Waste purification system

A method for rapidly growing unicellular algae and the like using nutrient wastes from sewage, after comminution of said sewage, removal of nonbiodegradable and large particles therefrom and reduction of turbidity thereof, comprising:

• continuously mixing the algae and wastes in water, with aerobic bacteria present in said wastes, said wastes being continuously supplied
• balancing the oxygen and carbon dioxide requirements of the mixture to maintain a desired symbiotic relationship between the algae and the bacteria,
• continuously flowing a shallow layer of the mixture beneath light of wavelength and intensity able to trigger photosynthesis in said algae for a light exposure of said shallow layer to its full depth for between one-half second and two seconds and then into a darkened zone for a much longer time, the light and darkness being alternated many times to effect growth of the algae and consumption of substantially all of said waste, and
• continuously separating and recovering an algae product and a purified water product.

A device adapted to growth of an algae product and purification of aqueous wastes, comprising in combination:

• a stationary, generally rectangular, opaque tank having a base, a first and a second side wall and two end walls, and being open at the top for exposure to light,
• said first side wall being in the form of a curved section generally shaped like the curve generated by translation of a parabola,
• injector means disposed in said base opposite said first side wall,
• horizontal baffle means disposed well in the upper portion of said tank and spaced downwardly from said top so as to divide the tank into a thin upper portion above said baffle means and a much larger portion below said baffle, and
• means for injecting fluid through said injector means into said tank toward said first side wall to impel fluid to move up said first side wall with a lenticular flow and to flow over said baffle means and back therebelow,
• the flow over said baffle means providing exposure to light and the flow therebelow resulting in exposure to darkness much longer in time than the exposure to light.

A device adapted to growth of an algae product and purification of aqueous wastes, comprising in combination:

• a tank having a base, a first and a second side wall and two end walls, and being open at the top,
• said first side wall being in the form of a section of a parabolic curve,
• injector means disposed in said base opposite said first side wall,
• horizontal baffle means disposed well in the upper portion of said tank and spaced downwardly from said top, and
• means for injecting fluid through said injector means into said tank toward said first side wall,
• some of said injector means being connected to a means disposed at said second side wall adapted to collect foam from the upper end of said tank.

A system for producing clean water and an algae product high in protein which comprises:

• a reaction zone,
• means to introduce algae into said zone,
• means to continuously introduce liquid organic waste material and aerobic bacteria into said zone to provide nitrogen and phosphorus nutrients for said algae,
• means to introduce at least one gas chosen from the group consisting of air and carbon dioxide into said reaction zone to admix and agitate said algae and said waste materials to form a biomass and for maintaining a desired balance between said algae and bacteria,
• means to circulate a portion of said biomass in a shallow, illuminated path so that said biomas is exposed to light of sufficient intensity and of suitable frequency for about one-half second to two seconds followed by a considerably longer period of darkness, the periods of light and darkness alternating to effect growth of algae and consumption of said waste materials,
• means to withdraw reacted materials from said zone and separately recover algae product and clean water, and
• means to recirculate some of said algae product to said means to introduce algae.

A device adapted to growth of an algae product and purification of aqueous wastes comprising:

• an opaque tank having an open upper end,
• means providing photosynthetic light above said open upper end,
• a horizontal baffle disposed in the upper portion of said tank and spaced downwardly a short distance from said open upper end so that most of said tank lies directly below said baffle and in darkness, being shielded from said light by said baffle, and
• means to circulate an aqueous mixture of said algae and aqueous waste first across over said baffle and then down below said baffle, and then back across over said baffle and so on for several circulation cycles, thereby providing short periods of light followed by longer periods of darkness between successive periods of light.

A device adapted to growth of an algae product and purification of aqueous wastes comprising:

• a tank having an open upper end,
• means providing photosynthetic light above said open upper end,
• a horizontal baffle disposed in the upper portion of said tank and spaced downwardly a short distance from said open upper end,
• means to circulate an aqueous mixture of said algae and aqueous waste across over said baffle and down below said baffle, thereby providing short periods of light followed by longer periods of darkness between successive periods of light,
• a plurality of injectors at the lower end of the tank, horizontally disposed and facing a first side wall of said tano,
• gas inlet means connected to some of said injectors, and
• a means disposed at a second side wall of said tank for collecting foam from above said baffle and conveying it to other said injectors.

A continuous system for producing clean water and an algae product high in protein which comprises:

• a. a reaction zone,
• b. means for continuously introducing algae into said zone,
• c. means for continuously introducing organic waste material with aerobic bacteria into said zone to provide nitrogen and phosphorus nutrients for said algae,
• d. means for continuously introducing controlled amounts of at least one gas selected from the group consisting of air and carbon dioxide into said reaction zone to admix and agitate said algae and said waste materials to form a biomass and to keep said algae and bacteria in a desired balance,
• e. means for continuously circulating a portion of said biomass in an illuminated path so that said bromass in exposed to a large series of limited alternate exposures to light of about one-half second to about two seconds each and to darkness for substantially longer times, to effect the growth of algae and consumption of said waste materials,
• f. means for continuously withdrawing reacted materials from said zone,
• g. means for ccntinuously and separately recovering algae product and clean water,
• h. means for circulating some of said algae product to step (b).

A device adapted to growth of an algae product and purification of aqueous wastes, comprising in combination:

• a generally rectangular, opaque tank having a base, a first and a second side wall and two end walls, and being open at the top for exposure to photosynthetic light means thereabove,
• said first side wall being curved outwardly in vertical section to induce lenticular flow,
• injector means disposed in said base opposite said first side wall,
• horizontal baffle means spaced downwardly from said top and disposed well in the upper portion of said tank, so that most of said tank lies directly below said baffle means and is shielded from exposure to light thereby, and
• means for injecting fluid through said injector means into said tank toward said first side wall for lenticular flow up said first side wall and over said horizontal baffle means for a short exposure to light and then down into said tank at said second side wall for a longer exposure to darkness and then again over said baffle means in a continuing cycle.

A method comprising culturing unicellular algae and bacteria at a substantially constant growth and nutrient uptake rate by

• applying to a mixture of algae and bacteria in water light of photosynthetic frequencies at an intensity sufficient for adequately triggering photosynthesis, for regular periods between about one-half second and about two seconds each in duration, alternating with regular periods of darkness sufficiently long to enable regeneration of the photoreceptors to take place, so that the predominant number of individual algae cells are maintained in a uniform state with no aging and without excess formation of lipids,
• said culturing being provided with a continuous supply of light transmitting nutrient-bearing liquid wastes in sufficient quantity and at such a rate that
• 1. the mixture does not become nutrient-limiting to the microorganisms in the culture, and
• 2. said mixture removes sufficient quantities of said nutrients that the liquid of said wastes causes no harmful degradation of aquatic environment in which said liquid may be discharged after treatment, said algae being periodically withdrawn, and a portion of same is recycled to make up said mixture.