Chapter-1
INTRODUCTION

1.1 	General
Wastewater normally consists of high contents of different organic and inorganic, bio and non-biodegradable components along with significant population of aerobic and anaerobic bacteria, which can easily assimilate biodegradable organic components of wastewater. 
Aerobic bacteria dominate the microbial population and activity in wastewater discharges as long as it is fresh and containing a reasonable level of dissolved oxygen. As wastewater continues flowing in the closed sewer system to be transported to the treatment plants, it develops deficiency of dissolved oxygen due to its regular consumption in biological oxidation processes. Under such circumstances demand of oxygen for microbial reactions exceeds its supply from atmosphere through its free surface. Slowly wastewater flowing in closed sewer pipes is devoid of dissolved oxygen completely. This environment is known as anaerobic environment, which stimulates the activity and growth of anaerobic bacteria. The action of microorganism on organic substrates lead to the gradual conversion of the substrate into more micro-organism until the substrate is exhausted enzyme act to break the organic matter quickly into water soluble nutrients and increase the chemical reaction between organic matter. The organic waste is metabolized down to water and carbondioxide providing the microorganism with energy for growth and reproduction.
Bacteria decompose the organic waste as quickly as possible it is also possible that they form a satisfactory flock which is effective separation of biological solids in the clarifiers.
1.2	Enzymes 
	Enzymes are protein molecules which serve to accelerate the chemical reaction of living cells. Enzymes display great specificity and are not permanently modified by their participation in reaction. Since they are not changed during the reaction and they are neither consumed nor produced during the course of a reaction and enzymes do not cause reactions to take place, they expedite  reactions that would ordinarily proceed, but at much slower rate, in their absence. In other words they do not alter the equilibrium constant of reactions that they catalyzed. Enzymes are highly specific for the reactions they catalyzed and produce only the expected products from the given reactant, or substrate (i,e. there are no side reaction) they work with in a moderate pH and temperature range. Enzymes often show a high specificity toward one substrate, although some enzymes have a broader specificity, using more than one substrate.
A great number of enzymes and bacterial preparations have been marketed as agents capable of solving problems related to the operation of septic tanks, sludge digestion units, and other treatment facilities, and for degrading biologically resistant, hazardous compounds.
1.3	Objectives of the Study   
The following objectives of the project are;
1.	To study the effect of use of Enzymes.  
2.	 To assess the implementation of the enzymes for treatment of sewage at 10 MGD sewage treatment plant, Kondli, Delhi.
3.	To study the effect of enzyme on sewage treatment plant. 
4.	Measurement of energy consumption during the trials and to work out the cost benefit analysis of use of enzymes. 

          

Chapter-2
LITERATURE REVIEW

2.1	Major Microbial Groups
The world of microorganisms is made of bacteria, fungi, algae, protozoa, and viruses. They are group together only because of their small size, and not by their function. If, for example, the same taxonomical rules were applied to larger animals, some fish, shrimp, green plants, birds and mammals would be grouped together. Some microorganisms such as viruses, bacteria, and protozoa are notoriously small, under one mm. Others, like algae and fungi, have large size relatives (such as the brown algae that is among the largest living organisms). Unlike larger organisms, the morphology of microorganisms is relatively poor and is confined to few shapes and colors. However, their poor morphology is compensated by great physiological versatility.
2.1.1	Viruses
	Viruses are very small, ranging between 0.01 and 0.03 microns, and only visible by using an electron microscope. They cannot live independently, and only multiply inside the cells of other organisms. However, their demand for a host is fairly specific. For example, it is unlikely that a crustacean virus will attack humans or fish. Viruses are also the simplest of all organisms and are made of nucleic acid (either DNA or RNA), frequently coated with a protein layer.

