Enhanced Extended AerationSewage solution that actually works…

The Environmental Engineering Specialist

Table of ContentSewage Pollution – Facts & figures

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Problems in waste water treatment4

Drawbacks in normal extended aeration 5

What is Enhanced Extended Aeration?6

Enhanced Aeration7

Enhanced Environment 8-9

Secondary systems – Hydroponics & Vacuum Sewerage System 10-11

Out of operation plants in Sabah12

Contact us 13

Residen

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Agricultural

POLLUTION SEWAGESewage water pollution is one of the major problems in cities. The sewage water is drained off into rivers without treatment. The careless disposal of sewage water leads to a chain of problems, such as spreading of diseases, eutrophication, increase in Biological Oxygen Demand (BOD), etc.

The waste water that flows after being used for domestic, industrial and other purposes is termed as sewage water. In ideal situations, the sewage water is channeled or piped out of cities for treatment. Bulk of the sewage contains water as the main component, while other constituents include organic wastes and chemicals.

Sad yet trueFACTSA survey was carried out and issued in July 2002 by the Sabah State Environmental Conservation Department – Capacity Building (ECD-CAB) which was supported by DANCED from Denmark on waste water treatment plants in Sabah. This survey was a cooperation between the Malaysian and Danish governments to map out the status of waste water treatment in Sabah.

The result from the survey was staggering and alarming! Almost two third (2/3) of the waste water treatment

plants are found to be out of operation in Sabah.

As can be seen, the report makes sad reading because few of the sewage treatment plants checked were operating. The situation has apparently not improved and it begs the question “where does all the untreated sewage go” and undoubtedly raw sewage enters the adjacent rivers flowing to the sea. Thus the sea area adjacent to the entry point of the river to the sea in particular will contain raw sewage even if diluted.

For every THREE STPs, TWO are out

of operation !!

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COMMONWASTE WATER

TREATMENT

Throughout the century, many waste water treatment methods have been invented and utilized to solve and minimize the potential health hazards caused by untreated waste water. All of these systems have their own advantages as well as disadvantages.

A better understanding in each of these systems will eventually lead one to the same conclusion. All of these systems are designed to cultivate and promote growth of active microorganisms as the ultimate tool to combat waste water. But often times, almost all of these systems have forgotten about the importance of providing the right environment consistently for bacterial growth in order for the plant to be effective. As a result of that, so many plants become merely concrete monuments that do not serve their purpose.

Trickling Filter- High capital costs

- Requires expert design and construction.

- Constant wastewater flow is a Must.

- Flies and odours are often problematic.

- Pre-treatment is required to prevent clogging.

- Dosing system requires more complex engineering.

RBC- High capital costs

- Requires expert design and construction.

- Mechanical parts such as shaft bearings require frequent maintenance

- Flies and odours are often problematic.

- Not all parts and materials may be available locally.

- Low dissolved oxygen concentration

- Solids accumulation at undesirable locations

Oxidation Pond- Slow and ineffective process due to long retention time

- Flies and odours are often problematic.

- Large footprint hence wasting useful development land

- Prone to the spreading of diseases

- Clogging of infiltration ponds is a recurrent problem

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Extended Aeration- Ineffective & trouble prone Returned Activated Sludge (RAS)

- Conventional aeration system requires high power usage

- RAS usually caused bulking in system

- Inconsistent sludge & discharge quality

- Larger footprint than Enhanced Extended Aeration system

The effectiveness and consistency of a plant boils down to providing the right habitat

consistently for active microorganisms growth.

There are many factors surrounding the failure of a plant and yet, they are often ignored until it wreaked havoc. A simpler and more effective solution is in need to ensure sewage pollution does not become worse.

What’s wrongwith

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DRAWBACKS

CONVENTIONAL EXTENDED AERATION

In conventional extended aeration plants, one process used is the activated sludge process in which air is passed through a mixture of sewage and old sludge to allow the micro-organisms to break down the organic components of the sewage. Sludge is continually drawn off as new sewage enters the tank and this sludge must then be settled so that the supernatant can be separated to pass on to further stages of treatment.

Sludge bulking occurs when the sludge fails to separate out in the sedimentation tanks. The main cause of sludge bulking is the growth of filamentous bacteria.

with

“ Sludge bulking is one of the major causes why so many conventional extended aeration plants failed.

The activated sludge process relies on satisfactory performance of oxidation and gravity settlement stages. No matter how efficiently the assimilable BOD is converted to particulate biomass, settle ability of the activated sludge dictates the overall efficiency of the activated sludge process. When settle ability deteriorates, incomplete separation in the settlement stage can cause high concentration of suspended solids in the final effluent. Eventually this bulking of sludge can lead to a loss of oxidation, further deterioration of effluent quality and in persistent cases, a complete breakdown of the entire treatment process.

