Microbial Processes Promising Technologies for Developing Countries (1979) / Chapter Skim
Currently Skimming:
7 Waste Treatment and Utilization
7 Waste Treatment and Utilization
Pages 124-141
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 124... ...
Additional pollution problems have arisen more recently because modern industry generates a multitude of nonbiodegradable organic material and heavy metals that find their way into municipal, industrial, and agricultural wastes. Some industrial effluents cause damaging biological effects as they are recycled through the plant and animal food chain.
|
From page 125... ...
The results of the commensal metabolism are the release of oxygen and synthesis of bacterial degradation products into new, protein-rich plant material. Algae and bacteria can be used for the treatment and conversion of human and animal wastes into forms useful for fish and animal feeds.
|
From page 126... ...
(sODs is the quantity of oxygen required by aerobic microorganisms to oxidize the biologically available organic matter in a waste material during 5 days at 20°C.) At lower temperatures, the loading limit will be correspondingly lower.
|
From page 127... ...
Integrated Ponding In the integrated pending process (see Figure 7.2) , a facultative pond is followed by an algal growth pond.
|
From page 128... ...
Integrated pond systems, though more costly than facultative ponds, require less land and produce an effluent superior with respect to both bacterial cell and salt concentrations. Integrated ponds principally consume solar energy; yet they produce an effluent equal in quality to that derived from electrical energy systems in which oxygen is supplied by mechanical aerators.
|
From page 129... ...
This conversion could be accomplished by decreasing the pond depth and recovering the algae by flotation, sedimentation, or straining. Algal Production Maximum algal production from domestic sewage and animal wastes is desirable, providing the wastes contain no toxic substances, because it permits conservation of fixed nitrogen in a form useful as animal feed.
|
From page 130... ...
Suitable substrates are: · Liquid wastes such as domestic sewage effluents; · Effluents from anaerobic ponds used to treat concentrated plant and animal wastes; · Digester effluents and residues; · Effluents from algal and manure fermentation systems used for methane production; and · Irrigation return flows, urban runoff, and dilute petroleum wastes after the addition of nutrients. Wastewaters should have a suitable sons, plus an algal growth potential not exceeding 500 mg/1.
|
From page 131... ...
Aeration and moisture content The aerobic approach is followed because higher temperatures are reached thereby and because anaerobic composting produces foul odors. Moisture content and aeration are interdependent.
|
From page 132... ...
With organic wastes, the proportion of carbon to nitrogen, the major nutrients, may require adjustment. These should be present in a ratio no greater than 30: 1.
|
From page 133... ...
These trials are needed because of the diversity of waste materials. Anaerobic Lagoons Anaerobic lagoons, designed to treat concentrated organic waste, provide a microbial environment in some ways similar to that found in the rumen or intestinal tracts of animals, in sewage sludge digesters, and in the muds and sediments of aquatic areas.
|
From page 134... ...
The maturation process may be shortened by the addition of dewatered digested sewage sludge from either a vigorously operating city sewage treatment facility or another functioning lagoon. The balance among the bacteria may be disturbed by overloading the lagoons with organic material.
|
From page 135... ...
Of the three groups of simultaneously operating microorganisms associated with anaerobic fermentation, the methanogenic bacteria are probably the most sensitive to charges in temperature, and are thus limiting for the fermentation process. Limitations Anaerobic lagoons operating at optimum rates of activity require temperatures of 29°-35°C and do best in tropical climates.
|
From page 136... ...
The results were a rapid production of acid and control of fetid odor in this aerobic, solid-substrate fermentation, with a final product with an amino acid content 18 percent greater than that of unfermented corn. The organisms in this process came from the waste, not the grain, and conditions favored proliferation of lactic acid bacteria from less than 1 percent of initial total microorganisms to dominant numbers within 12 hours.
|
From page 137... ...
In recycling animal waste for its nutrients, the dung of healthy animals is required; diminished disease potential is associated with acid production that kills coliform bacteria. But it is believed that many animal wastes can be refed to livestock without harmful effects to animals or risks to man.
|
From page 138... ...
The inoculum of lactic bacteria for this fermentation came from feedlot waste and grass. Lactic acid bacteria were isolated from fresh cattle waste in a feedlot and were identified as Lactobacillus plantarum, L
|
From page 139... ...
European Journal of Applied Microbiology 4:59-65. Recycling Animal Wastes by Anaerobic Fermentation Anthony, W
|
From page 140... ...
Recycling Animal Wastes by Anaerobic Fermentation W Brady Anthony, Animal and Dairy Sciences Department, Alabama Agricultural Experiment Station, Auburn University, Auburn, Alabama 36830, U.S.A.
|
From page 141... ...
W Smith, Biological Waste Management Laboratory, Agricultural Environmental Quality Institute, U.S.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.