Study Area 23 DELAWAS STP. Figure-2 Location of DelawasSewage Treatment Plant

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1 Study Area 21 According to 2010 report the New Delhi based Center for Science and Environment (CSE) put the effective treatment capacity at only 19% of total sewage generation compared to an installed capacity of 30%. The conventional engineered wastewater treatment system is extremely expensive and requires complex operations and maintenance. Add to this the complication and cost of expanding sewer networks, which are very rudimentary or non-existent in many Indian cities that mostly started off as unplanned settlements. The total capital cost of establishing collection and treatment systems for the entire urban wastewater generated is much more than what the government plans to spend; as a result progress in increasing coverage is likely to be slow in the foreseeable future (R. Kaur et al., 2012). Like any other infrastructure project in India, land conflicts often hold up sewage treatment plants (STPs) construction long after funds have been sanctioned. An important reason that STPs run below installed capacity is the lack of adequate sewer connection. Other important factors include frequent power cuts, lack of skilled workforce, and inability of urban local bodies (ULBs) to afford operation and maintenance costs. Sometimes, when industries operate within urban boundaries, untreated industrial effluent can damage STP equipments/processes leading to forced downtime (CPCB, 2005). As a result, untreated urban sewage is considered by far the largest source of surface water pollution since India s record on industrial wastewater treatment is somewhat better. Municipal sewage is also a leading cause of groundwater contamination near urban areas (Centre for Science and Environment, 2010). The state of Rajasthan is located in the northwestern part of the Indian subcontinent. In Rajasthan a large area is recognized as arid region (desert), and one of the driest states in India, particularly in the western areas, known as the Great Indian Desert or the Thar Desert. Jaipur, the capital city of Rajasthan state, was established in 1727 by the Rajput ruler

2 Study Area 22 Sawai Jai Singh II, who moved the capital of his kingdom from Amber because of acute water shortage. Unlike many other old cities of the period, Jaipur is characterized by carefully planned land use and an adequate water supply system. The city is at an altitude of 431 meters, with a flat topography and well-planned layout of streets and roads on a grid pattern. Jaipur is located of north latitude and east longitude. Its urban boundary extends from and 13 north latitude to north latitude and and 12 east longitude to and 21 east longitude. The climate of Jaipur is semiarid, and average annual rainfall is only 650 mm (26 inches). Most rain occurs during the monsoon season between June and September, when heavy rains and thunder storms are common. The temperature in Jaipur varies from 25 C to 45 C in summer months and from 8 C to 22 C during winter. As of 2011, Jaipur had a population of 3,073,350. The Population of the Jaipur Metropolitan area is 3,646,590. Jaipur is the 10th largest city of India according to census of Figure 1 shows the location of Jaipur in Rajasthan. Figure 2 shows the location of Delawas sewage treatment plant at Pratap Nagar in Jaipur city. Figure 1 Location of Jaipur in Rajasthan

3 Study Area 23 DELAWAS STP Figure-2 Location of DelawasSewage Treatment Plant

4 Study Area 24 There are two water sources Ramgarh dam and Bisalpur water supply, providing about two-thirds of the drinking and irrigation water to the city. In recent years, water levels in these lakes have dropped due to variable rainfall in the catchment. Jaipur also depends on a chain of 1,826 deep, large diameter tube wells drilled by the PHED. The entire city of Jaipur lies within a dark zone on the hydrological map of the region, meaning that the area is over exploited. Groundwater levels have been declining rapidly in recent years due to overdraft withdrawal beyond the safe yield (Jethoo, 2011). It is estimated that the water table is falling at the rate of between 1.5 to 3 meters per year due to over exploitation, and is now between 65 to 70 meters below ground in most areas. The withdrawal level is estimated to be 600% of the safe yield (Sunda, 2012). Lack of coordination among competing uses, and the absence of effective regulation have caused this situation. The fact that water is not priced according to its cost has only further promoted the misuse of water resources. Many industries have their own tube wells to augment their PHED provided water supply to ensure that their factories continue to operate. Figure-3 Shows the sewerage network coverage in Jaipur city. There are five major Sewage Treatment Plants (STPs) in Jaipur. Wastewater Treatment Capacity in Jaipur City Nagar Nigam Jurisdiction JDA Jurisdiction Barhampuri 27 MLD Jaisinghpura 50 MLD Ralawata 30 MLD (under construction) Gajadharpura 30 MLD (under construction) Delawas 125 ( ) MLD