Despite the vast literature available on the causes and control of activated sludge bulking, poor settle ability is still estimated to be one of the major operational problems in full-scales treatment plants installed world-wide. Control methods derived from the microbiological approach is slow to implement and quite expensive requiring considerable modification of existing plant design.

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A

FEDC

BG

A grease trapB bar screenC balance tankD anoxic reaction tankE enhanced micro-nutrient generationF enhanced specific microbe generationG settling tank

Grey water

RawSewage

Final discharge

Recycled liquor

air air

Sludgedryingbeds

FertiliserDrainage liquor

Chemical dosing

Installation of the complete Infiniti Sewage TreatmentSystem will result in low BOD, SS , NO3 and PO4

What is ENHANCED EXTENDED AERATION

What is Enhanced Extended Aeration?

Enhanced Extended Aeration is a revolutionary sewage treatment system that has been specially designed to address multiple issues plaguing the conventional systems over the years. By combining some of the latest technologies from US and EU, Enhanced Extended Aeration has simplified and improved the inefficiency and inconsistency in effluent quality.

It is a unique system that emphasize on creating a sustainable habitat for active microorganisms to grow themselves into a strong workforce for the plant. Much research and development work has been done in this area to pinpoint the optimum conditions. It is proven that when a desired condition has been created, everything else would subsequently fall in place.

System that allows you to drink without

boiling…

?

It is proven that when a desired condition has been created, everything else would subsequently fall in place.

“

It is a unique system that emphasize on creating a

sustainable habitat for active microorganisms to grow themselves into a strong workforce for the plant.

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Typical Oxygen Values

Type of Aerator Value

Paddle wheels 1 - 2kg of O2/kWh

Fine bubble 2 - 3kg of O2/kWh

Venturi 2 -2.5kg of O2/kWh

Surface 1 - 2kg of O2/kWh

Static tubular 1 - 2kg of O2/kWh

Brush 2.5 - 3.5kg of O2/kWhInfinity Enhanced Aeration 3.8 - 8.8kg of O2/kWh

It uses two separate aerated treatment reactor tanks which utilise enhanced micro-nutrient technology. The air bubbles are only 3mm in diameter compared to the normal 20mm which results in more rapid solution of the oxygen in the air giving much greater process control of the dissolved oxygen levels.

This is unique to Infinity Enhanced BioFiltration Sewage and Waste Treatment Systems and is a major development in efficient aeration. The control of dissolved oxygen is critical in any aerated waste water plant and can be a problem. The tiny air bubbles are generated on specifically designed grid fitted to the base of the reactor tanks to ensure even aeration and to keep the water in continuous movement ensuring efficient oxygen transfer.

ENHANCED AERATIONA major development in efficient aeration

The air bubbles are only 3mm in diameter compared to the normal 20mm which results in

more rapid solution of the oxygen in the air giving much greater process control of the

dissolved oxygen levels.

Traditional Fine Bubble

ø20mm

ø3mm

Infinity Enhanc

ed Aeratio

nNot only does Infinity Enhanced Aeration have higher oxygen solubility compared to other type of aerators, it also consumes less power and requires only small scale blower to generate the super fine bubble mist for ultra efficient aeration.

An efficient aeration system which requires less power consumption &

smaller blower to generate the highest oxygen level

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ENHANCED ENVIRONMENTCreating the desired bacterial growth environment

Infinity Enhanced Extended Aeration is all about creating the desired environment for active microorganisms to grow and multiply.

In order for a plant to be effective, there are two specific types of bacteria which need to be properly cultivated. Reactor tank 1 is a micro-nutrient generator that cultivates Nitrifying bacteria known as Nitrosomonas. These bacteria are the basis for all biological filtration. This production system utilize ammonia as the energy source for growth and produce nitrite as a by-product.

Reactor 1Enhanced Micro-nutrient Generation

Reactor 2 Enhanced Microbe Generation

Reactor tank 2 is an microbe generator that cultivates Nitrobacter bacteria which utilizes nitrite as an energy source and produce nitrate as a by-product. Studies have shown that nitrite concentrations should remain below 1mg/l in most cases but extremely high levels of nitrate (200 – 300mg/l) can be tolerated by aquatic species.

Species of Nitrobacter are gram negative, mostly rod-shaped, microbes ranging between 0.6-4.0 microns in length. They are obligate aerobes and convert nitrites into nitrates in the presence of oxygen.

2NO2 + O2 2NO3

Nitrobacter

Nitrosomonas is a genus comprising rod shaped chemoautotrophic bacteria. This rare bacteria oxidizes ammonia into nitrite as a metabolic process. Nitrosomonas are useful in treatment of industrial and sewage waste and in the process of bioremediation. They are important in the nitrogen cycle by increasing the availability of nitrogen to plants while limiting carbon dioxide fixation

2NH4 + 3O2 = 4H+ 2NO2 + 2H2OH4

Nitrosomonas Bacteria

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The photograph on the right shows a cross section of the internals of a carrier at high magnification showing the strong well developed biofilms that digests the sewage.

