SOLAR PV POWERED SOLAR PV POWERED DRINKING WATER UV DRINKING WATER UV DISINFECTION PLANT DISINFECTION PLANT

FOR RURAL APPLICATIONFOR RURAL APPLICATION

A. K. Pandey, P. R. Mishra, A. K. Pandey, P. R. Mishra,

S. Parthasarathi and J. C. Joshi*S. Parthasarathi and J. C. Joshi*

Rahul Multidisciplinary Research Centre, Delhi: E-mail: Rahul Multidisciplinary Research Centre, Delhi: E-mail: rmrcindia@gmail.comrmrcindia@gmail.com

*formerly at Indian Institute of Technology, New -Delhi*formerly at Indian Institute of Technology, New -Delhi

INTRODUCTIONINTRODUCTION

Water is an essential human need but it is becoming Water is an essential human need but it is becoming increasingly difficult to get source of water supply free from increasingly difficult to get source of water supply free from pollution. Over eighty percent infectious diseases are pollution. Over eighty percent infectious diseases are waterborne killing millions of children every year (1). It has, waterborne killing millions of children every year (1). It has, therefore become essential to treat water to make it potable. therefore become essential to treat water to make it potable. The problem of drinking water supply in the cities has been The problem of drinking water supply in the cities has been addressed successfully by disinfection by chlorination and by addressed successfully by disinfection by chlorination and by centralized water supply system. However our country is centralized water supply system. However our country is predominantly a rural society and there is no centralized predominantly a rural society and there is no centralized system of drinking water supply system in villages. People system of drinking water supply system in villages. People drink water from local sources like wells, tube-wells, hand-drink water from local sources like wells, tube-wells, hand-pumps or even rainwater en-catchments. This many-a-time pumps or even rainwater en-catchments. This many-a-time results in contamination of water. The microbial contamination results in contamination of water. The microbial contamination of water is the major source water borne diseases. Disinfection of water is the major source water borne diseases. Disinfection is a water treatment process, which aims at destruction or is a water treatment process, which aims at destruction or inactivation of disease producing organisms responsible for inactivation of disease producing organisms responsible for water- borne diseases. It is therefore essential to install water- borne diseases. It is therefore essential to install suitable disinfection system capable for supplying safe and suitable disinfection system capable for supplying safe and reliable drinking water in villages.reliable drinking water in villages.

There are presently three alternative disinfection methods in There are presently three alternative disinfection methods in common practice namely Chlorination, treatment with ozone or common practice namely Chlorination, treatment with ozone or ultraviolet rays. The destruction in ultraviolet disinfection is ultraviolet rays. The destruction in ultraviolet disinfection is physical while it is chemical in chlorination and ozone. The UV physical while it is chemical in chlorination and ozone. The UV disinfection comparatively has very low operating and disinfection comparatively has very low operating and maintenance cost, no residual effect, very short contact time for maintenance cost, no residual effect, very short contact time for disinfection and produces excellent result. It does not use any disinfection and produces excellent result. It does not use any toxic chemical so water chemistry is not changed. Therefore UV toxic chemical so water chemistry is not changed. Therefore UV disinfection process has been preferred over chlorination and disinfection process has been preferred over chlorination and ozone.ozone.Since there is no pressurized supply of water the disinfection Since there is no pressurized supply of water the disinfection system design must take this into account. Further electricity system design must take this into account. Further electricity from grid is often available for a limited period of time availability from grid is often available for a limited period of time availability safe drinking water has to be ensured through alternate and safe drinking water has to be ensured through alternate and preferably renewable source of energy. preferably renewable source of energy. The objective of the present work has been to design and The objective of the present work has been to design and develop a solar PV powered UV drinking water disinfection plant develop a solar PV powered UV drinking water disinfection plant suitable for rural application.suitable for rural application.SYSTEM DESCRIPTIONSYSTEM DESCRIPTION

This system consists of—This system consists of—Disinfection Unit and Electronic BallastDisinfection Unit and Electronic BallastElectronic Control Unit, Solar Module, Battery – BankElectronic Control Unit, Solar Module, Battery – BankThe Block-Schematic diagram of the system is shown The Block-Schematic diagram of the system is shown in Figure given in next slide:in Figure given in next slide:

Block-Schematic diagram of the systemBlock-Schematic diagram of the system

UV DISINFECTION UNITUV DISINFECTION UNIT The majorities of ultraviolet disinfection units The majorities of ultraviolet disinfection units

commercially available require pressurized commercially available require pressurized input water and hence are not suitable for rural input water and hence are not suitable for rural application. UV unit Model UVW2.3 NC(2) does application. UV unit Model UVW2.3 NC(2) does not require pressurized water as input as it is a not require pressurized water as input as it is a gravity fall system. It operates at 50 Watt power gravity fall system. It operates at 50 Watt power and is a designed for 24 hours use. This is and is a designed for 24 hours use. This is capable of disinfecting water at the rate of 15 capable of disinfecting water at the rate of 15 liters per minute (lpm). The unit operates by liters per minute (lpm). The unit operates by 12V DC Electronic Ballast. It is thus possible to 12V DC Electronic Ballast. It is thus possible to operate this unit directly by a 12V battery-bank. operate this unit directly by a 12V battery-bank. Therefore it has been preferred for rural Therefore it has been preferred for rural application. application.

