COPY RIGHTS : TO AVOID COPYRIGHT VIOLATIONS, ALL POSTS ARE SHOWN ALONG WITH SOURCES FROM WHERE ITS TAKEN. PLEASE CONTACT ME IN MY EMAIL SALEEMASRAF@GMAIL.COM , IF YOU ARE THE AUTHOR AND YOUR NAME IS NOT DISPLAYED IN THE ARTICLE.THE UNINTENTIONAL LAPSE ON MY PART WILL BE IMMEDIATELY CORRECTED.

I HAVE SHARED ALL MY PRACTICAL WATER TREATMENT EXPERIENCES WITH SOLVED EXAMPLE HERE SO THAT ANYBODY CAN USE IT.

SEARCH THIS BLOG BELOW FOR ENVO ,COMPACT STP,ETP,STP,FMR,MBBR,SAFF,IRON,ARSENIC,FLUORIDE,FILTER,RO,UASB,BIO GAS,AERATION TANK,SETTLING TANK,DOSING,AMC.

SEARCH THIS BLOG

Thursday, January 01, 1998

AZHARS BIRTH DAY

 

Syed Muhammad Azhar

DOB: 09/11/2005,

Not before 01/04/2005 , not later 31/03/2006

 

supplier of swimming pool delhi

 

Garv Marketing (Swimming Pools/Construction - Delhi)
Contact: Rakesh Sethi
D-16, Anand Niketan, New Delhi: 110001, Tel. No.26887225
Durga Hi Tech Engineers (Swimming Pools/Construction - Delhi)
Contact: Devender Singhal
9988-c, Yadav Bhawan, New Rohtak Road, New Delhi: 110005 Tel. No.25719275
Hindustan Millenium Pools (Swimming Pools/Construction - Delhi)
Contact: B K Grover
7A/3Rd Floor, Eok, Sant Nagar (S), New Delhi: 110065, Tel. No.26222923
Jean Desjoyaux Pvt Ltd (Swimming Pools/Construction - Delhi)
Contact: Sanjay
C-77, Preet Vihar, New Delhi: 110067, Tel. No.9810002853
Kalia Enterprises (Swimming Pools/Construction - Delhi)
Contact: Ashwani Kalia
103, Phase 3, Okhla Indl Estate, New Delhi: 110020, Tel. No.26313777
Nita Enterpirses (Swimming Pools/Construction - Delhi)
Contact: Ashok Soni
A 46, Part 2, South Extn, New Delhi: 110049, Tel. No.26255242
Oasis Leisure (Swimming Pools/Construction - Delhi)
Contact: Ramesh Nambiar
2, Hauz Khas Village, New Delhi: 110016, Tel. No.26963482
Potent Water Care Pvt Ltd (Swimming Pools/Construction - Delhi)
Contact: Mr. Devender Singhal
32 Csc12, Sector 3, Rohini, New Delhi: 110085, Tel. No.9810296455
Premium Pools (Swimming Pools/Construction - Delhi)
Contact: Vivek Mishra
402 Jop Plaza, Sector 18, Noida, Noida: 201301, Tel. No.9811217106
Prime Water Corporation (Swimming Pools/Construction - Delhi)
Contact: Chander Mehra
Gh-2/23-A, Ankur Apartments, Paschim Vihar, New Delhi: 110063, Tel. No.9811652120
Prince Traders (Swimming Pools/Construction - Delhi)
Contact: 05
G 20/2Nd, Green Park Main, New Delhi: 110016, Tel. No.26861577
Sushma Engg (Swimming Pools/Construction - Delhi)
Contact: Vinod
1810, 1St Floor, Kotla Mubarakpur, New Delhi: 110003, Tel. No.24621614
Swimware (Swimming Pools/Construction - Delhi)
Contact: Ashish Khanna
A-41, Chetak Apartments, Sector-9, Rohini, New Delhi: 110085, Tel. No.9810550560

SUPPLIER SOLAR WATER HEATING SYSTEM DELHI

Oorja Solutions

  • Business type: wholesale supplier, importer
  • Product types: photovoltaic modules, photovoltaic systems, solar water pumping systems, solar garden lights, solar roofing systems, solar outdoor lighting systems.
  • Address: G-56, Pankaj Central Market, I.P.Extnsion, Delhi, Delhi India 110092
  • Telephone: +91-9811047670
  • FAX: +91-11-22471667
  • Web Site: http://www.oorjasolar.com
  • E-mail: Send Email to Oorja Solutions

