Anaerobic pond

Anaerobic ponds are loaded such that anaerobic conditions prevail throughout the Hquid volume. One of the major problems with anaerobic ponds is the generation of odors. The odor problem can frequentiy be eliminated by the addition of sodium nitrate at a dosage equal to 20% of the appHed oxygen demand. An alternative is the use of a stratified facultative lagoon, in which aerators are suspended 3 meters below the Hquid surface in order to maintain aerobic surface conditions, with anaerobic digestion occurring at the lower depths. 

Attaway, H.H., Paynter, M.J.B., and Camper, N.D. Degradation of selected phenylurea herbicides by anaerobic pond sediment, J. Environ. Sci. Elealth, B17 683-700, 1982a. 

Sediment t,/2 = 38 h in anaerobic pond water sediment system (Wolt 1997). 

Therefore it is very common to find islands of solids floating in the anaerobic ponds. This often results in dead spots and short-circuiting in the ponds, which reduces the treatment efficiency of the system. Obviously it is very labor intensive and expensive to maintain the ponding system in very satisfactory conditions. It is also imperative to ensure that as little oil as possible is allowed to get into the anaerobic pond. Otherwise the oil will agglomerate with the rising solids brought up by the biogas and form a sticky scum that is difficult to remove. It is not advisable to allow excessive accumulation of the scum so that the effectiveness of the system is not adversely affected. 

Due to inadequate mixing by biogas, solid buildup at the bottom of the anaerobic pond poses another maintenance problem to the palm oil mills. Excessive solid buildup at the bottom of the ponds will reduce the effective digester capacity and consequently shorten the hydraulic retention time. Thus the treatment efficiency will be adversely affected. 

Phases gas-hquid bio solid liquid plus bio solid. Liquid plus bio solid anaerobic digesters (conventional first stage) batch microbiological treatment of municipal sludge no mixing use for <50 mVs. Other options include anaerobic ponds, facultative lagoons and ponds, and aerobic ponds. 

Facultative pond The most common type of pond in current use. The upper portion (supernatant) is aerobic, while the bottom layer is anaerobic. Algae supply most of the oxygen to the supernatant. 

Waste stabilization ponds are shallow basins into which wastes are fed for biological decomposition. The chemical reactions involved are the same as those that occur in the other biological processes. Aeration is provided by the wind, and anaerobic digestion may also occur near the bottom of deeper ponds. The ponds are very commonly used for sewage treatment and dilute industrial wastes. Waste stabilization ponds are normally used as the final treatment step for effluents because they are not effieient enough to be used on their own. 

Since the pond is easily accessible and shallow, scientists at ORNL performed several manipulative experiments with caissons to determine the effects of aerobic and anaerobic environments upon the speciation of actinide elements(9). 

Wu Q, DL Bedard, J Wiegel (1997b) Temperature determines the pattern of anaerobic microbial dechlorination of Arochlor 1260 primed by 2,3,4,6-tetrachlorobiphenyl in Woods Pond sediment. Appl Environ Microbiol 63 4818-4825. 

Due to the focus of this work, other biological processes will also be mentioned. They include trickling filters, coating biological contactors, pond stabilization, anaerobic digestion, and biological nutrient removal.23 5... 

CH4 emitted from manure depends primarily on (i) the management system such as solid disposal system, liquid disposal systems, e.g., ponds, lagoons, and tanks, which can emit up to 80% of manure-based CH4 emissions, while solid manure emits little or no CH4. (ii) Environmental conditions are also important. The higher the temperature and moisture, the more CH4 produced, (iii) CH4 emissions also depend on the quantity of the manure produced, which depends on the number of animals housed, the amount of feed the consumed, and the digestibility of the feed, (iv) Manure characteristics depend on the animal type, feed quality, and rumen microbes present in the rumen and digestive tracks. Manure handled in liquid form tends to release more amount of CH4 when compared to solid or manures thrown into the pasture, which do not decompose anaerobically. High temperatures with neutral pH and high moisture content enhance CH4 production [45],... 

Huber and coworkers123 also reported biomethylation of Pb2+ and of Me3PbX. They followed the redistribution of Me3PbX in anaerobic cultures (bacteria from the surface of a natural lake gron under N2, or from the anaerobic sediment of a small pond), and observed a rate increase, but less Pb2+ and more Me4Pb were obtained than were expected from equation 4 ... 

The system design is based on two upflow anaerobic bioreactors (ABRs) followed by three horizontal sub-surface flow (HSSF) wetlands cells. The water flows by gravity through the cells. Once treated, the water is stored in a holding pond and subsequently used for irrigation of a tree farm. 

Anaerobic digestion, like pyrolysis, occurs in the absence of air. But, the decomposition is caused by bacterial action rather than high temperatures. This process takes place in most biological materials, but it is accelerated by warm, wet and airless conditions. It occurs naturally in decaying vegetation in ponds, producing the type of marsh gas that can catch fire. 

Wu et al. [157] applied the most probable number (MPN) method to test the hypothesis that 2,6-dibromobiphenyl (26-BB) primes PCB dechlorination by stimulating the growth of microorganisms which dehalogenate 26-BB and PCBs. The experiments were conducted in anaerobic microcosms of Aroclor 1260-contaminated sediment from Woods Pond (Lenox, MA). They reported... 

Attaway, H.H., Camper, N.D., and Paynter, M.J.B. Anaerobic microbial degradation of diuron by pond sediment. Pestle. Biochem. Physiol., 17(1) 96-101, 1982. 

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