5 Study Area 25 The entire area under the Jaipur Municipal Corporation (JMC) is served by the wastewater collection network and two wastewater treatment plants in the north at Brahampuri and Jaisinghpura Khor on Delhi road, and at Delwas in south Jaipur. In addition, JMC has given Man Sagar Lake on lease for a period of 99 years to the Kothari Group, a business enterprise that has established a water treatment plant for its own use, and also supports conservation of the lake. JDA also plans to increase the capacity of the Vidhyadhar Nagar STP, and proposes a new plant in Vaishali Nagar. However, the tributary areas of Bambala Pulia and Kho Nagoriyan are not served with a wastewater treatment facility. Figure - 3 Sewage Network Coverage in Jaipur City

6 Study Area 26 Conventional wastewater treatment consists of a combination of physical, chemical, and biological processes and operations to remove solids, organic matter and, sometimes, nutrients from wastewater. General terms used to describe different degrees of treatment, in order of increasing treatment level, are preliminary, primary, secondary, and tertiary and/or advanced wastewater treatment. In some countries, disinfection to remove pathogens sometimes follows the last treatment step. Conventional STPs remove organic content from the water stream by reacting the proteins, fats and carbohydrates with oxygen from the air. This oxidation process is undertaken at ambient temperature by the enzymes secreted by aerobic bacteria and converts most of the organic material to carbon dioxide and water through dissimilatory process. The process also produces sewage sludge, or bio-solids, consisting of un-oxidized organic matter and predominantly bacterial cells. Some treatment plants further reduce the quantity of bio-solids through an anaerobic treatment process. Here, in the absence of air, anaerobic bacteria digest the bio-solids, producing "biogas", a mixture of methane and carbon dioxide. Methane is the main component of natural gas, and the biogas produced, can be burnt in an engine or turbine to produce power and generate electricity. In this way, anaerobic treatment can generate electrical energy used in the sewage treatment plant. A generalized wastewater treatment diagram is shown in Figure 4. Figure 5shows the general picture of waste water treatment plant.

7 Study Area 27 Figure 4: Generalized flow diagram for municipal wastewater treatment (Asano et al., 1985)

8 Study Area 28 Figure 5: General picture of waste water treatment plant. Rajasthan Urban Infrastructure Development Project (RUIDP) constructed and commissioned a 62.5 MLD 2 STP (Peak capacity 125 MLD) at Delawas, Pratap Nagar, Jaipur. Pratap Nagar lies between26º52 N latitude and 75º47 E longitude. The total area of Pratap Nagar is about 94 beegha. Figure-5 shows a general overview of Delawas Sewage Treatment Plant. A 62.5 MLD Sewage Treatment Plant at Delawas Jaipur under package no. JAI/WW/100 of ADB funded project under phase- I was constructed by RUIDP. Under JnNURM another MLD STP & Power generation unit operating from Sludge digestion from existing MLD STP (constructed by RUIDP) has been constructed by Jaipur Nagar Nigam in year

9 Study Area 29 Construction agency - M/s VatechWabag Pvt. Ltd. Chennai. RUIDP consultant - M/s Shah technical consultancy Services Mumbai. Figure -6 General Overview of Delawas Sewage Treatment Plant The objective of Delawas STP was to follow the waste water disposal standard set by RPCB/CPCB after treatment. Treatment is also necessary to remove the various contaminants present in sewage so as to produce an effluent and sludge, which can be disposed off into the environment without causing health hazards and nuisance. Earlier sewage was discharged directly in Amanishah nallah through 1800 mm outfall sewer at Delawas. Farmers were using this untreated sewage for growing vegetables were becoming harmful for peoples and increasing stomach/intestine diseases. Under ground water quality also deteriorated due to percolation of untreated sewage. The STP is in operation since beginning on its full design capacity. Figure-6 shows the sewerage coverage area of south zone of Jaipur city from Vidhyadhar Nagar to Pratap Nagar Sanganer. The farthest point is about 25 Km from STP and nearest is 1 Km. from STP. There is no pumping in sewerage network laid up to STP. Main trunk sewer reaching at STP site is 1800 mm in diameter Figure-7 shows the general Layout of STP.

