Tuesday, December 18th, 2018
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Sewage Treatment

Wastewater Treatment


Water 2000, Inc provide practical solutions for wastewater problems. We provide complete systems and services covering all areas of wastewater engineering as Consultancy,  Analysis, Design, Fabrication, & Turnkey Installations, Compacted engineering solutions, Chemical supplies, and products to improve biological processes.

The effluent treatment plants are designed by a team of renowned engineers and scientists having long experiences in wastewater management/ treatment. Therefore taking in depth the nature of problems being facted by the client, they come up with solutions that are on the cutting edge of recycling water. Beside wastewater treatment, our primary emphasize always also remains on waste minimization to zero discharge. Taking all parameters like technology, space, cost and power consumption, these plants come out on the top! Using newly discovered methods like high rate clarifier coagulation, precipitation with special polymer, bacterial augmentation and bio-media clarification. These techniques have resulted in better efficiency and reduction of weight and power consumption.

Our technologies ensures drastic savings in power consumption by almost 60% and in operation and maintenance cost as well. The much reduced sludge can be converted into vermicomposts and used as organic fertilizers for gardening and farming. The use of high grade FRP makes the entire plant very strong yet, exceptionally light, compact and portable. The special use of friendly bacteria makes the plant eco-friendly and completely odour free.

Alongwith complete plants on turn key basis we also provide the following equipments related to water and wastewater treatment.

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WASTE WATER TREATMENT SYSTEMS

Aerators, clarifiers, dosing systems, filters, solid contact stabilization units, activated carbon systems, bio discs and anaerobic system, fluidized media reactors, membrane bio-reactor, stabalization ponds, aerated lagoons, sequencing batch reactors (cbr), oxidation ditches, trickling filters, fluoride removal units, oleo chemical treatment, chromium treatment / recovery (tannery waste / cooling tower water), cyanide treatment, sludge treatment, other heavy metal removal

Clarifiers

High rate clarifiers, clari flocculates, lamella plate

Chemical dosers systems

Metering pumps, different pressure operated

Electro chlorinators

For on-site generation of chlorine from brine

Package sewage treatment plants

For hotels, hospitals based on extended aeration

Selectively adapted bacterial products

In effluent treatment for removal of cynaide, culture phenol, oil and grease and increased efficiencies of bod removal. Bacterial cultures (aerobic, anaerobic, special waste), micronutrients, settlement aids

Oil removal systems

Coalescers, drum, skimmers, polymers, activated carbon filters, oil water separators.

Water quality monitoring

Sampling, analysis

Instruments

Ph/redox, conductivity and dissolved oxygen

Test kits

Total water testing lab for chemical and bacteriological count

Disinfections system

Uv sterlizers, ozonator

In addition to the above effluent treatment pants and services, we are also working in the following areas of environmental management

SOLID WASTE MANAGEMENT

Recycling Systems, Balers, Shredders/Compactors, Hospital/ Industrail/ Sludge and Municipal Incinrators, Dust & Sludge Solidification

AIR/VAPOUR TREATMENT

Activated Carbon, Slovent Recovery, Odour Control, Mist Eliminators, Scrubbers, Dust Collect Equipment

Wastewater Engineering

Primary Treatment (ph adjustment /coagulation)

pH adjustment, neutralization, coagulation, flocculation are the primary treatment techniques used for all types of wastewater treatment. Neutralization of excess acid or alkali is achieved by pH control using a suitable dosing system designed to cope with the rapid change in effluent flow and concentration.

Dosing Pump PanelSmall Coagulation/Flocculation System

Coagulation, sedimentation, pH Control. Effective treatment of effluent is achieved by careful selection of chemical/biological treatments coupled to a treatment system capable of doing things right. Water 2000 provide a complete solution, from initial surveys to construction and installation of equipment.

We are not tied to one particular type of treatment technology and we design and build our own systems based on the practical evidence. It is important to build a relationship and work closely with our customers to ensure that each step of the process is fully understood.       

    Coagulation and flocculation are really quite easy in essence but don't mistake, it is a fine art to fully optimise the processes. We find that effluent treatment systems often under-perform because the treatment chemistry has not been revised in line with the effluent it is receiving. It is here that we have the experience to optimise the process or recommend alternative treatment materials.

Given our rounded background, we are able to improve effluent treatment from a diverse range of industries - Food processing, landfill

Jar Test

leachate, metal finishing, drum reconditioning, dyestuff manufacture to name some of the industry types we have helped.

