Renewable Energy by Bikash Pandey

Renewable Energy for Water Quality ImprovementRegional Integrated Workshop on Water QualityJune 29-July 2, 2004Hotel Himalaya: 

Renewable Energy for Water Quality Improvement Regional Integrated Workshop on Water Quality June 29-July 2, 2004 Hotel Himalaya Bikash Pandey Country Representative Winrock International, Nepal

Drinking Water Situation in Nepal: 

Drinking Water Situation in Nepal Around 75% of the population has access to basic water supply. By end of 10th 5-yr Plan (2002-2007), this is projected to increase to 85%. However, quality (treated) water supply is almost non-existent either in urban or rural areas. For rural areas, it is still thought that the best use of the next dollar invested is to bring piped water to more people, although this is changing. Most communities have access to springs or ground water. In urban areas, there is contamination after treatment. People either drink untreated water or treat it themselves.

Water treatment: 

Water treatment Traditional treatment is chlorination: Chlorine is inexpensive, easy to control, generally safe to use, and adapts to municipal or private systems. Chlorination effectively kills many disease-causing bacteria. However, it requires transport, storage, and proper use of chemicals which is difficult for communities in rural areas. Non-chemical and non-energy based treatment is also available: Slow sand filtration could be a very good option for both urban and rural systems. Requires space and good quality sand.

Energy to treat water: 

Energy to treat water In reality substantial amounts of energy is currently used to treat water. Most common methods in Nepal are: Boiling water And in small numbers: SODIS (Solar Water Disinfection) UV radiation Reverse osmosis Ozonation

Energy Consumption in treating water: 

Energy Consumption in treating water Boiling consumes large amounts of energy: Around 100 kWh per ton of water Costing between US$7 – $ 29 depending on fuel being used: kerosene, LPG, or electricity. Other technologies – SODIS, UV, Reverse Osmosis, and Ozonation use much less energy.

SODIS: 

SODIS Solar Water Disinfection Contaminated water is filled into transparent plastic bottles (PET preferred) and exposed to full sunlight for ~ 6 hours. Sunlight treats water through two synergetic mechanisms: Radiation in the spectrum of UV-A (wavelength 320-400nm) and increased water temperature. If the water temperatures raises above 50°C, the disinfection process is three times faster. Exposure to the sun for 6 hours if the sky is bright or up to 50% cloudy for 2 consecutive days if the sky is 100% cloudy, if water temperature of at least 50°C is reached, an exposure time of 1 hour is sufficient.

LBNL’s UV Waterworks Tech.(marketed by WaterHealth International (WHI): 

LBNL’s UV Waterworks Tech. (marketed by WaterHealth International (WHI) A compact, low maintenance device, uses UV to disinfect water UV disables DNA of viruses, bacteria, cysts Uses 60 W electricity, one UVW can disinfect 15 liters/min of water - provides safe drinking water for 2000 people Cost is $1500/unit; ~ 5 cents/ton of water disinfected. More than 200 UVW are in use (mostly in Mexico and the Philippines. Ideal for hospitals, schools, communities. Renewable energy (solar, wind) packages available from WHI. Easily connect to grid and micro-hydropower. More information on: http://www.lbl.gov/Tech-Transfer/success_stories/articles/WHI_more.html; info@waterhealth.com Note: need to pre-treat turbid water, or with high iron/magnesium, organic impurities

Reverse Osmosis Water Filter: 

Reverse Osmosis Water Filter Filters through semi-permeable membrane with microscopic pores (0.0001 microns) to reduce total dissolved solids (TDS) screen out bacteria, viruses, cysts some ions & metals (Arsenic, Cadmium, sulfates), particles (asbestos, cysts), organic chemicals and pesticides (benzene, trichlorobenzene). System is used by commercial water bottling companies. Needs to use sediment and carbon pre-filters to remove larger particles and protect membrane from Chlorine. “Wastes” around 5 times as much water as clean water delivered. Needs a minimum of 50 PSI pressure to push water through the membrane. With enough pressure can filter sea water. Need a pump (25 W for normal home use) if this pressure is not available. And hence Renewable Energy. Temperature sensitive: Filtration decreases 1 to 2 % for every °C below the standard temperature of 25°C. A 40-150 liters a day (family) system costs around US$300. Cost of filtration is $5 per ton of water.

Reverse Osmosis Filtration System: 

Reverse Osmosis Filtration System

Ozonation: 

Ozonation Ozonation is a water disinfection method first used in Nice, France in the early 20th century to improve drinking water taste and odor. By adding ozone to the water supply, disease-causing microbes (bacteria, viruses, Giarda and Cryptosporidium) are inactivated. More powerful than chlorine. Ozonation will oxidize organic and inorganic substances, it will remove unwanted taste, odor, and color in addition to being an effective disinfectant. Ozone is generated by accelerating electrons between two electrically charged plates in a process called "corona discharge." - Electrons flow at sufficiently high electrical potential through oxygen-enriched air. Cost of equipment and of electricity used.

Community Ozonation plants: 

Community Ozonation plants 16 solar and hydro-powered ozone water purifier units have been installed in the Annapurna area by ACAP (KMTNC)/ Empower Consultants/ Lotus Energy called SPOWTS (Solar Powered Ozone Water Treatment Systems). Villagers (Mothers’ Groups) sell drinking water to tourists and avoid pollution from plastic bottles. Rs 40 per bottle instead of Rs 120. Systems are available in both 220 VAC (hydro) and 12 V (solar) systems. Solar systems are typically powered by 2x100 Watt panels and a 550 watt inverter coupled with 250 AH of deep cycle battery storage. Cost of systems ($4,000 to $5,500).

Ozone water purifier – Lotus Energy Nepal: 

Ozone water purifier – Lotus Energy Nepal Ozone water purifier 220 V Ozone water purifier 12 V system Source: http://www.lotusenergy.com/ozone.htm

DEKA Portable Water Systems: 

DEKA Portable Water Systems Developed by Dean Kamen for use in developing countries (distillation technology) Applications: water purification, desalination, water reuse and recycling, providing ultra pure water for medical uses Output: 40 liters/hour; cost: $500; 5 year life; 50 kg Power demand: 500W (300W electrical, 200W thermal) Water recovery: contaminated water (75-95%); gray water (85%); sea water (75%) Simple maintenance by user twice a year Field tests being planned for later this year in Africa, India, Bangladesh, US Indian reservation

Summary: 

Summary Where public treatment facilities are not available, energy can be used to produce clean drinking water. Of these, boiling water is the most widespread but is inefficient and expensive ($7-29 / ton of water). SODIS and UV treatment are the least cost methods (5 US cents per ton for UVW) of treatment followed by more expensive methods like Ozonation, R-O ($5 per ton), and distillation.

Thank You!: 

Thank You!