10 Study Area 30 Figure - 7 Sewage Coverage Area of South Jaipur Figure - 8 General Layout of Delawas Sewage Treatment Plant

11 Study Area 31 Delawas wastewater treatment process It included following steps. Preliminary treatment Primary treatment (Physical treatment) Secondary treatment (Biological treatment) Preliminary treatment The objective of preliminary treatment is the removal of coarse solids and other large materials often found in raw wastewater. Removal of these materials is necessary to enhance the operation and maintenance of subsequent treatment units. Preliminary treatment operations typically include coarse screening, grit removal and, in some cases, comminution of large objects. In grit chambers, the velocity of the water through the chamber is maintained sufficiently high, or air is used, so as to prevent the settling of most organic solids. Grit removal is included as a preliminary treatment step for Delawas wastewater treatment. Flow measurement devices, often standing-wave flumes, are always included at the preliminary treatment stage. Approximately m3 inorganic matter released from Grit Separator per day at this STP. Also inorganic matter from Fine & Coarse screen gets about m3/day.

12 Study Area 32 Figure -9 A General view of Preliminary treatment tank Figure -10 Grit bars for Preliminary treatment

13 Study Area 33 Primary treatment The objective of primary treatment is the removal of settleable organic and inorganic solids by sedimentation, and the removal of materials that will float (scum) by skimming. Approximately 25 to 50% of the incoming biochemical oxygen demand (BOD5), 50 to 70% of the total suspended solids (SS), and 65% of the oil and grease are removed during primary treatment. Some organic nitrogen, organic phosphorus, and heavy metals associated with solids are also removed during primary sedimentation but colloidal and dissolved constituents are not affected. The effluent from primary sedimentation units is referred to as primary effluent. In many industrialized countries, primary treatment is the minimum level of preapplication treatment required for wastewater irrigation. It may be possible to use at least a portion of primary effluent for irrigation if off-line storage is provided. Figure 10 showing the inlet unit having waste water for primary treatment. Figure 11 Inlet Unit having waste water for primary treatment.

14 Study Area 34 Primary sedimentation tanks or clarifiers which used in Delawas STP are round basins, typically 3 to 5 m deep, with hydraulic retention time between 2 and 3 hours. Settled solids (primary sludge) are normally removed from the bottom of tanks by sludge rakes that scrape the sludge to a central well from which it is pumped to sludge processing units. Scum is swept across the tank surface by water jets or mechanical means from which it is also pumped to sludge processing units. In the digestion process, anaerobic and facultative bacteria metabolize the organic material in sludge, thereby reducing the volume requiring ultimate disposal, making the sludge stable (non-putrescible) and improving its dewatering characteristics. Digestion is carried out in covered tanks (anaerobic digesters), typically 7 to 14 m deep. The residence time in a digester may vary from a minimum of about 10 days for high-rate digesters (well-mixed and heated) to 60 days or more in standard-rate digesters. Digested sludge generation is about m3/day. Gas containing about Nm/3/day methane is produced during digestion and can be recovered as an energy source. In small sewage treatment plants, sludge is processed in a variety of ways including: aerobic digestion, storage in sludge lagoons, direct application to sludge drying beds, in-process storage (as in stabilization ponds), and land application.

15 Study Area 35 Figure- 12 Primary Clarifier for sludge removal Secondary treatment The objective of secondary treatment is the further treatment of the effluent from primary treatment to remove the residual organics and suspended solids. In most cases, secondary treatment follows primary treatment and involves the removal of biodegradable dissolved and colloidal organic matter using aerobic biological treatment processes. Aerobic biological treatment is performed in the presence of oxygen by aerobic microorganisms (principally bacteria) that metabolize the organic matter in the wastewater, thereby producing more microorganisms and inorganic endproducts (principally CO2, NH3, and H2O). Several aerobic biological processes are used for secondary treatment differing primarily in the manner in which oxygen is supplied to the microorganisms and in the rate at which organisms metabolize the organic matter.

