Until recently, the management of milking parlour effluent has received very little attention. The wastewater produced by milking operations comprises mainly milk solids and manure and can impose environmental threats to nearby water bodies if not properly treated before disposal. In this study, three bench-scale Sequencing Batch Biological Reactors were used to treat the UBC dairy barn milking centre wastewater. The experiment was designed to investigate the treatment efficiency of the reactors under different operating temperatures and different numbers of cycles employed per unit daily flow (for the same hydraulic retention time). Parameters studied included BOD₅, COD, Total Suspended Solids, NH₃-N, N0₂-NO₃-N and dissolved oxygen uptake. It was concluded that very high and consistent treatment efficiency can be achieved by using a Sequencing Batch Biological Reactor to treat milking centre wastes. Over 90% BOD₅ removal was observed in the room temperature and 30°C reactors. Even in low operating temperatures of 3.7 and 10.5°C, over 70% BOD₅ removal was attained. Removal of the other pollutional parameters studied was similarly excellent. Uncontrolled denitrification also occured to various degrees in all three reactors. It was also concluded that within the range studied in this experiment (4 to 8 cycles per day), changing the number of cycles employed per unit daily flow did not have any significant effect on the treatment efficiency of the reactors. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

An investigation of the trend over time of the concentration of selected soil leachate constituents contained in domestic effluent applied to a ferro-humic podzol forest soil was undertaken. From July 15, 1976 to November 12, 1976, 2 cm of domestic effluent, selectively supplemented with commercial fertilizer, was sprayed twice weekly to a 900 m² plot situated on a mountain slope. Ten porous plate tension lysimeters installed at various depths and locations in the forest soil continuously extracted the resulting soil leachate. The soil leachate samples collected twice per week over the duration of the study, as well as the applied effluent samples, were analysed for chloride, nitrate and total Kjeldahl nitrogen and total and orthophosphorus. Based on. the concentrations of nitrate nitrogen, total Kjeldahl nitrogen, and total phosphate in the applied effluent as well as the average volume of effluent applied over the total irrigation plot, k8A kg/ha (^3.2 lb/acre) nitrate nitrogen, 93-7 kg/ha (83-6 lb/acre) total Kjeldahl nitrogen, and ^3.5 kg/ha (38.6 lb/acre) of total phosphate were applied to the plot during the project period. The chloride ion gradually increased in concentration over the duration of the study until it eventually equalled the value of the chloride in the domestic effluent. This gradual increase was a possible result of the retention of the initial amounts of applied chloride on the anion exchange sites in the soil, which when satisfied, allowed subsequent amounts of applied chloride to move through the soil with the applied effluent. No ortho or total phosphorus was detected in the soil leachate samples collected over the duration of the study. While recognizing the possibility of microbiological immobilization of a portion of the applied phosphorus, the most likely retention mechanism was the adsorption of the phosphorus by the amorphous iron and aluminum compounds in the soil. Nitrate and total Kjeldahl nitrogen were detected in low concentrations in the soil leachate samples only in the time interval following the application of domestic effluent containing greatly increased effluent concentrations of nitrate and total Kjeldahl nitrogen. The increased concentrations resulted from the addition of commercial fertilizers to the treatment lagoon. Such trends suggest microbiological immobilization was playing a role in the removal of the nitrogen compounds. The retention of ammonia, the major component of total Kjeldahl nitrogen, on the cation exchange sites and the retention of nitrate nitrogen on the anion exchange sites would also be occurring. In order to investigate the magnitude of the reaction between phosphorus and the iron and aluminum compounds in the podzol soil, batch scale laboratory tests were undertaken. The time-phosphorus adsorption results indicate that the phosphorus reacts very quickly with the amorphous iron and aluminum compounds in the soil on the plot. The Langmuir and Freundlich isotherms were calculated as was the phosphorus adsorption maximum based on the Langmuir isotherm. The calculated phosphorus adsorption would probably give a conservative estimate of the phosphorus removal potential since the isotherm is based only on the initial and not the long term phosphorus adsorption reactions. Despite the fact that the soil water content was continually above the soil water content at the field capacity, no phosphorus and very little nitrogen was detected in the soil leachate samples. Such results suggest that a phosphorus or nitrogen balance may be a useful irrigation operating criterion rather than the commonly accepted water balance criterion. In such a situation the phosphorus or nitrogen requirements over the growing season of the crop would be evaluated and met by the application of domestic effluent. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