2.1.2	Algae
	Algae are photosynthetic organisms (contain chlorophyll) and obtain their energy from the sun and their carbon from carbon dioxide. Their size ranges from one micron to many meters. All organisms that use carbon dioxide for their carbon requirement are called autotrophs. Algae are generally beneficial in aquaculture by supplying oxygen and a natural food base for the cultured animals, such as dinoflagellates that cause the red ties.
2.1.3	Fungi
	Fungi are similar to algae, but they do not contain chlorophyll and require pre-formed organic matter as energy and carbon sources (e.g., sugars, fat, protein, and other carbohydrates). Such organisms are called heterotrophs. Fungi, ranging in size from a few microns to several centimeters, grow either independently by feeding on decaying matter, or in association with plants and animals..
2.1.4	Protozoa
Protozoa are heterotrophs, mostly free-living, feeding mainly by devouring smaller microorganisms. Their size ranges between two and 200 micron meters. A large group of protozoa, the Sporozoa, are parasites. Small numbers of protozoa contain chlorophyll and can switch between autotrophic and heterotrophic modes of feeding, based on light conditions.
2.1.5	Bacteria
	Bacteria range in size from 0.1 to 15 micron, with some " giants "that may reach half a millimeter. They make up the most metabolically diverse group of living organisms. Although some are parasitic to animals and plants, the majority of bacteria are free-living, having either a neutral or beneficial relationship with humans and other animals and plants. Their metabolic versatility is incredible: while most are heterotrophs, using either light or chemical energy. One of their most remarkable characteristics is their ability to multiply rapidly, with generation times usually ranging between minutes to hours.
2.2	Microbial Process 
Bacteria and other microorganisms, most notably fungi, are able to metabolize and transform numerous organic and inorganic compounds. Therefore, man has used them for thousands of years for making yogurt, pickles, bread, cheese, wine, and more recently for waste purification and wastewater purification. Process controlled by microorganisms can occur aerobically (in the presence of oxygen) or anaerobically (with no oxygen present). The starting materials and the end products of such processes vary based on the microorganisms' capabilities (as reflected in their genetic makeup), and the environment in which these processes occur (e.g., availability of oxygen, temperature, salinity, pH, etc.

