Faecal Sludge Natural Treatment Plant (FSNTP) at Ponnampatti Town Panchayat Trichy District, Tamil Nadu 1 Introduction

Faecal Sludge Natural Treatment plant (FSNTP) at Ponnampatti Town Panchayat Trichy District, Tamil Nadu 1 Introduction Ponnampatti Town Panchayat is located 64 km from Trichy on the Trichy-Madurai National Highway (NH-47) in Marungapuri Block of Trichy District, inclusive of Thuvarankurichi Town. In view of the very innovative and pioneering initiatives in the field of Solid Waste Management, sanitation, Faecal Sludge Management, Drinking Water Supply, continuous Sustained awareness programme, The Ponnampatti Town Panchayat was adjudged as the Best Town Panchayat by Tamil Nadu Government in 2017. It is fast developing as a Sanitation destination in the State and Country.

Tamil Nadu Chief Minister Edapadi Palanisamy hand over the Award to Mr. Shakul Ameed, E.O, in the presence of Ms. Girija Vaithiyanathan, IAS., Chief Secretary.

The PTP has a population of about 18,000 and is divided into 15 wards spread over an area of 10.83 km2. The area of the Resource Recovery Park is 2 acres (0.81 ha) and was established on a rocky rugged elevated space, is 3km from the Office. Total number of households is 4,120. Total administrative staff is 12 and has 48 field staff. It has two higher secondary schools, one matriculation school and 9 Panchayat Primary schools.

1. Sanitation Background in the Country: Flush Toilets linked to Septic Tanks or Leach Pits are the most popular types of toilets in unsewered area in India irrespective of whether it is a Metro, City, Municipality or a Panchayat. Use of Septic Tanks, an anaerobic baffled reactor as per theory, results in generation of sludge settling at the bottom which needs to be removed every -5 years to keep the Septic Tank functional without problems. The sludge from the Septic Tank generally referred to as Septage, in theory will be digested sludge. However, most of the Septic Tanks are not designed or constructed properly as per the stipulations in the BIS Code of IS 2470 Part 1. This makes the safe treatment and disposal of septage still more challenging a task since the material available by de-sludgng an improper Septic Tank will be a mixture of partially digested and undigested sludge along with some digested material and thus having characteristics resembling raw sewage than septage.

The faecal sludge removed from lakhs of houses in the Country are transported for disposal in a most unhygienic manner by faecal sludge tankers and are emptied in river, river beds, canal bunds and on deserted roads. (See photo) This practice contaminates the surface water, underground water and air. After knowing the major hygienic problems caused by the practice the Government of India formulated a Septage and Faecal Sludge Guidelines and ask the State Governments a formulate the Necessary Regulatory Acts. Tamil Nadu was the first State in the Country to come out with the septage management policy and formed the guidelines.

As per the act all the new households in the State will be granted approval for the construction only if the plan has a sanitary toilet as per the Public Health Act of the State. The approval for the use of the house after construction will be granted only after the house was provided a Septic tank as per the plans. The Town planning Act also was suitably amended. However, almost all urban local bodies were rather indifference in implementation of the Act. Naturally disposal of septic tank faecal sludge is standing is major health hazards a very large number of cities and towns in the Country.

2. Options for Treatment and Disposal/Reuse of Septage/Faecal Sludge 3.1. Background 2.1.1 Faecal sludge is often a misunderstood term. Even those in positions of authority use the term faecal sludge and excreta interchangeably. While excreta is the raw matter discharged from a toilet, the faecal sludge is the material which has undergone a certain amount of biological degradation in one or other means of collection and processing. In an ideal condition, the faecal sludge will be in fully processed condition and hence in a stabilized form. Due to this confusion, some among the very few initiatives in India to set up and operate faecal sludge treatments adopted the approach focusing on perceiving FS more are sewage while others approach starting from handling digested FS. While there is very little work done on analysing the potential of use of treated sludge alone or in combination with other materials as manure, considerable amount of time, energy and funds are spent to focusing on the effluents from the sludge processing systems. Over and above this, FS is perceived as a problem to be solved and not a resource to be utilised. 2.1.2 The type of toilet used has a significant impact on the characteristics of the sludge generated. For urine diverting toilets, there is practically no sludge with just the completely digested material in powder form as the end result. For flush toilets, the main options are Septic Tanks and Leach Pits for in situ treatment. In the case of the sludge from the pit of a Twin Leach Pit system is already fully digested material which can be used directly as manure without any concerns from the health angle. However, they may need to be removed by pumping which in turn warrants dilution of the same by addition of water. Either way, the material removed need not be

