Simple Respirometer Research Articles

Evaluation of the Efficiency of a New Aeration System at Henriksdal Sewage Treatment Plant

Henriksdal sewage treatment plant is the largest plant in Stockholm with a design flow of 370 000 m3/d. In one aeration tank of eleven a new fine-bubble aeration system has been in operation since August 1985. The tank is divided into 6 equal parts. The first part is an anoxic zone and the other five are aeration zones with tapered diffusers. Several instruments are installed in the block including separate air flow monitors in each of the five zones and D.O.-probes in the inlet and outlet of the zones. Equipment for flow measurement of settled sewage and return sludge is also installed. Every instrument is connected to a computer for data acquisition. To evaluate the efficiency of the aeration system the oxygenation transfer capacity has been calculated from the oxygen massbalance equation for each zone as a function of air flow. To solve this equation the respiration has to be known and this is done by a simple respirometer for samples of the MLSS in each zone. When the KLa-values are known as functions of the air flow the mass balance equation can be used to calculate the respiration rate in each zone. The computer has been logging data for 2 2 months, and it is possible to calculate the respiration rates in the different zones every hour during this period. It is very important to know the respiration along the tank and how it varies to get the optimal tapering of the diffusers when it is time to change the aeration system in the other 10 tanks. The calculations show a different pattern in the respiration over the year depending on the rate of nitrification. Another use of the calculation of the oxygenation transfer efficiency is to recognize if any long-term change occurs due to clogging of the diffusers.

Determination of Kinetic Constants of Activated Sludge Microorganisms

A respirometric method for measuring kinetic constants of activated sludge microorganisms by means of a simple respirometer was developed and tested by using two types of mixed culture. It has been found that both the maximum substrate removal rate and the half-velocity coefficient are basically lower with the mixed cultures cultivated in a completely-mixed reactor /filamentous/ than with those cultivated in a selector-type reactor /nonfilamentous/.

A comparison of the effects of eggshell porosity on the respiration and growth of domestic fowl, duck and turkey embryos

1. 1. Theoretical predictions of embryonic oxygen comsumption based on diffusion theory and measurements of the gas composition of the air-space were in good agreement with oxygen consumption measurements made with a simple respirometer. 2. 2. Embryos confined within high porosity eggshells could satisfy their high oxygen demand in the latter stages of incubation but embryos within low porosity shells showed a reduced rate of metabolism. 3. 3. The limiting effect of low eggshell porosity on the availability of oxygen was the major factor affecting the weight of the embryo a few days prior to hatch.

Short Term Effects of Aldrin and Swascofix CD‐38 on the Feeding and Respiratory Behaviours of Clarias batrachus and Cirrhina mrigala

AbstractFish were kept in non‐toxic water or at 0.5, 0.25 and 0.125 of the LC50,96h of the ten‐side or insecticide for 24 h and fed with toxified and non‐toxified feed. Toxified feed in normal water resulted in a maximum feed intake, while normal feed in toxified water resulted in a minimum one. In each case, the feed intake was lower compared with the control, and the feed intake was inversely proportional to the toxicant concentration. In a simple respirometer the oxygen consumption in mg · kg−1 · h−1 was tested for 1, 2, 4, 6, 8, 10, 12, 24, 36, 48, 60, 72, 84 and 96 h of exposure to 1.5, 1.0 and 0.5 of the LC50,96h of both substances. It was a flow device which was closed only for measurement for one hour. 1.5 LC50 Aldrin causes a continuous reduction of respiration until death. The same effect occurred with Cl. batrachus for 1.5 LC50 of the tenside, whereas with C. mrigala death was caused by a pronounced increase of respiration. In all other cases, after a phase of sensitization for 4 … 8 h respiration increased considerably to more than 300% of the control, which was followed after 12 … 24 h by acclimatization to normal respiration values.

Construction of a Simple Respirometer

The manometric method of measuring rates of oxygen consumption by organisms is extensively applied in biology laboratories. The respirometer, shown in figure 1, though simple, incorporates most of the basic elements of elaborate and expensive respirometers, and can be built inexpensively by high school students. This respirometer was used to determine the oxygen consumption of a cecropia moth cocoon over a two-month period. A larger device of the same type was used to determine the rate of oxygen consumption in mice throughout pregnancy. Two units with exactly the same components must be built: one will be used as a respirometer; the other with no living material in it, will be

A simple respirometer for measuring oxygen and nitrate consumption in bacterial cultures

A simple respirometer is described to measure simultaneously oxygen and nitrate concentrations. It proved to be an easy tool in denitrification studies. This was tested with Pseudomonas aeruginosa.

Bioenergetics of the Southern Harvester Ant, Pogonomyrmex Badius

The bioenergetics of the southern harvester ant were studied on the Savannah River Project, Aiken, South Carolina. Excavation of hills revealed that density of ants ranged from 4,000 to 6,000 per hill. Labeling ants with P32 indicated that only 10% of the ants in a colony were active above ground during any 2—week period (the limit of recognition of the label); thus, short—term marking recapture estimates based on above—ground individuals greatly underestimate the size of the colony. There were 27 hills per hectare on the study area. The consumption of oxygen of workers at various temperatures was determined in a simple respirometer, and the temperature at which the ants were living in the field was determined during a year's observation at mounds. The energy expense of heat production was calculated from the oxygen consumption and activity temperature records. Total energy flow (heat production plus tissue growth) was highest in summer and lowest in winter. The annual range was from 14 to 48 kgcal/m2/yr. Tissue growth was estimated to amount to only 0.09 kgcal/m2/yr. Energy flow in this species was higher than that of 2 vertebrate granivores studies in the same field, the old—field mouse and the savannah sparrow.

Divergence of Catalase and Respiration in Germination

1. Catalase decreases in early germination stages in six kinds of seeds tested. The initial decrease is followed by the rise generally reported for germination. 2. Catalase decreases slowly, almost to exhaustion in prolonged soaking of seeds in oxygen-free water. 3. There is a decrease of catalase in both the embryo and the endosperm of germinating wheat. The subsequent rise occurs not only in the embryo but also in the endosperm, although in a much less marked degree. 4. A simple respirometer is described, in which large quantities of material can be used, and consecutive readings taken at will on the same sample. By direct reading of the manometers both the oxygen and carbon dioxide can be determined without titration and with practically no calculation. 5. There is a large and immediate rise in respiration when seeds are put in germinating conditions. The early curve of respiration, therefore, diverges widely from the typical germination curve of catalase. 6. Catalase in ripening seeds decreases per un...