Plate -1 shows (Next Slide) the disinfection unit Plate -1 shows (Next Slide) the disinfection unit

The Electronic Control Unit (ECU) is the heart of the plant. It controls The Electronic Control Unit (ECU) is the heart of the plant. It controls and manages the entire plant. SPV and AC mains power is supplied to and manages the entire plant. SPV and AC mains power is supplied to the battery-bank by the ECU. It charges the battery-bank and has the the battery-bank by the ECU. It charges the battery-bank and has the following major functions:following major functions:It automatically switches to float charge mode if the battery voltage It automatically switches to float charge mode if the battery voltage reaches 14.2V and thus does not allow the battery- bank to get reaches 14.2V and thus does not allow the battery- bank to get overcharged. The overcharge causes damage to the battery -bank. overcharged. The overcharge causes damage to the battery -bank. Since in this configuration the battery is being charged both with solar Since in this configuration the battery is being charged both with solar power and AC mains a selector switch has been provided to sequence power and AC mains a selector switch has been provided to sequence the charging so that when the solar power is available the battery is the charging so that when the solar power is available the battery is charged by solar panel. The AC mains voltage is applied to the Switch charged by solar panel. The AC mains voltage is applied to the Switch Mode Power Supply (SMPS) the output of which is controlled by Mode Power Supply (SMPS) the output of which is controlled by charge controller for charging the battery- bank. charge controller for charging the battery- bank. It provides audio alarm if the battery-bank is discharged to a level, It provides audio alarm if the battery-bank is discharged to a level, which may be detrimental to its life. Once this critical level is reached which may be detrimental to its life. Once this critical level is reached it cuts of the load i.e. UV disinfection unit. This is essential to avoid it cuts of the load i.e. UV disinfection unit. This is essential to avoid the damage to the battery- bank.the damage to the battery- bank.The Electronic Unit automatically selects to charge the batteries The Electronic Unit automatically selects to charge the batteries either by solar power or by the ACC main power through its auto either by solar power or by the ACC main power through its auto select switch. It sequences the charging so that when the solar power select switch. It sequences the charging so that when the solar power is available the battery –bank is charged by solar panel.is available the battery –bank is charged by solar panel.

ELECTRONIC CONTROL UNIT (ECU)ELECTRONIC CONTROL UNIT (ECU)

SOLAR MODULESOLAR MODULE

Solar Photovoltaic Module uses Mono Crystalline Silicon Solar Cells. Solar Photovoltaic Module uses Mono Crystalline Silicon Solar Cells. These are high quality and high performance modules suitable for These are high quality and high performance modules suitable for power generation. The module has excellent durability to withstand power generation. The module has excellent durability to withstand extreme temperature and weather conditions of the high altitude, extreme temperature and weather conditions of the high altitude, desserts and coastal regions. The Electrical Parameters of the module desserts and coastal regions. The Electrical Parameters of the module (4) are as under:(4) are as under:

Max. Power -70 Watt (Wp); Rated Voltage VMPP- 17 Volts; Max. Power -70 Watt (Wp); Rated Voltage VMPP- 17 Volts; Rated Rated

Current IMPP- 4.25 A Current IMPP- 4.25 A

BATTERY- BANK BATTERY- BANK Battery-Bank consists of 6 Nos. of Gauntlet Tubular Cells of Nominal Battery-Bank consists of 6 Nos. of Gauntlet Tubular Cells of Nominal voltage of 12 volts and 120 AH capacity each. These cells have high voltage of 12 volts and 120 AH capacity each. These cells have high electrochemical efficiency and are designed to operate under electrochemical efficiency and are designed to operate under arduous conditions with emphasis on reliability, efficiency and low arduous conditions with emphasis on reliability, efficiency and low maintenance. maintenance. The System wiring Schematic is shown in Fig -2. The System wiring Schematic is shown in Fig -2.

System wiring SchematicSystem wiring Schematic

A demonstration model of solar PV Power system was assembled A demonstration model of solar PV Power system was assembled tested in the laboratory. Plate-4 shows the demonstration model in tested in the laboratory. Plate-4 shows the demonstration model in

the laboratory. the laboratory.

Plate- 5 shows the demonstration model and installed at Haiderpur Plate- 5 shows the demonstration model and installed at Haiderpur Waterworks, New- Delhi. Waterworks, New- Delhi.