One of the problems associated with the disposal of solid wastes in landfills, particularly in high precipitation areas, is the pollution caused by the production of the often highly contaminated leachate. This study was initiated to investigate the treatability of a low-strength municipal landfill leachate using aerobic digestion followed by activated carbon polishing, so that the most cost effective treatment system could be determined. Sludge desorption and leachate toxicity assessment were also included in the study. The aerated lagoon process alone was very effective in treating the leachate to a quality that is nearly acceptable for discharge to a receiving water. Only SO₄ and Fe in the settled effluent significantly exceeded the local requlatory standards for specific discharges. Carbon adsorption greatly improved the settled effluent quality in terms of color, Fe and COD. However, the addition of this polishing process for combined treatment may not be cost effective. For an influent COD of 1,600 mg/1 and with MLVSS concentrations ranging between 360 and 560 mg/1, the settled effluent COD removal increased from 82.6% to as high as 90.1% when 9C was increased from 2 to 10 days. For the corresponding influent BOD5 of about 1,000 mg/1 and with θ[sub c] greater than 3 days, the BOD5 removal efficiencies averaged 99.1% and the settled effluent BOD5's were no greater than 10 mg/1. This indicates that the raw leachate can be almost completely biodegraded by aerobic digestion. The metal removal efficiency in aerobic treatment was greater than 95% for Fe and Mn, better than 90% for Zn and Pb, and about 80% for Al. Metals expected to be mainly or significantly removed by chemical precipitation due to pH change during treatment included Ca, Fe, Mn, Zn and Pb. Analysis of the kinetic parameters associated with the biological treatment indicated that the concentrations of pollutants, such as heavy metals, in the leachate were not great enough to cause significant inhibition of biological growth. It also showed that this leachate could very likely be added to a domestic sewage, in a high percentage, for aerobic treatment without producing adverse effects. From a treatment efficiency point of view, the optimum solids detention time was found to be 7 to 10 days for leachate BOD₅ ranging from 1,000 to 3,000 mg/1. However, since the predicted θ[sub c] for failure was 0.42 day at 22°C for a 1,000 mg/1 BOD₅ leachate, a θ[sub c] of 2 to 4 days seems possible in the field. On the other hand, the effects of winter temperature on BOD₅ removal and sludge settleability, as well as many other unknown factors on the overall biological treatment efficiency must be considered. It was, therefore, felt that a solids detention time of 5 days or more would be the more realistic approach for a full-scale treatment system, despite the fact that an economic analysis favored a shorter θ[sub c]. / Applied Science, Faculty of / Civil Engineering, Department of / Unknown

Foam separation has been successfully developed on a 4-1 laboratory column, an 80-1 field column installation and a 6000 gal pilot plant trough type system as a novel process for detoxifying bleached kraft mill effluents. Toxic surface active materials such as resin and unsaturated fatty acids collect at the gas-liquid interface of rising air bubbles and concentrate in the foam. The highly toxic collapsed foam represents 1-2% by volume of the influent and is subsequently detoxified by biological treatment. Process parameters controlling detoxification efficiency are pH, gas-liquid interfacial area, initial toxicity level and mode of operation. The gas-liquid interfacial area and pH are of utmost importance. For a typical effluent with MST of 3-4 hr, approximately 20-2 30 m²/l of interfacial area given to an effluent at pH > 7.0 are required for detoxification. Foam separation is universally applicable and reliable for detoxifying kraft whole mill effluent. Over 80% of 205 samples from 10 Canadian mills were detoxified. A 1 gal/min, one and two stage continuous flow systems detoxified over 90% of samples at pH 8 and 1-2 hr retention time over 80 days of operation period. Study of detoxification mechanism indicated that foam fractionation accounts for 77.5% of detoxification, volatization for 5.4% and unidentified mechanisms for 17.1%. Depending on the mode of operation, up to 5% of effluent volume was discharged as foam. The foam volume could be reduced to < 2% by increasing foam retention time and enhancing internal reflux. Collapsed foam was readily detoxified by a biodisc or aerated lagoon process. In addition to detoxification, foam separation removed 20-60% of suspended solids, 66% resin acids, 12% B0D5 (10% TOC), 8% color and 80% foaming tendency. Suspended solids removal could be increased to 88% if an expensive dissolved air system were used for bubble generation. Commercially available equipment for foam generation and foam breaking was reviewed. Jet aerators and turbine systems were assessed as most suitable for commercial application. Pilot plant evaluation of this equipment indicated that reliable and consistent operation could be obtained. The results were used to establish empirical formulae for use in process scale up. During a 4 month continuous flow study, approximately 5-7 m²/l of gas-liquid interfacial area was provided to detoxify 80-100 gal/min of mill A effluent with MST of 6-10 hr. The detoxification success rate of a large number of samples increased from 50 to 86 and to 100% as the operation changed from 1 to 2 to 3 stages. The foam produced by the pilot plant was collapsed by a 12" diameter turbine at 100% efficiency all the time. Costs of foam separation were examined for a projected 3 stage foam separation process, treating 25 M gal/day of bleached kraft whole mill effluent. Capital costs for pH control, foam generation, foam breaking and foam treatment were estimated at $2.26 M. Operating costs were estimated at $2.35/ton of pulp. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

