There are two different kinds of Wastewater: 1. Domestic Sewage 2. Industrial Effluent
Human health protection from
- Pathogens,
- Chemicals
Environmental Protection with removal of
- BOD and COD
- Nutrients (e.g., N and P)
- Metals
Recovering of useful products like aquifer recharge and potable water)
Removal of
- Endocrine System disrupting compounds (EDCs),
- pharmaceuticals,
- personal care products (PPCP)
Treatment chemicals (e.g., lime)
As the world has industrialized and its population has growing, the problem of water pollution has intensified. With numerous factories having no choice, other than to inject untreated effluents directly into the ground, contaminating underground aquifers.
Another cause of water contamination is improper strategy of sewage treatment. Since human waste contain bacteria that can cause disease. Once water becomes infected with these bacteria, it becomes a health hazard. There are following sources of sewage effluent as:
- Residential apartment
- Commercial complex
- Public amenities/convenience
- Labour camp/Defence/Refugee camp
- Resorts & clubs
- Factories/Industries
Waste management is the collection, transport, processing, recycling or disposal, and monitoring of waste materials, without affecting humans and other life systems and without disturbing the environment. The term usually relates to materials produced by human activity either at home / office / industry / agricultural fields / mines etc. and is generally undertaken to reduce their effect on health, the environment or aesthetics. Waste Management is also carried out to recover resources from it.
Sewage / Effluent Treatment Plant is a facility designed to receive the waste from domestic, commercial, and industrial sources and to remove materials (containing physical, chemical, and biological contaminants) that damage water quality and compromise public health and safety when discharged into water receiving systems.
Key Components of treatment:
1. Sewage / Effluent collection tank: Where preliminary, effluent is collected.
2. Screening: Any solid materials like; iron particles, stones, plastic items, grassweed, polythene, paper, cloth etc. are checked through bar screen filter to avoid any damages of the transferring pump.
3. Equalization tank: In which, suspended material is mixed properly to make a homogeneous mixture. And stirring arrangement is employed in the tank.
4. Neutralization tank: Some chemicals are added for maintaining pH, and for quick flocculation.
5. Settler: After neutralization and flocculation of effluent, the suspended matter undergoes settling which is called sludge. Sludge tank: the settles sludge is collected into this tank.
6. Aeration tank/Bio reactor: where biomass is digested in aerobic condition. A mechanical aeration system is adopted in the tank for growth of bacteria which digest the biomass.
7. Lamella filtration: After aeration of effluent, it allows to further settling with certain contact time.
Gradually all solids matter deposits at the bottom while the liquid water passed to PSF
8. Pressure sand filter (PSF): Used to remove suspended impurities from the water.
9. Activated carbon filter (ACF): De colorize and De-odorize any smell or colour in the water.
10. UV/chlorination disinfection: After de-odorizing of water, it is disinfected by either UV (ultraviolet) or with chlorine. So that all types of micro-organisms, pathogens are killed before going to further use.
11. Final water discharge: The discharged water is used for various purpose like, gardening, cleaning, irrigation, car washing
Before we go into the discussions of various aerobic biological treatment processes, it is important to briefly discuss the terms aerobic and anaerobic. Aerobic, as the title suggests, means in the presence of air (oxygen); while anaerobic means in the absence of air (oxygen). These two terms are directly related to the type of bacteria or microorganisms that are involved in the degradation of organic impurities in wastewater and the operating conditions of the bioreactor. Therefore, aerobic treatment processes take place in the presence of air and utilize those microorganisms (also called aerobes), which use molecular/free oxygen to assimilate organic impurities i.e., convert them into carbon dioxide, water, and biomass. The anaerobic treatment process, on the other hand takes place in the absence of air (and thus molecular/free oxygen) by those microorganisms (also called anaerobes) which do not require air (molecular/free oxygen) to assimilate organic impurities. The final products of organic assimilation in anaerobic treatment are methane, carbon dioxide and biomass.
