ENVIRONMENTAL FRIENDLY TOILETS

ENVIRONMENTAL FRIENDLY TOILETS 

Indian Railways is running almost 10106 trains (approx: 40,000 passenger coaches), touching 7335 stations and handling about 1.9 crore passengers every day. An estimated two and a half million passengers use Indian Railway coach toilets daily, using a huge amount of water and creating aesthetic and hygiene related problems as the existing coach toilet systems discharge waste directly on to the tracks. 

This leads to unacceptable hygiene conditions, particularly in the railway stations and damage the rails. 

One of the key objectives of IR is to provide adequate passenger amenities in trains which include provision of clean and hygienic surroundings. Since majority of the existing toilets are discharging human waste directly onto the track, efforts are being made to introduce environment friendly toilet (EFT) systems. 

Few EFT systems are given below: 

• Controlled Discharge Toilet System 
• Zero Discharge Toilet System 
• Biological Toilets (Anaerobic / Aerobic) 
• Vacuum Toilets. 

Several types of toilet systems are in service and there is a need to work on incorporating knowledge from these to improve the designs. The adoption of a particular type of EFT in a train type mainly depends upon number of factors such as technology/product features and the type of train service.

Since the issue of EFTs on the trains is inviting greater attention in view of environmental and hygienic effect as well as passenger image building, high priority is accorded for this work. 

However, the challenges are not-so-disciplined Indian toilet habits, requirements of long distance travel, separating nondegradable waste, maintenance practices in Indian Railways, Minimum peripheral such as air and electricity, retro fitment on coaches in service, wide scale proliferation of technology and cost effectiveness. 

Controlled Discharge Toilets System: 

Controlled discharge toilets were the first to be experimented when LHB design stainless steel coaches were introduced for Rajdhani and Shatabdi trains in 2001-02. This system ensures that the waste from the toilet is retained in underslung tanks while the train is waiting at a station or it is passing through city limits. The waste is finally discharge on the track whenTrain picks up 30 kmph speed + 15 cycles of flush or when the train is de-accelerating and approaching to 30 kmph. 

Limitations: CDTS does not fulfill the requirement of green toilet i.e. ZeroDefection on the ground. It requires both pneumatics and electrics for operation. It requires other electronic gadgets like PLC etc. and requires frequent maintenance  

Working of Controlled Discharge Toilet System. 

The system comprises the following: 

Working: Passenger after using the toilet presses the flush button (Soft press). Check valve of water pressuriser opens and pressurised water flows from the circuit to the toilet bowl and flushing takes place. Simultaneously top flapper valve opens and flushed water along with waste goes to the retention tank. After the flushing check valve of water pressuriser and top flapper closes. 

At the end of every 15th cycle and if the speed of the vehicle is equal to or above 30 KMPH the bottom discharge valve will be opened and discharges take place. In the case of LHB coaches, the speed is sensed from the microprocessor provided for wheel slide protection. For conventional coaches individual speed sensors are provided in each bogie. Now a day’s GPS based speed sensor is also under trial. 

Vacuum Toilet System 

Based on the principle of direct transport from the toilet bowl to the tank aided by vacuum condition in the tank and pipeline. Water used per flush is 250ml only which is much less than other systems. Centralized tank that is fitted in this system retains the effluent and requires to be emptied. Effluent emptying facilities can be fixed or mobile type. In fixed type, evacuation pumps to be deployed at the terminating stations which transfer the  effluents to ground tanks or transferred to locations specified by municipal corporations. Mobile type units can be installed on trucks which can be used for collection at large stations and onward transportation to specified locations. 

Limitations: 

Does not work in the event of loco changeover/failure, due to non-availability of compressed air and does not work in stabled condition in platforms. 

The system needs better monitoring as several indicator and alarm signals are outputted by the system. 

If required conditions are not met, the system stops the toilet. Elaborate infrastructure needs to be built up for disposal of effluents from the retention tank. 

8.1 Zero Discharge Toilet System: 

This toilet works on the principal of solid liquid separation with solid portion stored- evacuated- transferred and dump into pits for composting and liquid portion filtered, treated, recycled for flushing purpose. These toilets have been developed by a consortium consisting of RDSO, IIT/Kanpur & URBANE Industries, Chennai under TMRS Projects. 

Advantages of the system: 

• There is no effluent discharge on track and has effective non-degradable waste segregation system. 
• Water is recycled for flushing. 
• It is completely Environment friendly as waste is converted to fertilizer. 
• The design is robust. 

Disadvantages: 

• This needs evacuation frequently and extensive ground facilities like pits, transfer pumps etc for composting. 
• It has higher operational cost. 
• Quality of recycled water for flushing needs improvement as it has mild stink. 
• Detention of rakes at pit lines is more. 

Aerobic type biological Toilet: 

Indian Railways has tried out bio digesters imported from M/s Microfore, USA where aerobic bacteria are used for decomposing the waste into gases and water. Liquid is discharged on the ground after chlorination. This system has been successful but periodic replenishment and high initial as well as maintenance cost are the stumbling blocks. 

Limitations: 

• The toilets has foul smell, there is lack of non-biodegradable separation system. 
• There is choking due to accommodation of non-biodegradable. 
• It requires periodic replenishment. 

8.2 IR-DRDO Anaerobic biological toilet system: 

In this technology anaerobic bacteria is used for decomposition. DRDO developed these bacteria for use in high altitudes areas like Siachen Glacier where de-composition of waste is not possible by natural process. This bacterium once charged does not require replenishment for long time and system is maintenance free. 