2.3	The Role of Bacteria In The Sewage Treatment Process
One area of sewage treatment that is not well understood is the bacterial decomposition process.
Bacteria may be aerobic, anaerobic or facultative. Aerobic bacteria require oxygen for life support whereas anaerobes can sustain life without oxygen. Facultative bacteria have the capability of living either in the presence or in the absent of oxygen. In the typical sewage treatment plant, oxygen is added to improve the functioning of aerobic bacteria and to assist  them in maintaining superiority over the anaerobes. Agitation, settling, pH and other controllable are carefully considered and employed as a means of maximizing the potential of bacterial reduction of organic in the wastewater.
Single-celled organisms grow and when they have attained a certain size, divide, becoming two. Assuming an adequate food supply, they then grow and divide again like the original cell. Every time a cell splits, approximately every 20 to 30 minutes, a new generation occurs. This is known as the exponential or logarithmic growth phase. At the exponential growth rate, the largest number of cells are produced in the shortest period of time. In nature and in the laboratory, this growth cannot be maintained indefinitely, simply because the optimum environment of growth cannot be maintained. The amount of growth is the function of two variables: - environment and  food. The pattern which actually results is known as the bacterial  growth rate curve. Initially dehydrated products (dry) must first re-hydrate and acclimate in a linear growth phase before the exponential rate is reached.
Microorganisms and their enzyme systems are responsible for many different chemical reactions produced in the degradation of organic matter. As the bacteria metabolize, grow and divide they produce enzymes. These enzymes are high molecular weight proteins.
It is important to recognize the fact that colonies of bacteria are literally factories for the production of enzymes. The enzymes which are manufactured by the bacteria will be appropriate to the substrate in which  the enzyme will be working and so you have automatic production of the right enzyme for the biological reduction of any waste material, provided you have the right bacteria to start with. Enzymes do not reproduce whereas as bacteria do.
Enzymes in biochemical reactions act as organic catalysts. The enzymes actually become a part of the action, but after having caused it, split off from it and are themselves unchanged. After the biochemical reactions are complete and products formed, the enzyme is released to catalyze another reaction. The rate of reaction may be increase by increasing the quantity of the substrate or temperature up to a certain point , but beyond this, the rate of reaction ceases to increase because the enzyme concentration limits it.
All treatment plants should be designed to take advantage of the decomposition of organic materials by bacterial activity. This is something you can equate to lower costs, increased capacity, and an improved quality of effluent; even freedom from bad odors which may typically result when anaerobe bacteria become dominant and in their decomposition process, produce hydrogen sulfide gas and similar by-products.
Consider the fact that the total organic load of wastewater or sewage is composed of constantly changing constituent, it would be quite difficult to degrade all of these organics by the addition of one enzyme, or even several enzymes. Enzymes are specific catalysts and do not reproduce. What is needed is the addition of an enzyme manufacturing system right in the sewage that can be pre - determined as to its activity and performance and which has the initial or continuing capacity to reduce waste.
At the present time, the addition of specifically cultured bacteria seems to be the least expensive and most generally reliable way to accomplish desirable results. When you add the right bacteria in proper proportions to the environment, you have established entirely new parameters of potential for the treatment situation.
2.4	Bacterial Growth    
Effective environmental control in biological waste treatment is based on an understanding of the basic principles governing the growth of bacteria, the microorganisms of primary importance in biological treatment.
2.4.1	General Growth Patterns In Pure Cultures  
Bacteria can reproduce by binary fission, by a sexual mode, or by budding. Generally, they reproduce by binary fission (i.e., by dividing, the original cell becomes two new organisms). The time required for each fission, which is termed the generation time, can vary from days to less than 20 min. For example, if the generation time is 30 min, one bacterium would yield 16,777,216 bacteria after a period of 12h. This computed value is a hypothetical figure, for bacteria would not continue to divide indefinitely because of various environmental limitations such as substrate concentration, nutrient concentration, or even system size.
2.4.2	Growth In Terms of Bacterial Numbers. 
	The general growth pattern of bacteria in a batch culture. Initially a small number of organisms are inoculated into a fixed volume of culture medium, and the number of organisms are inoculate into a fixed volume of culture medium, and the number of viable organisms is recorded as a function of time. The growth pattern based on the number of cells has four more or less distinct phases.
1.	The lag phase, upon addition of an inoculum to a culture medium, the lag phase represents the time required for the organisms to acclimate to their new environment and begin to divide.
2.	The log-growth phase. During this period the cells divide at a rate determined by their generation time and their ability to process food (constant percentage growth rate):
3.	The stationary phase. Here the population remains stationary. Reasons advanced for this phenomenon are (a) that the cells have exhausted the substrate or nutrients. Necessary for growth, and (b) that the growth of new cells is offset by the death of old cells.
4.	The log-death phase. During this phase, the bacteria death rate exceeds the production of new cells. The death rate is usually a function of the viable population and environmental characteristics. In some case, the log-death phase is the inverse of the log-growth phase.  
2.5	Function of Enzymes
Enzymes are "biological catalysts." "Biological" means the substance in question is produced or is derived from some living organism. "Catalyst" denotes a substance that has the ability to increase the rate of a chemical reaction, and is not changed or destroyed by the chemical reaction that it accelerates.
Generally speaking, catalysts are specific in nature as to the type of reaction they can catalyze. Enzymes, as a subclass of catalysts, are very specific in nature. Each enzyme can act to catalyze only very select chemical reactions and only with very select substances. An enzyme has been described as a "key" which can "unlock" complex compounds. An enzyme, as the key, must have a certain structure or multi-dimensional shape that matches a specific section of the "substrate" (a substrate is the compound or substance which undergoes the change). Once these two components come together, certain chemical bonds within the substrate molecule change much as a lock is released, and just  like the key in this illustration, the enzyme is free to execute its duty once again.
Enzymes or biological catalysts allow reactions that are necessary to sustain life proceed relatively quickly at the normal environmental temperatures. Enzymes often increase the rate of a chemical reaction between 10 and 20 million times what the speed of reaction would be when left uncatalyzed.
2.5.1	How Enzymes Aid In Digestion 
An enzyme is a chemical catalyst that breaks up long, complex waste molecules (Hydrolytic Reaction) into smaller pieces, which can then be digested directly by the bacteria.
Enzymes are simply chemicals - they are not living  things, and they cannot grow or reproduce themselves. Enzymes are manufactured by bacteria, and used by the bacteria in order to digest waste. The enzymes that are mixed into the products are actually produced by special  bacteria, extracted from them in dry form, and blended into the mixture.
Enzyme are added to help them go to work faster. When added to the organic waste, the enzymes immediately go to work breaking down the waste into water - soluble nutrients for the bacteria to digest. The enzymes break the large, complex molecules of starches, proteins, carbohydrates, and cellulose into smaller, simpler pieces. These enzymes act like chemical "knives", chopping the large molecules of waste into smaller pieces of water - soluble nutrients for the bacteria. The growing bacteria will then start to produce more enzymes on their own, creating a continuing cycle of enzyme production.
2.6	Factors affecting enzymatic activity 
Enzyme activity is a measure of how much reaction rates are increased. Factors that affect enzyme activity are: concentration, temperature, and pH
2.6.1	Concentration    
If we keep the concentration of the substrate (the compound on which the enzyme works to speed up the reaction) constant and increase the concentration rate of the enzyme, the rate increases linearly. That is, if the enzyme is doubled, the rate also doubles.
R
A
T
E
          Concentration 
2.6.2	Temperature
Temperature affects enzyme activity because it changes the three-dimensional structure of the enzyme. In uncatalyzed reactions, the rate of activity usually increases as the temperature increases. The effect of temperature on enzyme catalyzed reactions is different. When we start at a low temperature, an increase in temperature first causes an increase in reaction rate. Once an optimum temperature is reached, the substrate may then not fit properly onto the changed enzyme surface. Therefore the rate of reaction beginning to decrease.

