INDUSTRIAL EFFLUENT TREATMENT

INDUSTRIAL EFFLUENT TREATMENT AND MONITERING: 

Presented By: SUMIT KUMAR MITTAL I.S.F College of Pharmacy, Moga (Punjab) Department of quality assurance I NDUSTRIAL EFFLUENT TREATMENT AND MONITERING

DEFINITION: 

Industrial effluent are materials generally discarded from industrial operations or derived from manufacturing processes. DEFINITION

PowerPoint Presentation: 

Wastewater treatment is a series of steps. Each of the steps can be accomplished using one or more treatment processes The major categories of treatment steps are : Preliminary treatment - Removes materials that could damage plant equipment or would occupy treatment capacity without being treated. Primary treatment - Removes settle able and floatable solids ( may not be present in all treatment plants). Secondary treatment - Removes BOD, dissolved and colloidal suspended organic matter by biological action. Organics are converted to stable solids, carbon dioxide .

PRELIMINARY TREATMENT: 

PRELIMINARY TREATMENT It is the initial stage in the wastewater treatment process. The purpose of preliminary treatment is to protect plant equipment by removing those materials that could cause clogs, jams, or excessive wear to plant machinery . Preliminary treatment may include many different processes

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Screening The purpose of screening is to remove large solids, such as cans , rocks etc., from the flow before the flow moves on to downstream processes . Shredding As an alternative to screening, shredding can be used to reduce solids to a size that can enter the plant without causing mechanical problems or clogging. Shredding processes include comminution

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Grit Removal The purpose of grit removal is to remove the heavy inorganic solids that could cause excessive mechanical wear. Grit removal may be accomplished in grit chambers or by the centrifugal separation of sludge . Preaeration In the preaeration process (diffused or mechanical), wastewater is aerated to achieve and maintain: aerobic state

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strip off hydrogen sulfide (to reduce odors and corrosion ) agitate solids (to release trapped gases and improve solids separation and settling ) All of this can be accomplished by aerating the wastewater for 10 to 30 min . Chemical Addition Chemical addition is made to the waste stream to improve settling, reduce odors, neutralize acids or bases, reduce corrosion.

PRIMARY TREATMENT: 

The purpose of primary treatment is to remove settleable organic and floatable solids . Primary treatment reduces the organic loading on downstream treatment processes by removing a large amount of settleable, suspended, and floatable materials . In this the velocity of the wastewater through a clarifier is reduced approximately 1 to 2 ft /min , so that settling and floatation can take place. Slowing the flow enhances removal of suspended solids in wastewater PRIMARY TREATMENT

SECONDARY TREATMENT: 

The main purpose of secondary treatment/biological treatment is to provide BOD removal beyond what is achievable by primary treatment . There are two commonly used approaches the trickling filter the activated sludge Process SECONDARY TREATMENT

Trickling filters: 

A trickling filter consists of a bed of coarse media, usually rocks or plastic, covered with microorganisms . The trickling filter process involves spraying wastewater over a solid media such as rock, plastic. As the wastewater trickles over the surface of the media, a growth of microorganisms (bacteria, protozoa, fungi, algae) develops . As the wastewater passes over this slime, the slime adsorbs the organic (food) matter. This organic matter is used for food by the microorganisms . At the same time, air moving through the open spaces in the filter transfers oxygen to the wastewater. Trickling filters

Activated Sludge: 

Activated Sludge Activated sludge Process

PowerPoint Presentation: 

It is a treatment technique in which wastewater and reused biological sludge full of living microorganisms are mixed and aerated. The biological solids are then separated from the treated wastewater in a clarifier . The microorganisms are mixed thoroughly with the incoming organic material, and they grow and reproduce by using the organic material as food . As they grow and are mixed with air, the individual organisms cling together (flocculate ).Once flocculated, they more readily settle in the secondary clarifiers . The activated sludge is constantly growing, and more is produced than can be returned for use in the aeration basin.

DISINFECTION OF WASTEWATER: 

Like drinking water, liquid wastewater effluent is disinfected . In this Chlorination for disinfection is done. The purpose of chlorination is to reduce the population of organisms in the wastewater to levels low enough to ensure that pathogenic organisms will not be present in sufficient quantities to cause disease when discharged. DISINFECTION OF WASTEWATER

PERFORMANCE MONITORING OF TREATMENT PROCESSES: 

Biological Processes Three different types of monitoring parameters can be distinguished. Parameters that are essential to ensure the biological process are functioning optimally such as pH , dissolved oxygen (DO), and nutrients . Parameters that provide diagnostic check on the “health” status of the various unit operations and unit processes e.g. mixed liquor volatile suspended solids (MLVSS), sludge volume index ( SVI) Parameters that indicate the efficiency of the treatment system such as biological oxygen demand (BOD) and chemical oxygen demand (COD). PERFORMANCE MONITORING OF TREATMENT PROCESSES

Dissolved Oxygen: 