Ferric Sulphate, Aluminium Sulphate,  PAC etc are our basic workers...

Recently developed high charge amine, iron and aluminium products are also available with us and and show benefits in:

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Reduced Coagulant Consumption

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Reduced Sludge

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Reduced Consumption of Alkalinity, (Less pH Correction)

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Reduced Treatment Cost

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Wide Tolerance to Variable Loads

Following initial site tests, we support our site trials to ensure that treatment materials are performing effectively.

Sewage Treatment PlantSewage Treatment Plant

Sewage Treatment: Effluent Treatment Plant

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Oxidation Ditches

An oxidation ditch is a large holding tank with a shape similar to that of a race track. The tank is shallow, averaging about 3 feet deep, and is constructed with an impermeable lining. This gives the wastewater plenty of exposure to the open air for the diffusion of oxygen, helping prevent anaerobic conditions from occurring. One or more mechanical surface aerators are attached to the side of the ditch. Although surface aerators can vary depending on the design of the system, most resemble a large circular brush. The aerators slowly rotate to introduce oxygen to the wastewater without causing too much turbidity.

Raw sewage is delivered to the ditch where it is slowly mixed by the aerators. Longer retention time will allow for a greater amount of organic atter within the sewage to be broken down by the aerobic bacteria. After treatment the effluent is then pumped to a settling tank where the sludge and the water are allowed to separate. From here most of the wastewater goes on to other treatment processes. The sludge is removed from the bottom of the settling tank and a portion is returned to the ditch to facilitate microbial activity in the next batch of sewage.

Oxidation ditches can be built to accommodate the needs of several thousand people. They are suitable for communities with limited access to land. Initial construction costs are relatively expensive, yet the system's energy demands are moderate. The system requires a moderate amount of skill to operate and maintain, and it works well under most weather conditions.

Trickling Filter

Trickling filters are circular tanks containing a media of either rock or plastic. Trickling filters using rocks are shallow with wide diameters, and made with reinforced concrete built into the ground to support the weight of the rocks. Systems designed with plastic media do not need as much support and so can be built above ground. Because of this, they are referred to as tower filters. Tower filters are typically 20 to 30 feet high and have a smaller diameter than the filters with rock media. Most systems use a rotating distributor to spray effluent onto the surface layer of the media, but some use a fixed distributor. Rotating distributors spread the effluent more evenly than fixed distributors, but they require more energy to operate. The distribution of the effluent can either be intermittent or continuous depending on the system. When continuous, a portion of the wastewater is recirculated back to the distribution system.

Sewage first goes to a settling tank where much of the solid matter settles out of the wastewater. The wastewater is then pumped to the distributor, which sprays it onto the surface of the media. The media act as a substrate to which microorganisms attach themselves. Empty space between the media allows for the presence of air, creating an aerobic environment for the microorganisms. Plastic media have significantly more empty space, thus allowing for a greater oxygen transfer. As the wastewater passes over the media, these microbes feed upon organic material. The microbe population eventually grows to form a layer of slime over the media. Portions of this slime are sloughed off each time wastewater passes through the filter. After it has been collected in an underdrain beneath the filter, the wastewater is then sent to a second settling tank where slime debris is allowed to settle out.

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Sequencing Batch Reactors

Sequencing batch reactors use an aeration process to treat wastewater. A specific volume of wastewater, called a batch, is first screened to remove larger particles within the water. It then may undergo primary treatment in a septic tank before delivery to the reactor. The reactor is a tank into which air is pumped to ensure that a sufficient supply of oxygen is present for aerobic biochemical processes to occur. The addition of oxygen allows microorganisms to consume dissolved organic matter in the wastewater that are not removed by a screening or settling process. After a specified period of aeration, the wastewater in the reactor is allowed to settle. The sludge that settles on the bottom now primarily consists of the microorganisms that have fed on the organics in the wastewater. Sequencing batch reactors utilize an activated sludge treatment process. After the treated effluent is discharged, all but a small portion of the sludge, which is rich in microorganisms, is removed from the reactor. This helps quickly reestablish a population of microorganisms within the next batch of wastewater delivered to the reactor, reducing the amount of time necessary for treating each batch. Usually more than one reactor is needed so that while one batch of wastewater is being treated, additional flow can be directed elsewhere. The number of reactors ultimately depends on the expected volume of wastewater flow and the amount of time allowed for treatment of each batch in the reactor. A longer retention period produces less sludge and cleaner effluent.