R
A
T
E
0	20	30	40	50
  Temperature (C°)	
2.6.3	pH 
Since the pH of its environment changes the conformation of a protein, we can anticipate effects similar to those observed when the temperature is changed. Each enzyme operates best at a certain pH. Once again, within a narrow pH range, changes in enzyme activity are reversible. However, at pH extremes (either acidic or basic), enzymes are denatured irreversibly, and enzyme activity cannot be restored by changing back to the optimal pH.    

R
A
T
E

pH	4	5	6	7	8	10

2.7	Bacterial / Enzyme Digestion
Bacterial digestion is the process of bacteria, consuming organic matter. Enzymes act to break the organic matter into water - soluble nutrients, which the bacteria digest. Using complex chemical reactions, the organic waste is metabolized down to water and carbon dioxide (the final metabolic waste products), providing the bacteria with energy for growth and reproduction. It may be simply shown by the following equation:
2.7.1	Aerobic Digestion
Organic waste + water -----Enzyme----> water soluble nutrients + oxygen ----Bacteria---> water + carbon dioxide

2.8	Enzymes And Its Application 
2.8.1	The Product 
The product known by brand name (EnviroSEB-E) is being manufactured by M/s. Advanced Biochemical Limited, Mumbai in association with specialty Enzymes and Biochemical Co., USA. This product is a scientifically designed blend of select enzymes and special microbes. The enzymes help in rapid breakdown of the biological matter while the specially selected strains of microbes ensure rapid reduction in BOD levels. Enviro SEB-E is 100% eco-friendly, safe and non-hazardous product. 
2.8.2	Product Specification 
S.No.	Particulars	Specifications	
1	Name of the product	EnviroSEB- E	
2.	Description 	of white liquid 	
3.	Batch No.	ENV 040401	
4.	Odour	Fruity Fermented odour	
5.	Identification 	Heterophilic co-existing multiple specific blended with specific enzymes 	
6.	Solubility	Soluble in water	
7.	pH	 8.5	
8.	Total Viable count 	600 millions cfu/ml 	
9.	Specific gravity	0.995	
10.	Shelf Life 	Upto 3 month when stored at ambient temperature 	
2.8.3	Advantages:
•	Rapidly reduces the BOD, COD and TSS. 
•	Rapid recovery time from upsets.
•	Improves settling of flock formation in the final clarifier.
•	Improves waste degradation of specific target compounds.
•	Increases the wastewater treatment systems capacity.
•	Enable to absorb the shock of toxic influent.
•	Enhances the stability of wastewater treatment systems.
•	Enhances odor control through natural organic acid oxidation.
•	Environmental friendly, biodegradable component for broader activity spectrum.