considered as sewage but the treatment, disposal/reuse method starts from dewatering rather than any pre – processing. Septic Tank sludge contains a mixture of fully digested sludge, partially digested material and a small quantity of fresh excreta.

2.1.3 Where Septic Tanks or Leach Pits are connected to a flush toilet, the feed determines the characteristics. The possibilities include all kind of discharges which include kitchen effluent, laundry effluent, bath water and toilet discharges, excreta alone or a combination of two or three streams mentioned. However, in India, we have a unique situation in which the tank which goes by the name Septic Tank, could be a huge tank with or without lining which effectively is an underground storage tank which if lined, may require frequent emptying and if unlined may need emptying only very rarely. In the case of a lined tank which requires frequent emptying, the material pumped out, is effectively equivalent to raw sewage. While it is acceptable that the material so removed is treated and disposed or used safely, it would be far more logical to modify such systems to make them good in situ treatment systems. Such initiatives had been made in India with good success rates and methodologies to convert such systems that too will be an objective of this guide.

2.1.4 In a system with Twin leach Pits or Urine Diverting Dehydration Toilets, the material emptied is almost safe to handle. However, in a Septic Tank, the situation is somewhat different since the contents could be a mixture fresh excreta, partially digested excreta and fully digested sludge. Handling of septic sludge constitutes a serious health risk, since people handling these materials may be exposed directly to pathogens. From human health risk a basic distinction should made between sludges, which, upon collection, are still relatively fresh or contain a fair amount of recently deposited excreta and sludges which have been retained in on-plot pits or vaults for months or years and are virtually free of pathogens. Black water, constitute high-risk material and exhibits characteristics similar to sludges collected at short intervals e.g. from public toilets with only holding tanks rather than a processing cum disposal system.. Special care is therefore necessary to prevent accidental contact and spills during

emptying of toilet pits or vaults by vacuum trucks, where varying amounts of water or wastewater are collected alongside the accumulated solids.

2.1.5 In most of India, disposal of faecal sludge has been a major issue but not addressed seriously by the authorities. In certain areas, there are common Sewage Treatment Plants (STP) which anyway have facility for treatment and safe disposal of sludge. Most of the STPs in India accept Septage/faecal sludge for a fee. Field observations, however, indicate that this facility is rarely being utilised by the public or local bodies. The reasons could be one or more of the following ❖ Distance of the STP from the point of collection ❖ The fee charged by the operators of the STP ❖ Lack of awareness on the side of operators of STP or the transporters of faecal sludge or even both ❖ Absence of legally binding guidelines of collection, transportation, treatment and disposal/reuse of faecal sludge.

2.1.6 Surprisingly no proper inventory has been made concerning quantities of the faecal sludge that needs to be disposed, or the type of sludge (quality) that needs to be treated and disposed. In the latter case a distinction should be made between fresh and old sludge, and septic tanks containing only toilet water (black water) or those containing toilet and wash water (black and grey water) and, possibly, even rain water.

2.1.7 Since the raw faecal sludge often has partially digested or even fresh excreta in it, many FSTPs adopt a system similar to Sewage Treatment Plants (STP) using one or the other aerobic systems for sewage treatment, followed by dewatering of the aerobic sludge obtained from the Sewage Treatment Plants. In cases when the faecal sludge is having a high solids content, the same is often diluted with water first in order to process in the STPs.

Prima facie, it looks counterproductive since dewatering should be, in theory, the first step for processing the faecal sludge. Due to this factor, a section on sewage treatment systems too is added to this guide so that users can deal with a given situation appropriately.

