I agree. With a captive top of the column like that, simple circuitry can tailor the amount of air injected at the bottom, and therefor adjust the amount of power needed to run the thing. Good find.
The Coming Green Wave: Ocean Farming to Fight Climate Change
Offshore Aquaculture… mostly at a trade deficit, exposing people to contamination, disease and unnecessary antibiotics…
Floating Oyster pens…
This is something that compliments what I want to do nicely. Are there other groups of symbiotic species that have been tested together?
Most of what I know, I’ve picked up across too many sources and too much time to document well. By and large, it’s a matter of picking a starting point. Kelp. as a food-source, can be used for Abalone and smaller species of ‘feeder-fish’, the feeder-fish then upgrade the kelp for larger, carnivorous, pelagic, marketable fish, so you pick one, based on the other, but all species are chosen with the specific environment in mind.
Consider, first and foremost, the water temperature determines what can be grown, beginning with the type of kelp, the feeder-fish, and the market fish. There are different types of Abalone, Oysters, crabs, even lobster that can grow in the various zones. You want to choose the best combination for your area.
FYI, The Christian Science Monitor’s online headline is about fish farming:
And mentions as follows:
It’s called integrated multi-trophic aquaculture, a 21st-century name for a practice first developed in ancient China.
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Special Thanks to @frabrunelle for reopening the topic for me.
In the same vein as the IMTA and using the Kelp to mitigate wastes, while also being a food-sorce in the semi-open food chain, I recently came across more Biogas digester stuff… Digesters that use undiluted Seawater, rather than fresh water.
Basically, rather they have used 2 methods. Acclimate digesters to use seawater, and source the microorganisms from sediment under the ocean.
I’ll try to post links to documentation, in the next few days. However, this also makes easier use of digesters and seawater flush-toilets (somewhat common for smaller ocean-going vessels), to help provide energy for seasteads, and, at the same time, minimize difficulty in treating. utilizing sewage, without massive holding capacity, and the hydroponics Wilfried Ellmer finds so disgusting, despite full treatment and conversion to viable, valuable fertilizer. Simply discharging alternating-current through the effluent will release Chlorine, thereby sanitizing it for discharge, the same way smaller vessels do. However, using Kelp and filter-feeders to mitigate pollution would definitely be beneficial. At the same time, it minimizes the chances of a shipping accident, releasing untreated sewage, either from holding, or a tanker to carry it elsewhere for treatment.
That would be handy. Looking forward to reading those sources and your application idea.
Biogas from Organic Waste Diluted with Seawater
Laboratory glass digesters were used to study the possibility of using seawater to dilute organic wastes for biogas production. The pulverized solid excrement of camel was diluted with distilled water (as a control treatment), synthetic seawater (total soluble salts 40490 ppm), or diluted seawater (20245 ppm) to give 10% total solids and one liter volume. The experiment was continued for 60 days. The highest biogas cumulative volume (20 L) was obtained from the diluted seawater treatment, while the lowest volume (9.5 L) was that obtained from the seawater treatment. However, tne seawater treatment showed an increase in the biogas production rate at the end of the experimental period. It seems from the results that seawater can be used as a diluent in the anaerobic digestion of organic wastes if diluted below the inhibitory level, or through the slow acclimation of the micro-organisms involved in biogas production to the seawater conditions.
CHARACTERIZATION OF THE STRUCTURE AND DYNAMICS OF MICROBIAL
COMMUNITIES IN SEAWATER ANAEROBIC BIOREACTORS BY USING NEXT
Due to its cost effectiveness and sustainability, anaerobic digestion (AD) has become a
widely adopted technology for wastewater treatment as well as bioenergy production. However,
knowledge of the structure and the dynamics of microbial communities involved in this process is
essential to improve system performance and optimize system operations. Here we investigated the
performance and the dynamics of the microbial communities in intermediate (10ppt) and high
(35ppt and 30ppt) salinity laboratory scale multi-stage anaerobic reactors fed with marine
macroalgae (Sargassum spp.) over 180 performance days by using barcoded 454 pyrosequencing
of 16S rRNA genes. The outcome of this survey may be summarized in five major findings: (1)
The intermediate salinity bioreactor is significantly more efficient in terms of biogas production
than the high salinity bioreactor; (2) The alpha diversity was found to decrease over time in
response to the adaptation of the microbial communities to different environmental factors; (3)
Fermentative Bacteroidetes and Firmicutes were the predominant and the most stable microbial
groups in the mature anaerobic reactors; (4) The PCoA reveals significant Beta diversity
attributed to reactor salinity (R= 0.54, p = 0.002), which is an indicator that salt concentration is
a strong ecological factor that shapes the biogas reactor microbial communities, (5) No significant
partition of microbial communities was observed in either the 2L two-stage bioreactors, or
the 15L three-compartment reactor systems; and (6) Finally, in spite of the crucial role of
methanogenic Archaea for biogas production, they are present as a remarkably small fraction (1-
2%) of the mature bioreactor microbial communities. The characterization of the biogas produced
and additional meta-metabolomics studies are suggested in order to better understand the microbial
community functions in these systems.