AAA Electronics

  • Business type: manufacturer, retail sales, wholesale supplier, exporter, importer
  • Product types: LED lighting, solar air heating system components, solar electric power systems, solar garden lights, solar roofing systems, steam turbine electric generators.
  • Address: 4/5845 Street No 6 Dev Nagar Karol Bagh New Delhi, New Delhi, Delhi India 110005
  • Telephone: 09818770179
  • FAX: 011-25138837

Catalyst Renewable Energies (P) ltd

  • Business type: manufacturer, retail sales, wholesale supplier
  • Product types: hydro energy system components (small), wind energy system components (small), solar roofing systems, hybrid power systems, backup power systems, sealed lead acid batteries.
  • Address: 252, Aravali Apartments, Alaknanda, New Delhi India 110019
  • Telephone: 9811599967
  • FAX: 91-11-26482709

Jet-Electro Mech Engg. Pvt. Ltd

  • Business type: manufacturer, designer, Retail sales, wholesale supplier
  • Product types: On-Line UPS (On-line ups)single phase and three phase, Line interactive ups, Digital inverters, stablizers, Constant voltage stablizer ( CVT ), SERVO VOLTAGE STABLIZERS SPECIAL KIND OF SERVOS, CVT, STABLIZER IS ALSO MANUFACTURED AS PER REQUIREMENTS UP TO VERY HIGH RATINGS OTHERS ELECTRONICS CIRCUITS DEVELOP AS PER REQUIREMENTS ISO 9001: 2000 CERTIFICATION w jet-electro com or the1234dotcom SOLAR INVERTERS, solar electric power systems, solar outdoor lighting systems, solar roofing systems, solar street lights, solar lantern, home lighting systems, street lighting systems, solar accessories, emergency lights, solar products.
  • Service types: on line ups AMC, Annual Maintenance Contract, quality manufacturing & designing
  • Address: 146 Patparganj Main Market, Delhi 91, Delhi, India 110091
  • Telephone: +91-11-22755877,22792249, 22758225, 0-9810610239

ROYAL INDIA SOLAR

  • Business type: manufacturer, wholesale supplier, retail sales, exporter, importer
  • Product types: CENTRAL HEATING WITH SOLAR ENERGY (NO ELECTRICITY REQUIER), SOLAR POWER FOR PAY & DISPLAY PARKING MACHINES, SOLAR AIR-CONDITIONER, COOLING & HEATING OF HOTELS- HOSPITAL-AND COMMERCIAL UNITS, SOLAR (AC/DC) HYBRID INVERTERS, SOLAR LED LIGHTS, LED LANTERNS, LED GARDEN LIGHTS, DC CEILING & TABLE FANS, SOLAR INVERTER, PHOTOVOLTAIC MODULES, REMOTE HOME POWER SYSTEMS, SOLAR GARDEN LIGHTS, SOLAR OUTDOOR LIGHTING SYSTEMS, RADIO CONTROLLED CARS WITH RACE TRACKS, SOLAR WATER HEATING SYSTEMS,SOLAR POOL HEATING,SOLAR SPACE HEATING,SOLAR ROOFTOP SYSTEMS, SOLAR LANTERN, COOL CAPS, SOLAR/DYNAMO RADIO, SOLAR VENTILATOR,SOLAR MOBILE PHONE CHARGER, COMPLETE RANGE OF SOLAR ROAD SAFETY PRODUCTS INCLUDING SOLAR POWERED ROAD STUDS & SOLAR DELINEATOR,MICRO-HYDRO TURBINES (1 K.W TO 200 K.W),MICRO-HYDRO TUBEWELL TURBINE (NEW INVENTION)TO GENERATE ELECTRICITY WITH TUBEWELL WATER FLOW..
  • Service types: consulting , design, engineering, project development services etc.
  • Address: ROYAL (INDIA) TECHNO-PROJECTS PVT.LTD -- RZ-95,Street no. 9, Near Nirankari Satsang Ashram,New Uttam Nagar,, New Delhi, Delhi India 110059
  • Telephone: 0091-11-25633872 Mobie No. 0091-9891926299 & 9891450054
  • FAX: 0091-11-25633872

Sunflower Solartech (India)

  • Business type: Supply of solar equipments, inverters, batteries, ups,charge controllers etc.
  • Product types: energy efficient homes and buildings, rechargeable batteries, solar electric power systems, solar garden lights, solar water pumping systems, solar roofing systems, All solar related equipment.
  • Service types: Installation/Erection of solar projects
  • Address: New Delhi, India 110018
  • Telephone: 9213564876
  • FAX: 91-11-26216972

SUNPOWER engineering Co.