<p>A computer technique for the optimization of thermal waste destruction systems for various design modes, with emphasis on satisfying the air pollution limitations is discussed. The approach considers the incineration of wastes by addition of fuels to permit the thermal destruction of waste materials which are potential pollutants. The computer optimizing package developed utilizes a modified form of a NASA chemical equilibrium program, the Pasquill-Gifford gas diffusion equation and an optimization routine. </p><p>The method employed incorporates the mathematical modeling of elementary incineration systems, with consideration of the practical aspects of the problem. The final computer design and assessment package is flexible and is developed in a way that permits upgrading and modification for realistic systems. </p> / Thesis / Master of Engineering (ME)

A test method and the associated equipment have been developed to investigate the effect of suspended solids on the flow of fluid into a deep injection well system. Preliminary testing indicates that the equipment and test method can be used to determine the permeability of rock samples with a high degree of accuracy. Additionally this equipment can be used in a testing program which will eventually lead to the development of guidelines for the degree of pre-injection treatment required for suspended solids so that the operational life of the well is not impaired.

Submitted in fulfilment of the requirements of the egree of Master of Technology: Chemical Engineering, Durban University of Technology, 2011. / The South African electroplating industry generates large volumes of hazardous waste water that has to be treated prior to disposal. The main source of this waste water has been the rinse system. Conventional end-ofpipe waste water treatment technologies do not meet municipality standards. The use of technologies such as membranes, reverse osmosis and ion exchange are impractical, mainly due to their cost and technical requirements. This study identified source point reduction technologies, close circuiting of the electroplating process, specific to the rinse system as a key development. Specifically the application of a low flow counter current rinse system for the recovery of the rinse water in the plating bath was selected. However, the recovery of the rinse tank water was impeded by the low rates of evaporation from the plating bath, which was especially prevalent in the low temperature operating plating baths. This master’s study proposes the use of an induced draft evaporative cooling tower for facilitation of evaporation in the plating bath. For total recovery of the rinse tank water, the rate of evaporation from the plating bath has to be equivalent to the rinse tanks make up water requirements. A closed circuit plating system mathematical model was developed for the determination of the mass evaporated from the plating bath and the cooling tower for a specified time and the equilibrium temperature of the plating bath and the cooling tower. The key criteria in the development of the closed circuit plating system model was the requirement of minimum solution specific data as this information is not readily available. The closed circuit plating system model was categorised into the unsteady state and steady state temperature regions and was developed for the condition of water evaporation only. The closed circuit plating system model was programmed into Matlab and verified. The key factors affecting the performance of the closed circuit plating system were identified as the plating solution composition and operational temperature, ambient air temperature, air flow rate and cooling tower iv packing surface area. Each of these factors was individually and simultaneously varied to determine their sensitivity on the rate of water evaporation and the equilibrium temperature of the plating bath and cooling tower. The results indicated that the upper limit plating solution operational temperature, high air flow rates, low ambient air temperature and large packing surface area provided the greatest water evaporation rates and the largest temperature drop across the height of the cooling tower in the unsteady state temperature region. The final equilibrium temperature of the plating bath and the cooling tower is dependent on the ambient air temperature. The only exception is that at low ambient air temperatures the rate of water evaporation from the steady state temperature region is lower than that at higher ambient air temperatures. Thus the model will enable the electroplater to identify the optimum operating conditions for close circuiting of the electroplating process. It is recommended that the model be validated against practical data either by the construction of a laboratory scale induced draft evaporative cooling tower or by the application of the induced draft evaporative cooling tower in an electroplating facility.

