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Full-Text Articles in Engineering
Optimering Van Koagulasie En Flokkulasie In Die Herwinning Van Koelwater Uit Oliesintese-Afvalwater, Johannes Van Leeuwen, P. Wille
Optimering Van Koagulasie En Flokkulasie In Die Herwinning Van Koelwater Uit Oliesintese-Afvalwater, Johannes Van Leeuwen, P. Wille
Johannes van Leeuwen
The activated sludge process, which is used in the purification of an oil synthesis effiuent, produces an effiuent which is high in turbidity. The water also contains a lot of dispersed bacterial growth which is not removed during sedimentation. Flocculation is essential to remove these materials. The average diameter of the colloids was found to be 0,92/'m. The zeta potential of the colloids was determined in an attempt to correlate it to the amount of flocculant required. The value was relatively constant at -13,88 mV, which indicates that a cationic·coagulant was required. The required dosage to achieve clarification by means …
Ozonation For Non-Filamentous Bulking Control In An Activated Sludge Plant Fuel Synthesis Waste Transfer, Johannes Van Leeuwen
Ozonation For Non-Filamentous Bulking Control In An Activated Sludge Plant Fuel Synthesis Waste Transfer, Johannes Van Leeuwen
Johannes van Leeuwen
A zero discharge mode of operation at the South African fuel synthesis plants necessitates the infinite recycle of treated industrial waste water. The treatment process incorporates activated sludge units in which non-filamentous bulking and carry-over of solids often occurs. The use of ozone for the control of this non-filamentous binding was investigated on a 33 l/d small pilot-scale plant. An ozone dosage of 1 g per kg mixed liquor suspended solids per day could reduce the diluted sludge volume index from an average of 125 to about 70 ml/g mainly by preventing zoogleal growths, the main contributor to the non-filamentous …
Bulking Control With Ozonation In A Nutrient Removal Activated Sludge System, Johannes Van Leeuwen
Bulking Control With Ozonation In A Nutrient Removal Activated Sludge System, Johannes Van Leeuwen
Johannes van Leeuwen
The control of sludge bulking by ozonation was studied on four parallel pilot-scale (100 l/d) biological nutrient removal systems. Bulking was caused by filamentous organisms which typically occur in nutrient removal systems, i.e. Type 0092, Tpye 0041 and Microthrix parvicella. Continuous dosing of ozone, at 1; 2 and 4g O3/kg mixed liquor suspended solids (MLSS).d resulted in a diluted sludge volume index of about 50 ml/g less than the unozonated control. Ozonation was more effective in the sludge cycle than directly into the aeration basin. Nitrification-denitrification was not affected, not even at dosages of 30 g O3/kg MLSS.d. Biological phosphate …
Ozonation At The Stander Water Reclamation Plant, Johannes Van Leeuwen, J. Prinsloo
Ozonation At The Stander Water Reclamation Plant, Johannes Van Leeuwen, J. Prinsloo
Johannes van Leeuwen
The results achieved by ozonation at the Stander Water Reclamation Plant, Pretoria, are discussed. A packed column together with an injector mixing device gave ozone· utilization levels higher than 95 % at dosages of about 10 mg/ dm3. Redistribution plates in the packing proved necessary to prevent poor adsorption due to backmixing in the gas phase. Disinfection is satisfactory if total oxidant residuals can be maintained at more than 0,2 mg/dm3 for 15 min. The results indicated that ozonation also lowered the chemical oxygen demand and total organic carbon concentration in the water. In spite of the fact that it …
Studies On Disinfection And Chemical Oxidation With Ozone And Chlorine In Water Reclamation, W. R. Ross, Johannes Van Leeuwen, W. O. K. Grabow
Studies On Disinfection And Chemical Oxidation With Ozone And Chlorine In Water Reclamation, W. R. Ross, Johannes Van Leeuwen, W. O. K. Grabow
Johannes van Leeuwen
Laboratory studies showed that Pseudomonas aeruginosa, Aeromonas hydrophila and Acinetobacter anitratum are more resistant to chlorine and ozone than Escherichia coli. Pseudomonas aeruginosa was the most resistant of all strains tested and was selected as test organism for pilot plant studies on the efficiencies of chlorine and ozone disinfection. The disinfectants proved equally efficient for the disinfection of chlorine demand-free water but ozone was much more efficient in the case of water with a chlorine demand. This difference was confirmed to be due to the property of chlorine to react with nitrogenous substances to form chloramines which are less efficient …