  • Business type: retail sales
  • Product types: photovoltaic systems, photovoltaic module mounting systems, hybrid power systems, solar roofing systems, solar charge controllers, building integrated photovoltaic systems, Specialization in Solar Photovoltaic -Utility Grid / D G Hybrid Systems for House holds, Industry and Academic Institutions, Total Power Solutions..
  • Service types: consulting, design, installation, engineering, project development services, site survey and assessment services, architectural design services, contractor services, maintenance and repair services
  • Address: B- 27, CEL Apartments, Vasundhara Enclave, Delhi, Delhi INDIA 110096
  • Telephone: +919810510495
  • FAX: +911122633988

http://energy.sourceguides.com/businesses/byGeo/byC/India/byP/solar/sroof/sroof.shtml

negative health effects of drinking softened water

Health risks

There has been much publicity over the years about the negative health effects of drinking softened water, but recent research showed that the amount of salt consumed by drinking softened water is insignificant when compared to overall daily salt intake. Anyway over the past 25 years research has continued to amass in support of the beneficial role of minerals in water: studies of populations in areas of naturally occurring hard water and soft water have found few occurrences of cardiovascular diseases, cancer, diabetes, respiratory diseases or other health problems in hard water areas.
A domestic, innovative system, which can be used to get perfectly balanced proportions of minerals good for our health in drinking water, is provided by Lenntech. For more information go to our home water filter web page.

In the draft of the rolling revision of the WHO guidelines for drinking-water quality, titled 'Health risks from drinking demineralised water' by F. Kožíšek, the possible health consequences of low mineral content water consumption are divided in the categories: direct effects on the intestinal mucous membrane, practically zero calcium and magnesium intake, low intake of other elements, loss of calcium, magnesium and other essential elements in prepared food, possible increased dietary intake of toxic metals, possible bacterial re-growth.

 

More information on drinking water purification systems for domestic water

 

Direct effects on the intestinal mucous membrane

It has been demonstrated that consuming water of low mineral content has a negative effect on homeostasis mechanisms. Homeostasis literally means 'same state' and it refers to the process of keeping the internal body environment in a steady state. In his publication Kožíšek states that "experiments in animals have repeatedly shown that the intake of demineralized water leads to diuresis (increased urination caused by substances present in the kidney tubules), extra cellular fluid volume and serum concentration of sodium and chlorine ions and their increased elimination from the body, lower volumes of red blood cells and other hematocritic changes (alteration of the number of red blood cells)". A German study carried out by th German Society for nutrition proved instead that if distilled water is ingested, the intestine has to add electrolytes to this water, taking them from the body reserves. After the ingestion of distilled water the electrolytes dissolved in the body water are further dilute. Inadequate body water redistribution may compromise the function of vital organs.

In the past, acute health problems were reported in mountain climbers who had prepared their beverages with melted snow. which was not supplemented with necessary ions. A more severe course of such a condition coupled with brain oedema, convulsions and metabolic acidosis was reported in infants whose drinks had been prepared with distilled or low mineral bottled water (CDC 1994).

 

Practically zero calcium and magnesium intake
Calcium  and magnesium  are essential elements for our body. They can be provided to our organisms by food, but even the diets rich in calcium and magnesium intake may not be able to fully compensate their absence in drinking water.
Calcium is part of bones and teeth. In addition, it decreases neuromuscular excitability, is beneficial to the conducting myocardial system, heart and muscle contractility, intracellular information transmission and blood clotting. Osteoporosis is the most common manifestation of calcium deficiency; a less common but proved disorder attributable to Ca deficiency is hypertension.
Magnesium plays an important role as a cofactor and activator of more than 300 enzymatic reactions including glycolysis, ATP metabolism, transport of elements such as sodium (Na), potassium (K) and calcium through membranes, synthesis of proteins and nucleic acids, neuromuscular excitability and muscle contraction etc. It acts as a natural antagonist of calcium. Magnesium deficiency increases risk to humans of developing various pathological conditions such as vasoconstrictions, hypertension, cardiac arrhythmia, atherosclerotic vascular disease, acute myocardial infarction, preeclampsia in pregnant women, possibly diabetes mellitus of type II and osteoporosis (Rude, 1998; Innerarity, 2000; Saris et al, 2000).

