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Public Health Engineering © First national water policy 1987. * Air prevention & control of pollution Act - 1981. «— Water prevention & control of pollution Act - 1974. « — The Environment protection Act - 1986 m= Types of Water Demand- i, Domestic Water Demand- Per Capita Demand (q)- _ Total yearly water requirement of the city in litre 4 365 Design population @ = Max. daily demand = 1.8 x Avg. daily demand. © Max. hourly demand = 1.5 x Avg. demand hourly of As per IS 1172: 1993 Max. day. own Lig | Hig ||* Max. hourly demand or peak demand 2.7 x Avg. ped) | (ped) hourly demand. Bathing 55 75 Coincident/Dratt Demand: - It is maximum daily demand when added to fire Flushing of water closets 30 | 45 draft for working out total draft. Washing of cloths 20 25 max. daily demand + Fire demand 5 F @ = Itisthemax.of Washing utensils 10 15 sapbaMNraRtaRd Washing the house 10 15 Peak Factor- Lawn watering & gardening - 15 Max hourly water di d Cooki 5 5 Peack factor =————>—_____ ooking Aveg.daily water demand Drinking 5 5 Total] 135 | 200 Peak factor ¢ =——~—— Population HIG = High income group LIG = Low income group Population Peak Factor ii Industrial water demand- Upto 50,000 3 Total water demand = 20 - 25% of the total demand 50,000 - 200000 2.5 of the city. > 200000 2 iii, Fire demand- | liter per capita per day For Rural Water supply iy. Water losses and theft- 10 - 15% of total demand. Water Demand in India- As per IS : 1172-1993, Total quantity of water. {a) For high income group (full flushing system)- 200 (domestic) + 135 = 335 lped. Fire Demand 15 Iped Public Use 25 Iped Industrial Use 40 Iped Losses, Wastage thefts 55 Iped Domestic Purpose 135 Iped Total 270 Iped {b) For low income group (without flushing system)- 135 (domestic) + 135 = 270 Iped. Domestic Demand 200 Iped Public use 10 Iped Industrial + Commercial Demand | 70 Iped Losses and thefts 55 Iped ‘Total | 335 Iped Peak Hours- The peak demand for water is usually from 6AM to 9AM and from 6PM to 8PM these are called peak hours of water demand. Note- © Max. consumption may be raised upto 200% of the avg. daily demand. @ Fire Demand Formula- For smaller towns (P < 50,000) fire demand is not calculated. e Bouston's formula - e Freeman'sformula - Q=l 130(2 Mm, 10) « Kuichling's formula - * National board or fire Under writes formula- |Q =4637VP(1—0.01VP) Engineering Capsule 2.0 118 YCT © Asper manual of the ministry- liter (P > 50000) Where, Q =Required quantity of water (ltr/min) P = Population (thousands) & Population forecasting methnd- (i) Arithmetic increase method- (Suitable for older and larger cities) (ii) Geometric increase method- (For young and rapidly developed cilies) Assumption- % in population increase from one to another decade remains constant, r\y Pp, =P,(14—_ 00} (iii) Incremental Increases method- —, nint+)Dy PL =P,+ a nx (iv) Zoning/Master plan/density method (best method)- This method is prepared by dividing the city into various zones such as residential, commercial, industrial ete. and population densities for these zones are predetermine. (v) Logistic curve/Decreasing rate of growth method- As per P.F. Verhulst. It is used when the growth rate of population due to births, deaths and migrations are given. py) —py log H-E |-log FAP joe t 5 es : P. Where, P, = Saturation population, k = Constant P, = Population at the starting point P = Population at any time, t = time in years {vi) Ratio and Correlation method (vii) Growth composition analysis method (viii) Graphical extension method (ix) Comparative graphical method lm Design period of water supply components- Storage reservoirs/Dams 30 Infiltration works 30 Conveying pipes for raw water 30 & clear water Distribution system, pump 30 house and pipe connection to several treatment units Water