Chapter-3

Methodology

3.1	Trials Project Set-Up 
The trials of Enzymes Technology were proposed to be conducted at 10 MGD STP, Kondli, Delhi, the period of trial was suitably fixed for three months in order to study the effect of continuous uses of enzyme for a longer period to create stable condition. This STP is based on Activated Sludge Process Technology and was commissioned in the year 2001. The set-up for trials of enzymes at this plant mainly included continuous application of Enzymes and testing of effluent parameters. The Energy Savings were achieved through reduction in aeration by stopping aerators for extended period of time.
3.2	 Plant Description
The 10 MGD plant was constructed and commissioned in 2001. The treatment process followed at the plant is the Conventional Activated Sludge Process. The typical units are as follows:
•	1 mechanical bar screens 
•	1 grit chambers 
•	Parshall flume with ultrasonic-type flow meter 
•	2 primary settling tanks with central drive mechanical sludge rakes 
•	Raw sludge pump house 
•	Aeration tank with 14 nos. surface aerators, each 40 hp (30 kW) 
•	2 secondary settling tanks 
•	Return sludge pumping house 
•	4 digesters provided with MS dome and gas mixing 
•	2 gas holders 
•	12 sludge drying beds 
3.2.1 	 Bar Screen
      The raw sewage first enters ‘Bar Screen’. The screen arrests large floating objectionable matter.
      The screens used are ‘S’ type screens. These are Hindustan Dorr Oliver’s screens. These have reciprocating rake mechanism and are angled into the channel with a slight bent invert at the bottom to facilitate easy collection and withdrawal of screenings. The raking mechanism meshes with the bars which are spaced at suitable spacing.
      The rake runs in a track and is pulled up the slope by two cables which automatically reverse direction at the top of stroke. At this point the toggle rake shaft, which is attached to the track, pulls it and rake away from bars for the descending stroke. When the rake reaches bottom, the toggle shaft pushes it against the bar and the raking operation is repeated. The rake scraper is raised and lowered by the action of rake, pushing the screening for disposal. The drive consists of gear suitable for such application.
      One of the prominent advantages of Door Bar Screen is that it has no revolving, rotating, drive portion below water level. Thus the chances of mechanical failure due to chokage, rusting, wearing are minimized. 
3.2.2 	GRIT CHAMBER 
      This has been designed to remove grit consisting of sand, gravel, cinders or other heavy solid materials that have subsiding velocities or specific gravities substantially greater than those of the organic putrescible solids in waste water. By providing detritors, the moving mechanical equipments further downstream in the plant are protected to a great extent from abrasion and accompanying abnormal wear. Such degritting devices also reduce the formation of heavy deposition in pipe-lines, launders and conduits and reduce frequency of cleaning of the tanks that may be otherwise required due to excessive accumulation of grit in such units.  
3.2.3	 Primary Clarifier
      The Primary Clarifier of fixed bridge type has been provided to enable settlement of suspended solids in raw sewage. The settled solids is raked to the central discharge cone from where it is taken by gravity to a raw sludge pump house for further pumping to the digester.
      The primary clarifier is also equipped with a skimmer scum trough and scum baffle to remove all floating suspension present in raw sewage.
      The primary clarifier aids settlement of suspension and reduce the BOD in raw sewage by about 40% before it is conveyed to the aeration tank for biological oxidation. 
3.2.4 	Aeration Tank
      For the oxidation of organics (BOD) by aerobic biological treatment, conical type of slow speed surface aerators have been used in the aeration tank.
      The aerator ensures that the biomass developed in the tank remains in suspension and is uniformly distributed throughout the tank for optimum stabilization of sewage. Further, it also ensures that the maximum oxygen is transferred to liquid phase for utilization by micro-organism developed in the tank.  
3.2.5	 Secondary Clarifier
      The aeration tank contents (MLSS) are settled in secondary clarifiers. The clarifier is a circular R.C.C. tank with bottom feed entry and comprises a feed well. The clarifier mechanism is centrally driven and consists of rake arms and squeegees to scrape the settled sludge to the control discharge cone. Settled sludge from the secondary clarifier is conveyed to a return sludge sump for recycle to the aeration tanks. The overflow represents treated sewage conforming to desired limits. 
3.2.6	 Return Sludge Pumps
      Return sludge pumps of the horizontal, centrifugal, non clog type are being used to pump return sludge collected in the sludge sump. 
3.2.7 	Raw Sludge Pumps
      Raw sludge pumps of the CI. horizontal, centrifugal, non-clog type are being used to pump sludge collected in the sludge sump. These pumps have been designed for pumping raw sludge in 3-4 hrs/day to the digester.  
3.2.8	 Digester
      The mixed sludge (primary + excess secondary) is being digested in digesters with concrete tank and mild steel dome. The digesters work on gas mixing system.
   Anaerobic Digester performance is achieved by efficient mixing system by recycled digester gas injection. The benefits of this system are:
•	Maintenance of even sludge temperature providing physical, chemical and biological uniformity throughout the digester. 
•	Elimination of sludge/water bonding. 
•	Rapid distribution of raw feed, reducing risk of short circuiting to discharge. 
•	Maximum prevention of scum/crust formation on the surface which inhibits gas rise in the operation of digester. 
•	Minimizes grit and heavy particle settlement. 
. 
      The sludge is retained in the digester for a period of about 30 days during which it undergoes anaerobic digestion. The digested sludge is settled at the bottom which is collected by the sludge draw off pipe. The scum floating at the top is skimmed off. The clear supernatant is removed and recycled to the inlet of the primary clarifier under gravity. The gas produced is collected at the top of the digester and conveyed to the ‘Gas Holder’ 
3.2.9 	Sludge Drying Beds
      The digested sludge from the digester is applied on the sludge drying beds with filter media comprising fine sand of 100 mm, coarse sand 100 mm, and gravel of 150 mm.
      The filtrate from the sludge drying beds is pumped back to primary clarifier. The dry cake formed on the top of the media is raked off periodically and is disposed off suitably. 
3.3	Application of Enzymes 
3.3.1	Quantity Applied 
The initial quantity of enzymes applied for the trials was based on the following recommendations of pollution control officer, Thane: 
I.	5 Kg of Enviro SEB-E. per MGD to be used in the effluent initially. 
II. 	Slow mixing is required per hour every day for proper dispersion of Enzymes and doze is reduced to 2.5 Kg/MGD after 2 months. 
		Therefore, the trials were started with the initial quantity of 5.0 Kg of Enzymes per MGD of sewage to be treated. Since the trials were conducted at 10 MGD STP, the total initial quantity of enzymes used was about 50 Kg. Per day. 
3.4	Uniform Dozing of Enzymes 
The influent flow at the Sewage Treatment Plant is not uniform. It varies over a period of 24 hours with peak inflow during morning hours and very low discharge during night hours. Therefore, it was required that the dozing of Enzymes is maintained at the same rate as that of influent so that the uniform mixing of enzymes is ensured throughout the period of 24 hours. To achieve the above, it was required to study and measure the influent flow pattern over a period of 24 hours and superimpose the pattern on the dozing rate. 
3.5	Influent Flow Pattern 
The influent at 10 MGD STP at Kondli is reaching from the Kalyanpuri sewage pumping station. An electronic flow meter is installed in the inlet Channel of 10 MGD plant. The measurement of influent was undertaken at this point and hourly readings of incoming flow rate were recorded continuously with effect from 01-11-2006 to 10-11-2006. The summary of these measurements is given in  It was observed that the influent Flow rate reached a maximum of 13.91 MGD at noon and a minimum value of 3.36 MGD at night. The average influent Flow pattern and its variation over a period of 24 hours is depicted as shown in table 1 and figure.1.   