3.2 Options of Treatment Technologies

3.2.1 Settling/thickening tank

In settling or thickening tanks, the solids accumulate at the bottom and the clarified supernatant usually needs to be further treated. The accumulated sludge is removed periodically through draw-off pipes. Another possibility of sludge removal is manually or by front-loaders after removal of the liquid column and a period of drying. Removed sludge requires further treatment.

Design: Settling tanks need sufficient volume for sludge accumulation and sufficient depth of the liquid column (> 1.5m) to allow good settling. The tanks should be equipped with baffle walls to maintain hydraulic conditions favourable to good settling and to retain floating scum. Design varies depending on the way of sediment removal. The tank size is estimated by choosing the sludge removal interval (2 weeks to 2 months) and with the assumed rate of accumulated sludge volume per incoming solids load of 5-9 l/kg total solids (TS).

Settling tanks can be used for partially stabilized faecal sludge (e.g. sludge from septic tanks) and most other sanitation facilities. Settlings tanks are not appropriate for very fresh sludge from public toilets, but may still be suitable if the fresh sludge is diluted with more stabilized sludge. Advantages: ❖ Simple and reliable process. ❖ Little land requirement. ❖ Partially segregates liquid from solids facilitating further treatment. Disadvantages: ❖ Not suitable for fresh faecal sludge. ❖ Treatment needed as it only partially dewaters faecal sludge. 3.2.2. Settling / Sedimentation / Stabilization pond

Stabilization ponds comprise one or more series of different ponds (lagoons). Usually the first pond is an anaerobic pond, followed by a facultative ponds and maturation ponds, depending on the required treatment efficiency. Sedimentation ponds can be segregated form stabilisation ponds too. 3. 2. 2.1. Sedimentation ponds for treatment of sludge The sedimentation ponds use the same principle of sedimentation of solids as settling tanks. Ponds are larger and have longer sediment removal intervals. Due to the high volume and long retention time, they provide a good stabilization capacity for fresher sludge. The sediment is removed after removal of the liquid column and a period of drying. Both liquid and sediments require further treatment. Sedimentation ponds are designed as anaerobic ponds with a sufficient storage volume for sludge accumulation. Sludge is removed once, twice or more often per year. At least two parallel ponds are required to assure continuous operation. The organic load of anaerobic ponds is 250-350 g BOD5/m3.d; the volume of accumulated sludge per incoming solids load is 0.8-2 l/kg TS. Sedimentation/stabilization ponds can be used as the primary treatment unit for faecal sludge when land availability is not a constraint.

Advantages: ❖ Simple operation ❖ Low construction costs ❖ Better sedimentation properties compared to settling tanks ❖ Stabilization capacity Disadvantages: ❖ High land requirements ❖ Further treatment needed 3.2.2.2 Ponds for secondary treatment (of liquids) Stabilisation ponds can treat wastewater from sedimentation ponds, settling tanks etc. Stabilization ponds are designed for organic loading rates. Anaerobic ponds have 2-3 m depth, remove 60-70 % of BOD5 and produce no bad odours when loaded with 250–350 g

BOD5/m3.d. Facultative ponds are 1-2 m deep and loaded with 350 kg BOD5/ha.d. Ponds can be used when sufficient land is available. High ammonia concentrations in the effluent for example in FS from public toilets may inhibit growth for algae and bacteria and thus the functioning of ponds.

Advantages: ❖ Simple, well-known and reliable technology. Disadvantages: ❖ High land requirements.

❖ Possible inhibition of functioning through NH3/NH4+ in case of very fresh sludge.