Thesis (Ph.D.) -- McMaster University, 1997. / Includes bibliographical references (leaves 170-178). Also available via World Wide Web.

No description available.

Submitted in fulfillment of the requirements of the degree of Master of Engineering: Chemical Engineering, Durban University of Technology, Durban, South Africa, 2015. / The implementation of new water regulations from the local government has been a motivation for most industries to treat the effluent before disposal or reuse within the plant, in order to save costs and avoid sanctions. Tongaat-Huletts sugar refinery has therefore invested in this collaborative research with the Durban University of Technology in order to investigate new technologies for wastewater treatment and water recovery using an organic coagulant called chitosan. Chitosan is a natural non-toxic polymer extracted from the exoskeleton of crustaceans. Chitosan has gained extensive attention as a coagulant in the treatment of wastewaters from various industries. However, no attention has been given to the coagulation of effluents from the sugar industry using this polymer. In this work, chitosan coagulant (CCo) was prepared by dissolution of known amounts of chitosan powder in aqueous acid at 50℃. The solution was diluted to desired concentrations using distilled water at room temperature. The removal of impurities using chitosan was investigated for two effluent streams from the sugar refinery, namely the final effluent (FE) and the resin effluent (RE) by applying the one-factor-at-a-time (OFAT) method. The optimum chitosan loading was found to be 138 mg/l for the RE and 7.41 mg/l for the FE, beyond which the efficiency of the coagulant decreased. The coagulation of FE removed 97% of the total suspended solids (TSS), 61% colour and 35% chemical oxygen demand (COD). The treatment of RE resulted in the removal of 68% TSS, 30% colour and 15% COD due to its high content of impurities. Therefore, RE was not considered for statistical studies. The Box-Behnken (BBD) design, which is a statistical response surface methodology (RSM) model was used to study the simultaneous effect of pH, coagulant loading and settling time on the removal of the COD, TSS and colour, with the help of an overlay plot for the FE. The optimum values from the overlay plot were 92% for TSS, 83% for colour and 29% for COD. The model equations generated by the BBD for individual responses involved all the manipulated variables contrary to the OFAT which only considered one manipulated parameter per response. Moreover, the BBD allowed the simultaneous analysis of all the parameters and the identification of interactions which occur when the effect of one factor is dependent on the level of another. The most important interaction for the removal of TSS was the combination of the variation in pH and coagulant dosage. The COD removal was mostly affected by the interaction between the coagulant loading and the settling time. The colour removal increased with the simultaneous increase of the pH and the settling time. A comparative study between the wastewaters from the sugar industry, the brewery industry and milk processing industry revealed that the performance of the chitosan was also affected by the amount of total dissolved solids (TDS) in the wastewater. A model was developed relating the TSS, COD and TDS from all these wastewaters, and was used to predict the TSS removal for the effluent from the olive oil mills and the wastewater from the winery. Chitosan can be considered as a good alternative to inorganic and synthetic coagulants for the pre-treatment of the FE due to its ability to efficiently remove the levels of TSS and colour. Furthermore, the production of chitosan from crustacean shells is a good method of reducing pollution from the fishery industry. Chitosan can be produced locally at low cost due to both the abundance of crustacean shells in the coastal regions of South Africa and the simplicity of its preparation process. It is recommended that a mathematical model be developed to accurately predict the influence of chitosan on all types of effluent. Such a model will provide an indication of the performance of the chitosan and guide experimenters. It is further recommended that the effect of the use of organic coagulants on the destabilization of dissolved solids in wastewater be given greater attention.