Aeration Treatment Research Articles

Long term BOD determinations on biologically treated and untreated kraft mill effluent discharged to Lake Saimaa, Finland

Long-term BOD determinations have been carried out on kraft pulp mill effluent over a period of more than 200 days using the conventional dilution method and utilizing a special bottle sealing technique. Determinations were made at the temperatures 2, 5, 10 and 20°C on untreated effluent and on effluent treated by an experimental biological extended aeration treatment plant which treated effluent discharged to Lake Saimaa in eastern Finland. BOD curves have been constructed for up to a period of 200 days and the results indicate that untreated effluent exerts a two-stage BOD on receiving waters, the second stage commencing after approx. 28 days. Treated effluent was found to have a low BOD and showed no second stage of oxygen uptake.

Studies on the Growth of Tobacco Roots : XI. Effect of root-cutting and no aeration to roots on the contents of nicotine in the whole leaves

For the purpose of finding the influence of root-cutting and no aeration treatment to roots at flowering stage on the content of nicotine in the whole leaves, experiments were conducted by using several varieties of water-cultured and field-grown tobacco. The results obtained were as follows. 1. According to the data of water-culture experiment, nicotine concentration in the leaves of Hicks and MC subjected to no aeration treatment was lower than that in the root-cut tobacco. On the other hand, the whole leaves of non-topping tobacco contained lower quantity of nicotine than those of the topped tobacco subjected to no aeration and root -cutting. 2. In Hicks variety, a close relationship was observed between the respiratory rate of whole roots and concentration and content of nicotine in the whole leaves. In MC variety, the correlation between the respiratory rate of whole roots and nicotine concentration was significant. 3. According to the data of field experiment, concentration and content of nicotine in the whole leaves of high nicotine varieties from which the adventitious roots originated from stalk base had been cut off tended to increase by lower topping, and tended to decrease by higher and non-topping. In low nicotine varieties, effect of cutting adventitious roots was not so remarkable as high nicotine varieties.

Versatility and Expandability of Pretreatment

Pretreatment processes are designed to precondition water and wastewater for subsequent operations. Processes for water include watershed management, reservoir storage t screening, sand traps, aeration, and chemical treatment. Pumps, racks, grinding, grit removal and washing, preaeration, flotation, and chemical treatment are used for wastewater. The combination of processes varies with each installation, but depends largely on the characteristics of the raw water and wastewater and the degree of treatment to be provided. Planning and designing for pretreatment must be based on a detailed understanding of the processes and their functions. A good design must meet the immediate and the future treatment objectives, and allow for changes and future expansion in treatment units and processes.

Studies on the Effects of Soil Physical Conditions on the Growth and Yield of Crop Plants : VIII. Efects of aeration treatment on the nutrient absorption and tuberous root formation of sweet potato.

By managing so that a tuberous root forming place and a nutrient-absorbing place could be distinguished, the authors made these experiments to probe the effects of aeration treatment to each place and the amount of fertilizer (ammonium sulfate and potassium sulfate) on the growth of the top parts and the thickening of tuberous root. The results obtained may by summarized as follows. 1) The authors investigated the effects of aeration treatment in the soil where nutrient-absorbing chiefly took place, the condition of the soil where tuberous root was fomed being equal. As a result, it was observed that the growth of the top parts and the thickening of tuberous root were checked by the poor of the soil aeration and the soil compaction of a nutrient-absorbing place. However, when air was injected and O2 concentration in soil air was increased, the growth of the top parts and the thickening of tuberous root were remarkably promoted. On the other hand, when N gas was injected in that place and O2 concentration in soil air was decreased, the growth of non-tuberous root was promoted and the weight of the top parts increased, although the thickening of tuberous root was hampered and its weight decreased. When the soil of a nutrient-absorbing place was loose and the soil aeration was kept to be excellent, both the growth of the top parts and the thickening of tuberous root were greatly promoted and-the weight of tuberous root could be increased. 2) The authors examined the effects of fertilizer treatment to a tuberous root-forming place and a nutrient-absorbing place on the thickening of tuberous root. As a result, it was found that to apply much nitrogenous fertilizer (ammonium sulfate) promoted the growth of the top parts remarkably but hampered the thickening of tuberous root to some extent. On the other hand, to apply a great deal of potash fertilizer (potassium sulfate) hardly affected the growth of the top parts. but promoted the thickening of tuberous root and increased its weight. 3) The authors examined the effects of soil aeration to tuberous root-forming place on the growth of the top parts and the thickening of tuberous root, the condition of a nutrient-absorbing place being equal (in water culture). When N gas was injected in the soil and of concentration in soil air was decreased, the growth of the top parts was not affected so much, but the thickening of tuberous root was checked and its weight was decreased considerably.

Aerobic treatment of dairy wastes.

Disposal of dairy wastes is of importance to all branches of the dairy industry, from the simple shipping and bottling of milk through the manufacture of milk products, including cheese, butter, ice cream, and processed milk. Drainage and washings are the main sources of wastes, with an occasional addition of surplus buttermilk, whey or spoiled materials. About 1 per cent of fluid milk entering a plant is lost even under good waste-preventing practices. Wash and cooling waters dilute this milk so that about 0.1 to 0.2 per cent milk solids is in the waste. This industrial waste with a 5-day biochemical oxygen demand (BOD) of 800 to 1500 parts per million (ppm) is a much stronger polluting agent than the same volume of domestic sewage with a BOD of about 200 ppm. Increasing demands for clean streams, failure of existing aeration systems to prevent odor and acid formation in dairy wastes, and the need for simplified small disposal systems induced the Dairy Industry Committee to present the problem to the Department of Agriculture. The low concentrations of solids in dairy waste does not warrant costly installation for anaerobic disposal. The relatively great oxygen demand, as well as the ready biochemical availability of the major constituents, lactose and protein, suggested studying an aeration treatment. Aerated or activated sludge processes for waste purification use microorganisms for the conversion of soluble oxygen-demanding organic materials to innocuous substances. Aerobic activities of the sludge microorganisms were investigated in these studies, in which a 0.1 per cent solution (1000 ppm) of dried skim milk was used as synthetic waste (table 1) having the

Aerobic Treatment of Dairy Wastes

Disposal of dairy wastes is of importance to all branches of the dairy industry, from the simple shipping and bottling of milk through the manufacture of milk products, including cheese, butter, ice cream, and processed milk. Drainage and washings are the main sources of wastes, with an occasional addition of surplus buttermilk, whey or spoiled materials. About 1 per cent of fluid milk entering a plant is lost even under good waste-preventing practices. Wash and cooling waters dilute this milk so that about 0.1 to 0.2 per cent milk solids is in the waste. This industrial waste with a 5-day biochemical oxygen demand (BOD) of 800 to 1500 parts per million (ppm) is a much stronger polluting agent than the same volume of domestic sewage with a BOD of about 200 ppm. Increasing demands for clean streams, failure of existing aeration systems to prevent odor and acid formation in dairy wastes, and the need for simplified small disposal systems induced the Dairy Industry Committee to present the problem to the Department of Agriculture. The low concentrations of solids in dairy waste does not warrant costly installation for anaerobic disposal. The relatively great oxygen demand, as well as the ready biochemical availability of the major constituents, lactose and protein, suggested studying an aeration treatment. Aerated or activated sludge processes for waste purification use microorganisms for the conversion of soluble oxygen-demanding organic materials to innocuous substances. Aerobic activities of the sludge microorganisms were investigated in these studies, in which a 0.1 per cent solution (1000 ppm) of dried skim milk was used as synthetic waste (table 1) having the