3.2.2.3. Natural drying Storage on land for over at least 6 months allows natural pathogen die-off in dewatered sludge from settling facilities or drying beds. Further drying of sludge contributes to pathogen die-off and increases the safety of the method. Protection against rain may be required depending on the climatic conditions. Storage and natural drying will be used if the faecal sludge is to be reused in agriculture and if co-composting or constructed wetlands (other processes delivering hygienically safe bio solids) are not favoured. Advantages: ❖ Inexpensive and simple Disadvantages: ❖ High land requirements. 3.2.3. Drying beds for treatment of solid fraction Drying beds typically consist of a gravel matrix supported sand filter with a drainage system at the bottom. Raw or pre-settled sludge is loaded on the bed and the water is percolated through the filter and to some extent by evaporation. The dewatered sludge can be used as manure with further treatment for pathogen removal Percolate quality improves through filtration but usually requires polishing treatment. Various designs have been developed for drying of digested sewage sludge. The most frequently used type is the sand drying bed (see drawing). They can be designed for a loading

rate of 150-200 kg total solids (TS) per m2 and year. Dried sludge can be removed after 7 to 14 days, depending on climatic conditions. Drying beds can be used as first treatment stage and as second stage for dewatering of settled sludge removed from settling or thickening tank. Drying beds cannot receive undiluted fresh faecal sludge due to poor dewatering characteristics and odour emissions. Drying beds can be used for dewatering and drying of septage, septage/public toilet sludge mixtures at volumetric ratios > 2:1 and of primary pond sludges with initial TS content varying from 1.5- > 7%. Dewatering performance varies with the initial TS and total volatile solids (TVS) content and the applied loads. Advantages: ❖ Low moisture content of dried solids ❖ Relatively good percolate quality (compared to settling facilities). ❖ Technology is well known and reliable. Disadvantages: ❖ Solids are not yet hygienically safe (unlike constructed wetlands). ❖ Low drying propensities in rainy season. 3.2.4. Constructed wetlands for treatment of sludge / effluent The exact treatment process in a reed bed is still not fully known. It is believed that essentially the process is similar to any other biological treatment system except that various forms of micro-organisms such as aerobic, anaerobic or anoxic may co-exist. It is believed that a significant portion of the micro-organisms responsible for treatment are aerobic in nature and they generally find the root structure of reeds and other plants as the habitat.

They get the atmospheric oxygen transferred by the reeds to the root structure. Although reed beds were originally developed in industrialised countries, results from Kerala and Tamil Nadu (India) show that the combination of various micro-organisms provides effective treatment to complex organic effluents. It may be that favourable climatic conditions (high temperature & sunshine) contribute at least partially to the performance. Two major types are distinguished according to the direction of the flow. The vertical flow system is suitable for treatment of faecal sludge, whereas the horizontal as well as the vertical flow system is used for liquid waste treatment. 2.4.1. Vertical flow treatment system to treat faecal sludge A vertical-flow constructed wetland comprises gravel and sometimes sand and is planted with marsh plants. The sludge is loaded on the bed and dewatered by percolation and by evapo-transpiration through the plants. The root system of the plants maintains the permeability of the sludge layer and sludge can be added continuously. Sludge has to be removed only once every few years. The long solids retention period favours further mineralization and pathogen die-off and allows direct reuse of solids in agriculture. Percolate quality considerably improves but may still require a polishing treatment. Design: The filter and drainage system of constructed wetlands is similar to a drying bed. The plants should be local marshland species that are tolerant to a wide range of environmental conditions (varying humidity, salinity). A freeboard for sludge accumulation of up to 1 m should be provided. Optimal performance has been observed for the loading rate of 250 kg total solids (TS) per m2 and year. The sludge accumulation is then approximately 20 cm per year. Post treatment of liquid effluents from primary treatment assures that the final effluent can be discharged into surface waters with no harm for the environment and public health.

Advantages: ❖ Includes dewatering and stabilization in a single treatment stage, unlike any other treatment techniques. ❖ Dewatered sludge can be used in agriculture without further treatment. Disadvantages: ❖ Only limited data available from field cases. In conventional sand beds, each layer of sludge must be removed when it reaches the desired moisture content, prior to application of the next sludge layer. In the reed bed concept, the sludge layers remain on the bed and accumulate over a period of many years before removal is necessary. The significant cost savings from this infrequent cleaning is the major advantage of reed beds. Frequent sludge removal is necessary on conventional sand beds, since the sludge layer develops a crust and becomes relatively impermeable, with the result that subsequent layers do not drain properly and the new crust prevents complete evaporation. When reeds are used on the bed, the penetration of the stems through the previous layers of sludge maintains adequate drainage pathways and the plant contributes directly to dewatering through evapotranspiration. This sludge dewatering method is in use in Europe, and there are approximately 50 operational systems in the United States. All of the operational beds have been planted with the common reed (Phragmites australis). Experience has shown that it is necessary to apply well-stabilized wastewater sludges to these beds.