The system was evaluated and The system was evaluated and passed as per IS: 10500 by Delhi passed as per IS: 10500 by Delhi Jal Board, New Delhi (5) for Jal Board, New Delhi (5) for treatment of microbial treatment of microbial contamination of western Yamuna contamination of western Yamuna Canal Water for different microbial Canal Water for different microbial count and turbidity and flow rates count and turbidity and flow rates over a period of six months. Some over a period of six months. Some of the results are given belowof the results are given below

Based on the results of the studies it is concluded that this Based on the results of the studies it is concluded that this system is capable of supplying safe drinking water free of system is capable of supplying safe drinking water free of microbial contamination at the rate of 15 liters / minute i.e. microbial contamination at the rate of 15 liters / minute i.e. 900 liters/hour. An added study in the turbidity / microbial 900 liters/hour. An added study in the turbidity / microbial count with this system where the UV lamp is designed for 120 count with this system where the UV lamp is designed for 120 mJ / cm2 indicated that the system can astonishingly treat mJ / cm2 indicated that the system can astonishingly treat water in view of the MPN coliform count at lower or turbidity water in view of the MPN coliform count at lower or turbidity free water, but not higher than 22 NTU, as the microbial count free water, but not higher than 22 NTU, as the microbial count are beyond the rejection limit as per IS: 10500.are beyond the rejection limit as per IS: 10500.The system works both with Solar and AC mains power and The system works both with Solar and AC mains power and operates by 12 Volt DC power supplied by the battery – bank operates by 12 Volt DC power supplied by the battery – bank therefore it can deliver drinking water without any outage therefore it can deliver drinking water without any outage even on no- sun days. even on no- sun days. Thus it is concluded that the system can solve the problem of Thus it is concluded that the system can solve the problem of drinking water in rural areas where microbial contamination is drinking water in rural areas where microbial contamination is a major problem. Due to the redundant design of the system a major problem. Due to the redundant design of the system drinking water supply is ensured under all weather conditions.drinking water supply is ensured under all weather conditions.

CONCLUSIONS AND FURTHER STUDIESCONCLUSIONS AND FURTHER STUDIES

Based on the results the following studies could be Based on the results the following studies could be undertaken with a view to have large-scale undertaken with a view to have large-scale deployment.deployment.Pilot models of such systems could be installed at Pilot models of such systems could be installed at various locations for field trial. The field study will various locations for field trial. The field study will provide useful data on reliability of the system. It provide useful data on reliability of the system. It will also provide the much-needed users feedback. will also provide the much-needed users feedback. This will enable adoption of technology for This will enable adoption of technology for commercial production.commercial production.The system is modular in design up-gradation of the The system is modular in design up-gradation of the system to 1 to 5 lakh liters /day so as to provide for system to 1 to 5 lakh liters /day so as to provide for larger habitation could be undertaken. Since the larger habitation could be undertaken. Since the system consumes power at a phenomenally low system consumes power at a phenomenally low level it can easily be provided, by solar power.level it can easily be provided, by solar power.The system could be coupled to harvested The system could be coupled to harvested rainwater.rainwater.

ACKNOLEDGEMENTACKNOLEDGEMENT

The financial support provided by the Department The financial support provided by the Department of Drinking Water Supply, Rajiv Gandhi National of Drinking Water Supply, Rajiv Gandhi National Drinking Water Mission, Ministry of Rural Drinking Water Mission, Ministry of Rural Development, Government of India for carrying out Development, Government of India for carrying out this work is gratefully acknowledgement. Our this work is gratefully acknowledgement. Our sincere thanks are due to Delhi Jal Board, Delhi for sincere thanks are due to Delhi Jal Board, Delhi for evaluation of the unit and approving it. We are evaluation of the unit and approving it. We are thankful to Shri R. M. Deshpande, Senior Advisor, thankful to Shri R. M. Deshpande, Senior Advisor, Government of India, Ministry of Rural Government of India, Ministry of Rural Development and Dr. C. S. Sastri, Advisor, Central Development and Dr. C. S. Sastri, Advisor, Central Electronics Limited, Sahibabad for their continued Electronics Limited, Sahibabad for their continued support and suggestions to this work from time to support and suggestions to this work from time to time. time.

REFERENCESREFERENCESWater Policy Reforms Program- Nov. 1999, World Bank Water Policy Reforms Program- Nov. 1999, World Bank Institute Institute UV Waterworks, USAUV Waterworks, USA Guidelines for drinking-water quality. - 2nd ed. v. 1. Guidelines for drinking-water quality. - 2nd ed. v. 1. Recommendations 1. Drinking water – standards, ISBN 92 4 Recommendations 1. Drinking water – standards, ISBN 92 4 154460 0 (v. 1) (NLM Classification: WA 675)154460 0 (v. 1) (NLM Classification: WA 675) Central Electronics Limited, Sahibabad, India, Electrical Central Electronics Limited, Sahibabad, India, Electrical Specification leaflet, 2001Specification leaflet, 2001 Report of the Delhi Jal Board, Delhi Report of the Delhi Jal Board, Delhi

Thank YouThank You