Researches and studies proved that water low in magnesium can cause increased morbidity and mortality form cardiovascular disease, higher risk of motor neuronal disease, pregnancy disorders, preeclampsia. Water low in calcium may be associated with higher risk of fracture in children, certain neurodegenerative diseases, pre-term birth and low weight at birth. Lack both in calcium and in magnesium can also cause some types of cancer.

 

Water hardness and cardiovascular disease

Over 80 observational epidemiological studies relating hardness and cardiovascular disease risks  have been realized and their results had been discussed by experts at the meeting organized by the WHO European Centre in Rome on November 11-13, 2003. The conclusions are quoted in the WHO report titled: 'Nutrient minerals in drinking-water and the potential health consequences of long-term consumption of demineralized and remineralized and altered mineral content drinking-waters', published in August 2004.

It was observed a positive (protective) association between cardiovascular disease mortality and increased water hardness in countries around the world, both for population and on individual-basis. It was then supposed that these beneficial health effects can possibly be extended to large population groups on a long- term basis by adjusting the water quality.

It was pointed out that magnesium and possibly calcium may be effective in reducing blood pressure in hypertensive individuals. Nutritional studies suggest that some other micronutrients may have a beneficial role associated with their presence in drinking water, even is they have not extensively considered in these epidemiological studies yet. More studies are needed to better understand the possible risks and benefits of essential and trace elements found in water.

The discussion group concluded there is sufficient epidemiological evidence of and inverse relationship between magnesium concentration in drinking water and ischemic heart disease mortality, and therefore the reintroduction into demineralised water in the remineralisation process would likely provide health benefits. There are, in fact, no known harmful human health effects associated with the addition magnesium within a large range and the nutritional benefits are well known. It is thought that adding calcium provides the same benefits, however, a correlation between calcium in drinking water and decreases in the occurrence of heart disease is not yet proven substantially. 

 

Low intake of some essential elements

The contribution of water to uptake of some essential elements for humans is important because the modern diets are often not an adequate source of some minerals. Moreover these minerals are often present in water as free ions, so they are more readily adsorbed from water compared to food. Recent epidemiological studies suggest that low mineral drinking water may be a risk factor for hypertension and coronary heart disease, gastric and duodenal ulcers, chronic gastritis, goitre, pregnancy complications and several complications in infants. A study of this kind conducted in 1992 by Lutai on two populations living in areas with different levels of dissolved minerals showed that the population of the area supplied with water low in minerals showed higher incident rates of these disease. Children living in this area exhibited slower physical development and more growth abnormalities, pregnant women suffered more frequently from oedema and anaemia.

 

High loss of calcium, magnesium and other essential elements in food prepared with low mineral water

If soft water is used for cooking it can cause substantial losses of all essential elements from food. In contrast, if hard water is used, the loss of these elements is much lower. Since the current diet of many people does not provide all the necessary elements in sufficient quantities, it is important to not loose essential elements and nutrients during cooking. Therefore, in the areas supplied with soft water, we have to take into account not only a lower intake of magnesium and calcium from drinking water but also a lower intake of magnesium and calcium from food due to cooking in such water.

 

Risk from toxic metals

Low mineralised water is highly aggressive to materials with which it comes into contact. It  easily adsorbs metals and some organic substances from pipes, coatings, storage tanks and containers. Moreover, calcium and magnesium in water and food are known to have an antitoxic activity: they can prevent the absorption of some toxic elements from the intestine into the blood. Population supplied with low-mineral water may be at a higher risk in terms of adverse effect from exposure to toxic substances compared to populations supplied with water of average mineralization. Calcium and to a lower extent also magnesium in both drinking water and food were previously found to have a beneficial antitoxic effect since they prevent – via either a direct reaction resulting in an no absorbable compound or competition for binding sites – absorption or reduce harmful effects of some toxic elements such heavy metals.

 

Possible bacteria contamination of low-mineral water

The bacterial re-growth is encouraged by the lack of a residual disinfectant and by the possibly great availability of nutrients in aggressive water, such the low-mineral water, particularly if it has a high temperature.