It is worth noting that the internal surface of the carrier protects the biological layer from attrition as the carrier is moved around in the waste liquor by the air bubbles. Thus digestion and break down of the sewage occurs far more rapidly, and it also develops less sludge.

ENHANCED ENVIRONMENTThe ideal habitat for nitrifying bacteria…

The method of bacterial development is also unique and utilises the growth of biofilms which are far more resilient to process disturbances compared to other types of biological treatment processes such as conventional extended aeration. The biofilms are encouraged to grow inside a specially designed plastic carriers with high internal surface areas where they are protected from attrition as the carriers touch each other during the continual movement due to the aeration using millions of tiny air and with this technology.

It is possible to handle extremely high loading conditions without any problems of clogging. Also the system makes it possible to treat both industrial and municipal wastewater on a smaller footprint than is necessary with conventional waste treatment plants.

Specially designed plastic habitats with high internal surface areas are

key to providing a safe haven for the bacteria to grow.

Illustration of recirculation system of plastic habitats in reactor tanks.

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HYDROPONIC SYSTEM

STP Hydroponic Basins

Aeration

Final Discharge

As with all sewage treatment plants, sludge is developed as part of the sewage treatment process. In the final clarifier our system utilises tilted tube technology to very effectively remove suspended solids from the final effluent. Also if low phosphate is a requirement of the discharge standards, we can easily treat the liquor in the settlement tank to remove phosphates. Also by recirculating the final effluent denitrification can be achieved. If the final effluent is to be used for hydroponics in particular nitrate and phosphate are plant nutrients and their removal will not take place. Any phosphate removed will become part of the sludge and add to the fertiliser qualities of the dried sludge.

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VACUUM SEWER SYSTEM

1. Gravity Pipe work from domestic plumbing

2. PE Collection Pit

3. Pneumatic Vacuum

Interface Valve

4. Vacuum reticulation pipe

work

5. Vacuum Pump Station

Environmentally Sensitive Areas

Difficult Engineering Solutions

Geographically Unique

Protected Mangroves High Flow Situations Deserts

Fishing and Aquaculture Reserves

Integrated gravity and pumped solutions or replacement

Monsoonal or cyclonic conditions

Tourism Areas Man Made Islands High humidity

Protected Species Floating and Above Water Housing

Rising water table affected areas

Historic Sites needing minimal disturbance.

Extreme temperatures Dense urban environments

Lens and other water supply protection

Earthquake prone or volcanic areas

Marinas

Chemical Spill Mitigation Sporting arenas with infrequent flows

Golf course resorts

Eradication of disease carrying vermin

Temporary structures Canal developments

Vulnerable Health Issues Integration with low flow or vacuum toilets

Beach and sandy areas

Acid Sulphate Soils and contaminated areas

High Tidal conditions Remote islands or towns

Intermittent power and water supply

Reduction of Carbon Footprint

Historic cities

Vacuum sewers are a cost-effective, environmentally friendly alternative to traditional gravity sewers providing low maintenance, efficient and reliable sewage collection.

A vacuum sewer system uses the differential pressure between atmospheric pressure and a partial vacuum maintained in the piping network and vacuum station collection vessel. This differential pressure allows a central vacuum station to collect the wastewater of several thousand individual homes, depending on terrain and the local situation. Vacuum sewers take advantage of available natural slope in the terrain and are most economical in flat sandy soils with high ground water.

In addition to using less water, the technology requires very little electrical energy, is self-contained and is virtually odorless. Because operation of the vacuum collection system is monitored by the control panel, leaks occurring anywhere in the system can be easily identified and quickly isolated and repaired.

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Type: Oxidation Pond.

Location: Keningau

Status: Stagnant water & Out of operation.

Type: RBC

Location: Taman Khidmat KK

Status: Drums have stopped rotating. Abandoned.

Type: Conventional Extended Aeration

Location: Taman Muhibbah Tawau

Status: Aeration system is out of operation. No visible turbulence observed.

OUT OF OPERATION PLANTS

Type: Trickling Filter

Location: Taman Indah Permai KK

Status: Water spraying but bar not rotating

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Agent/ Distributor

Contact Us

Tomher Environmental Sdn. Bhd

Mile 16.5, Jln Bukit Giling,Off Jln Tuaran Lama, P.O.Box A-83, 89357Kota KinabaluSabah, Malaysia.

Tel: 6(088)-788999Fax: 6(088)-793111Email: info@tomher.com.my

drwilsonf@yahoo.com.au

www.tomher.com.my

Copyright 2009. Tomher Environmental Sdn Bhd. All rights reserved. All trademarks are the property of their respective owners.

The Environmental Engineering Specialist

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