Algae WWT Biodiesel 5

8/8/2019 Algae WWT Biodiesel 5

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The sludge has a high N&P content and can be used as a fertilizer



Jason Selwitz was a graduate student in Regenerative Studies at CalPoly Pomona shown here withdifferent strains of algae growing on primary wastewater. This research was conducted at the JohnT. Lyle Center for Regenerative Studies. http://www.csupomona.edu/~crs/ For a look at what is

happening around the planet regarding algae-based biodiesel production go to:http://peswiki.com/index.php/Directory:Biodiesel_from_Algae_Oil



ABSTRACT

Two strains of green, freshwater microalgae,Chlorella protothecoides and Botryococcus braunii ,

were used in experiments to determine whether theycould individually enhance the quality of one liter ofprimary treated human wastewater. A third groupingof algal strains, from Pond #6 at the John T. LyleCenter for Regenerative Studies, was also utilized.The protocol established called for analysis of thealgal oil content using gas chromatography/mass

spectrometry.Over the course of five day residence times, waterquality improved as biochemical oxygen demandwas reduced, and ammonia was converted to nitrate.Algal oils were produced and extracted, althoughratios of key fatty acid methyl esters were lower than

anticipated. Results from using specific strains ofalgae to treat wastewater and produce biodieselcaliber oil offer the foundation for future research.While several projects throughout the world areunderway to commercialize production of biodieselfrom algae, the scientific literature recommendspairing such efforts with wastewater treatment. Asclimate change emerges, the need for expandedreserves of water coincides with interest to developdomestic sources of cleaner burning fuel.

Initial Algae-Wastewater-Biodiesel Research under the supervision of Dr. Stephen Lyon



The following is a hypotheticalmodification of a wastewater

treatment facility.



A Regional Wastewater Control Facility discharges 30 MGD into a local river

Possible Reconfiguration of a Regional Wastewater ControlFacility to Yield Multiple Benefits

treatment wetlandsdesigned to removealgae solids



General flow patterns of the water from the treatment facility through the oxidation

ponds, wetlands and to the dissolved air flotation (DAF) tanks. The green line indicates

the flow of the concentrated algae solids back to the first oxidation pond.

post wetlands treatment includes:ammonia stripping towers, DAF,chlorination, dechlorination anddischarge

Free surface constructedwetlands designed toremove algae solids

Oxidation Pond #1Oxidation Pond #2

Oxidation Pond #3



Effluent from theconstructed wetlands

entering the DAF tanks



Algae sludge being concentrated atthe surface of the DAF chambers

before being pumped back tooxidation pond #1.



Theoretical reworking of the oxidation ponds where Hypalon® curtains with floating tops andweighted bottoms allow for serpentine flow within each pond to develop more of a plug flow throughthe three ponds. This allows for more thorough nutrient stripping by the algae. The influent to thepond contains a pure strain of algae grown in photobioreactors. The algae are filtered off after

leaving oxidation pond #3 and the water goes through a final polishing stage in the constructedwetlands.

algaefiltration

system photobioreactor providesinoculum for the ponds



Examples of large-scale algae culturing operations throughout the world



Examples of simple algae

concentration and processing



What to do with the algae biosolids?

• All planktonic algae produce oil in the form of triglycerides to keepthem buoyant in the water column. In some species, the oil contentof the algae is 40-60% of its dry weight. For the algae in the oxidationponds it is assumed that the percentage of oil is 15%.

•The relatively simple mixture of the oil with sodium or potassiumhydroxide and methanol plus heat yields a commercially viable fuel.Biodiesel from algae produces far more fuel per acre of land thanvegetable oil sources.

• The oil needs to be separated from the algae by various means(chemical, mechanical, thermal, etc).

• The algae biomass can be added to the digester to produce more

methane.

• The flow chart on the next page shows the outcome of modifyingthe current operations at the facility. The boxes with the double linesindicate a beneficial end product.



ABalgae biomass

reclaimedwastewater

NaOH/KOH

methanol

heat*

Biodiesel

Chemical feedstock forphytochemicals and/or

polymer production

Sludge digester for methane production

Electricity production via cogeneration

Exhaust gases are bubbled into the oxidation ponds toabsorb carbon dioxide and promote algae growth,possible carbon credits for removal of greenhouse gases

algaeoil

Effluent fromOxidation Pond #3

separation of algaefrom the water

ConstructedWetlands

* there are alternative biological, chemical and physicalprocesses that are being developed to produce biodiesel



15500.7184935.402735.4214988.606813.0045420400

11625.5363701.552051.5611241.455109.7534065300

7750.3642467.701367.717494.303406.5022710200

3875.1821233.85683.853747.151703.2511355100

1937.5910616.93341.931873.58851.635677.5050

(15% of TSS)

tons/ yearlbs/ daytons/ yearlbs/ dayKg of oil/dayKG total/ daymg/L

biosolidsbiosolidsoil yieldoil yieldTSS@ 30 MGDTSS

The current TSS values leaving Oxidation Pond #3 are 30-70 mg/L. Under controlledculturing conditions including the venting of carbon dioxide from the cogeneration plant

there could be a substantial increase in the algae biomass produced in the oxidationponds. Estimates are given below for the yield of oil and biosolids for a TSS range of50-400 mg/L assuming an oil content of 15% of the dry weight of the algae. The oil

would go to biodiesel production and the biosolids could be used as a chemicalfeedstock for polymer production or for more cogeneration by adding the algae

biosolids to the digester.

e.g. 683.85 tons/year = 1,367,700 lbs/year ÷ 7.34 lbs/gal = 186,335 gal/year

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Algae WWT Biodiesel 5