16 Study Area 36 High-rate biological processes are characterized by relatively small reactor volumes and high concentrations of microorganisms compared with low rate processes. Consequently, the growth rate of new organisms is much greater in high-rate systems because of the well-controlled environment. The microorganisms must be separated from the treated wastewater by sedimentation to produce clarified secondary effluent. The sedimentation tanks used in secondary treatment, often referred to as secondary clarifiers, operate in the same basic manner as the primary clarifiers described previously. The biological solids removed during secondary sedimentation, called secondary or biological sludge, are normally combined with primary sludge for sludge processing. Common high-rate processes include the activated sludge processes, trickling filters or biofilters, oxidation ditches, and rotating biological contactors (RBC). A combination of two of these processes in series (e.g., biofilter followed by activated sludge) is sometimes used to treat municipal wastewater containing a high concentration of organic material from industrial sources. Activated Sludge In Delawas STP for secondary treatment activated sludge system is use. In the activated sludge process, the dispersed-growth reactor is an aeration tank or basin containing a suspension of the wastewater and microorganisms, the mixed liquor. The contents of the aeration tank are mixed vigorously by aeration devices which also supply oxygen to the biological suspension. Aeration devices commonly used include submerged diffusers that release compressed air and mechanical surface aerators that introduce air by agitating the liquid surface. Hydraulic retention time in the aeration tanks usually ranges from 3 to 8 hours but can be higher with high BOD5 wastewater. Following the aeration step, the microorganisms are

17 Study Area 37 separated from the liquid by sedimentation and the clarified liquid is secondary effluent. A portion of the biological sludge is recycled to the aeration basin to maintain a high mixed-liquor suspended solids (MLSS) level. The remainder is removed from the process and sent to sludge processing to maintain a relatively constant concentration of microorganisms in the system. Several variations of the basic activated sludge process, such as extended aeration and oxidation ditches, are in common use, but the principles are similar. Figure - 13 Aeration tank in processing stage

18 Study Area 38 Figure - 14 Secondary treated waste water after aeration Power consumption accounts for almost 75% of the expenditure on operation and maintenance of any sewage treatment plant working on aerobic biological process. STP Delawas, Jaipur based on conventional activated sludge process apart from power generation, energy saving measures taken for the plant operations has resulted in substantial saving in the energy costs. Power Generation Plant has been installed under JNNURM & is in operation since The power generation unit is in operation & about 7000 units power per/ day in being generated from gases produced during digestion of sludge at existing MLD STP. This is an example of waste to energy. It is saving about lacs power charges /month. The power generation unit cost was about Rs crores. Air blowers are being operated with Variable Frequency Drive (VFD). Man Machine Interface (MMI) is provided through Programmable Logic Control System (PLC) for handling anaerobic sludge digesters that produce about Nm3 of gas per day, which is being utilized for power generation. This has made the STP almost self-sufficient (except for

19 Study Area 39 meeting peak hour demand) in terms of power requirements. The increase in sludge at PST will reduce the BOD load on secondary treatment unit and will help in reduction in power consumption of aeration tank. Sewage treatment is a significant user of energy. Operation of pumps, blowers and other equipment at a typical sewage treatment plant (ASP /extended aeration) per person an annual electrical energy consumption requirement is in the range of KWh (Arceivala and Asolekar, 2006). Thus, substantial input of energy is required to treat sewage from densely populated areas, and sewage treatment often comprises the largest use of electricity by local governments.

20 Study Area 40 Figure- 15 & 16 Power generation at Delawas STP Reuse of effluent (treated waste water) from STP Delawas:- Ø Effluent (treated waste water) can be used for agriculture & industrial purpose after giving some further treatment Ø Digested sludge is good manure & can be used as manure in Agriculture & nursery. Jaipur Municipal Corporation is also planning to provide 20 MLD of treated water from Delwas STP to Mahindra Special Economic Zone (SEZ) for nondrinking uses, such as irrigation for gardening, firefighting, etc.