Mass culture of algae in wastewater can significantly contribute to the management of freshwater ecosystems by providing a more environmentally sound approach to reducing the eutrophication potential of point sources of human wastes than is achieved by current treatment practices. Incorporating algal systems into conventional wastewater treatment has the potential to improve the water quality of the effluent by reducing the nutrient and metal loads into freshwater ecosystems. The use of algae to treat wastewater has been investigated for over 40 years, with one of the first descriptions of this application being reported by Oswald and Gotaas (1957). For a historical survey of outdoor algal mass culture efforts, including wastewater treatment, see Goldman (1979a) and Soeder (1980). Most research has focused on suspended microalgae growing in shallow, artificial ponds containing sewage. However, in recent years there has been an increased research emphasis on the use of nonsuspended algae, either as unialgal cultures immobilized in a polymeric matrix or as attached algal communities (biofilm/periphyton) growing in shallow, artificial streams or on the surfaces of rotating biological contactors (RBC/biodiscs). In this minireview, I focus on the use of algae in advanced treatment of wastewater, comment on some of the advantages and disadvantages of this biotechnology, and suggest the likely direction of future research in this area. First, I briefly survey the extensive work on suspended algal systems, with emphasis on more recent research. Then I follow this with a more complete summary of the research on nonsuspended algal systems.

Wastewater treatment with suspended and nonsuspended algae

Wastewater treatment and algal production in high rate algal ponds with carbon dioxide addition

Production and emission of CO2 from different sources have caused significant changes in the climate, which is the major concern related to global warming. Among other CO2 removal approaches, microalgae can efficiently remove CO2 through the rapid production of algal biomass. In addition, microalgae have the potential to be used in wastewater treatment. Although, wastewater treatment and CO2 removal by microalgae have been studied separately for a long time, there is no detailed information available on combining both processes. In this review article, microalgae-based CO2 biofixation, various microalgae cultivation systems,¯ and microalgae-derived wastewater treatment are separately discussed, followed by the concept of integration of CO2 biofixation process and wastewater treatment. In each section, details of energy efficiency and differences across microalgae species are also given.

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The Use of Microalgae for Coupling Wastewater Treatment With CO2 Biofixation.

Encephalomyocarditis viruses adsorb to introduced organic and inorganic solids in water over a wide range of pH and with various concentrations and species of metal cations. Visible flocculation of solids was not a prerequisite for significant virus association. Virus adsorption to natural solids in various types of natural waters was significant but variable. Clay-adsorbed virus retained its infectivity in tissue culture monolayers. These solids-associated viruses also retained infectivity in mice.

https://aem.asm.org/content/aem/30/2/212.full.pdf

Association of Enteroviruses with Natural and Artificially Introduced Colloidal Solids in Water and Infectivity of Solids-Associated Virions

https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1461&context=water_rep

The effect of carbon on algal growth—Its relationship to eutrophication

The UCLA Hydrogen Car: Design, Construction, and Performance

Dissolved Solids Removal from Waste Water by Algae

Results of investigation to reclaim waste water for eventual reuse; experimental algae pond, constructed as third stage to follow secondary clarifier, was operated at 4 flow rates; comparison of influent and effluent water quality by physical and chemical analysis was made at each flow rate; effluent was clear, odorless, and meets (USPHS) standards for potable waters, with exception of bacterial count.

Experimental activated sludge and trickling filter treatment system showed that virus can be removed effectively when heavy flock loading is maintained in the activated sludge unit. The trickling filter did not perform as well. Water reclamation from sewage for reuse can be developed with greater confidence when more is known concerning the virus removal mechanism. Reliability of designed treatment processes can be obtained by building facilities and testing their performance and observing details of operation. To accomplish these objectives, a 14,000 gal-per-day system, operating on domestic sewage, was used. To make certain that virus were present during the tests, the influent was heavily inoculated with coxsackie A-13. Test animals for observing the presence of virus were mice. Reclaimed waste water in arid regions may become a part of the water supply spectrum. During the first developmental steps, it will be possible to evaluate further the virus removal on a large scale before direct reuse in water supply is considered.

Virus Removal in Sewage Treatment

Carbon dioxide as an indicator of chemical air quality, its relationship to other indices of air pollution, and its characteristics in an urban atmosphere were the points of investigation in this study. It was found that carbon dioxide is as good an indicator of chemical air quality in an urban atmosphere as any other indicator presently used. On days of high pollutant concentrations, CO2 concentrations were correspondingly high, and on days of lower pollutant concentrations, CO2 concentrations were correspondingly lower. Diurnal and seasonal variations of carbon dioxide, carbon monoxide, nitric oxide, nitrogen dioxide, and oxidant reflected this relationship. In all types of fossil fuel combustion, CO2 - together with the other products of combustion processes - is produced in a fairly standard proportion as an exhaust product. Since fossil fuel combustion products are a major source of reactants and pollutants in air pollution, CO2 can be used as an indicator of air quality even though it is not a toxic substance. The high magnitudes of CO2 concentrations found in the atmosphere, and the simplicity of CO2 measuring equipment, also help to make CO2 an attractive indicator of air quality. A projected use of CO2 in air quality analysis is presented.more » Data from a mobile CO2 unit are presented as they relate to a freeway study, a residential study and an ocean study. 34 references, 15 tables.« less

Albert F. Bush

Papers

The UCLA Hydrogen Car: Design, Construction, and Performance

Dissolved Solids Removal from Waste Water by Algae

Dissolved Solids Removal from Waste Water by Algae

Virus Removal in Sewage Treatment

Carbon dioxide as an indicator of air pollution