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1977 - 19792

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    The occurrence of chromatiaceae in waste treatment lagoons and their utilisation to treat fellmongery effluent : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biotechnology at Massey University
    (Massey University, 1979) McFarlane, Paul Northcote
    A study of the occurrence of Chromatiaceae in waste treatment lagoons was made. To determine the important factors leading to their dominance, an investigation of the effect of various environmental parameters on the growth of a Chromatium species was made. Chromatium minutissimum was isolated and identified from an anaerobic lagoon treating meatworks effluent. An experimental design was used to screen the effects of temperature, pH, sulphide and acetate concentrations and light intensity on the batch growth of this bacterium in pure culture. Empirical models were developed which described the maximum population and the exponential growth rate as a function of these variables. Comparison of these models with lagoon data indicated that they provided a conservative estimate of the exponential growth rate and maximum population under lagoon conditions and that, under the range of environmental conditions expected in New Zealand, the hydraulic retention time is of major importance in limiting the development of this phototrophic bacterium in lagoons. The developed models may possibly be used to characterise the growth of other Chromatiaceae. To study the growth of the Chromatiaceae in mixed culture various lagoon samples were incubated in daylight. A succession from anaerobic non-phototrophic bacteria to phototrophic bacteria to algae was observed in these batch cultures. Thus, in addition to low hydraulic retention times preventing the growth of the Chromatiaceae, competition from the algae precludes their dominance at longer retention times. Seven lagoon systems in which the Chromatiaceae were known to occur were then investigated. The lagoons studied ranged from facultative to anaerobic. The wastes treated varied from domestic sewage to strong industrial and agricultural effluents. A succession from non-phototrophic anaerobes to Chromatiaceae to algae was observed in many instances and a three stage succession theory was formulated. This theory was used to explain the occurrence of the Chromatiaceae in all the lagoon systems studied and it may be used to design lagoons in which the dominance of the Chromatiaceae is favoured or prevented. The study of the lagoon systems indicated the potential of the Chromatiaceae for treating effluents containing reduced sulphur compounds. In N.Z., fellmongery effluent is the most important sulphide-bearing effluent. Experiments were therefore performed to develop criteria for the design of anaerobic lagoons using the Chromatiaceae to treat fellmongery effluent. Experiments were conducted to determine the effects of temperature and sulphide concentration on the performance of .088 m3 laboratory lagoons, in which Thiocapsa roseopersicina was dominant, treating a synthetic fellmongery effluent. Temperatures from 10°C to 25°C and influent sulphide concentrations of 200 mg/l to 1,500 mg/l were studied. Good treatment was obtained under a wide range of conditions although inhibition of growth occurred at influent sulphide concentrations of approximately 900 mg/l. Concentrated fellmongery effluents may therefore be treated by these lagoons. COD removals varied from 66.1% - 87.1% and sulphide removals from 89.5% - 98.4%. Design equations which described the performance of the laboratory lagoons were developed. To confirm the accuracy of these equations, pilot scale experiments were conducted on a 5.74 m3 lagoon system treating actual fellmongery effluent. A good degree of treatment was again achieved and the laboratory-developed equations provided a good estimate of the pilot-scale effluent over the range of conditions studied. Suitable criteria have therefore been developed for the design of anaerobic lagoons using the Chromatiaceae to treat fellmongery effluent.
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    Studies in anaerobic/aerobic treatment of dairy shed effluent : a thesis presented in partial fulfilment of the requirement for the degree of Doctor of Philosophy in Agricultural Engineering at Massey University, Palmerston North, New Zealand
    (Massey University, 1977) Warburton, David John
    Increases in herd size and enforcement of water quality regulations have created an effluent disposal problem for the New Zealand dairy industry. Spray disposal to land and lagooning are commonly used but mechanical failures, management requirements and pressure on land have limited their suitability in many situations. This project was established to consider an alternative system. Initial studies revealed that anaerobic treatment in unmixed, non-insulated tanks, followed by trickling filter aeration, might be suitable. Two laboratory scale and one field treatment plant (1/15 - 1/20 full scale) were constructed to investigate the system. A factorial experimental design allowed investigation into three anaerobic treatment levels with a 3 x 3 aerobic treatment interaction nested within each anaerobic treatment. Anaerobic residence times of 5, 7.5 and 10 days provided loading rates of 1.35 - 0.63 kg COD/m3-day and 1.36 - 0.67 kg T S/m3-day. Removals between inlet and outlet averaged 71% and were insensitive to loading rate. Total solids accumulation rates of 40-50% TS input rate suggests that anaerobic tank design should be based on solids accumulation rate and cleaning frequency. The stone media trickling filter was loaded at approximately 0.61 kg COD/m3-day. Aeration periods of 1, 2 and 3 days and hydraulic loads of 2.8, 10.1 and 18.2 m3/m2-day were studied to determine their influence on treatment efficiency. Multiple regression analysis indicated that the longer residence times and higher recycle rates improved treatment efficiency. Removals varied with the measured parameters but ranged from 42-66% for COD. Design alterations to allow the final discharge to be taken from the bottom of the filter, after settling, would increase aerobic treatment efficiency above 75% COD removal. Prediction of treatment efficiencies beyond the monitored operating conditions suggested that only marginal improvements could be made. The TS accumulation rate in the aerobic phase was approximately 13% of the TS input rate or 56% of the BOD removal rate. Overall plant treatment efficiencies of 80-89% were obtained. Removals in excess of 92% could be achieved with minor design alterations. Maintenance and operational requirements were minimal. The only problem with the system was an average 15 fold increase in NO3-N and 4 fold increase in DIP under conditions for optimum removal of the other parameters. Intermittent land disposal could reduce this problem. Treatment comparison between similar laboratory plants, and between laboratory and field plants which varied by a scale factor of 56, suggests that identically designed plants would give a similar performance and that there is little scale effect. Increasing the scale only improved treatment efficiencies under unstable aerobic conditions, i.e., high recycle rates and low residence times. Increasing scale gave some decrease in maintenance and operational problems. Design of a full scale plant, based on daily pollution loads from a 250 cow dairy shed, suggests that the system is a viable proposition.