Either aerobic or anaerobically digested sludges are acceptable, but untreated raw sludges with a high organic content will overwhelm the oxygen-transfer capability of the plants and may kill the vegetation. The concept will also work successfully with inorganic water treatment plant sludges and high-pH lime sludges. The structural facility for a reed bed is similar in construction to an open, under drained sand drying bed. Typically, either concrete or a heavy membrane liner is used to prevent groundwater contamination. The bottom medium layer is usually 25 cm (10 in) of washed gravel (20 mm); this layer contains the under drain piping for percolate collection. An intermediate layer of pea gravel about 8 cm thick (3 in) prevents intrusion of sand into the lower gravel. The top layer is 10 cm (4 in) of filter sand (0.3 - 0.6 mm). The Phragmites rhizomes are planted at the interface between the sand and gravel layers. At least 1 m (.3 ft) of free board is provided for long term sludge accumulation. The Phragmites is planted on about 30-cm (12-in) centres, and the vegetation is allowed to become well established before the first sludge application.

The root system of the vegetation absorbs water from the sludge, which is then lost to the atmosphere via evapotranspiration. It is estimated that during the warm growing season this evapotranspiration pathway can account for up to 40 percent of the liquid applied to the bed. These plants are capable of transmitting oxygen from the leaf to the roots; thus, there are aerobic micro sites (on the root surfaces) in an otherwise anaerobic environment, which can assist in sludge stabilization and mineralization.

Performance It is estimated that 75-80 percent of the volatile solids (VSS) in the sludge will be reduced during the long detention time on the bed. As a result of this reduction and the moisture loss, a 3-m-deep annual application will be reduced to 6-10 cm of residual sludge. The useful life of the bed is therefore 6-10 years between cleaning cycles.

Benefits

The major advantage of the reed bed concept is the ease of operation and maintenance and the very high final solids content (suitable for landfill disposal). This significantly reduces the cost for sludge removal and transport. A 6 to 7 year cleaning cycle for the beds seems to be a reasonable assumption. One disadvantage is the requirement for an annual harvest of the vegetation and disposal of that material. However, over a 7-year cycle, the total mass of sludge residue and vegetation requiring disposal will be less than the sludge requiring disposal from sand drying beds or other forms of mechanical dewatering.

Pictorial representation of Reed Bed for Sludge Treatment

3.2.4.2. Horizontal and vertical flow systems for the treatment of liquids

Constructed wetlands, reed bed systems or planted soil filters are natural systems treating low solid wastewater. This can be pre-treated wastewater from a flush toilet or faecal wastewater from a urine diversion toilet, either combined with wastewater from the kitchen and bathroom, or separate from it.

It consists of a sand-gravel matrix (sealed at the bottom) planted with wetland plants like Phragmites, Typha, Scirpus etc. Horizontal flow soil filters are commonly found, and easier to construct than vertical flow filters, but they are less efficient at eliminating nitrogen. Wastewater is treated through several processes, in which bacteria and fungi play important roles. After treatment, the effluent can be discharged into surface water or used for irrigation/groundwater recharge. Applying conditions ❖ Wetland biomass can be harvested and put to appropriate use depending on the species selected. ❖ Design and construction require a solid understanding of the treatment process. ❖ The amount of technical equipment needed is very small. Costs vary from INR 400- INR 1000 depending on cost of land, availability of material for medium, type of construction (which in turn depends on soil conditions), access to the site for transportation of construction materials, availability of vegetation for planting etc. Advantages: ❖ Easy to operate. ❖ Low O & M costs ❖ Removes pathogens partially from wastewater. ❖ Effluent will meet irrigation standards. ❖ Aesthetic appeal.