 

Harmful effects of hard water

No evidence is available to document harm to human health from harder drinking water. Perhaps only a high magnesium content (hundreds of mg/l) coupled with a high sulphate content may cause diarrhea. Other harmful health effects were observed in water rich in dissolved solids (above 1000 mg/l of TDS) showing mineral levels that are not common in drinking water. In areas supplied with drinking water harder than 500 mg/l CaCO3, higher incidence rates of gallbladder disease, urinary stones, arthritis and arthropathies as compared with those supplied with softer water were reported (Muzalevskaya et al, 1993). An epidemiological study carried out in a particular region (Tambov) found hard water (more than 400-500 mg/l of CaCO3) to be possible cause of higher incidence rates of some diseases including cancer (Golubev et al, 1994).

 

Sensorial disadvantages of hard and soft water
Higher water hardness may worsen sensorial characteristics of drinking water or drinks and meals prepared with such water: formation of a layer on the surface of coffee or tea, loss of aromatic substances from meals and drinks (due to bonding to calcium carbonate), unpleasant taste of water itself for some consumers.
Very soft water, such as distilled and rain water as two extreme examples, is of unacceptable taste for most people who usually report it to be of unpleasant to soapy taste. A certain minimum content of minerals, the most crucial of which are calcium and magnesium salts, is essential for the pleasant and refreshing taste of drinking water.

 

Fluoride in drinking water

Most drinking waters contain some fluoride. Processes such anion exchange, demineralisation and some other treatments which will remove it, affecting its concentration.

High levels of excess fluoride intake cause crippling skeletal fluorosis. This is almost always associated with high fluoride intake from drinking water. Ingestion of excess fluoride during tooth development, particularly at the maturation stage, may also result in dental fluorosis.
The optimal drinking water concentration of fluoride for dental health is generally between 0.5 to 1.0 mg/litre and depend upon volume of consumption and uptake and exposure from other sources. These values are based on epidemiological studies. The WHO drinking water quality guideline value for fluoride is 1.5 mg/l. The US Environmental Protection Agency has set a Maximum Contaminant Level of 4.0 mg/l in the US based upon prevention of crippling skeletal fluorosis and a guidance of 2.0 mg/l to avoid moderate dental fluorosis.

A decision to use demineralised water as drinking water sources without addition of fluoride during remineralization will depend upon many factors: the concentration of fluorine in the existing local supply, the volume of water consumed, the prevalence of risk factors for dental caries, oral hygiene practices, level of public dental awareness, presence of alternative vehicles for dental care and fluoride available to the whole population.

              

 

Desirable mineral content of demineralised drinking water

In the late 1970's, the issue of an optimum composition of drinking water, particularly if obtained by desalination, was in the centre of attention of the WHO. The WHO also emphasized the importance of mineral composition of drinking water and warned e.g. against the use of cation exchange sodium cycle softening in water treatment (WHO, 1978; WHO, 1979).

In the 1980's the wave of interest in the effect of water hardness on cardio vascular diseases morbidity rather subsided; it seemed that any new insight into the issue could not be expected. The focus was on confirming the role of magnesium as a crucial factor of hardness and on first attempts of more general quantification of its protective effect.

In the 1990 criticisms of the existing studies started to make a new challenge to publications of further studies. These critics asserted that morbidity was evaluated at a population group based level, rather than at an individual-based level and individual exposure to calcium and magnesium from water was not established. In other studies, the confounders possibly involved in cardio vascular diseases morbidity such as age, socio-economic factors, alcohol consumption, eating habits, climatic conditions etc. were not adequately taken into account.

Most new epidemiological studies of the 1990's were able to specify the effect of either calcium or magnesium and also focused on morbidity other than cardio vascular diseases. During the 90's research confirmed a protective effect of both drinking water magnesium and calcium against cardio vascular diseases, and more data on beneficial effect of these elements in drinking water on human health were presented.

More recent studies have provided additional information about minimum and optimum levels of minerals that should be in demineralised drinking water. These studies suggest for magnesium a minimum of 10 mg/l and an optimum of 20-30 mg/l, for calcium a minimum of 20 mg/l and an optimum of about 50 mg/l, for fluoride an optimum of 0.5 – 1 mg/l and a maximum of 5 mg/l. For total water hardness the sum of calcium and magnesium should be 200 to 400 mg/l.

At these concentrations, minimum or no adverse health effects were observed and the maximum protective or beneficial health effects of drinking water appear to occur.

