Treatment Options for Rainwater Harvesting Systems For more information go to:
Rainwater is in Abundance
Rainwater often used for non-potable water applications
Benefits of Rainwater Provide water for rural areas Reduce the dependence and demand of public water supply Reduction of water bills Additional water supply for fire protection or emergency use Reduce land erosion and flooding Reduce salt accumulation in soil which can be harmful to root growth
Rainwater quality affected by atmospheric contamination Carbon dioxide (CO2) levels - affect pH, creating acidic water Pollution from industry - industrial pollution such as sulfur dioxide Pollution from agriculture – pesticides and herbicides
Rainwater quality affected by roof or other catchment surfaces
Maintaining Roof Water Quality Regularly inspect and clean gutters, roof catchments and tank screens. Remove overhead branches and clear trees near roof. Consider installing gutter screens or guards. Ensure tank does not become a mosquito breeding site by preventing access and cleaning screens regularly. Examine tank for accumulation of sludge every year and remove by siphon or by empting the tank. Shock sanitize by adding 40 mm of liquid bleach or 7 grams of granular calcium hypo-chlorite per 1000 liters of water.
Basic Rainwater System with manual roof-washer
Basic Roof Washers
Commercial Roof Washer Valves The roof washer is sized to collect at least 30 liters of water for every 100 sq m of catchment area.
Commercially Available Roof Washer
Large capacity rainwater storage tanks
Polyethylene Tanks
Polyethylene tanks are light
Underground Tanks
Ferro Cement Tank
Water Quality of Rain Water
Rainwater Quality (Malaysia)
Typical rainwater LSI Corrosive water can cause heavy-metals such as lead to leach into water from: Fixtures Appliances Water heaters Brass fixtures Brass valves
Copper corrosion from rainwater
Langelier Index pH Alkalinity Calcium carbonate Total dissolved solids Temperature
Calcite – Calcium Carbonate
Calcite pH Neutralizers/Filter Systems
Neutralizer with UV Sterilizer
UV Sterilizers
Chlorination Liquid bleach chlorine feeder Solid pellet chlorine feeders
Ozone Treatment
Corona Discharge Ozone Generator with Air Dryer
Ozone Bubbler with Compressor
Rainwater Collection Tank with Ozone Bubbler and automatic ORP controller
Ozone Bubbler in Outside Shed
Ozone Bubbler in Shed
Ozone Bubbler With UV and Calcite Carbon Filter System
Ozone Diagram with Contact Tank
Ozone Recirculation System with UV and Calcite-Carbon Filtration System
Automatic Controls ORP can be used to control disinfection
Filtration 50 / 5 Micron
Filtration 1 Micron
Ultra-Filtration