Disadvantages: ❖ Larger area requirement when compared to other alternatives 3.2.5. Co-composting with organic solid waste (post treatment of solids) Composting (one material) and co-composting (two or more materials) represent generally accepted procedures to treat excreta. To start the composting process, the blended compostable material is placed in windrows (long or round piles). The ‘recipe’ combines high-carbon and high-nitrogen materials. Air is added to maintain aerobic conditions, either by turning the windrows or by forcing air through them. To adequately treat excreta together with other organic materials in windrows, the WHO (1989) recommends active windrow co- composting with other organic materials for one month at 55-60°C, followed by two to four months curing to stabilise the compost. This achieves an acceptable level of pathogen kill for targeted health values. Adding excreta, especially urine, to household organics produces compost with a higher nutrient value (N-P-K) than compost produced only from kitchen and garden wastes. Co-composting integrates excreta and solid waste management, optimizing efficiency. Applying conditions ❖ The type of material, the climate, the amount of space and the equipment and funds available all influence the system design, especially type (e.g. windrow) and size, recipe, and level of technology. ❖ Special measures, such as more frequent turning or covering the piles can accommodate extremes of climate or temperature. ❖ Composting is a bio-chemical process, not a bio-mechanical one, and as such requires experience and practical knowledge, together with a high level of management. Advantages: ❖ Flexible approach with highly variable capacity ❖ Operation and maintenance requires moderate professional experience. ❖ Through co-composting, a useful and safe end product is generated that combines nutrients and organic material.

Disadvantages: ❖ Limited control of vectors and pest attraction. ❖ Lower cost variants have a high land requirement.

3.2.6. Anaerobic digestion

Applying conditions ❖ Digesters are best suited to warm climates. ❖ They are most appropriate in rural areas where animal manure can be added to the process. ❖ The digestion process is sensitive to both temperature and materials. Both need to be controlled. ❖ Relatively high skills are needed for construction. Operation and maintenance, however, are simple for batch systems.

❖ Investment costs vary greatly depending on the overall plant concept. Costs for biogas production increase with decreasing climatic temperatures. Life expectancy ranges from about 20 - 25 years. Advantages: ❖ Excreta ‘out of sight’. ❖ Net production of clean renewable biogas. ❖ Elimination of visual contaminants (e.g. toilet paper). ❖ Minimal operational control and maintenance.

Disadvantages: ❖ Gas safety risk. ❖ Insufficient pathogen removal without appropriate post treatment of sludge. ❖ Slurry from digesters has to be removed and treated [NWP, 2006] ❖ Some control needed 3.2.7. Biogas treatment plant

Advantages: ❖ Production of combustible and generation of revenues. ❖ Stabilization of fresh sludge. ❖ Low requirement of land. Disadvantages: ❖ The primary function of a biogas reactor is biogas production rather than sludge treatment. Hence biogas reactor is to be considered as an additional treatment process rather than as an alternative. ❖ Settling in digesters is incomplete and effluents require more extensive treatment than effluents from other primary FS treatment processes. ❖ The structure is rather expensive, and operation requirements are quite considerable. ❖ Removal of settled and thickened solids can cause difficulties.

3.3 Selection of Technology From the above options, a system comprising of a Vertical Flaw Constructed Wetland (also known as French Constructed Wetland) was selected as the treatment option for the faecal sludge and a Horizontal Flow Constructed Wetland as the tr4atment method for treating the percolate from the VCWL to meet reuse standards. The proposal included the option of the sludge treated in the VCWL to be co composted based on the results achieved in Ketti, Nilgiris, TN, India and Balangoda, Sri Lanka.