Methane Production from the Anaerobic Digestion
of some Marine Macrophytes
Clifford Habig and John H. Ryther
School of Forest Resources and Conservation
University of Florida Gainesville~ FL
The methods used in"this study have emphasized low-cost, non-intensive anaerobic
fermentation. Energy inputs to the digesters were minimized, with temperature
maintenance above 250C via heat lamps being the only significant input. The
digesters were only briefly stirred during loading, and the pretreatment of raw
seaweed (coarse chopping) represents minimal substrate preparation. Even with
such low energy inputs, the methane production of these digesters compares well
wi th that of other manure and plant biomass digesters (6, 7,8,12,13,14). In
fact, the only signi.ficant difference between this study and the previous one using
Graci1aria (7) is the high methane production at 30 days retention time reported
in the latter study. Equally good methanogenisis did not occur until 40 days
retention time in the present experiment. This difference can be attributed to
either the slightly lower temperature of this experiment, variability of seaweed
batches or a combination of the two factors.
The net energy production of these simplified digesters most probably would
equal or exceed that of other digesters, since all previous digesters were maintained
at slightly higher (30-350C) to much higher (55-58oC) temperatures. Many also
involved a considerable amount of mixing. Considering Jewel1’s (13) observations
on cow manure digesters, these increased inputs, along with increased construction
costs of elaborate digesters, tend to shift the net energy and economic balance
toward lower temperature, simplified digesters . However, 27 0C may represent the
lowest practical temperature for operating these seaweed digesters, since temperatures
below this appeared to greatly reduce gas output.
Microbial Ecology of Anaerobic Digesters: The Key Players of Anaerobiosis
Fayyaz Ali Shah, Qaisar Mahmood,* Mohammad Maroof Shah, Arshid Pervez, and Saeed Ahmad Asad
Anaerobic digestion is the method of wastes treatment aimed at a reduction of their hazardous effects on the biosphere. The mutualistic behavior of various anaerobic microorganisms results in the decomposition of complex organic substances into simple, chemically stabilized compounds, mainly methane and CO2. The conversions of complex organic compounds to CH4 and CO2 are possible due to the cooperation of four different groups of microorganisms, that is, fermentative, syntrophic, acetogenic, and methanogenic bacteria. Microbes adopt various pathways to evade from the unfavorable conditions in the anaerobic digester like competition between sulfate reducing bacteria (SRB) and methane forming bacteria for the same substrate. Methanosarcina are able to use both acetoclastic and hydrogenotrophic pathways for methane production. This review highlights the cellulosic microorganisms, structure of cellulose, inoculum to substrate ratio, and source of inoculum and its effect on methanogenesis. The molecular techniques such as DGGE (denaturing gradient gel electrophoresis) utilized for dynamic changes in microbial communities and FISH (fluorescent in situ hybridization) that deal with taxonomy and interaction and distribution of tropic groups used are also discussed.
Treatment of seafood-processing wastewaters in mesophilic and thermophilic anaerobic filters
Authors: Mendez, Ramon; Lema, Juan M.; Soto, Manuel
Source: Water Environment Research, Volume 67, Number 1, January/February 1995, pp. 33-45(13)
Publisher: Water Environment Federation
Wastewaters from fish-canning industries have a high concentration of organic polluting substances (10–50 g chemical oxygen demand L−1 [COD]) and, in some cases, a high content of sea salts (Cl−: 8–19 g L−1, Na+: 5–12 g L−1, SO2− 4: 0.6–2.7 g L−1). The presence of high sodium ion concentrations in wastewaters with high organic content traditionally is considered as a very negative factor for their anaerobic treatment. In fact, both the presence of Na+ and SO2− 4, transformed into H2S during the anaerobic degradation process, may cause toxicity and inhibition on the methanogenic process.
This work deals with the operation and treatment efficiency of two lab-scale mesophilic and thermophilic anaerobic filters (MAF and TAF, respectively). So that the adaptation of anaerobic sludge to high saline concentrations is attained, a prolonged start-up period of about nine months was necessary. After this, a stable operation and similar treatment efficiencies were reached, even when organic loading rate (OLR) as high as 9 kg COD m−3 d−1 (TAF) or 24 kg COD m−3 d−1 (MAF) were applied at chloride concentration of 13 g L−1. At these conditions, the COD removal reached 73% (TAF) and 64% (MAF), and the COD methanized reached 69% (TAF) and 66% (MAF). The sulphate in the influent was removed practically completely, leading to a H2S concentration in the biogas between 3–4%.
In spite of the lower specific activity of sludge from MAF (0.21 g COD g−1 volatile suspended solids [VSS] d−1) than from TAF (0.66), the MAF reached a higher OLR than TAF. This fact can be explained because of the higher retention of sludge into MAF (72 g VSS L−1) than TAF (10 g VSS L−1). Two practical conclusions may be derived from this work: the thermophilic operation needs the use of a packing material with a higher capacity to retain biomass and the mesophilic operation requires a more frequent detachment of biomass from the support in order to avoid clogging problems.
Methods for the conversion of fish waste from aquaculture systems to methane via a modified uasb reactor
US 20110039321 A1
A process for treatment of sludge made up of saline organic solids or organic waste produced in a saltwater or brackish aquaculture system is described. The process includes use of a modified reactor, operating under anaerobic conditions, which yields methane from the digestion of the saline organic solids. Modification of a traditional reactor to include a packing substrate provides for saline waste digestion not previously known. Additionally provided is a process for producing methane from the digestion of organic solids. Inclusion of and use of modified reactors in aquaculture systems is also provided.
Method for conversion of halophytic biomass to biogas via thalassic anaerobic digestion
US 20140377828 A1
Described is a process for the conversion of halophytic plant biomass containing saline organic solids into biogas through anaerobic digestion. Operation of the process with saline (e.g., seawater) as liquid media under the method conditions taught leads to biological conversion of the organic matter into biogas. Additionally described is a method for pretreatment of the biomass under mild physicochemical conditions to increase the bioavailable fraction of the biomass for conversion.