The removal of dissolved and particulate biological oxygen demand (BOD) and the stabilization of organic matter present in water can be achieved biologically using variety of microorganisms. They are responsible to oxidize the dissolved and particulate carbonaceous organic matter to mineral constituents of CO2 and H2O.
- Suspended-growth processes
- Attached-growth processes
- Combined processes
- Lagoon processes
BOD: biological oxygen demand (BOD) is the amount of oxygen required by aerobic biological microorganisms to decompose organic material in water at certain temperature over a period.
COD: chemical oxygen demand (COD) is a measurement of the oxygen required to oxidize soluble and particulate organic matter in water using a strong oxidizing agent.
COD values are always greater than BOD values because COD captures both biodegradable and non-biodegradable substances, whereas BOD only entails biodegradable ones.
Nitrification: The two-step biological process by which ammonium (NH4+) is converted first to nitrite (NO2-) and then to nitrate (NO3-).
DE nitrification: the biological process by which ammonia (NO3-) is converted to nitrogen (N2) and other gaseous end products.
Sewer Line, Septic Tank, Wastewater Treatment plant
As a Wastewater treatment technology, MBR is a superior technology compared to conventional activated sludge processes (CASP) in which a membrane replaces secondary settling tank of the conventional ASP to separate effluent from activated sludge. The main advantages of MBR technology compared to conventional activated sludge process are:
- smaller aeration tank and footprint due to the higher mixed liquor suspended solids (MLSS) concentrations and higher volumetric loading rate,
- lower sludge production, and
- improved Treated water quality owing to membrane filtration.
Fouling propensity of the membranes is evaluated through monitoring pressure drop across the membranes, which is referred to as trans-membrane pressure (TMP), and recovery rate. High TMP values and low recovery rate indicate that membranes are fouled and need to undergo cleaning.
Submerged MBRs are generally less energy intensive than side-stream MBRs, as employing membrane modules in a pumped side-stream crossflow demand high energy consumption due to the high pressure and volumetric flows imposed.
Removal of wastewater constituents such as rags, sticks, floatable, grit, and grease that may cause maintenance or operational problems with the treatment operations, processes, and ancillary systems.
Removal of a portion of the suspended solids and organic matter from the wastewater.
Enhanced removal of suspended solids and organic matter from the wastewater, typically achieved by chemical addition and/or filtration.
Removal of biodegradable organic matter (in solution or suspension) and suspended solids. Disinfection is also typically included in the definition of conventional secondary treatment.
Removal of residual suspended solids (after secondary treatment) usually by granular media filtration or micro screens. Disinfection is also typically a part of tertiary treatment. Nutrient removal is often included in this definition.
IN MBR context, based on the definition, no fouling is observed below critical flux, while above critical flux fouling occurs.
The selection of pre and/or post-treatment technologies is a function of feed water quality, discharge requirements, and application. Typically, screening and oil & grease removal is required prior to MBR to protect membrane’s surface from any possible damage caused by aggregates of hair or debris.
There are two main reasons for aeration:
- To provide dissolved oxygen (DO) for maintaining a viable microorganism population for biological treatment.
- To keep MLSS in suspension.
Typically, anaerobic digestion (methanogenic treatment) is being implemented for sludge treatment. This can be performed under two different temperature conditions:
The process by which the nitrate (NO3-) nitrogen is converted biologically to nitrogen gas in the absence of oxygen (i.e., denitrification).
When bacteria are used for water purification there are two sorts of transfer; one of these is aerobic transfer. This means, that bacteria that are oxygen dependent are converting the contaminants in the water. Aerobic bacteria can only convert compounds when plenty of oxygen is present because they need it to perform any kind of chemical conversion. Usually, the products they convert the contaminants to are carbon dioxide and water.
Our package sewage treatment plant has a relatively low odour profile. Our treatment reactors are all sealed and installed below grade. This limits the amount of odour that can escape. In addition, we can install an activated carbon scrubber system to clean the collected off gasses before releasing them to the atmosphere. We can also use sludge bagging systems to dewater wasted solids before disposal thus eliminating another possible source of odour.