The management of Septage or Faecal Sludge is generally the responsibility of the concerned local body. In that context. the system to be adopted , in the case of small local bodies like Ponnampatti Town Panchayat, need to be Low Maintenance and user friendly. The previous experience with local bodies like Balangoda in Sri Lanka and Ketti Town Panchayat in Nilgiri District had provided adequate information to design a low maintenance system which could deliver a saleable end product while keeping the Operations & Maintenance (O&M) costs low. The approach is being replicate elsewhere in Kenya, Ethiopia etc. over and above other localities within Sri Lanka. From the above options, a system comprising of a Vertical Flaw Constructed Wetland (also known as French Constructed Wetland) was selected as the treatment option for the faecal sludge and a Horizontal Flow Constructed Wetland as the tr4atment method for treating the percolate from the VCWL to meet reuse standards. The proposal included the option of the sludge treated in the VCWL to be co composted based on the results achieved in Ketti, Nilgiris, TN, India and Balangoda, Sri Lanka.

3. Details of the Ponnampatti FSNTP Ponnampatti Town Panchayat does not have a sewer system (aka UGD too) and the usual practice for householders is to construct septic tanks. In the absence of any dedicated place for disposal of faecal sludge, the same was being disposed in unhygienic and unscientific manner in Ponnampatti too.

One reason Ponnampatti attracts several sanitation activists from various parts of India and abroad is the Cost Effective Faecal Sludge Natural Treatment Plant for treatment of the septic tank faecal sludge in the a Town Panchayat and surrounding Village Panchayats. Dr. Shakul Ameed, Executive Officer, Ponnamapatty Town Panchayat, decided to go for a viable cost effective FSNTP suited for the Panchayat. While FINISH Society, Lucknow supported the project financially, Er. Anand Ganesaiyer, an International Consultant from The Solutions Centre, Cochin was the Technical Consultant who designed the system and Padmashri Dr. M. Subburaman, coordinated the project execution. The project cost Rs. 10.5 lakhs in 2018. FINISH (Financial Intervention in Sanitation and Hygiene), Lucknow provided Rs. 6 lakhs and the PTP 4.5 lakhs including collection tank, 1HP motor. Design considerations Although text books give an extremely conservative loading rate of 2m3/m2/yr, the field experience even in colder zones indicate that a loading rate of 10-20 times this is possible The VCWL in Ponnampatti was designed with dimensions of 12.0 m x 4.0 m x 1.0 m Thus the plan area adopted was 48 m2. The dry and extremely hot conditions in Ponnampatti indicated successful loading rates of upward of 40 m3/m2/yr by achieving a daily loading rates of 6-7 m3/m2/yr. The bowsers in use in Ponnampatti area are basically of 3000 L capacity. Two loads per day is what this unit effectively takes care of treat to meet the specifications regarding various parameters. Site Selection The FSNTP is located in the Resource Recovery Park of the Town Panchayat which was originally the land fill of the Ponnampatti was on a rocky elevated site 3km from the Office. The FSNTP was located at the highest point of the site so that the treated water could

pumped discharged from the collection tank and distributed by gravitational flow to various parts in the campus for irrigation of several varieties of saplings, plants, fruits etc., Technical Details:

Modules ❖ Septage feed inlet The septage from the house is transported to the FSNTP by a tanker (5000 Litres capacity) and is drained into an inlet. At the bottom of the inlet a screen is fixed to prevent plastic or other materials escaping into the Vertical Cultivated Wetland (VCWL). The septage is let into first chamber from the inlet. Inlet Tank

❖ Chambers There are three VCWL chambers all serving for the same purpose. At the bottom all the three VCWLs are connected by an open drain. To prevent the filter material blocking and choking the connecting drains, it is covered by stainless, steel nets.

❖ VCWL In the VCWL, for filtering the faecal sludge, from top to bottom filter materials are laid. The top layer is sand layer and below two layers second and third are filled with blue metal 20mm, 40mm. The solids in the septage are retained at the top sand layer. The clear fluids flow down through the filter media to the bottom drain. The VCWL drain pipe is connected to the Horizontal Cultivated Wetland (HCWL).

1. There are three separate VCWLs. Each of the VCWLs can be connected separately with appropriate pipe and valve system from the inlet chamber.

❖ Vegetation The vegetation used are mainly Phragmites sp and Canna indica.