Difference between aerobic bacteria and anaerobic bacteria: 

Anaerobic Bio digester provided under the toilet in the coaches: 

• The size of the tank is 1150 x 720 x 540 mm, made up of stainless steel, under slung on mounting brackets in the coaches. 281 
• The tank has 6 partition walls inside the tank (seven chambers). 
• Poly grass mat for protection of bacteria inside the partition walls. 
• Ball valve with handle for operation for making toilet direct discharge in case of chocking. 

Total volume of tank – 400 ltrs 

Effective volume of tank – 300 ltrs 

Empty tank weight – 110 Kgs 

Full tank weight – 410 Kgs 

Height from Rail level – 225 mm 

There are Seven chambers in the tank. First chamber has grill partition so that non-bio-degradable objects do not pass to further chambers. Fecal matter in slurry form goes from 1st chamber to 2nd chamber through a pipe (from bottom of first chamber). Slurry flows from 2nd chamber to 6th chamber through slits in the partitions. From 6th chamber to 7th chamber it flows through a pipe (from bottom of the 6th chamber). From 7th chamber to the chlorinator it flows through a pipe (from top of the 7th chamber).Finally chlorinated water is discharged to the ground. Nylon matting is provided on all walls for colonization of bacteria. Four variants and its Limitations: 

SALIENT FEATURES: 

• Bad smell in toilets from the tanks is not there. 
• Fecal matter in the tank is not visible. 
• Infestation of cockroaches & flies is nil in this system. 
• Clogging of digester is not noticed. 
• The effluent is free from odour and solid waste. 
• There is reduction in pathogens by 99% and organic matter by 90%. 
• No maintenance and adding of bacteria/ enzyme is required during service. 
• Removal of solid waste is also eliminated. 
• Use of phenyl/ cleaning agents is permitted up to 100ppm. 
• Cleaner undergear components and end body, for hygienic working in maintenance lines. 

Improvements in the designs: 

The sliding valve is replaced with ball valve. In the case of the toilet getting choked, the failsafe valve cannot be made operational in the entire journey as ball valve cannot be operated from inside the toilet. Further, in case train is standing at a station toilet adjacent to platform cannot be made operational because of space constraint for operation of valve. Hence the valve is provided with arrangement to be opened with a foot pedal from inside the toilet itself in the case of choking during run, and it automatically closed on release of the foot. 

One dust bin is provided inside the toilet which can be used for disposing the non bio degradable items, as the passengers have tendency to throw the objects into the lavatory pan and cause choking. 

For awareness among the passengers, particularly Non AC passengers, Pictorial stickers are provided inside the toilet to educate passengers for Do’s and Don’ts. 

Brief about bacteria (Anaerobic bacteria): 

The bacteria double its population within 6 to 8 hours. It dominates and decomposes fecal matter in to liquid and gases. It can be kept for 3-4 months at ambient temperature and can withstand sub zero temperature as well as upto 60 degree centigrade. The cold temperature would not affect the inside process because Anaerobic process is exothermic in nature hence in cold regions heat will be available inside the chamber because of chemical process. 

Maintenance of Bio-toilet system: 

• Inspect complete toilet system including under slung equipments visually. 
• Check the toilet system for any deficiency. 
• Clear the chocked chute in bio-toilets and preferably keep the system in direct discharge mode during cleaning the toilets. 
• Toilets fitted with bio-digester should be preferably cleaned by pressurised water cleaning system so as to minimise the water usage. 
• Charge the chlorination chamber with chlorine tablets as per the requirement. 
• Collect the samples as per the schedule and sent for laboratory tests. 
• Charge the bio-culture if required based on the test reports of the samples collected. Guidelines for handling the bacteria: 
• Wear gloves while handling bacterial culture. 
• Store bacterial culture in container with lid which can be closed. 
• During transportation, lids should be tightly closed and during storage, lids should be kept loose to facilitate escape of gas generated inside the container. 
• Do not mix detergents/acids with bacteria at any stage during use. 
• Clean/sanitize hands with detergents/soap after handling the bacteria. 

Testing of Effluents of Bio-toilet: 

Sample shall be collected on quarterly basis and sent for testing. Samples will be collected randomly from a lot of 5% coaches of the total coach holding but minimum one coach of each type at an interval of every three months during the trial period. 

Sampling will start after coach has been in passenger service for 10 days or more and collect samples from the bio digester 30 minutes after the train becomes stationery/still. Open the sample port and let water drain for 2 minutes to remove settled solids particles and to ensure that sample is representative of the system 

The samples should be collected and sealed in presence of Railway representative. At least one test every quarter shall be carried out in Govt lab. In case the samples do not meet requirement, test shall be repeated after taking necessary corrective actions within a fortnight. Sample shall be collected in 2 liter plastic bottle by simply opening the knob provided in the sampling port. Date and time of sampling and coach No. must be mentioned on the bottle. Sample collected in the bottle shall be transported to lab at the earliest but not later than 24 hours after collecting of the sample. 

During POH of the coach fitted with Bio toilet, the tank shall be removed from the coach and kept at safe place and refitted on the same coach after other attention on the coach. In case there is any damage or leakage the inoculums shall be drained and the tank repaired. After repairing and fitting on the coach it has to be refilled with required level of fresh culture (approx 120 liters) before dispatch of coach.