Quality Parameter + + ¥ A. Physical B. Chemical C. Biological 1. Colour 1. Chlorides 2. Suspended Solid 2, Dissolved gases 3. Taste and Odour 3, Iardness 1. Organic matter & Microorganism 3. Biological activity 4. Temperature 4. pH value 5. Turbidity 5. Alkalinity 6. Acidity 7, Metals & other chemical substances 8. Total solid Odour is based on pO value- pO Value Indication 0 No Perceptible odour 1 Very Faint odour 2 Faint odour 3 Distinct odour 4 Strong/very distinct odour 5 Extremely/very strong odour @ Measurement of Turbidity- Turbidity A aluminium rod with platinum Rod needle is inserted in water then the (field method) |depth at which platinum needle becomes invisible gives turbidity in PPM. Jackson's It is based on the principle of light Turbidity absorption. meter e It is suitable, if turbidity > 25 (Laboratory |ppm. method) Nephelometer|It is a technique to measure level of light scattered by the particles at right angles to the incident light beam or scattering principle. Components Design period It measure low turbidity with in years very high precision. Water treatment units 15 It is based on a colour matching Electric motors and pumps 15 technique and used for measuring, low turhidity < 1 . Balancing tanks Service 15 ow turbidity < Ppm feSeevOIES head wets > Bluc cobalt plate is used. Civil Engineering Capsule 2.0 119 YCT = Alkalinity— Major source- HCO; , CO,” andQH™ Minor source- HS” ,HSiO;, HPO,” m Nitrogen content- Free Ammonia or |It indicates. first stage! Ammonia nitrogen |decomposition of organic) matter and recent pollution. @ Potable water $0.15 mg/f Albuminoid Ammonia or Organic Nitrogen It indicates quantity of nitrogen present in water in the form o! under composed organic matter. @ Potable water + 0.30 mg/l. Nitrite show the presence of! Nitrite(NO;~) partly oxidized organic matter. It is very dangerous for health. @ Permissible amount- 0 (zero). Nitrate (NO; ) - |Nitrate, represent the fully’ oxidized organic matter. @ Permissible limit- 45 mg/l. Dissolved Solids(D.S.)- It consist of inorganic salts like sulphates, chlorides, bicarbonates and carbonates etc. [Ds. = Electrical conductivity p(mho/cm)x 0.65] | Dissolved solids = Total solid — suspended solid] Coliform Test- i. Presumptive test- * If total coliform is present then the test is known) as presumptive test. le If gas is produced, it indicates B-Coli. le = Negative result indicates water is fit for drinking. ii, Confirmed test- When in test water sample fecal coliform is| present then test is known as confirmed test. Completed test In this case water sample is presentation of E-coli bacteria tested for! B-Coli Index- @ It is a number or index which represent number of B-Coli per C.C. of sample of water. @ B-Coli index varies - 3 to 10. E-Coli (Escherechia coliform)- It is present in intestine of people and animal. They are harmless non-spore forming gram negative bacteria. Most probable number (M.P.N.) MPN is a method used to estimate the concentration of available micro-organisms in a sample. @ It indicates the bacterial density/consistency present in water. @ MPN removes the drawback of B-Coli index. 2 BOD: . Shape of bacteria Name It is defined as the anon of onygen required by Spherical Con He Caeas bacteria in decomposing organic matter under Rod Bacilli aerobic condition at 20°C over a period of $ days. Twisted rod Spirilla ® BODafter 5 days at 20°C is taken as standard BOD. Spiral curve B piral curve Spirallum [BOD, = Oxygen consumed x Dilution factor/ratio] Irregular Vibrio Chain Streptococus =[[D.O)initias — (D-O.) tinai] * dilution factor] Double Diplococus Single Cocei or Cocus LJ Dilution factor/ratio = Final volume Sample volume Parameters Diseases [Non-biodegradable organic - COD — Ultimate BOD Absence of fluorides | Dental, fragile bones, skelctal fluorosis m@ Total Standard