Introduction:
Without water and sanitation, survival is a question. Both are intricately interlinked with human life! According to studies, rainfall has been decreasing over the last 80 years and according to researchers, Man-made atmospheric pollutants cause the unprecedented decline in the last 448 years. (Source: The Hindu 17.05.2019 – “Tree ring data helps track rain-fall levels”).
The freshwater that is available today is the same from the time the world came into being; if so why the shortage? One reason is the exploding population and other improper and wasteful practices.
For having given up the natural process of cleansing we are dependent on mechanical sources to treat our Bio Sewage Treatment Plants which proves insufficient due to high volume, human lethargy and indifference. The expanding urbanisation has given room for multi-storied living style with dependence of water mostly/partially on external sources. Available infra-structures insufficient to carry the waste water or non-availability of infra-structure has made a “MUST” for every apartment complex to have their own expensive treatment plants and the recurring cost of processing and maintenance is also very expensive.
In Germany, it is said, that a glass of water on the dining table has gone through 10 stomachs. It shows the height of re-cycling/re processing waste-water, As we do not understand the necessity of conservation we waste a lot of water from which 80% could be recycled and re-used thus reducing the pressure on fresh-water. People buying apartments at exorbitant cost are burdened with recurring high maintenance cost of Rs. 3/- to 5/- per sq.ft and monthly EMI towards housing loans for a considerable long term. By the time the liabilities are settled, most would have left behind their prime of youth and resigned to their fate to continue paying the monthly maintenance.
This is where the anaerobic biological sewage wastewater treatment methods can play a crucial role. Unlike the present equipment which requires continues electricity, manpower and constant upkeep is avoided; initial installation and equipment cost is minimal and cuts out recurring expense. This would be a major relief to the users.
Technology - Anaerobic Treatment
Anaerobic treatment is a process where wastewater or material is broken down by microorganisms without the aid of dissolved oxygen. However, anaerobic bacteria can and will use oxygen that is found in the oxides introduced into the system or they can obtain it from organic material within the wastewater. Anaerobic systems are used in many industrial systems including food production and municipal sewage treatment systems.
Anaerobic digestion is commonly used to treat sludge in the first areas of a wastewater treatment plant. This process is popular because it is able to stabilize the water with little biomass production. Anaerobic treatment occurs in many different stages.The key microorganisms are methane formers and acid formers. The acid formers are microorganisms that create various acids from the sludge. Methane formers convert the acids into methane.
The Anaerobic sewage treatment plant system has its place in the world today. They are very different in the process but are used to achieve maximum degradation, while meeting the strict regulations set by the environmental agencies that regulate what is released into the air, ground, or water.
Treatment Process
1. Anaerobic Treatment
2. Fixed Anaerobic media
3. Clarification of wastewater/Settlement of Solids
4. Filtration of water
5. Tertiary treatment - Ozonation
Biological Treatment
Bio Collection tank: The wastewater treatment first comes to the Bio Collection tank. MBBR is that part of the system where Micro Organisms act as the catalyst to oxidize the organic waste and convert it into gases such as Carbon Dioxide and Water. Anaerobic bacteria will be introduced to the system to increase population.
Figure 1: FLOW DIAGRAM - Schematic of an anaerobic filter. Gas is evacuated by the venting opening at the upper right
Fixed Media Bioreactor
The Treatment Plant works on the principle of Fixed Media Bioreactor Process.
What is Fixed Media Bio reactor
• Bio Reactor works on the principle of Attached Growth.
• The Bioreactor tank consists of Fixed Media. Media is in suspension- Specific gravity< water
• Fixed bio mat Media on which microorganisms grow.
Clarification Of Wastewater / Settlement Of Solids
After achieving a complete development of microorganisms over a retention period of 24-48 hours the wastewater moves to the settling tank of solids or flocks takes place. Clear supernatant from the settler will flow by gravity to the Intermediate Bio septic tanks.
Filtration of WasteWater
Sand filters: These filters are normally used to remove suspended solid substances that cause turbidity from water. Their operation is very simple and consists in allowing water to pass through several layers of quartzite (sand) and, possibly, a layer of anthracite. The water passes through the filtering part, moving in the top-down direction, and during the process the substances retained on the first upper layer of sand increase filtration efficiency in the subsequent layers.
Activated Carbon Filters: Natural carbon from various sources (organic or inorganic) can be activated by means of a process which consists in creating minute holes inside granules (micropores). This process occurs inside special furnaces with injections of high temperature steam.
The main advantages of this type of carbon are absorption through their porosity of particular types of molecules and, as additional advantage, mechanical filtration with results similar to those obtained with sand filters. Benefits of filters:
• Eliminate unpleasant odours and tastes
• Remove organic pollutants
• Allow for filtration as additional benefit
• Gives better clarity of water
Bio Sewage Treatment Plant | Normal Sewage Treatment Plant | |
1 | Anaerobic STP (biological) | Aerobic STP (Normal, using chemicals) |
2 | No electricity required to treat sewage | Required electricity for 20 hours per day to treat sewage |
3 | No Maintenance, except bio enzyme tablets dosage monthly once | Require 3 manpower, works round the clock in 3 shifts to run the plant |
4 | Treated water infiltration into soil base and only 10% treated water available for garden | Treated water is 10,000 ltr per day, must be utilized either for gardening or flushing purposes, if excess then has to be pumped out thru lorries |
5 | Meets PCB Norms in water quality | Meets PCB Norms in water quality |
6 | One time investment on infrastructure | Electrical items have to be replaced often to run the plant |
Table 1: Comparison Chart - Aerobic Vs Anaerobic
Tertiary Treatment - Ozonation
To disinfect the harmful bacteria in the treated water as well as to remove the refractory organics from the intermediate tank water, in this tank ozone treatment will be done. The clear treated water from the final tank is discharged for reuse.
Reuse of Treated Water: The treated water can be reused for the horticulture purpose.
Figure 2: Comparison Chart Sludge production Aerobic Vs. Anaerobic
CASE STUDY
Name of the Client: Shantiniketan Educational Institutions Bilekahalli Branch
Segment: School toilet & hand wash waste water
Capacity: 100 KLD plant
Location: Bangalore
Technology used: Anaerobic treatment with Ozone tertiary treatment.
Table 2: Before treatment wastewater parameter
Table 3: After treatment - Bio STP treated water Lab test report
Figure 3: Raw Water Sample Figure 4 - Bio STP treated water sample
Conclusion
In recent times awareness regarding STP has grown and as per law since it is mandatory it has been implemented by the infrastructure companies and later Residential associations have not got much knowledge on maintenance of STP and due to high cost associated with maintenance, STP does not function in most of the residential flats.
In a nutshell, Bio STP is an ideal treatment system which treats the Sewage treatment plants water without electricity and maintenance. And does not require manpower to manage the plant and at the same time gives you high quality treated water meeting Pollution Control Board norms.
About The Author:
Dakshayani S Dalavai is the Proprietrix of Pratiks Enviro Solution.An MBA from IIM-Ko zhikode, her fo c us area of vrork - Water & Waste water treatment and Scient:ifu water body RRR proc e ss (Repair; Rejuvenation & Restoration). She worked as Business headwith Hindustan liver - (Unilever) water div ision - handIed research & dev elopment for water product devel opment and developed sales team for the Tamil Nadu region. Her specializ ation is Bio ST P ( sewage treatment without electric ity) Bio Toi let, Bio R eme di ation treatment for water bodie s, S eptic tank management, Sewage water treatment,Effluent water treatment, RO / DM plant etc. she can be reached at pratiksenvirosolutions@gmail.c
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