1 DESIGN OF SEWAGE TREATMENT PLANT( STP) FOR DAYANANDA SAGAR INSTITUTE , BENGALURU PiyushTomer *2 ,MD Wasiuddin *2 ,Mohammed Parvez *2 , Madhu HS *2 ,Somya HN *1 1(Assistant professor, Dept. of Civil Engineering, DSCE, Bengaluru, India) 2(Research scholar, Dept. of Civil Engineering, DSCE, Bengaluru, India) Abstract— The Dayananda Sagar College Engineering is one of the important educational institutes in the state of Karnataka with a large number of people residing in its campus consisting of a number of laboratories of various departments, residential units, academic blocks and number of hostels. A study on wastewater characterization of treatment plant will be performed followed by the design of sewage treatment plant. The whole project study involves the analysis of pH value, total solids, total suspended solids, hardness, acidity, alkalinity, chloride, chlorine, BOD, COD, DO & turbidity. A sewage treatment plant is quite necessary to receive the hostels, college and laboratories waste and removes the materials which pose harm for general public. Its objective is to produce an environmentally-safe fluid waste stream (or treated effluent) and a solid waste (or treated sludge) suitable for disposal or reuse (usually as farm fertilizer). The main purpose of Sewage treatment process is to remove the various constituents of the polluting load: solids, organic carbon, nutrients, inorganic salts, metals, pathogens etc. Effective wastewater collection and treatment are of great importance from the standpoint of both; environmental and public health. Sewage/Wastewater treatment operations are done by various methods in order to reduce its water and organic content, and the ultimate goal of wastewater management is the protection of the environment in a manner commensurate with public health and socioeconomic concerns. In this report Sewagetreatment techniques, factors affecting selection and design Sewage systems are discussed briefly. Keywords - Physicochemical parameters; sewage treatment plant; wastewater collection; designing. 1) INTRODUCTION The objective in wastewater treatment is to provide a low- cost process that is reliable meeting effluent quality standards. The contaminants in wastewater are removed by physical, chemical, and biological means. The individual methods usually are classified as physical unit operations, chemical unit processes, and biological unit processes. These operations and processes occur in a variety of combinations in treatment systems, it has been found advantageous to study their scientific basis separately because the principle involved do not change. Traditional design procedures for wastewater treatment systems attempt to minimize total capital cost by considering steady state concepts for unit processes and design guidelines. Recent work has minimized capital as well as operation and maintenance costs using a single objective function and steady state models which are flawed because plant inputs vary as much as seven-fold during a 24-hour period. This paper presents the technical aspects of the design for a sewage treatment plant with a capacity of 1000 cubic meters (m3 ) per day in Dayananda Sagar College of Engineering.
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DESIGN OF SEWAGE TREATMENT PLANT( STP) FOR DAYANANDA SAGAR INSTITUTE , BENGALURU
1(Assistant professor, Dept. of Civil Engineering, DSCE, Bengaluru, India) 2(Research scholar, Dept. of Civil Engineering, DSCE, Bengaluru, India)
Abstract— The Dayananda Sagar College Engineering is one of the important educational institutes in the state of Karnataka with a large number of people residing in its campus consisting of a number of laboratories of various departments, residential units, academic blocks and number of hostels. A study on wastewater characterization of treatment plant will be performed followed by the design of sewage treatment plant. The whole project study involves the analysis of pH value, total solids, total suspended solids, hardness, acidity, alkalinity, chloride, chlorine, BOD, COD, DO & turbidity. A sewage treatment plant is quite necessary to receive the hostels, college and laboratories waste and removes the materials which pose harm for general public. Its objective is to produce an environmentally-safe fluid waste stream (or treated effluent) and a solid waste (or treated sludge) suitable for disposal or reuse (usually as farm fertilizer). The main purpose of Sewage treatment process is to remove the various constituents of the polluting load: solids, organic carbon, nutrients, inorganic salts, metals, pathogens etc. Effective wastewater collection and treatment are of great importance from the standpoint of both; environmental and public health. Sewage/Wastewater treatment operations are done by various methods in order to reduce its water and organic content, and the ultimate goal of wastewater management is the protection of the environment in a manner commensurate with public health and socioeconomic concerns. In this report Sewagetreatment techniques, factors affecting selection and design Sewage systems are discussed briefly. Keywords - Physicochemical parameters; sewage treatment plant; wastewater collection; designing. 