The treated water from the VCWL is the passed into the Horizontal flow constructed wetland (HCWL). The top portion of the HCWL also planted as in the case of the VCWL.

The treated effluent from the HCWL flows in to the collection Tank by gravity. The picture of the Collection Tank is given below. From this tank, the water is sent out for irrigation and sustaining a small fish pond within the premises.

From the HCWL the treated water by gravitational flows is drained into a collection tank. With a submersible pump the water from the collection tank is pumped up for use in the various blocks of vegetables and fruit plants in the RR Park.

The FSNTP was constructed in just 6 months time. It was commissioned in March 2018 by the Mr. S. Palanisamy, IAS. Director of Town Panchayats, Tamil Nadu.

FSNTP Operational Procedure: • The septage tanker is parked near the inlet and tanker lid is opened slowly and the septage is filled in the inlet.

• The valve of the first VCWL is opened and gently when the septage starts filling up the VCWL.

The septage is treated and purified by the filter materials and the plants and goes to the Collection tank via the two VCWLs and one HCWLs.

The Purified water which is almost colourless and odourless from the HCWL goes to the falls into the collection tank.

Septage collected from Tanker Treated percolate of Septage

❖ When the first VCWL is full and the sewage is getting treated the septage from the next tanker is fed into the second VCWL and then to the third VCWL. Generally the treatment and purification will be completed in one VCWL in one week. ❖ The FSNTP of the PTP is getting about 7,000 Litres of treated water per day which is used for the various needs of the Resource Recovery Park. It may be mentioned that getting water in the rocky hilly terrain is a very difficult and hence the FSNTP is a boon to the Ponnampatti Town Panchayat. Recycling of Treated water: The treated water could be pumped out from the collection tank and distributed by gravitational flow to various parts in the campus for raising several varieties of saplings, plants, fruits etc., there are over 200 varieties of plants, trees and their nurseries. To cover the entire garden area sprinkler facilities have been provided in strategic locations. Visitors wonder how on such a rocky slop these fruit trees and plants are growing very well [Papaya- 4 varieties, banana, sugarcane, vegetables, maize, cumbu (millet)]. Different species of trees are also growing well.

Co composting with FSNTP Sludge: The nutritious dried sludge from the FSTP is mixed with the compost under co- composting method for the plants and also for sale to the Farmers and Householders.

Since it is cost effective and is locations specific depending on the number of householders, could be designed and commissioned with in a very short period the FSNTP is being visited by Sanitation specialist, activists and a large number of senior Government officials besides Municipal Commissioners, Town Panchayats Executive Officers and Funding Agencies.

The FSNTP requires very minimal operation and maintenance effort and is only wholly done by a team of five SHG members. The process of co composting of processed septage along ith degradable municipal wastes or mixing of treated sludge/sptage with processed compostyields a manure fit for application in agriculture. Research in Sri Lanka on he quantity of the co compost than can be used for each of the agricultural produces can be takn as a general guideline in South India too since such an extensive research and field study is yet to take place with the available field cases of using this approach for Septage Management. The Nutritional efficacy of the sludge and harmful effects if anywhere tested and approved by the Environment Department of the Tamil Nadu Agriculture University,

Coimbatore, TamilNadu Pollution Control Board and Chennai Laboratory Testing Pvt Ltd the indicative of results are given below.

5 Conclusion It can be seen that most of the pollution control measures tend to opt for power intensive technologies which in turn causes resource depletion and/or causes pollution elsewhere. By adopting a Low Maintenance Technology, already proven to similar sites elsewhere, Ponnampatti Town Panchayat has shown a new model which can be emulated other local bodies of similar features with minimum effort.

Value addition to wastes is a crucial step in waste management. Both septage and degrdeable organic wastes in a town are essentially of organic origin but passing through different processes before getting classified as waste. Hence arriving at a safe end product after processing which carries a commercial value with it is an ideal step towards low cost waste management and eventually it can lead to Zero Waste Zero Cost Panchayats.

M. Subburaman Managing Trustee