Nutrient requirements Water

Fertilization of ponds to increase productivity is the next level of intensity with respect to fish culture, followed by provision of supplemental feeds. Supplemental feeds are those that provide some additional nutrition but caimot be depended upon to supply all the required nutrients. Provision of complete feeds, those that do provide all of the nutrients required by the fish, translates to another increase in intensity. Associated with one or more of the stages described might be the appHcation of techniques that lead to the maintenance of good water quaUty. Examples are continuous water exchange, mechanical aeration, and the use of various chemicals used to adjust such factors as pH, alkalinity, and hardness. 

The Action plans will also include options for controlling nutrient inputs in the upstream catchments of affected stillwaters. These are likely to include reduction of nutrients from both point and diffuse sources and a range of different combinations aimed at reaching the target concentrations of nutrients required to achieve control in the receiving waters. 

Recently, anaerobic filter process has been widely used for the treatment of various waste-waters because of several advantages over aerobic process such as lower nutrient requirement, less surplus sludge production, and energy recovery via methane production [1]. Although many types of anaerobic filter process have already been successfully commercialized, the details of their complicated process dynamics are still challenging issues to be clarified for their stable operations. 

Typically, the manufacture of a batch of biopharmaceutical product entails filling the production vessel with the appropriate quantity of purified water. Heat-stable nutrients required for producer cell growth are then added and the resultant medium is sterilized in situ. This can be achieved by heat, and many fermenters have inbuilt heating elements or, alternatively, outer jackets through which steam can be passed in order to heat the vessel contents. Heat-labile ingredients can be sterilized by filtration and added to the fermenter after the heat step. Media composition can vary... 

Cyanobacteria are ideal solar energy converters because they require only the sun, mineral nutrients, and water for Ho production. Their waste bodies can feed fishes [4]. 

This lack of development in aquatic allelochemistry appears an anachronism. It is not. Specifically reflecting the pervasive and peculiar effects of water, analysis of allelochemical events in aquatic systems has presented unique problems. Among the most significant are (a) the widespread and unpredictable occurrence of secondary activity, and (b) the difficulties of distinguishing between ultra-trace nutrient requirements and allelochemical effects. Both generate a need for unusually rigid experimental control. 

FedorakPM, Hrudey SE. 1986. Nutrient requirements for the methanogenicdegradation of phenol and p-cresol in anaerobic draw and feed cultures.Water Res 20(7) 929-933. 

The initial assumption might be that a photobiological H2 process would not require any raw materials. However, any biological process requires water and an adequate supply of macronutrients (i.e., nitrogen and phosphorus) and possibly some supplemental micronutrients, depending upon what nutrients and minerals are already present in the water supply to the process. One method to reduce raw material costs would be to utilize the waste stream from another process. For example, effluent streams from wastewater treatment anaerobic digesters are nitrogen rich, and blowdown streams from power plants are relatively pure. 

To revisit our general recipe for NPP, environmental factors influence the rate at which light, CO2, nutrients and water are combined to form NPP. Any of these environmental factors or resources may constrain NPP, and it is ultimately a proper balance of these factors that is required for plant production. However, the importance of interacting controls in determining ecosystem processes demonstrates that NPP is not a simple function of the ratio of resources available and the environmental conditions. This simple stoichiometric approach would be valid only if plants responded passively to, and had no effect on, their environment. Plants, however, play an active role in their response to, and mediation of, resources and their environment. Within the constraints of their environment, they actively mediate the resource availability and environmental conditions that constrain NPP. Ultimately, biogeochemical cycling is driven by the interactions between organisms and their physical and chemical environment. NPP is therefore sensitive to... 

Fleischer EJ, Broderick TA, Daigger GT, Fonseca AD, Holbrook RD, and Murthy SN. Evaluation of membrane bioreactor process capabibties to meet stringent effluent nutrient discharge requirements. Water Envir Res. 2(X)5 77 162-178. 

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