1) INTRODUCTION The objective in wastewater treatment is to provide a low- cost process that is reliable meeting effluent quality standards. The contaminants in wastewater are removed by physical, chemical, and biological means. The individual methods usually are classified as physical unit operations, chemical unit processes, and biological unit processes. These operations and processes occur in a variety of combinations in treatment systems, it has been found advantageous to study their scientific basis separately because the principle involved do not change. Traditional design procedures for wastewater treatment systems attempt to minimize total capital cost by considering steady state concepts for unit processes and design guidelines. Recent work has minimized capital as well as operation and maintenance costs using a single objective function and steady state models which are flawed because plant inputs vary as much as seven-fold during a 24-hour period. This paper presents the technical aspects of the design for a sewage treatment plant with a capacity of 1000 cubic meters (m3 ) per day in Dayananda Sagar College of Engineering.
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2) STUDY AREA Study Area of DSCE Campus
DSCE is located in Shavige Malleshwara Hills, 1st Stage, Kumaraswamy Layout, Bangalore, Karnataka. It is a sector of Dayananda Sagar Institutions. The institute is named after its founder, Shri R Dayananda Sagar. It is an autonomous institute affiliated to Visvesvaraya Technological University. 3) LITERATURE REVIEW Pramod sambhaji patil et.al.(2016) studied on design of sewage treatment plant for dhule city . Some treatment units are designed like screens, grit chamber, storage tank, settling tank, aeration tank and skimming tank. The effluent can also be used for artificial recharge of ground water, flushing, foam control, fire protection, lawn sprinkling . Murthy polasa et.al (2014) reviewed about design of sewage treatment plant for gated community. In this project three types of treatment unit operations are conducted. Like physical, chemical and biological processes. By increasing the detention time of sewage in each treatment unit increases the efficiency of removal unwanted impurities . M. Aswathy et al.(2017) studied on analysis and design of sewage treatment plant of apartment in Chennai. This project is studied that domestic and commercial waste and removes the material with possess harm from generated public. To produce an environmental sewage fluid waste stream and solid waste suitable from disposal of use. N. S. Ramya et al.(2015) reviewed on design of sewage treatment plant and characteristics of sewage. The growing environmental pollution need for decontaminating water results in the study of characterization of waste water especially domestic sewage. The waste water leads to developing and implementing new treatment techniques to control nitrogen and other priority pollutants.
4) FACTORS AFFECTING SELECTION AND DESIGN OF SEWAGE/ WASTEWATER TREATMENT SYSTEMS
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A. Engineering factors • Design period, stage wise population to be served and expected sewage flow and fluctuations. • Topography of the area to be served, its slope and terrain; tentative sites available for the treatment plant, pumping stations, and disposal works. • Available hydraulic head in the system up to high flood level in case of disposal into a river or high tide level in case of coastal discharges, • Groundwater depth and its seasonal fluctuations affecting construction, sewer infiltration. • Soil bearing capacity and type of strata to be met in construction and on-site disposal facilities, including the possibilities of segregating sludge and sewage and reuse or recycling of sludge water within the households. B. Environmental factors •Surface water, groundwater and coastal water quality where wastewater has to be disposed of after treatment. •Odor and mosquito nuisance which affects land values, public health, and well-being, and Public health considerations by meeting the requirements laid down by the regulatory agencies for effluent discharge standards, permissible levels of microbial and helminths quality requirements and control of nutrients, toxic and accumulative substances in the food chain. C. Process consideration • Wastewater flow and characteristics • Degree of treatment required • Performance characteristics • Availability of land, power requirements, equipment and skilled staff for handling and maintenance. D. Cost consideration • Capital costs for land, construction, equipment etc. •Operating costs including staff, chemicals, fuels and electricity, transport, maintenance, and repairs etc.