Bacteriological Test- e Excess of lead Anemia Total Count or Agar Plate Count ‘Test- Excess nitrates Methcmoglobinemia or |e Hot Count—Sampleare placed for 24 hour at 37°C. blue baby syndrome * Cold Count- Sample arc placed for 48 hour at 20°C Absence ofiodine | Goitre + For Potable watcr, Total count # 100per C.C. Excess of chlorides | Hyperchlorcmia Engineering Capsule 2.0 121 YCT w As Per IS : 10500 : 2012 Drinking Water Magnesium (Mg) 30 100 Property of Types of test/instrument Maw: 7 0.1 03 water used for measurement eparcne-(Mn) - — - Phenolic Compounds 0.001 0.002 Ilardness EDTA Method (C,H;OH) Turbidity Turbidity meter’ Nephlometer/Jacsion Sulphate (SOs) 200 400 turbidity meter Zinc (Zn) 5 15 Bacteria count MPN test, Membrane filter Copper (Cu) 0.05 15 technique Free residual chlorine 0.2 1 pil Potentiometer, Aquascope Total dissolved solid 500 2000 Colour Tintometer, Nesler tube Moxie Chemicals Parameccn Dissolved Winkler's method Calcium (Ca) 15 200 Davee 0.01 0.0: Arsenic (As. ; .05 Organic matter | BOD Test, COD Test rsenic (AS) Cadmium (Cd) 0.003 No Taste and Odour | Osmoscope relaxation Total dissolved Di-ionic tester Lead (Pb), Selenium 0.01 No solid (Se) relaxation Chlorides Mohr's method Silver (Ag) 0.1 No Volatile solid Muffle furnace relaxation Settleable solid Imhoff Cone Mercury (Hg) 0.001 No relaxation Specification- Treatment method for various impuriti Water Quality Acceptable! Permissible Impurities Treatment method Parameter Limit Limit Floating objects | Screening (mg/h (Mesh) (Larger and heavy) Physical Parameter Suspended solids | Sedimentation Turbidity LsTy SNTU Colloidal solids | Sedimentation with Colour STCU 15 TCU coagulation Taste and odour 1 TON 3 TON Micro-organisms | Filtration, Disinfection Chemical Parameter Dissolved gases _| Aeration Alkanity 200 600 Colour Adsorption through activated ; carbon, chlorination, pH value 6.88.5 Ho. sedimentation and coagulation relaxation oy Turbidity Coagulation with Hardness (CaCOs) an 500 Sedimentation, filtration Chlende (C1) 20 000 Taste & odour Chlorination, filtration Free NH; 0.15 No Sedimentation, Coagulation relaxation Adsorption Nitrate (NO;) 45 No Hardness Zcolite process, Lime soda relaxation method Nitrite Nil oo Steps of water treatment- Fluoride (F) 1 15 Serccning —> Prc-Scdimentation — Acration > ~ Coagulation & Flocculation » Post Sedimentation Tro Fe) a3 No —+ Filtration — Disinfection + Water softening > relaxation Cine: Distribution. Civil Engineering Capsule 2.0 122 YCT Back wash velocity 45 cm/min. Max. head loss 2.5 to 3.0 meters Contact period- 20 minute Residual chlorine- 0.10-0.20 ppm m@ Circular Sedimentation tank- Useful for small treatment plant. « Flowing rate at surface area- 2000 ihrs./m? Volume of tank, m@ Pressure filters- « It is less efficient than the rapid gravity filters in removing bacteria and turbidities. « — It may be horizontal or vertical type and used for the treatment of industrial or swimming water. Rate of filtration |6000-15000 //hrs/m” of filter area. Diameter tank 15-3m Depth 3-8m. @ Order of effectiveness of chemical compound- HOCI > ClO, > Cl, > Chloramines| e = |NH,+Cl,—*>HCl + NH,Cl (Monochloromines) e |NHCI, +Cl,—“<++HCl + NHCl, (Di-chloromines) Water for back washing |2 - 4% of total water Dewble . in this method. chlorination is-done at filféed chlorination two different points during the water treatment process Uniformity Coefficient, C, | 1.3 - 1.7 7 . : : 5 - Break point |Tt is the differonce of applicd chlorine Nuliber.of init N=122/Q chlorination |& residual chlorine beyond Q = Plant capacity in breakpoint MLD. Residual chlorine at this stage = 0 Loss of head Initial- 30 em Super It is a application of chlorine beyond Final- 3m chlorination | the stage of break point. Removal of turbidity 40 ppm residual chlorine — 0.2 to 0.3 ppm