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Item Understanding the mechanisms involved in Escherichia coli decay during wastewater treatment in High Rate Algal Ponds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Environmental Engineering at Massey University, Palmerston North, New Zealand(Massey University, 2019) Chambonnière, PaulLittle is known about the mechanisms and magnitude of pathogen disinfection in High Rate Algal Ponds (HRAPs). However, maturation ponds are used worldwide for wastewater disinfection, and pathogens can experience similar environmental conditions in maturation ponds and HRAPs. The literature suggests that pathogen removal in maturation ponds is primarily supported by sunlight-mediated mechanisms (direct DNA damage, endogenous photo-oxidation, and exogenous photo-oxidation), and a range of poorly characterized ―dark‖ mechanisms. Based on this evidence, and knowing HRAPs are specifically designed to optimize light supply into the broth, there is reason to believe sunlight mediated disinfection mechanisms should be significant in HRAPs. This thesis therefore aimed at identifying and quantifying the mechanisms responsible for Escherichia coli (E. coli) decay in HRAPs under the hypothesis that understanding the mechanisms involved in disinfection during wastewater treatment in HRAPs can provide the scientific foundation needed to optimize the design and operation for this critical wastewater treatment service. E. coli was selected for being an established indicator of the removal of faecal contamination during wastewater treatment. Two pilot scale HRAPs (0.88 m3) were commissioned and monitored over 1-2 years, showing a mean E. coli decay coefficient of 11.90 d-1 (std = 24.05 d-1, N = 128), equivalent to a mean E. coli log removal of 1.77 (std = 0.538, N = 128) when operated at a hydraulic retention time (HRT) of 10.3 d (std = 2.01 d, N = 139). Hourly monitoring showed high daily variations of E. coli log removal (up to 2.6 log10 amplitude) during the warmest summer days, with the lowest E. coli cell counts observed in the late afternoon, when the broth pH, dissolved oxygen concentration, and temperature typically reached peak values in the HRAP. No mechanisms driving E. coli removal in HRAP could be identified during the monitoring of pilot scale HRAPs so a mechanistic study of E. coli decay was performed at laboratory and bench scale to individually quantify potential mechanisms. At laboratory scale under various conditions (e.g. darkness vs sunlight exposure, neutral pH vs alkaline pH, RO water vs filtered HRAP broth), direct DNA damage, endogenous photo-oxidation, and high-pH toxicity were identified as the main mechanisms contributing to E. coli decay. Exposure to potentially toxic algal metabolites and exogenous photo-oxidation were not found to be significant under the conditions tested. Natural decay (i.e. decay in conditions identified not to be detrimental to E. coli survival) was never significant. The impact of predation could not be investigated due to technical challenges although pilot scale observations suggested this mechanism may be significant in certain conditions. Subsequent bench-scale tests conducted in HRAP broth indicated that temperature-dependent uncharacterized dark decay (i.e. decay in conditions not known to be detrimental to E. coli survival) was likely to be the dominant mechanism of E. coli removal under conditions relevant to full-scale operation. Temperature-dependent high-pH toxicity was confirmed to further increase E. coli decay at pH levels commonly reached in HRAPs. The contribution of sunlight mediated mechanisms was however not significant. Exposure to toxic algal metabolites was suspected to cause significant E. coli decay at times of extreme photosynthetic activity, but more research is needed to confirm this mechanism and its true significance. Results from laboratory scale and bench scale experiments enabled the development of a model capable of predicting E. coli decay in HRAP broth according to pH, temperature, and sunlight intensity distribution. A model predicting HRAP broth temperature and pH according to design and weather data was also developed and validated against data from the pilot scale HRAPs monitored during this study for temperature (average absolute error of predictions 1.35°C, N = 25,906) and pH (average absolute error of predictions 0.501 pH unit, N = 23,817). Coupling the E. coli decay model with the environmental model enabled long term predictions of E. coli removal performances in HRAP for various weather conditions, design, and operational regimes. Simulations predicted that a 3-HRAPs series would sustain average yearly E. coli log-removal of 3.1 in Palmerston North, New Zealand when operated in conditions similar to the pilot scale HRAPs used in the present study. Such performance would deliver year round compliance with local microbial quality guidelines. Disinfection performance could be further improved by increasing the hydraulic retention time, lowering the depth, or collecting the effluent once daily in the late afternoon while letting HRAP depth fluctuate. Overall, this research challenges the common belief that sunlight mediated disinfection mechanisms contribute the most to pathogen removal in HRAPs. Instead, uncharacterized dark decay was predicted to cause 87% of the total E. coli decay over one year simulation. High-pH toxicity may significantly contribute to overall E. coli decay in specific conditions (e.g. low depth where high-pH toxicity was predicted to account for 33% of total yearly E. coli decay), while sunlight mediated disinfection was limited under