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5) METHODOLOGY Flow chart for STP
6) RESULTS AND DISCUSSION Estimation of sewage generation The current population of DSCE has been calculated for the estimation of the total sewage generation. Ultimate design period= 30 years. Approximately, present population in DCSE =8500. Assume, after 30 years population will be 11,000 (considering, 30% population will be increase) . water consumption = 135 lpcd . Assume, Sewage generation per day = 80% of supplied water Total sewage generation = 8500 × 135 × 0.8 = 9,18000 l/d We assume peak factor=3 Hence, Design flow capacity (maximum) =0.069 m3/s Since, Institution need 150KLD Hence, Total requiremnt = 150000 lpd or 1.736x10-3 m3/sec.
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STUDY OF PHYSIOCHEMICAL CHARACTERSTICS OF WASTE WATER
* Calculation for collecting pit Reterion force required = 4KN Avg design flow = 150/24 = 6.25m3/hr Capacity of collection sump = 4x6.25 = 25m3
Assume liquid depth = 4m Area, required for collection tank = 25/4 = 6.25m2
Let it be a circular tank d = 3m
* Design of sewer chamber(screen bar) Qmax = 0.001736 m3/sec Assumption, shape of bar = MS flats
Parameters Raw waste water STP Effluent
ODOR AGREEABLE NON AGREEABLE
PH 7.87 7.5
TURBIDITY (NTU) 12.7 1.8
SUSPENDED SOLIDS
(mg/l) 250 10
ALKALINITY
(mg/l) 600 200
BOD @ DAY5
(mg/l) 300 20
COD (mg/l) 503 55
DO (mg/l) 6.6 7.2
NITRATE (mg/l) 10 0.2
SULPHATE (mg/l) 415 200
IRON (mg/l) 0.3 0.0
CHLORINE (mg/l) 0.2 0.0
E- COLI PRESENT ABSENT
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Size = 10mmx50mm Clear spacing between bars= 20mm Assume At peak flow, net area required = 0.001736/0.8 = 0.00217m2 Gross received area = 0.00217x1.5 = 0.003255m2 Gross vertical area = 0.003255xsin80 = 0.003055m2 Provide depth = 0.3m Width of channel = 0.003055/0.3 = 0.0106 ≈ 0.011m Provide 20 bars of 10mmx50mm at 20mm clear spacing
* Design of Grit chamber Design flow = 150KLD Surface loading = 1100m3/sqm/day To amount for balance and short reduce the surface loading to about 600m3/sqm/day Area required = 150/600 = 0.25m2
provide 0.60m dia chamber(circular) Detention time = 60sec Volume = (150x60)/(24x3600)= 0.1042m3 Liquid depth = volume/area = 0.1042/0.25 = 0.4168m Size of grit chamber = 0.60x(0.4168+0.3) = 0.60x0.7168m
*Check for horizontal velocity Cross sectional area of grit chamber = 0.60x0.4168 = 0.25m2 Velocity = 150/(0.25x24x3600) = 0.00694m/sec = 0.6cm/sec 0.6cm/sec <18cm/sec (hence ok) Grit chamber assumed = 0.05m3 per 1000m3 of sewage flow even though the grit chamber rated still grit storage is provided for avg flow. Storage volume required = (150x8x0.05)/24x1000 = 0.0025m3 Grit storage area = 0.2826m2
Grit storage volume = 0.0025/0.2826 = 0.008846m Provide grit chamber of size = 0.6x(0.45+0.3) = 0.6x0.75m Out flow from grit chamber shall be carried to the aeration tank through a 600mm wide RCC channel provided with fine bar screen, the clear spacing between the bars shall be 100mm.