De- Chlorination Use to removal of excess chlorine from water Dechlorination Chemical compounds - Sodium thiosulphate (Na;$20;) Sodium bisulphate (Naz H SO.) Sodium meta sulphate (Na; S; Os) Sulphur dioxide (SO,) (Gas/liquid form) Sodium sulphite (Na2SO3) Potassium permagnate (KMnO,) Activated carbon Testing of Chlorine Residue- Orthotolidene Test ii, Chlorotex Test Starch Iodide Test iv. Colour matching method v. DPD (Diethyl! Phenylene diamine) test Note- © Alum is better coagulent when raw water is alkaline with high turbidi m De-fluoridation- The removal of fluoride from drinking water is known as de-fluoridation. . a. b. c. d. e. f. g . © |NHCI, +Cl, #4 4HCI + NCI, | Methods to remove excess fluorine- (Clitvogen trichloromines) Tr Chiloriaats Activated Alumina |It is an excellent medium to m Types o! lorinadion* remove excess fluorine along Plain Done if water is only chlorinated. with NaOH solution. chlorination | And turbidity<10 NTU Activated carbons |It is based on adsorption Dose- 0.5 mg/ltr. technique. Ext Chlorine is added _before| Nalgonda method |Aluminium salts responsible chlorination |Sedimentation, filtration, coagulation for removal of fluoride from hia . ground water. Residual chlorine- 0.1 - 0.5 ppm Normal dose- 5 - 10 ppm. Reverse Osmosis /It is & simple Solition for (R.O.) process removing fluoride from Post- Chlorine added after the filtration (hyper filtration) | drinking water. Chlorination | Process . « Efficiency — 85-92%. Engineering Capsule 2.0 124 YCT Electro-dialysis Membranes allow the ions to pass but not the water. Bone charcoal It is the oldest known de- Flexible/Universal Bituminous Joint Used where pipes laid in soft and marshy soil and settlements of ground occurs. fluoridation technique used Victaulic Joint Suitable for steel and iron pipes, and also successfully removes which are laid in the exposed arscnic from water. position. Ton exchange Efficiency- 90 - 95%. Screwed and|Used for low diameter steel and absorption Socket Joint galvanized iron service pipes technique It is usually used in pipe fitting * Nalgonda technique uses alum with prior mixing of inside homes. lime (CaO) or sodium carbonate (Na,COs). Collar Joint It is leak-proof joint adopted for @ Desalination- It is the process of removing salts or other minerals and contaminants from sea water, blackish water, and waste water. Method of Desalination- (i) Freezing of water, (ii) Evaporation (iii) Reverse Osmosis (iv) Electrodyalysis Note- © Copper sulphate is used to removal of algae from water. Activated carbon is used to control taste and odour and to remove fluoride from water. w Layout of water distribution- © Dead Suitable for old cities where end/Tree/closed the houses come up in a System unplanned way. Grid iron System/|It is provided and more Interlaced/Reticular| suitable for well planned System cities. Ring/Circular The supply main is laid all System along the peripheral roads and sub mains branch out from the mains. Radial System Supply pipes are laid radially ending towards the periphery and water flow towards these large dia. hume-pipes, asbestos) cement pipe and concrete pipes. = Order of tapping water- Service main —> Applying ferrule > Goose neck — Stopcock — Meter mw Types of Valves- Shut-off/Gate/Bib cock/SInice Valve Installed in the pipeline to regulate and control the water flow. Reflux/Check/Non- Returning valve It allow the water to flow in one direction only or check the flow of| ‘water in the reverse direction. Air/automatic/Air Relief valve Provided at the summit point of] water mains to release the accumulated air. Pressure Relief’ safety/ automatic cut-off valve To Reduces excessive pressure in the pipe line. Scour /Blow-off/ drain /wash-out valve Installed at the low level (depression or valley) dead ends of the pipe line and removes sand & silt. Butterfly Valve Placed on the distribution pipes to control water like a sluice valve Float Ball Valves {Installed in service tanks/domestic water storage tanks to maintain fixed water level. outer periphery. @ Types of Pipe Joints- Pipe joint Use Socket and spigot|It is permanent Joint and mostly Joint used to connect cast iron pipes Flanged Joint ‘Used for connecting pipes carrying water under high pressure and where the vibration is high. Expansion Joint /Used where expansion or shrink fin length occurs duc to change of | atmospheric temperature. @ Nature of sewage- Fresh Sewage Stale sewage Slightly alkaline Acidic Sewage Liquid (99.9%) Solid (0.1%) Organic solid Tnorganie solid (45%) (55%) Civil Engineering Capsule 2.0 125 YCT Circular Sewer} Suitable for separate sewerage|| ™ Size of Various Pipe Used in Sanitary— Dia. < 80 cm system. Pipe Diameter (mm) (economical) |e It can carry max. discharge and Baad self cleaning velocity can be Soil pine 190 achieved casily. Waste water pipe Semi-Circular | Suitable for large sewers with Horizontal 30-50 Sewer Icss available headroom. Vertical 75 - 100 Egg-shaped/ It is highly adopted for large Vent Pipe 50 ‘i sewers which built up on the site. Oval Serer . e Rain Water Pipe 150 e Adopted for both separate and combined systems. Anti-siphonage pipe 50 * Most efficient for main and trunk|| m Types of trap- sewers. — A . an ; Anti siphonage/|It prevents siphon action during @ It givesthigher velocity at-lowest grevak/resealing flushing and does not allow the flow. , . trap 'vessel’s water-seal to break. Inverted Egg -| Best f in, trunk and outfall 7 A ted ave hed Sohiee Hints EDES Sosa Floor/Nahani Trap) This trap is installed at the each Shaped Sewer | sewers. floors to collect liquid waste Semi-elliptical |e More stable and adopted for soft from bathrooms, Kitchens, Sink, Section soil. ‘wash basin and verandah etc. Dia. > 1.8m. sa i W.C. Pan (Basin)|It is a glazed china-ware trap Horse-shoe Suitable for outfall sewer, mostly Trap filled below the W.C trap. type sewer used in tunnels. Anti-siphon pipe is used for this (Dia.- 1.8 m) trap. Note- Gulley/Yard Trap |Waste water coming from the © Decreasing order of sewer size- Outfall sewer > kitchen, bathroom and wash Main sewer > Lateral sewer > House sewer. basin is dumped in the gulley Manhole is provided at- trap before releasing it into the i. Starting point ii. Junction of pipeline domestic sewer. iii, Change ofdirection iy. Change of diameter Intercepting It is used to prevent the entry of y. Change of gradient vi. Crossing of roads Trap/Sewer sewer gases from public sewer vii, 30 m to 300 m in straight length of the sewers. Trap/Master Trap |line into the house drains. m@ Spacing of Manholes (IS : 4111/1742 : 1960)- @ Pipes used in sanitary system dae (cm) of Manhole interval Rain Water/down| Used to bring the rain water ewe (m) Pipe from the roof to the Various <30 45 type of pipes 31-60 15 Soil Pipe ‘Used to flush the sewage from 61-90 90 the flush latrinc. 91-120 120 Waste Water Pipe |Installed to take out waste water from bathrooms, kitchens, wash 121-150 250 ‘basins etc. > 150 300 Vent Pipe and|Provided for ventilation purpose Drop Manhole- Anti-Siphonage to. facilitate the exhaust of foul Pipe gases into the atmosphere. It is provided, when two sewers (main & branch) flowing at different levels have a vertical gap of more than 60 cm in the intersecting water levels. pipe. Cowl is a perforated cap provided at the top of vent Civil Engineering Capsule 2.0 127 YCT Water proofness testing of sanitary pipes- i, Air test ii, Smoke test iii, Colored water test iv. Ilydraulic Test y. Smell Test Water Closet (W.C.) Pan- It is connected to the sewage pipe by a trap on its bottom. Characters of Waste Water (Sewage) t + Physical Characteristics. Chemical Characteristics (which can be sensed) — (which cannot be sensed) (i) Suspended solids (i) Total dissolved solids (ii) Temperature (ii) Alkalinity (iii) Turbidity (iii) Hardness Biological Characteristics (Biological activity) Micro-organism Organic matter (iv) Colour (iv) Dissolved oxygen (D.O.) ‘Aerobic Bio-degradable \(v) Taste/Odour (v) Chemical oxygen demand (C.0.D.) i hi (vi) Bin-chemieal oxygen demand (B.0.D.) Paculalive Noii-bio-degradeable (vii) Oxygen consumed (O.C.) (viii) Nitrogen content (ix) Fluoride (x) Chloride content (xi) Metals (xii) Dissolved gages Note- ii, Medium Note- = Sonoscope is used in detection of leakage in sereen- © inclination of screen should be underground water mains. (Opening size6 | 39°. 60°. © COD- It indicates biodegradability of the waste water. 40 mm) Fine screen removes 20% COD = Biodegradable organics + Non-Biodegradable organics. THOD = COD 2 BOD 2 TOC (Total organic compound) BOD =(DO, - DO,) x Dilution factor. Tests for B.O.D.— (i) Direct Method— In this method, sewage-sample is placed in a special vessel in contact with a fixed volume of oxygen. {ii) Dilution Method- 5- days B.O.D. = Loss of oxygen x Dilution ratio (mg/litre) B day B.O.D. =[(D.0.) nist — (D-O.)rinat] * Dilution factor] Note- = HNO, H,CO;, H,SO, present in acidic rain. BODs _6go,], |BODw — 990, BOD,, BOD,, + For B.O.D. test size of bottle- 300 m/. = B.O.D of municipal sewage 100-500 mg//. PRIMARY TREATMENT- Under this treatment, floating and suspended organic matier mixed in sewage is removed. - iii. Fine screen (Opening size 1.5 - 3mm) suspended particles. Grit chamber ( Installed before primary sedimentation tank) It removes inorganic grit/ suspended particles whose S.G > 2.65 and eff. size of] particles > 0.2 mm. Detention period - 40 - 60 sec. Flow velocity- 0.15-0.30 m/sec. Depth- 1-1.8m Detritus Tank {It removes grit and fine sand particle whose effective size < 0.2 mm. Detention period- 3 - 4 min. Flow velocity- 0.9 m/sec. To separate grease, oil and other smooth substance from sewage. Skimming Tank Detention period, 3 - 5 min. Grease‘Trap Grease and oil traps are used to Name of Treatment Activity exclude grease and oil from waste Treatment ater: Sereens Used to remove large size on i. Coarse sereen [Particles as suspended solids,|| # Sedimentation Tank- or racks leaves, paper rags, straws,|| It is done to remove fine suspended and dissolved (opening size--45° |B**>4Be; Bravel, sand. substances. mm) It fulfill 30 - 35% BOD demand. Engineering Capsule 2.0 128 YCT Sludge recycle and rate of return sludge- Qn Xe Q X,-X, (iot/svD 7 Where, Various unit of sludge treatment- @ Oxidation pond- Septic tank Width 0.9m Length 2 - 3 times the width Depth 12-1.8m Free board 0.30 m Detention period 12 - 36 hr. Cleaning period 6 month - 3 year) Rate of sludge accumulation 30 lit./person/ycar Area (each unit) 0.2 - 0.4 hectare Depth 1-18 COD reduction 25 - 50% Detention time 2 - 6 weeks (168 - Dissolved matter/suspended |60 - 70% 1008) hrs. solids removal capacity B.O.D. removal 80 - 90% m@ Stages in Sludge Digestion- Pathogenic bacteria remove |99.9% 1, Acid The fresh sewage sludge begins Sludge accumulation 2-5 em/year Fermentation/ |to be acted upon by anaerobic = ; Acid and facultative bacteria called Length of tank (L¥ 750m) |3 * width of tank production _|acid formers. Suspended solid removal | 90% stage Duration- 7-15 days Organic loading Hot —_countries-150- pH value- 5-6. (In kg/hectare/day) 300 ; 2. Acid Organic acids and nitrogenous (Cold countries- 60. - Regression [Compounds are decomposed to 90 form carbonate and ammonia like = Oxidation ditch- elements. © — Itis a modified form of activated sludge process. Duration- 3 month e Very high efficiency. PH value increases- 6-7. . In the oxidation ditch, the excess sludge is taken to 3. Alkaline This sludge is granular and drying