The main advantages of sequencing batch reactors is that they produce effluent low in organic compounds and thus can be used to meet strict effluent standards. The system can be effectively used as part of a larger system when the removal of the nutrients nitrogen and phosphorus are required. Other advantages are that it can be located on a small area of land, and it is relatively easy to expand this system by adding additional reactors. However, the operation of this system is more complex than others. The system does tend to be more costly to construct and operate than most others, yet it usually has fewer maintenance problems over its lifetime.

Lagoons

Lagoons are essentially artificial ponds, called cells, that are built into or above the ground. The number and size of these cells depend on the needs of the community. Systems that use several smaller cells have proved to be more effective than one large cell for treating wastewater. Cells are lined with clay or other impervious materials to prevent groundwater contamination. There are four basic types of systems: anaerobic, facultative, aerated lagoons, and stabilization ponds. They vary according to the amount of dissolved oxygen typically present in the water. Their purpose is to retain wastewater for an extended period of time. This acts to stabilize wastewater as heavier particles sink to the bottom and lighter ones rise to the surface. The retention period gives microorganisms time to feed on the nutrients and trace elements in the water.

Anaerobic lagoons have steep sides and can be as deep as 20 feet. They develop a thick crust on the surface which inhibits oxidization, but serves to trap in heat. This makes anaerobic lagoons more suited to colder climates. They typically use less land, but require a longer retention period than the others. They can cause odors, especially when being cleaned.

Facultative lagoons have an aerobic top layer and an anaerobic bottom layer. They tend to be large and shallow (3-8 feet) to allow for maximum diffusion of oxygen, which occurs at the surface, and for the maximum amount of algae growth to take place. The algae helps the treatment process by using nutrients in the wastewater. Facultative lagoons cause less odor, but may have problems functioning during cold periods when ice forms on the surface.

Aerated lagoons and stabilization ponds are both aerobic systems. Stabilization ponds are the shallowest of all the systems, usually just 2 feet deep. They rely on surface diffusion of oxygen and algae growth to oxygenate the wastewater. Stabilization ponds require a large area of land, typically about 1 acre for every two hundred people, and are usually located in areas where the climate permits year round algae growth. Aerated lagoons create aerobic conditions through mechanical means. Mechanical aeration allows these lagoons to use 60% to 90% less land area than stabilization ponds. Limitations of surface space or cold winter temperatures are two reasons for mechanical aeration.

Biochemical Oxygen Demand ( BOD) is defined as the quantity of dissolved oxygen which is able to oxidize the organic components in the water with the assistance of microorganisms and under defined experimental conditions. The BOD is an empirical biological taste in which the water conditions such as temperature, oxygen concentration or type of bacteria play a decisive role . These and other factors therefore cause the reproducibility to be much less than that of pure chemical tests. In

Spite of this disadvantage , the BOD is of special importance in the assessment of polluted surface waters and waste water . Its application is indispensable as in lying out data during the construction of sewage works.

A reaction time of 5 days is normally used for the measurement (BOD5) . The dilution method is described here in which oxygen - saturated dilution water is added to the sample . Manometric measuring systems are commercially available and and deliver useful results although the data from both techniques are not directly comparable . Furthermore, it is also not permissable to convert results obtained for a particular incubation period (e.g. BOD after 5 days) in to results for other times

Chemical Oxygen Demand (KmnO4 consumption and oxidation with K2 Cr2 O7)

Chemical oxygen demand (COD) is defined as the amount of oxygen in the form of oxidizing agent consumed in the oxidation of organic water components. The degree of oxidation depends upon the type of substance, pH value, temperature, reaction time and concentration of oxidizing agent as well as the type of added accelerators, if any.

If you already have a system and are looking to outsource its running and maintenance, contact us to informally discuss our service packages. Trained engineers are ready to take on day-to-day running and ensure that the system is operating to consent and as efficiently as possible.

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CLARIFICATION TECHNOLOGY

Fundamentals:-
In fundamentals of clarification technology we will discussed about Coagulation, flocculation and sedimentation phenomena.

Description:-
Clarification removes suspended matter from wastewater. Surface waters require clarification because they have moderate to high levels of suspended matter. Well waters do not require clarification because they have low levels of suspended matter.

The suspended matter in water includes two kinds of particles:
o Settle-able Particles (macro-particles, typically visible to the eye)
o Non-Settle-able Particles (micro-particles, normally visible through a microscope)

Settle-able particles are particles in water that settle out over time. The water itself is clear, indicating an absence of suspended matter (turbidity). If non-settle-able particles had been in the water, the water would not be clear. This "turbidity" would have indicated the presence of non-settle-able particles. Turbidity is an indirect measurement of the amount of suspended matter (settle-able particles and on-settle-able particles) in water. Clarification uses chemicals and sedimentation to remove suspended matter (settle-able particles and non-settle-able particles). Several steps are involved.

