NOVELTY - A solar disinfection reactor comprises: compound parabolic collector, where collector includes a reflective coating, a receiver pipe supported by bottom of compound parabolic collector, at least one water storage container fluidly coupled to receiver pipe, and a fluid flow system for delivering water under constant flow from water tank through receiver pipe, where collector is configured to collect solar UV radiation and utilize radiation to disinfect water.    USE - As solar disinfection reactor for disinfecting water; and for microbial inactivation prediction by solar radiation where simple model for atmospheric radiative transfer of sunshine (SMARTS) is used to predict solar UV intensity as function of geographic location and time, particularly at geographic locations where there are insufficient water treatment systems (claimed).    ADVANTAGE - The solar disinfection reactor provides extension of solar disinfection (SODIS) to develop continuous flow solar UV reactor to disinfect water intended for low-income communities in developing countries. The prior art SODIS systems appear to depend largely on wavelengths of solar UV radiation greater than 320 nm, where antimicrobial activity is slow and generally ineffective. As such, SODIS systems accomplish microbial inactivation by thermal processes (i.e. heating of water), as opposed to photochemical processes. The improved solar disinfection reactor accomplishes microbial inactivation through photochemical processes, and is also based on continuous-flow operation, whereas prior art SODIS systems are operated in batch mode. The continuous-flow solar UV reactor is benefited from solar radiation collection system to collect and concentrate solar radiation. The radiation collected is transferred to UV-transparent pipe through which water flows. The system is modeled to simulate UV intensity distribution in pipe, and with knowledge of fluid mechanics in pipe, UV dose distribution can be estimated. The continuous-flow solar UV reactor is useful in places suffering from lack of public drinking water supply in remote, poor communities in developing countries, by providing small, inexpensive point-of-use system that can be used by one household or group households to produce potable water; does not require chemicals or electricity; and requires minimal maintenance. The point-of-use solar UV disinfection is different from conventional UV systems; as it does not use lamps, electricity or batteries. The system can also serve people in refugee camps, disaster areas and remote rural areas in developing countries where potable water is scarce. The system can also be implemented in developed countries in areas that experience intense solar UV irradiation on regular basis. The SMARTS model can be used to provide estimates of solar UV spectrum at locations for which measurements are generally not available, such as in developing countries. It is indicated that model results agree well with measurements at locations used for validation of model and data from numerous studies. In addition, it is noticed from SMARTS output results that unpredictable aerosols, such as dusts blown up by wind, can be source of uncertainty data for locations where reactor may be used. The simulations at different aerosol conditions showed that presence of aerosols causes reduction in solar UV radiation significantly. Real time data for atmospheric parameters obtained by SMARTS model increases accuracy for predictions and local airports, and provides first source for these parameters, especially for atmospheric turbidity which affects significantly solar UV radiation received.    DETAILED DESCRIPTION - A solar disinfection reactor comprises: compound parabolic collector, where collector includes a reflective coating, a receiver pipe supported by bottom of compound parabolic collector, at least one water storage container fluidly coupled to receiver pipe, and a fluid flow system for delivering water under constant flow from water tank through receiver pipe, where collector is configured to collect solar UV radiation and utilize radiation to disinfect water. The receiver pipe is configured to transmit solar UV radiation, and is made from UV radiation transparent material. The reflective coating is subjected to surface treatment selected from anodization and polyvinyl fluoride coating. The reactor further comprises plastic tubing fluidly coupling water tank to receiver pipe. The water storage container includes influent water storage container for holding influent water and effluent water storage container for holding effluent water. The fluid flow system is a peristaltic pump, and is non-electric. An INDEPENDENT CLAIM is included for method for microbial inactivation prediction by solar radiation where simple model for atmospheric radiative transfer of sunshine (SMARTS) is used to predict solar UV intensity as function of geographic location and time, involving: utilizing numerical modeling procedure to simulate UV dose distribution delivery, utilizing segregated flow model to predict dose response behavior of reactor, utilizing numerical modeling procedure and segregated flow model to predict microbial inactivation by reactor, and choosing place for reactor in geographic location and time based on utilizing steps.    DESCRIPTION OF DRAWING(S) - The figure shows picture of prototype of solar disinfection reactor.