beds. Fermentation |stable and does not give Sewage loading rate 2.5 m’/kg/day offensive odors. Detention period 10 - 15 hours Duration- > 1 month. BOD removal 98 - 99% © Digested sludge pH > 7. suspended solids 95% @ = Order of sludge digestion- removal Acid Fermentation > Acid regression — Alkaline Shape Oval fermentation. Length 200 - 1000 m @ B.LS Standards for Sewage Disposal Width 1-5m Parameter | Domestic Industrial sewage Depth 1-1.5m sewage = BOD removal for various units is given below: Discharge |Into surface | Surface Public Unit BOD removal % water source | Waler Sever Oxidation Ditch 98% BODS 20ppm_ [30 ppm [500 ppm Oxidation pond 90% pH - $.5-9.0 5.5-9.0 Aerated lagoons 65 - 90% Suspended] 30 ppm |100ppm |600 ppm Trickling filters 80 - 90% solid Civil Engineering Capsule 2.0 130 YCT m Sewage Treatment as per Dilution Factor- Dumping on | Garbage is taken out of the slum and Dilution Sewage treatment level land dumped in low-lying sites or pits. factor Pulverization| This method of waste disposal is = 500 No treatment is required. Raw sewage adopted in advanced Countries can be directly disposed into river. Composting |This is ccologically adoptable method 300-500 | Sewage should be released into the of solid waste disposal. river after its plain-sedimentation so ¢ For Rural areas, preparing manure that the volume of suspended solids from waste is the best way to should not exceed 150 PPM. dispose it 150-300 | Sewage should be scdimented with Burien | eis acopted forrurel areas, condensation, so that the amount of - - - solids suspended in the effluent docs Feedingto | This method is quite popular in not exceed 60 PPM. Hogs western countries & America. 8-150 The sewage should be treated || @ Air Pollutions are Classified as- extensively. The content of suspened ‘Types of Pollutants solids should not be *30 ppm and 5 day B.O.D should 420 ppm. Natural Pollutants Anthropogenic Pollutants e Dust 4 <8 The sewage should be completely || poticns treated before it discharge into water. ¢ Fores fire Primary Pollutants Secondary Pollutants © Volcanoes @ Zone of pollution in river system- i. Zone of clear water- Dissolved oxygen rise up to its saturation value clear water, and presence of fishes. Zone of degradation- D.O. level falls due to the decomposition of organic matter in this zone. Water becomes dark and turbid . Fishes may present while algae are absent. . 1. @ (ii) (iii) Primary Pollutants (90%) Finer particles (dia. < 100u) Coarse particles (dia. > 1001) Sulphur dioxide (SO) (Prime constituent of air pollution) Oxides of nitrogen (NO, NO) Carbon monoxides (CO) (iv) (vy) (vi) Halogen compounds iti, Zone of active decomposition- (vii) Volatile organic compounds > In this zone exist heavy pollution and water is very | (viii) Lead (Pb) dark and turbid. (ix) Radioactive substances > — D.O. level falls to zero and critical oxygen deficient | 2, Secondary Pollutant (10%) OSEUFE. It is formed due to interaction between two primary » Fishes and algae are absent in this zone. or more pollutants. iv. Zone of recovery- i. Ozone (O;) ii, Formaldehyde (CHO) > Level of D.O. is increases and may reach to PAN (Peroxy acetyl ntrate) iv. Smog saturated value. v. Photochemical Smog, vi. Formation of acid mist Fishes and algae are re-appear. vii. Sulphuric acid viii, Chlorofluorocarbon ( CFC) Ways to disposal af garbage- = Composition & Structure of Atmosphere— Throwing It is a simple method of waste eaves PELE IRIS CHD) eR COPEL into Sea disposi, ‘Troposphere |0- 11 15° to— 56°C Where there is lack of proper place to Stratosphere [11-50 —56° to— 02°C dump the garbage it is burnt in the /Mesosphere 50 - 85 02° to —92°C Incineration formaces. a 0 * Most suitable method for urban Thermosphere /85 + 500 Bohteil 2005 area. Exosphere > $00 >1500°C Engineering Capsule 2.0 131 YCT 