First, coagulation destabilizes the particle surface charge that keeps the particles in solution. Once destabilized, the particles no longer repel one another and come together as floc.
Second, floc agglomerate into larger particles and Polymers are used to enhance the flocculation process.

Third, sedimentation causes agglomerated floc to settle out. The settled floc is collected and concentrated for discharge to waste, called clarifier blowdown, or recycled to the coagulation step, called sludge recycle. Clarified water is collected and flows out of the clarifier.

Coagulation:-
The first step of the clarification process in wastewater treatment is coagulation. Particles in water have a naturally occurring negative charge. This causes them to repel each other and stay in suspension. When this charge is destabilized, the particles no longer repel one another, and can come together in closer proximity. A chemical salt, called a coagulant, is mixed with the inlet water to destabilize the charge. Common coagulants are aluminum sulfate (alum), ferric sulfate, ferric chloride and organic coagulant. The coagulants provide a positive charge, in the form of metallic cations, that destabilize the natural negative charge of the particles. The metallic cations combine with hydroxide in the water to form a metallic hydroxide that is an insoluble compound. The destabilized particles and metal hydroxide precipitates agglomerate into small, visible particles called floc. Color, organic matter and colloids, including colloidal silica, are removed by becoming bound up in the floc. The precise mechanism for removal- absorption, adsorption, co-precipitation, or a combination-is not fully understood.

The addition of too much coagulant can cause the suspended matter to be re-dispersed with the opposite charge. The amount of removal is dependent upon the coagulant dosage and the pH.

Alum (aluminum sulfate), ferric sulfate, ferric chloride and organic coagulants are acidic salts and decrease the pH of the influent water. Because of this, the pH of the water must be adjusted with caustic (sodium hydroxide) or another alkaline (high pH chemical).The adjustment is to a pH of 5.5 to 6.5 and is done to achieve the lowest residual of suspended matter. Lime is used as the coagulant when the treatment objective is hardness reduction. The dosage depends on the desired operating pH of the clarifier. For the greatest removal of hardness, the pH range is 9.5 - 10.5. Feed of coagulant alone does not produce satisfactory floc in waters having a low suspended matter concentration. In this instance, bentonite clay is added. Bentonite clay creates an artificial base of settleable macroparticles that seed the growth of floc.

Polymers are added to reduce the amount of coagulant required, broaden the working pH range and create denser, heavier floc that settles out more easily. Polymers are long-chain organic compounds of high molecular weight that bridge floc particles together or modify their surface charge.

In almost all cases, the water to be treated is disinfected with either gaseous chlorine or sodium hypochlorite. This oxidizes organic matter in the water that has taste and odor and certain metals, such as manganese and iron. When oxidized, these constituents are transformed into a form that can be removed during clarification. Their removal is important because they can cause fouling of process components.

Coagulation is carried out in a fast mix chamber. Fast mix is required because the coagulant and water must be thoroughly mixed to allow the suspended matter and coagulant to come into contact with each other. If it is not fast mixed, some suspended matter may not come into contact with coagulant, the surface charge will not be destabilized and flocculation will not occur. As flocculated water flows into the slow mix chamber, polymer is added.

Flocculation:-

In the next step of clarification, the small floc (microfloc) is allowed to grow into larger floc, called macrofloc or agglomerated floc. This process, called flocculation. Flocculation is accomplished by gently stirring the coagulated water to assure contact between microfloc particles and polymer. The polymer enhances agglomerated floc formation. As the agglomerated floc continues to grow, it becomes denser and heavier, allowing it to settle. Mixing too rapidly can create what is called floc shear. Shear is the breaking apart of existing floc particles. The agglomerated floc, or macrofloc, is sheared back into microfloc.

Mixing too rapidly can create what is called floc shear. Shear is the breaking apart of existing floc particles. The agglomerated floc, or macrofloc, is sheared back into microfloc.

Sedimentation:-

The final step of the clarification process is sedimentation. In this step, agglomerated floc settles out to form sludge and the sludge is transported to the sludge concentration chamber by the scraper. The sludge thickening pickets concentrate the sludge. The sludge is discharged to waste in a process called clarifier blowdown. Above the sludge, clarified water is collected in the outlet launder and flows forward for use or further treatment.

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