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    Interactions of effluents with a river system : a thesis presented in partial fulfilment of the requirement for the degree Master of Technology (Biotechnology) at Massey University
    (Massey University, 1979) Hooper, Glenda Wynne
    The lower Oroua River, Manawatu, was studied during the 1977-1978 summer and 1978 autumn to determine what effect two waste discharges had on the quality of the river. The two discharges were both organic in nature, one being effluent from Thomas Borthwick & Sons (Feilding) meatworks and the other was the effluent from the Feilding Borough Council sewage treatment plant. Both wastes had been biologically treated, Borthwick's wastes by ponding and the Feilding domestic sewage by trickling filtration. Chemical, microbiological and biological parameters were considered with respect to the effect that the effluents had on the river. The chemical parameters studied were dissolved oxygen, pH, BOD, COD, suspended solids, total kjeldahl nitrogen, nitrate, total phosphorus and orthophosphate. Broad microbiological groups of proteolytic, lipolytic and saccharolytic bacteria were used to quantify the microbiological effects while a brief study was also made on the presumptive and faecal coliforms. The macro-invertebrates and benthic algae were the biological factors studied. The results showed the Borthwick's effluent to be of very high quality and having minimal effect on the Oroua River. In comparison, the Feilding domestic sewage was of poor quality and it appeared that the trickling filter was seriously overloaded. Consequently this discharge had a pronounced effect on the Oroua River. Most of the chemical parameters were affected by this discharge as were the microbiological densities. The growth of algae did not appear to be influenced by any nutrient input by the discharges. During daylight hours the high amount of algal photosynthesis more than compensated for the oxygen demand from degradation of organic matter below the Feilding domestic sewage and supersaturated dissolved oxygen levels were recorded. However, at night the combination of this oxygen demand and that of algal respiration resulted in severe oxygen deficits. The structure of the macroinvertebrate communities in the Oroua River upstream of the 2 discharges had changed imperceptibly since 1956 (Pol. Adv. Council, 1957). The macroinvertebrate community structure below the Borthwick's meatworks discharge indicated that the river quality had improved substantially since 1956 while the community below the sewage discharge showed that the river recovered in a shorter flow distance. The chemical results were found to corroborate the macroinvertebrate results.
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    Studies into the hydraulics of waste stabilisation ponds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Environmental Engineering at Massey University, Turitea Campus, Palmerston North, New Zealand
    (Massey University, 2001) Shilton, Andy
    Wastewater stabilisation ponds are used extensively to provide wastewater treatment throughout the world. A review of the literature indicated that, while understanding the hydraulics of waste stabilisation ponds is critical to their optimisation, the research in this area has been relatively limited and that there is a poor mechanistic understanding of the flow behaviour that exists within these systems. Traditional tracer studies were used in this study but, in addition, new methodologies were developed involving drogue-tracking techniques to directly quantify the internal flow pattern. The investigation included study of physical scale models in the laboratory, operational ponds in the field and the simulation of both using computational fluid dynamics (CFD) mathematical modelling. Twenty experimental configurations were tested in the laboratory with the variables being: retention time; outlet position; inlet type and position; and the influence of a baffle. Ten of these experimental cases were then mathematically modelled and, in general, the simulations had close similarity to the experimental data. In the next phase of the work, the tracer and drogue tracking techniques were applied on two full-scale waste stabilisation ponds in the field. For one of the ponds a large scale model was also constructed. Mathematical modelling was again performed and a high degree of similarity was achieved. The study then finished with a broad review of wind effects and an investigation of integrating a biodegradation equation within the CFD model. While it was concluded that a CFD model cannot always be expected to precisely predict the performance of a field pond, this work has validated its use to the extent that it can be pragmatically applied for the systematic evaluation of alternative baffle, inlet and outlet configurations, thereby, addressing a major knowledge gap in waste stabilisation pond design.