*Design of primary sedimentation tank Computation of the surface area of each channel A = 150/15 = 10m2
*Design of the hopper bottom Computation of sludge production Determination mass of primary sludge generated Asssume 60% Ms = 60% of suspended solids = 0.60x250x250x103 = 22.5x106 = 22.5kg/d = 0.93kg/hr Vs = 22.5/(998.2x1.03x0.06) = 0.3647m3/d = 0.01519x4 = 0.06m3
Hopper bottom capacity Capacity(C) = 0.01519X4 = 0.06m3 Volume(V) = H(B2+AB+A2)/3 =0.4(0.62+0.4x0.6+0.42)/3 = 0.10133m3 Compute depth for the tank bottom slope Assuming 6% slope of tank bottom Ds = (6-0.6)x0.06 = 0.324m Depth of bottom slope = 0.165m Free board = 0.3m D = 2.5+0.30+0.324+0.4 = 3.524m ≈ 3.6m Overall length (20% increase) = 1.2x6 =7.2m L = 7.2m B = 2m Diameter of sludge removal pipe = 100mm Design of aeration tank
Average flow = 150 m3/ day Total BOD entering STP = 300 mg*/L Assuming that negligible bod is removed in screening & grit chamber , BOD left is the effluent Y= 20/mg/L The BOD of sewage coming to aeration tank Yo= 300mg/L The BOD left in Effluent = 20 mg/l Maximum efficiency required = 280/300 = 93% Volume of aeration taken area be designed by assuming suitable values of ML SS = 3000mg/l (3000-3500mg/l) F/M ratio = 0.15 F/M=O/V = Yo ___ Q=100, V=$ YT Yt = 3500mg/L 0.15=3500mg/L 0.15= 150*300 ______=86m3 V*3500 T=[V] ___*24 Length = 4m
Assuming factor of safety 2*0.09 = 0.18m3/mm Required =1620/150 =10.8 m3 =1620/(200-14.36)*20=0.436 m3/kg of BOD
Power Required for Diffuse Aeration Pf=1.1L ___ =1.037 1.08 80% of efficiency Pt = 1.05 ___ 0.80 =1.31=1.5 Hence Power = 1.5 BHP Two Segment each of 0.8120Hp
(i)Complete ratio & flow to be required (Q+Qr)
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Q=0.78 Q=0.78*150 LCD =117 LCD
Sludge Waste Ratio 1. (86*3500)
____________=3.76m3/d 10*(0.8*10000)
2. Qw V 86 __ ___ 8.6m3/d 0c 10
Mass of Sludge to be washed per day Mass = Mass of solids –mass of suspended Yas =Y ________ 1+Kd*Qc Px = 0.3125 *150*(200-14.30) = 8.7Kg/d _______ 105 Px = Px 8.7 __ __ =10.87Kg/d 0.8 0.8 10.87-3.75 =7.125Kg/d
Sludge drying beds Sludge applied for drying beds = 100Kg/ MLD Sludge applied =7Kg/d +22.5 =30Kg/d Specific Gravity=1.015 Solid Content =1.5% Volume of Sludge = 30 1 __ _______________=1.96m3 1.5% 1000*1.015 Period of Each Cycle = 365 ___ =11 days 33 Volume of Sludge = 2*11=22m3 Speeding a layer of 0.3m/ Cycle Provide 4 Beds of 5*4 m Area provided = 80mz area Sludge tank dimension = 3m*2.7m*3m
Decant Tank(Secondary Clarifier ) Unliec other treatment process in SSB the classified water tank is designed to ideal decant prove each batch is 86m3/ batch This Classified water tank dimension (4*3*4)*2 8*3*4m
Final collection tank Depending upon amount of water in decant tank Volume = 8m*3m*4m
Second Type STP Every thing is same grit chamber and collection pit is replaced by equalization tank
Equalization Tank Design avg flow= 150KLD Destaration time =12 Hrs Volume =150*12
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_____ = 75m3 24 Dimension=6m*4m*3.5m
Tertiary treatment units
The wastewater after biological treatment still contains some solids, colour, odourand harmful micro-organisms. The pressure and filter and activated carbon filters are used to remove the solids and colour. The disinfection rocess is used to remove the micro-organisms and odour.
