispatch the equipment as per the terms of delivery. 
If payment is not made within 15 days from the date of Performa Invoice, we reserve the right to divert the ordered material. We will give fresh delivery period and new price at the time of diversion which will be binding on the purchaser and contract cannot be rendered void on this account.  If the goods are not diverted, charges for storage, insurance and interest at 1% of the Invoice value each week/part thereof commencing 15 days from the date of Proforma Invoice will be charged. Warehousing charges are subject to a maximum of 5% of the Invoice value.
WARRANTY
The equipment supplied by us shell be warranted for 12 months from the date of installation and commissioning or 18 months from the date of supply for any manufacture defect, however defect arise due to miss handling, incorrect operation wear and tear shell be entertained with reasonable charges. The warranty of all instruments and pump and motor and other equipment except prefabricated items will be covered under actual manufacturer’s warranty conditions. 
HANDOVER 
Unless and otherwise specified in the order and accepted, handing over of the equipment and / or installation would be considered as completed and a formal completion certificate shall be issued by the purchaser / user. 
The equipment/system, to be supplied by us, shall be site erected and commissioned at purchaser’s site. 
This equipment/system shall be legally transferred to the buyer only after realization of full and final payment. 
MODE OF DELIVERY 
The goods may be dispatched in one or more lots at our option. If we are required to dispatch the goods on behalf of customer, we can arrange to do so on freight to pay basis on the understanding that no liability is attached to us. In such case, Freight charges contracted by us on behalf of the purchaser shall be final and binding on the purchaser. 
CANCELLATION 
Order received and acknowledged by us shall not be subject to cancellation, either wholly or partly for any reason whatsoever without our written consent. 
FORCE MAJEURE 
The order from the purchaser is subject to force majeure by which it means, such as war, invasion, civil disobedience, govt. orders or restrains, strike, lockout, riots, fire, epidemics, sabotages, trade embargoes, earthquakes, floods, accidents, breakdown of machines, delay or inability to obtain labour, raw material, wagons, shipping space or any other process, which is beyond our and our supplier’s control. 

JURISDICTION 
All contracts between purchaser and ourselves are deemed to have entered into in DELHI and are therefore subject to the Jurisdiction of Courts in DELHI. 

Excluded

Extra as per actual or customer's scope

Battery Limit:-  From Collection/Equalization Tank  Up to Tertiary Treatment
Interconnecting pipe lines are included
Thickness of MS Plate shall be 5mm
Aeration Grid shall be in GI (B Class) while submerged lines shall be UPVC
All interconnecting lines shall be UPVC (40 schedule) upto 200KLD, interconnecting pipe lines shall be MSEP (B class) more than 200KLD 
Earthling/electrical/civil or not included in specification, shall be in client/customers scope