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    Treatment of meat processing wastewater for carbon, nitrogen and phosphorus removal in a sequencing batch reactor : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Process & Environmental Technology at Massey University
    (Massey University, 2002) Thayalakumaran, Nagalingam
    The typical New Zealand meat processing industry wastewater was treated by a laboratory scale Sequencing Batch Reactor (SBR) to determine an effective operating cycle for biological carbon, nitrogen and phosphorus removal. The Activated Sludge Model No. 1 and Model No. 2 with modifications were used to simulate the treatment of meat processing wastewater using the SBR. The average values of main pollution parameters of the wastewater were characterised as 1390 mg total COD L-1, 755 mg soluble COD L-1, 75 mg L-1 NH3 - N, 145 mg L-1 TKN and 34 mg L-1 TP. The readily biodegradable COD (RBCOD) accounts for 15 - 18% of the total COD, while the inert soluble and particulate portion were 4% each. In order to establish an effective operating cycle for the simultaneous removal of nutrients and organic carbon, different dissolved oxygen (DO) concentrations in the mixed liquor, duration of operating phases and hydraulic retention time (HRT) of a 6 h cycle were tested. The most effective cycle consisted of seven phases. The first two hours of the anaerobic period was followed by the aerobic and anoxic periods. The first aerobic period was maintained at a DO concentration of 0.5 ±0.25 mg L-1 for 1 h, the second aerobic period for 1 h at a DO concentration of 3.75 ±0.25 mg L-1 and the third aerobic period for half an hour at 0.5 ±0.25 mg L-1 DO concentration. A half an hour anoxic period followed the first aerobic period. A settling period of 0.75 h followed the third aerobic period. The last quarter of an hour was for decanting and idling. The solids retention time (SRT) was 15 d, while the HRT was 2.5 d. Greater than 99% removal of biodegradable soluble COD, NH3 - N and PO4 - P was achieved in the effective operating cycle where the TN and TP in the wastewater were reduced to 10 mg L-1 and 1.0 mg L-1, respectively. In addition the soluble COD was reduced to 98 mg L-1. The key kinetic and stoichiometric parameters for ASM 1 and ASM 2 models were determined using batch tests. The heterotrophic maximum specific growth rate, yield coefficient and the half saturation constant were 2.0 d-1, 0.63 mg cell COD (mg COD)-1 and 8 mg L-1 respectively. The maximum specific growth rate of autotrophs was 0.65 - 0.80 d-1. The anaerobic phosphorus removal stoichiometric coefficients were also determined in batch tests. During the anaerobic period, when 1 g of acetate COD was initially present, 1.48 g of PHA COD was stored while 0.48 g of P was released. The batch trials conducted using acetate to assess the influence of Mg2+ in P uptake showed that the Mg2+ could limit the P uptake and the uptake rate could be represented by Monod type kinetics. In the Monod kinetic expression the Mg2+ half saturation constant was found to be 4.7 mg L-1 The molar ratio of Mg2+ with P was 0.21 during the anaerobic period, and 0.33 during the aerobic period. The SBR performance was modelled using ASM 1 and ASM 2 models after the addition of more processes in these models. Ammonification of the soluble organic N process rate was modified in the ASM 1 model. Similarly it was necessary to add anoxic P uptake and anoxic growth processes involving PHA of Bio-P bacteria in the ASM 2 model. Glycogen storage and glycogen lysis processes of Bio-P bacteria were added in the ASM 2 model to understand the involvement of glycogen in P removal. Also a modification was performed to the storage process of poly-P in the ASM 2 model to account for potential Mg2+ limitation in meat processing wastewater treatment for P removal. During the settling period anoxic hydrolysis was assumed to be negligible. The calibrated ASM 1 and ASM 2 models in general well simulated the effluent NH3 - N, NO3 - N and PO4- P of SBR cycles carried out in distinctly different periods of time and in different batch tests. As the calibrated modified ASM 2 model was able to predict the performance of an SBR cycle conducted over a time period of three months, it was used to identify the most promising treatment strategies of the SBR performance. Variation in duration of feed cycle during the first non-aerated mixed period did not affect the effluent NO3 - N, NH3 - N and PO4 - P concentrations significantly. DO concentration of 3.75 mg L-1 during the third aerobic period instead of 0.5 mg L-1 increased the effluent NO3 - N and PO4 - P concentrations. The simulations confirmed that the operating conditions identified in a 6-h cycle period for the simultaneous organic carbon and nutrient removal are effective.