Pressure sand filter
Pressure sand filter with various grades of pebbles and sand media help in the removal of residual suspended solids. The filter will be operating in the pressure range of 3-3.5 kg/cm2. Residual suspended solids. The filter will be operating in the pressure range of 3-3.5 kg/cm2
Assuming a loading rate of 6.0 m / hr. Design flow = 150 m3 /day and considering 20 hr/day of operations of PSF The recommended PSF dimension is 1.2 dia and height 3 m. Suitable designed Backwashing system is adopted.
Activate Carbon Filter
Considering the same parameters for designing the activated carbon filter, the recommended dimensions for ACF is 1.2 m Dia and height 3.0 m
Disinfection
In order to disinfect the treated effluent various disinfection methods like chlorination, ozonation etc can be used. However chlorination is proved to be cheaper and relatively effective. Hence the same system is adopted. The chlorine can be administered in the form of liquid or solid (bleaching powder) into the treated effluent channel. An automatic electronic metering system can be chlorination and to allow residual chlorine of more than 1 mg/1 in the treated effluent.
Thus the final treated water is used for gardening, flusing, car wash etc.
Detail Drawings of Proposed STP Units, DSCE Map, DSCE Sewer line Map for New and Old STP
ENTRY
NEWSTP
OLDSTP
PRESENTSEWER LINE
DSCE CAMPUSSEWER LINE MAP
ENTRY
NEWSTP
OLDSTP
OLD STPSEWER LINE
NEW STPSEWER LINE
DSCE CAMPUSMODIFIED SEWERLINE MAP
EQUALIZATION TANK
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12 mm Dia Bars @ 100 c/c
10 mm Dia Bars @ 100 c/c
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SEWAGE TREATMENT PLANT REINFORCEMENT
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7) CONCLUSION The ultimate goal of wastewater treatment is the protection of the environment in a manner commensurate with public health and socio-economic concerns. Based on the nature of wastewater, it is suggested whether primary, secondary and tertiary treatment will be carried out before final disposal.The results obtained from the study suggest that the conventional activated sludge has low degree of flexibility and treatment efficiency: however ,the attached growth technologies are remarkably superior in pollutant elimination even of low HRT from residential waste water. Therefore the project that we took in relating the design and analysis has been successfully carried out and completed with the requiring details and information that is related and hence the process, nature, requirements, sample and tests which has been in accordance to the project has been conducted by our team.
8) REFRENCES 1). Manual on water supply and treatment, C.P.H.E.E.O., Ministry of Urban Development; Government of India, New Delhi. 2). Manual on Sewerage and Sewage Treatment, C.P.H.E.E.O.,Ministry of Urban Development; Government of India,New Delhi. 3). Jayshree Dhote, Sangita Ingole (2012); Review on Wastewater Treatment Technologies. 4). International Journal of Engineering Research and Technology. pp. 2-5. 5). IS: 3025 (PART 10) – 1984, Methods of sampling and test for water and wastewater. 6). IS: 4764 – 1973, Permissible limits for sewage effluents in waste water. 7). A.K. Jain; Environmental Engineering, Khanna Publishing House. 8). S.K. Garg; Water supply and Sewage Disposal Engineering Vol 1&2, Khanna Publishing House. 9). Tchobanoglous, George; Burton, Franklin L.; Stensel, H. David; Metcalf & Eddy, Inc. (2003). 10) .Wastewater Engineering: Treatment and Reuse (4th ed.). McGraw-Hill 4. 11).Sanjay Kumar; Sanghi, Rashmi (2012). Advances in Water Treatment and Pollution Prevention. Springer 12)Waste water treatment concepts and design approach , G L Karia, R A Christian.