DO can be measured by using a portable hand held DO meter Biological unit processes require a sufficient amount of dissolved oxygen (DO) for growth and metabolism of microorganisms . DO concentration of about 1.5 to 4 mg/L needs to be maintained in all the areas of the aeration tank and 2mg/L is a commonly used value . Oxygen limited growth environments may promote the predominance of filamentous organisms affecting the settleability of sludge . Dissolved Oxygen

pH:: 

The optimum biological activity of the microorganisms for the treatment process is in the pH range from 6.0 to 9.0. Mixed Liquor Suspended Solids and Mixed Liquor Volatile Suspended Solids The mixed liquor suspended solids (MLSS) and mixed liquor volatile suspended solids (MLVSS) are commonly used to represent the microorganisms in biological treatment processes especially the activated sludge process. MLVSS is the volatile fraction of the MLSS. pH:

PowerPoint Presentation: 

MLSS concentration should be maintained within the range of 1500 to 3000 mg/L for a conventional activated sludge process and 3000 to 6000 mg /L for an extended aeration activated sludge process Sludge Volume Index The sludge volume index (SVI) is the volume in milliliters occupied by 1 g of a suspension after 30 min settling. The Sludge Volume Index ( SVI) is used as an indication of the settling characteristics of the sludge . SVI measurements also yield information used to establish the proper recirculation ratio for optimum process efficiency and maximum solids concentration in the waste sludge. Poor settling sludge will result in low concentration of solids in the return-activated sludge and thus the concentration of microorganisms in the aeration tank drops.

SVI = settled sludge volume (mL/L) X 1000   suspended solids (mg/L)   : 

SVI = settled sludge volume (mL/L) X 1000 suspended solids (mg/L) SVI values and sludge settling characteristics

Nutrients: 

Many industrial effluents are deficient in nutrients hence to ensure adequate amounts of nutrients are supplied to the aeration tanks, nutrient balance should be periodically checked. In terms of the basic nutrients of Nitrogen (N) and Phosphorus (P), the rule of thumb for the weight ratio of BOD: N: P should be approximately 100 : 5: 1 . Typical signs of nutrient deficiency are filamentous growth and bulking of activated sludge . Nutrients

Biological Oxygen Demand: 

BOD refers to the amount of oxygen that would be consumed if all the organics in one liter of water were oxidized by bacteria and protozoa The first step in measuring BOD is to obtain equal volumes of water from the area to be tested and dilute each specimen with a known volume of distilled water which has been thoroughly shaken to insure oxygen saturation. After this, an oxygen meter is used to determine the concentration of oxygen within one of the vials. The remaining vial is than sealed and placed in darkness and tested five days later . BOD is then determined by subtracting the second meter reading from the first. Biological Oxygen Demand

PowerPoint Presentation: 

BOD Level (in ppm) Water Quality 1-2 Very Good There will not be much organic waste present in the water supply. 3-5 Fair: Moderately Clean 6-9 Poor: Somewhat Polluted Usually indicates organic matter is present and bacteria are decomposing this waste. 100 or greater Very Poor: Very Polluted Contains organic waste.

Chemical Oxygen Demand (COD): 

The amount of oxygen needed to consume the organic and inorganic materials is called the Chemical Oxygen Demand (COD ) Now a days various equipment are available for determination of COD Chemical Oxygen Demand (COD) Spectroquant® Test Kits for COD Analysis It can measure much higher levels of COD even when sample contains significant chloride. Nine different COD test kits cover the measurement range from 4.0 – 90,000 mg/l

PowerPoint Presentation: 

AppliCOD® - On-line COD Monitor

Physicochemical Process: 

Removal of Pollutants by Redox Reactions Many of the chemical and the biochemical processes encountered in the treatment of industrial effluents can be described fundamentally as oxidation-reduction systems . ORP measurement has been be utilized successfully to monitor cyanide oxidation and chromate reduction. The ORP measurement can be made electrometrically using the millivolt mode of a pH meter. Physicochemical Process

Removal of Metals by Ion Exchange: 

In this process, ion-exchange operations are usually monitored by monitoring conductivity . M ore accurate control can be achieved by using conductivity ratio measurement . Comparison of conductivity, pressure difference and metals concentration at the column’s inlet and outlet and within the column will enable one to detect the onset of breakthrough Removal of Metals by Ion Exchange

Removal of Metals by Electowinning: 

Electrowinning is an electrochemical process that can be employed to remove metallic ions . An advantage of electrowinning is that the metal removed from the effluent is plated out as a solid metal . Electowinner is equipped with an on-line metal sensor to provide real-time monitoring of the concentration of the metal to be removed. To monitor the efficiency of the electrowinning process other parameters monitored are current, voltage and temperature. Removal of Metals by Electowinning

REFERENCES: 

http:// www.environmental-expert.com/water-wastewater/bod-cod/products/keyword-chemical-oxygen-demand-test-kits-11046 http:// www.environmental-expert.com/products/applicod-on-line-cod-monitor-56165 http:// www.doe.gov.my/portal/wp-content/uploads/2010/07/Technical-Guidance.pdf http://discovery.bits-pilani.ac.in/~bvbabu/BVBabu_Water_Digest_Jan_2008.pdf REFERENCES