Conclusion and recommendations
Minerals are important parts of drinking water and are of both direct and indirect health significance. Sufficient evidence is now available to confirm that a certain minimum amount of minerals in water is desirable, since their deficiency have many negative health effects: diseases and possible aggression from toxic elements and bacteria.
The optimum Ca and Mg levels in drinking water should lie within the following ranges: from 20 to 30 mg/l for Ca and from 40 to 80 mg/l for Mg and from about 200 to 400 mg/l for water hardness.
Unfortunately, over the past two decades little research attention has been given to the beneficial or protective effects of drinking water substances. 
As recommended in the rolling revision of the WHO guidelines for drinking water quality, titled: 'Nutrient minerals in drinking-water and the potential health consequences of long-term consumption of demineralised and remineralized and altered mineral content drinking-waters', there is a need for more precise data on the impact of water composition and intake under a broader range of physiologic and climatic conditions, in order to more precisely evaluate the importance of minerals in drinking water on mineral nutrition. Additional studies should be conducted on potential health consequences associated with consumption of both high and low mineral content waters in addition to consideration of water hardness. When studies are conducted, investigators should consider exposures to both calcium and magnesium levels in combination with other minerals and trace elements that may be present in hard and soft waters. National governments and water suppliers should be encouraged to practice stabilization of demineralised water with additives that will increase calcium and magnesium levels and to conduct studies that monitor public health impacts. Community and bottled water suppliers should provide information to the general public and health professionals on the composition of water for constituents including possibly beneficial substances. Water bottlers should also consider providing waters with mineral compositions that are beneficial for population segments.

saleem asraf syed imdaadullah
Syed Envo Protect (I) Pvt Ltd
311/22, Zakir Nagar, New Delhi-25
Landline:011-26985165
Mobile:9899300371
email: saleemasraf@gmail.com
blog: http://saleemindia.blogspot.com
web site : www.envo.8m.com

calculators online for activated sludge process

 
 
saleem asraf syed imdaadullah
Syed Envo Protect (I) Pvt Ltd
311/22, Zakir Nagar, New Delhi-25
Landline:011-26985165
Mobile:9899300371
email: saleemasraf@gmail.com
blog: http://saleemindia.blogspot.com
web site : www.envo.8m.com

DESIGN ASPECTS OF ACTIVATED SLUDGE PROCESS...http://www.flygt.se/1260859.pdf

 
 
saleem asraf syed imdaadullah
Syed Envo Protect (I) Pvt Ltd
311/22, Zakir Nagar, New Delhi-25
Landline:011-26985165
Mobile:9899300371
email: saleemasraf@gmail.com
blog: http://saleemindia.blogspot.com
web site : www.envo.8m.com

DESIGN EXAMPLE OF ACTIVATED SLUDGE PROCESS


Design Examples...

Design Example of Conventional Activated Sludge Process...

An activated sludge system is to be used for secondary treatment of 10,000 m3/day of municipal wastewater. After primary clarification, the BOD is 150 mg/L, and it is desired to have not more than 5 mg/L of soluble BOD in the effluent. A completely mixed reactor is to be used, and pilot - plant analysis has established the following kinetic values ;
  • Y = 0.5 kg / kg
  • kd = 0.05 1 / day
Assuming an MLSS concentration of 3,000 mg/L and an underflow concentration of 10,000 mg/L from the secondary clarifier, determine ;
  • The volume of the reactor
  • The mass and volume of solids that must be wasted each day
  • The recycle ratio
"Schematic Diagram of the System"...


Solution...
"Reactor Volume"...
"Excess Solids"...

"Mass Balance"...


Design Example of Extended - Aeration Activated Sludge Process (Package Plant)...

A prefabricated package plant is to be used to treat the wastewater from a resort area consisting of 550 individual family residences. The average occupancy has been estimated to be 2.9 persons per residence. Use a flow of 230 L/person.day and a daily peaking factor of 2.5 for flow, BOD5 and SS. Use an hourly peaking factor of 4 for sizing the sedimentation facilities. Select the type of package plant and size the principal components of the plant. Effluent BOD5 concentration of the process must be or lower than 30 mg/L.

Solution...