Newer technology does not mean it is better. MBRs can cost substantially more to operate and maintain than extended aeration systems. Our treatment process is time tested, effective and reliable
Wastewater Treatment Purpose: To manage water discharged from homes, businesses, and industries to reduce the threat of water pollution. Wastewater Treatment
Pre-treatment Occurs in business or industry prior to discharge Prevention of toxic chemicals or excess nutrients being discharged in wastewater
Preliminary Treatment
- removes large objects and non-degradable materials
- protects pumps and equipment from damage
- protects pumps and equipment from damage
Bar Screen catches large objects that have gotten into sewer system such as bricks, bottles, pieces of wood, etc.
Grit Chamber removes rocks, gravel, broken glass, etc.
Mesh Screen removes diapers, combs, towels, plastic bags, syringes, etc.
Measurement and sampling at the inlet structure Measurement and sampling at the inlet structure water samples are taken for determination of suspended solids and B.O. D
Suspended Solids the quantity of solid materials floating in the water column
B.O.D. = Biochemical Oxygen Demand
- a measure of the amount of oxygen required to aerobically decompose organic matter in the water
- Measurements of Suspended Solids and B.O.D. indicate the effectiveness of treatment processes
- Both Suspended Solids and B.O.D. decrease as water moves through the wastewater treatment processes
Primary Treatment
- a physical process
- wastewater flow is slowed down, and suspended solids settle to the bottom by gravity
- wastewater flow is slowed down, and suspended solids settle to the bottom by gravity
Sludge from the primary sedimentation tanks is pumped to the sludge thickener.
more settling occurs to concentrate the sludge prior to disposal
Primary treatment reduces the suspended solids and the B.O.D. of the wastewater.
From the primary treatment tanks water is pumped to the trickling filter for secondary treatment.
Secondary treatment will further reduce the suspended solids and B.O.D. of the wastewater
Secondary Treatment
- Secondary treatment is a biological process
- Utilizes bacteria and algae to metabolize organic matter in the wastewater
- In Cape Girardeau secondary treatment occurs on the trickling filter the trickling filter does not “filter” the water
- water runs over a plastic media and organisms clinging to the media remove organic matter from the water
- From secondary treatment on the trickling filter water flows to the final clarifiers for further removal of sludge.
- The final clarifiers are another set of primary sedimentation tanks.
Which is the most appropriate & Most suitable Technology?
[table id=5 /]- Type of submerge membrane
- Different material
- PVDF, PES, PP. PTFE Etc.
Different material
PVDF, PES, PP. PTFE Etc.
Pore Size
- FS: 0.1
- HF: 0.04 & 0.2
For MBR, the recommended value is a MLSS concentration of less than 12,000 mg/L.
Periodical cleaning is recommended to ensure stable operations. (The cleaning frequency depends on the water quality.)
This varies depending on the cleaning frequency and concentration of chemical used for cleaning. Contact us for details. The imemflo Membrane Module enables use of a high-concentration chemical and exhibits high recovery performance. (Refer O&M manual)
The hollow fibre membranes used in the imemflo HFMBR Membrane Module are exceptionally strong and are not broken during normal operation.
NaOCl is effective for organic fouling. Use an acid (sulfuric, hydrochloric, citric, etc.) for inorganic fouling. The imemflo Membrane Module has excellent chemical resistance and can be used with solutions ranging widely from pH 3 to 11. It is recommended to make preliminary tests to find out right type of chemical and its optimum concentration.
In the case of pressurized membrane modules, it is recommended to perform backwashing on a regular basis. But in imemflo MBR membrane we don't require Regular backwash.
The imemflo MBR Membrane Module has long-lasting hydrophilic properties compared to membranes made of other materials, so you can store it dry.
imemflo offers a variety of services to maintain your membrane treatment system. (Available for a fee.)
HF- 2.5 year
The membrane is robust enough for a service up to 5 years. However, the service life depends on the operating conditions. Please contact us for warranty information.
In general, select module type according to the turbidity of the raw water.
For aeration, please refer our technical data sheet
It is confirmed that the removal rate is 99% or more for oil contained feed water at a level of approximately 800 mg/L