3.6	Dozing Pattern of Enzymes 
Since there was a large variation in the rate of influent flow at 10 MGD STP Kondli, it was considered necessary to calibrate the dozing rate of enzymes according to the influent rate. Therefore, a dozing pattern was arrived at by superimposing the influent flow pattern on the dozing pattern. In order to avoid frequent variation of dozing rate over a period of 24 hours, the dozing pattern was divided into four intervals and the average dozing rates were worked out for all these intervals. The details of dozing pattern and divisions in four intervals are shown in figure.2 
3.7	Dozing Equipments Setup 
The dozing of Enzymes was undertaken as per the above slabs of dozing rates during different time intervals. In order to ensure control on uniform rate of dozing and quantity of Enzymes, special dozing equipments setup comprising of followings were deployed. 
1.	Dozing Pump 
2.	Measuring Tank 
3.	Delivery pipe 

3.7.1	Dozing Pump 
A pump with flow rate control device was installed at Grit Chamber to control the rate of dozing of enzymes as per the dozing pattern worked out based on the influent flow pattern. 
The dozing pump was equipped with the rate control knob. The calibration of the Pump was carried out by setting minimum and maximum range of dozing rates. The rate of dozing was controlled by setting the rate control knob at appropriate scale depending upon the interval of dozing. 

3.7.2	Measuring Tank & Delivery Pipe 
The enzymes were poured in the Measuring Tank having storage capacity of '100 liters. The Pump was connected with this measuring tank and the enzymes were pumped into the Delivery pipe. The delivery pipe was installed at the flow channel after the Grit Chamber. 

3.8	Measurements 
The, trial measurements were categorized in two stages i.e. Pre-trial measurements and On-trial measurements. The Pre-trial measurements consisted of assessment of all parameters during normal functioning of the plant based on activated sludge process. The On-trial measurements were aimed at to ascertain various parameters during the trial period when the plant was functioning with Enzymes Technology. 
3.8.1	Pre-Trial Measurements 
	Before 	starting the trial, the following measurements were recorded for different processes and functioning of the plant. Pre-trial measurements were carried out for a period of about three weeks. , 
3.8.2	Flow Measurements 
The Influent flow rates at 10 MGD unit were recorded on hourly basis through the study and details are shown in table 3. The measurements were taken through electronic Flow measurement device installed at the inlet channel of the plant. 