  1. The total number of person : (550 home)(2.9 person/home) = 1,595 person
  2. The corresponding average flowrate : (1,595 person)(0.230 m3/person.day) = 366.85 m3/day
  3. The corresponding peak daily flowrate : (366.85 m3/day)(2.5) = 917.13 m3/day
  4. The average BOD5 load : (1,595 persons)(80 g BOD5/person.day) = 127,600 g BOD5/day
  5. The corresponding BOD5 concentration : (127,600 g/day) / (366.85 m3/day) = 348 g/m3 (mg/L)
  6. The average SS load : (1,595 persons)(90 g SS/person.day) = 143,550 g SS/day
  7. The corresponding SS concentration : (143,550 g/day) / (366.85 m3/day) = 391 g/m3 (mg/L)
  8. The peak daily BOD5 load : (127.60 kg BOD5/day)(2.5) = 319.00 kg BOD5/day
  9. The peak daily SS load : (143.55 kg SS/day)(2.5) = 358.88 kg SS/day
  10. An extended aeration activated sludge process package plant is selected
  11. The aeration time : 1.0 day
  12. The aeration tank volume : (366.85 m3/day)(1.0 day) = 366.85 m3
  13. The oxygen transfer efficiency : 6 %
  14. The specific weight of air : 1.26 kg/m3
  15. The oxygen content : 23.2 %
  16. The air requirement : (319.00 kg BOD5/day) / (1.26 kg/m3)(0.232)(0.06) = 18,187.83 m3/day
  17. The peak hour factor for the settling tank : 4
  18. The overflow rate for settling tank : 24 m3/m2.day
  19. The surface area of settling tank : (366.85 m3/day)(4) / 24 m3/m2.day = 61.14 m2
  20. The hydraulic detention time for settling tank : 0.5 h
  21. The volume of the settling tank : (366.85 m3/day)(4)(0.5 h) / 24 h/day = 30.57 m3


Design Example of SBR...

A sequencing batch reactor activated - sludge process is to be used to treat wastewater with the characteristics given below. Determine the mass of suspended solids in the reactor over a 7 - day operating period. The effluent is to have 20 mg/L of BOD5 or less. Determine also the depth of clear liquid measured from the top of the settled sludge to the lowest liquid level reached during the decant cycle. Use the following design criteria and constraints.

Data...
1 - Influent flow-rate = 3,800 m3/day 10 - Concentration of settled sludge = 8,000 mg/L
2 - Influent suspended solids = 200 mg/L 11 - Settled sludge specific gravity = 1.02
3 - Influent VSS = 150 mg/L 12 - 60 % of reactor volume will be decanted each day
4 - Wastewater temperature = 20 °C 13 - Liquid depth of SBR = 6.60 m
5 - Hydraulic detention time = 24 h 14 - Sludge wasting is done once a week
6 - F/M = 0.1 kg BOD5/kg MLVSS.day 15 - 65 % of effluent is biodegradable
7 - MLVSS/MLSS = 0.80 16 - BOD5 = 0.68 BODL
8 - Y = 0.65 kg/kg 17 - BODL of one mole cells = 1.42 times of X
9 - kd = 0.05 1/day 18 - C : N : P is suitable



Day

Average BOD5 (mg/L)

1

250

2

400 *

3

400 *

4

400 *

5

400 *

6

250

7

250

*

Increase over 250 mg/L is soluble BOD

Solution...

  1. Biodegradable portion of effluent biological solids = (0.65)(20 mg/L) = 13.0 mg/L
  2. Ultimate BOD of the biodegradable effluent solids = (13.0 mg/L)(1.42 mg/mg) = 18.5 mg/L
  3. BOD5 of effluent suspended solids = (18.5 mg/L)(0.68) = 12.6 mg/L
  4. Influent soluble BOD5 escaping treatment = 20.0 mg/L - 12.6 mg/L = 7.4 mg/L
  5. Tank volume = (3,800 m3/day)(1.0 day) / 0.60 = 6,333.33 m3
  6. MLVSS = (3,800 m3/day)(250 g/m3)(10- 3 kg/g) / (6,333.33 m3)(0.1 kg/kg.day) = 1,497 g/m3
  7. Total SS in the reactor = (200 - 150 mg/L) + (1,497 mg/L) / 0.80 = 1,921 mg/L
  8. The mass of VSS in the reactor = (6,333.33 m3)(1,497 g/m3)(10-3 kg/g) = 9,481 kg
  9. The total mass of SS in the reactor = (6,333.33 m3)(1,921 g/m3)(10-3 kg/g) = 12,166 kg

    "Mass of SS in the Reactor"...

    "Solid Production"...

  10. The net mass of VSS in the system at the beginning of 1st day = (0.65)(250 - 7.4 g/m3)(10-3 kg/g)(3,800 m3/day) - (0.05 1/day)(9,481 kg) = 125 kg/day
  11. The mass of inert SS added in 1st day = (200 - 150 g/m3)(10-3 kg/g)(3,800 m3/day) = 190 kg/day
  12. The mass of SS at the end of 1st day = 12,166 kg/day+125 kg/day / 0.80+190 kg/day = 12,512 kg

Results...

