First paragraph: Culturing fish requires that the animals be confined in some controllable volume such as a pond, raceway, net pen, or tank. An important goal with the culturing system is to provide the fish a satisfactory culture environment so that growth and conversion of feed is as efficient as possible. Choice of the culture system is partly dependent upon the species of fish being cultured. Salmonids require very high water quality in comparison with carp and catfish, which have less-stringent water-quality requirements. The largest-scale production systems in the world have generally been constrained to ponds. As an example, the U.S. catfish industry produces 200 million kg per year from pond systems that consist of units that are typically between 2.5 to 5 ha in a rectangular shape. Raceway construction typifies the production systems used to produce salmonids, and in particular trout, and in both Europe and the United States the majority of production occurs for these species in raceways. Tanks, round, hexagonal, or octagonal, are commonly used for a variety of species, but generally for smaller scales of production. This trend is changing, however, with some of the largest farms concentrating on the use of tank structures. The advantage of tank culture is that it lends itself to easy maintenance because tanks can be designed to be relatively self-cleaning of fish waste and uneaten feed. For indoor fish farms, tank culture is by far the most dominant method of culture. In Norway, all juvenile salmon are produced in tanks using a range of tank sizes from 3 to 15 m in diameter and up to 4 m in depth. Recent advances in indoor culture technology indicate that indoor fish farming and tank culture may become the standard of the future, particularly in the United States, where environmental considerations and constraints may force tank culture in which waste streams can be controlled. Net pens are used mainly for larger fish and on sites that have good natural water currents. Net pens are generally considered cheaper per unit of fish-carrying capacity than land-based units. Most of the adult salmon production in the world uses net-pen culture systems. Each of these culture-system types is discussed in the following sections. A key factor in selecting the appropriate culture system is the scale of operation intended. Small-scale operations of 12,000 to 20,000 kg per year often are economically competitive only because of local market opportunities and the use of family (subsidized 245 or noncosted) labor [1, 2, 3]. Sedgwich [1] found that 20,000 kg of trout production was the smallest farm that could provide a viable income if fish production were the sole source of income. Intermediate-sized operations do not appear to offer much advantage.
ABSTRACT Anew design concept for poultry housing, referred to as the FLEX House, is presented and evaluated. The FLEX House allows greater flexibility in management operation by providing either an enclosed mechanically ventilated house or an open walled, naturally ventilated house. Thus, management decisions may be made by the operator rather than a management method being fixed by the initial choice of housing style.
This chapter contains sections titled: Positive attributes Overview of system engineering Culture tanks Waste solids removal Cornell dual-drain system Settling basins and tanks Mechanical filters Granular media filters Disposal of the solids Biofiltration Choice of biofilter Aeration and oxygenation Carbon dioxide removal Monitoring and control Current system engineering design Recirculation system design Four major water-treatment variables Summary of four production terms Stocking density Engineering design example Conclusion References
People are definitely a company’s greatest asset. It doesn’t make any difference whether the product is cars or cosmetics. A company is only as good as the people it keeps.Mary Kay Ash (1915–2001; U.S. Business Executive)
The feasibility of digesting untreated sand-laden dairy manure (SLDM) and sand-manureseparator (SMS) liquid effluent was explored. The SMS successfully reclaimed an average of 46%by mass of sand from influent SLDM with a range of 39 53%, under two separate operatingconditions over six sampling trials. The loss of fine sand in the SMS liquid effluent stream averaged50% with a range of 43 58% of the total SMS influent sand mass, under two separate operatingconditions over six sampling trials. The large amount of dilution water required to separate SLDMusing a SMS normally requires a larger digester, compared to untreated SLDM. This increased sizealso increases the construction costs and the heat required to keep the digester at operatingtemperature. The theoretical biogas production from a digester designed for untreated SLDM wouldprovide excess energy when burned to maintain mesophilic temperatures in the digester.Conversely, there is insufficient energy from the burned biogas generated from a digester designedfor the liquid effluent from a sand manure separator, if the digester influent temperature was 50oF orless. The measured angle of repose of sand in the laboratory digestion chambers was 45 degreesfrom the horizontal. If no sand was removed from an untreated SLDM digester, calculations basedon the laboratory data concluded the digester cell would fill with settled sand in 1.1 years. Amathematical model predicted no removal of sand by scouring action from the digester.
You must never try to make all the money that’s in a deal. Let the other fellow make some money too, because if you have a reputation for always making all the money, you won’t have many deals.J. Paul Getty
A mathematical model for simulating broiler growth is presented. The model consists of: 1) weather model, 2) building model, and 3) broiler model. Values were calculated daily for building ventilation, supplemental heat, feed consumption, and growth as affected by thermal characteristics of buildings and outside environmental parameters. The unique characteristic of the model is that inside temperature and humidity conditions are not specified, but both are allowed to vary within a broad range. The model predicts daily inside temperature and humidity conditions based upon bird age, outside temperature, and potential ventilation capacity. Prediction of bird feed conversion and flock fuel usage was verified with commercial integrator data.
A computer model characterizing the performance of a spray tower oxygen absorption system was developed based on finite difference mass transfer calculations. Performance was assessed in terms of oxygen utilization, transfer efficiency, and economy. Pilot scale tests verified model assumptions and performance predictions. Simulation runs indicated spray tower head and oxygen feed requirements for desired changes in dissolved oxygen (DO) exceeded those required for packed column equipment. Spray tower performance was improved by increasing hydraulic loading from 35 to 85 kg m−2 s−1 and by increasing tower height from 1·25 to 2·50 m. The effluent DO concentration that minimized variable costs of oxygen transfer was lower in the spray tower than in the packed tower, indicating clean water use of the spray tower will be limited to moderate effluent DO requirement applications (DO <20 mg l−1).
'/%3e%3cuse xlink:href='%23a' transform='rotate(23.036 .093 25.536)'/%3e%3cuse xlink:href='%23a' transform='rotate(45.87 1.273 16.18)'/%3e%3cuse xlink:href='%23a' transform='rotate(69.945 .996 12.078)'/%3e%3cuse xlink:href='%23a' transform='rotate(20.66 -19.689 31.932)'/%3e%3c/svg%3e)