3.8.3	Influent & Effluent Parameters: 
The samples of influent and effluent were lifted  periodically during the pre-trial period for testing the same for the following parameters: 
1. pH 
2. Suspended solids (55) 
3. Biological-Oxygen demand (BOD) 
4. Chemical-Oxygen Demand (COD) 
5. Coliform Count 
	The results of the samples for the above-mentioned parameters reflect the normal functioning of the plant before starting trials and during the trial period. The parameters are summarized in table 5 & 6.
3.8.4	On-Trial Measurements 
All measurements undertaken during the pre-trial period were continued during the actual trials. In addition to that the following measurements were also reordered. 
1. Quantity of Enzymes consumed 
2. Dissolved Oxygen (DO) in Aeration tank. 
3.8.5	Measurement of Quantity of Enzymes 
	The measurements regarding quantity of Enzymes consumed were recorded on hourly basis. The quantity consumed per day was worked out on the basis of dozing rate applied. The data regarding variation of actual quantity of enzymes consumed over the period of study is shown in table 7. The using of enzymes pattern are shown in figure 3.
3.8.6	Measurement of Dissolved oxygen (Do) 
The measurement of dissolved Oxygen in the Aeration Tanks was also undertaken to ensure that no septic conditions develop in the Aeration tanks. The Dissolved Oxygen (DO) levels in Aeration Tanks were also considered a major criterion for ascertaining the optimum quantity of Enzymes was regulated based on the availability of Dissolved Oxygen levels in the effluent as measured in the aeration tanks.
3.9	Influent & Effluent Parameters
	The samples of influent and effluent were lifted periodically during the pre-trial period for testing the same for the same for the following parameters:
1.	pH
2.	Suspended solids (SS)
3.	Biological-oxygen demand (BOD)
4.	Chemical-oxygen Demand (COD)
5.	Coliform Count
	The result of the samples for the above mentioned parameters reflect the normal functioning of the plant before starting trials and during the trial period. The parameters are summarized in the 
3.9.1	On-Trial Measurements
All measurements undertaken during the pre-trial period were continued during the actual trials. In addition to that the following measurements were also reordered.
1.	Quantity of Enzymes consumed
2.	Dissolved oxygen (DO) in Aeration tank.
3.9.2	Measurement of Quantity of Enzymes  
The measurements regarding quantity of Enzymes consumed were recorded on hourly basis. The quantity consumed per day was worked out on the basis of dozing rate applied. The data regarding variation of actual quantity of enzymes consumed over the period of study as shown in table 

Chapter-4

RESULT AND DISCUSSION

The results of study were carried out in accordance to the objectives of the project.
4.1	Analysis For Ascertaining Successful Implementation of The Enzymes Technology
The successful implementation of the Enzymes Technology is governed by the compliance of the permissible effluent parameters as per prescribed Standards. The design parameters and the prescribed parameters are summarized as below:
	BOD (mg/l)	SS (mg/l)	
Plant Design Parameters	20	30	
Prescribed Parameters as per Delhi Pollution Control Committee 	30	50	
    
 The results of samples collected during the trials period were tested for various parameters such as pH, BOD, COD & SS. In additional to that test were also carried out for coli form count. The detailed results of various parameters such as pH, BOD, COD & SS in additional to that test were also carried out for coliform count the results of various parameters for pre-trial period and on-trial period are shown in table 5 & table 6 and the trends of the results are shown in figure 4 to figure 8.
It is seen from above trends of the results of trails that the effluent parameters were found to be within the prescribed criteria as per Delhi Pollutions Control Committee. The average value of these parameters during the trial period are as follows:
	Results (Avg.)	
Parameters 	Influent 	Effluent 	%
Reduction	
pH	7.3	7.8	-	
BOD(mg/l	230	24	89.56%	
SS(mg/l)	361	36	90.03%	
COD(mg/l)	500	80	84.00%	
Coliform
(MPN/100ml)	2.48x109	5.61x107	97.74%	
   
4.2	Measurement of Energy Consumption During the Trials And to Work out The Energy Savings. 
The measurements for the energy consumptions were recorded as mentioned above. The measurement recorded in INCOMER reflects total energy consumption for the Plant. Separate recordings for various units such as Aerator, Raw sludge, and Return sludge were also recorded. The numbers of aerators running were also recorded on hourly basis.
The data/details of Energy measurements are summarized in the table-4. The saving in the Energy consumption has been worked out by comparing the total energy consumed during the period of trials with the Energy consumption during the normal functioning of the plant.

ELECTRICITY METER

The Scheme network of energy meters is as shown below:

AREATOR ENERGY METER
Multiplication factor 200

INCOMMER ENERGY METER
Multiplication factor 300

DIGESTER, LIGHT & OTHER ENERGY METER
Multiplication factor 20

RETURN SLUDGE
ENERGY METER 
Multiplication factor 20

RAW SLUDGE ENERGY METER 
Multiplication factor 20

4.2.1	Normal Energy Consumption  
The normal energy consumption for the plant has been worked out based on the average consumption as recorded in the INCOMER during the PRE-TRIAL period before starting the Energy savings. Since during the entire trails period, 14 aerators were functioning, average Normal energy consumption works out to 6462 units of electricity per day. 
4.3	Energy Consumption During Study  
The energy consumption during trials was mainly affected by the Nos. of aerators operating per day. As the Enzymes started functioning, the aeration was continuously reduced by reducing the Numbers & hours of operations of aerators n the aeration Tank.
The daily consumption as recorded in the INCOMER reduced from an Average value of 6462 units to an average value of 3655 units during the last week. The trends of savings in Electricity consumption as per INCOMER and as per nos. of aerators running per day are shown in table-8 and table-9, and saving of energy also shown in  figure-9 and figure-10.
4.4	Cost-Benefit Analysis
In order to work out the economies of the enzymes technology in terms of financial savings, and benefit components have been identified and corresponding financial effects are calculated based on trail measurements and other related data/records. 
The main cost components associated with the enzyme technology are as follows:
1.	Cost of enzymes 
2.	Cost of manpower support
The cost associated with above component has been worked out of daily basis and the details are placed in the annexure.
The main benefits components for using Enzymes technology are as follows:
1.	Savings in Electricity Consumption 
2.	Anticipated Savings in Maintenance cost of Aerators
3.	Anticipated Savings in manpower & operation cost
The savings in electricity consumption has been worked out as per the actual measurements of Energy.
The anticipated savings in maintenance cost of Aerator works out as follows:
Cost of one Aerator considered 	=	Rs. 8.00 lacs
Annual maintenance cost @ %		=	8,00,000x0.06
						=	48,000/-
    Anticipated Savings per day 	=	Rs. 132/-
The anticipated savings in operation and manpower cost works out as follows:
Maintenance contract for providing manpower and operation	=	Rs.2.00 lac per month	
Component of this cost associated with the Aerators is considered as 25% of the total contract	=
=	2,00,000x0.25
Rs. 50,000/- per month
	
Therefore, anticipated savings per day 	=	Rs. 1667/-	

The detailed calculations for cost components and benefit components are shown in the tables 11.
The cost-benefit curve has been drawn based on cost and benefit streams worked out as above. The cost and benefits data has been plotted on daily basis. The trends of figures are shown in the figure 11.
It is seen that the cost from initial value of Rs. 30,000/- and starts decreasing as the trials progress. The table cost at the end of trials reaches a value of Rs. 5338/- per day.
Similarly the benefits from the trials starts once the aeration operations are reduced. The stable benefits reached an average value of Rs. 18050/- per day. Therefore the net savings works out to as follows:
Stable benefits at the end of trails 	=	Rs. 18050/- per day 	
Stable cost at the end of trails 	=	Rs. 5338/- per day	
Stable net savings 	=	Rs.12,712/- per day	
Savings per Annum	=	Rs. 46.40 lacs	
  
The cost –benefit curve is shown in figure-11

Chapter-5

Conclusions and recommendations

Conclusion
The following conclusions are drawn based or interpretations of the study:
•	The technology of Enzymes was found to be effective in treatment of sewage. 
•	The trials of Enzymes have been successfully conducted at the 10 MGD STP Kondli, Delhi.
•	The Technology is very simple in application and can be deployed in any exiting STP with minimum instrumentation & equipments.
•	The Enzymes technology has been able to meet the prescribed Effluent Parameters.
•	The Enzymes have also been effective in reducing the coliform concentration by 97.74%
•	The Enzymes were also found effective in improving the ambient air quality by reducing the odor emanating from the sewage.
•	The quantity of Enzymes required was reduced up to 0.80 kg/ day per MGD of sewage treatment.
•	The Technology is economically viable as the projected benefits from the project works out to Rs. 46.40 lacs per annum for 10 MGD of Sewage Treatment.
Recommendations   
•	Although the technology is able to meet the prescribed parameters of effluent as per DPCC guidelines, the Design parameters of STP i.e. BOD=20 mg/l and SS = 30 mg/l could not be achieved during the study however there seems to a possibility of achieving higher standards of effluent if the technology is deployed for a longer and continuous basis.
•	The main component of the technology i.e. Enzymes are proprietary items being manufactured solely by one manufacturer. The availability of the enzymes in sufficient quantity with reasonable cost needs critical review before implementing this Technology on large scale & regular basis. 
•	If the enzymes are tried on open nallah / sewer reduction of sludge, odor, BOD, suspended solid and other parameter are likely. It will further result in saving of energy at sewage treatment plant.      

Reference
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List of some websites visited: 
www.canadianencyclopedia.
www.bccresearch.com
www.noharm.org/details.
www.microtack.com
www.dyadic-group.com/wt/dyad/waste_treatment -
sci.agr.ca/sthyacinthe/biblio/i/mia