Day

BOD (mg/L)

Px (kg/day)

SSi (kg/day)

VSST (kg/day)

SST (kg/day)

1

250

125

190

9,590

12,512

2

400

487

190

10,077

13,289

3

400

462

190

10,539

14,055

4

400

439

190

10,978

14,794

5

400

417

190

11,395

15,505

6

250

27

190

11,422

15,728

7

250

26

190

11,448

15,950



Calculation of Oxygen Requirement...

Calculate oxygen requirement of a complete - mix activated sludge process treating domestic wastewater having flowrate of 0.25 m3/sec. BOD5 concentration of settled wastewater is 250 mg/L. The effluent soluble BOD5 is 6.2 mg/L. Increase in the mass of MLVSS is 1,646 kg/day. Assume that the temperature is 20 °C and the conversion factor, BOD5 / BODL is 0.68.
"Oxygen Requirement"...


Design Example of Final Settling Tank...

A column analysis was run to determine the settling characteristics of an activated sludge suspension. The results of the analysis are shown below.
"Results of the Column Analysis"...


The influent concentration of MLSS is 3,000 mg/L, and the flow rate is 8,000 m3/day. Determine the size of the clarifier that will thicken the solids to 10,000 mg/L.

Solution...

1. Calculate the solids flux from the above data : G = MLSS (kg/m3) . Velocity (m/h)
"Results of the Solid Flux"...


2. Plot solids flux vs. MLSS concentration as shown below. Draw a line from the desired underflow concentration, 10,000 mg/L, tangent to the curve and intersecting the ordinate. The value of G at the intersection, 2.4 kg/m2.h, is the limiting flux rate and governs the thickening function.
"Solid Flux vs MLSS Concentration"...


3. Determine total solids loading to the clarifier.

(8,000 m3/day)(1/24 day/h)(3,0 kg/m3) = 1,000 kg/h

4. Determine the surface area of the clarifier.

(1,000 kg/h) / (2.4 kg/m2.h) = 416.7 m2

5. Calculate the diameter of the clarifier.

SQRT[(4/3.14)(416.7 m2)] = 23 m

6. Check clarification function.

(8,000 m3/day)(1/24 day/h) = 333 m3/h

(333 m3/h) / (1.21 m/h) = 275 m2

Result...

Because 275 m2 < 416.7 m2, the thickening function governs the design.

Design Results of an Extended Aeration ASP...
Parameter Result
Value Unit
Influent parameters
Population equivalent 45,000 pe
Average daily flow 11,500 m3 / day
Average daily flow 133 L / s
Peaking factor 1.80 -
Design flow 863 m3 / hr
Design flow 240 L / s
PWWF 25,000 m3 / day
PWWF 289 L / s
PWWF 1,042 m3 / hr
BOD design load 3,150 kg / day
Aeration tank
F / M 0.05 kg BOD / kg MLSS . day
MLSS concentration 4,000 mg / L
Aeration volume required 15,750 m3
HRT @ avg flow 32.9 hr
HRT @ design flow 18.3 hr
Approximate tank size
Depth 4.0 m
Width 35.0 m
Length 112.5 m
Secondary clarifier
SVI 150 g / mL
Sludge volume load 0.06 m3 / m2 . day
Surface area required 8,625 m2
Overflow rate 0.10 m3 / m2 . hr
Diameter 104.8 m
Average depth 3.5 m
Volume 30,188 m3
HRT @ average flow 6.3 hr
HRT @ design flow 3.5 hr
Sludge handling
Sludge production rate 0.95 kg TS / kg BOD
Sludge production 2,993 kg TS / day
Days storage in aeration tank 2.6 by incr. MLSS by 0.5 kg / m3 . day
Days storage in aeration tank 5.3 by incr. MLSS by 1.0 kg / m3 . day
Volume @ 0.8 % 374 m3 / day
HRT thickener 18.0 day
Volume thickener 6,733 m3
Height 4.0 m
Diameter 46.3 m
HRT @ 2 % 45 hr
Volume @ 3 % 99.8 m3 / day
HRT 67 day
Dewatering capacity 15.0 m3 / hr
Dewatering duration 46.6 hr / week
Dewatering volume @ 18 % 16.6 m3