all simulated designs and operations (highest contribution predicted being 16% of total yearly E. coli decay). Because this study also confirmed the potential of HRAP to achieve sustained wastewater disinfection, further research is needed to better characterize dark decay mechanisms (for E. coli and other key indicators) as this knowledge has the potential to further improve HRAP design and operations for wastewater disinfection.Item Investigation into combined ozone and biological treatment of pulp bleaching effluent : a thesis submitted in partial fulfillment of the requirements for the degree of Master of Technology in Environmental Engineering at Massey University(Massey University, 1999) Zhang, YanmingAn investigation into combined ozone and biological treatment of pulp bleaching plant effluent was conducted. Treatment efficiencies were evaluated in terms of color, COD and BOD 5 removal. The effectiveness of ozone oxidation and subsequent biological treatment of pulp bleaching effluent were examined separately and the overall color, COD and BOD 5 removal through the two-stage combined treatment were determined. Ozone pretreatment was carried out in a vertical column batch reactor under a constant ozone flowrate 5 L/min condition. Changes of color. COD and BOD 5 in pulp bleaching effluent during ozonation process were recorded. The subsequent biological treatment was investigated in two lagoon systems. One was an anaerobic-aerobic lagoon system and the other was an aerated lagoon system. The separate contribution made by each zone of the anaerobic-aerobic lagoon to the overall effluent treatment was evaluated. To assess the effect of the ozone pretreatment on the followed biological treatment, the ozonated bleaching effluent and the non-ozonated raw bleaching effluent were parallelly operated in identical biological systems. Comparison of results obtained from treatment of the ozonated and non-ozonated effluent identified the improvement of a two-stage combined treatment over a biological treatment alone. Results obtained from ozone treatment of two batches of Eo and mixed (Eo and DC) bleaching effluent indicate that ozone was most effective in color removal (up to 74% measured at pH 7), followed by BOD 5 increase (up to 39%) and lesser effective in COD removal (up to 19% only). A color removal formula was developed to model color removal kinetics. The mathematical formula succinctly describes the color removal performance and offers an alternative option to study color removal kinetics during ozone treatment of pulp bleaching effluent. Because of the ozone pretreatment, the effectiveness of the subsequent biological treatment for COD and BOD 5 removal was improved. However, when the followed biological system included an anaerobic zone, a considerable color increase (98%) in the ozonated effluent was observed during the treatment. If the followed biological treatment was carried out under an aerobic condition only, the color increase in the ozonated effluent was very small (21%). This observation suggests that biological treatment of ozonated effluent should avoid involving an anaerobic condition, otherwise the color removal achieved during the ozone treatment would be lost in the subsequent biological stage. It would obviously be economically infeasible. The combined ozone oxidation and biological treatment regime improved the overall color removal (34-68%), COD removal (45-51%) and BOD 5 removal (82-95%) over a single stage biological treatment which only achieved up to 17% color removal, 30-35% COD removal and 64-92% BOD 5 removal. For removal of COD and BOD 5 , the combined ozone with anaerobic-aerobic lagoon treatment outperformed marginally the combined ozone with aerated lagoon system. However, for color removal, the efficiency of the combined ozone with aerated lagoon treatment was much higher (68%) than that of the combined ozone with anaerobic-aerobic lagoon treatment (43%). The anaerobic zone of the anaerobic-aerobic lagoon was identified as the main sources of color increase and limited the overall color removal for such a combined treatment. In summary, the combined ozone with aerated lagoon system was the better option for treatment of pulp bleaching plant effluent.Item A biological treatment system for fellmongery wastes : a thesis presented in partial fulfilment of the requirement for the degree Master of Technology in Biotechnology at Massey University, Palmerston North, New Zealand(Massey University, 1973) Ryder, Michael DesmondThe fellmongery process involves the removal of wool from sheep and lamb skins prior to tanning. The pelts also must be free from epidermic, sweat and fat glands, muscle tissue, blood vessels, fat cells and collagen fibrous tissue. The process consists of the following operations:- (1) Washing of pelts. (2) Lime/Na2S paint application. (3) Wool removal; manual pulling. (4) Lining; removal of residual wool, pelt conditioning, carried out in a "dolly" or drum. (5) Deliming and bating; removal of lime liquor and extraneous pelt matter, "dolly" or drum processing. (6) Pickling; preservation; "dolly" or drum processing. Thirty-nine fellmongeries, which were operating in New Zealand at the end of 1972 (42), were all departments of meat processing works. [From Introduction]Item Tracer studies of a subsurface flow wetland : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Technology in Environmental Engineering, Massey University(Massey University, 1996) Prasad, Julius NarendraThe use of constructed wetlands represents an innovative approach to wastewater treatment. However, the treatment performance of constructed wetlands has been variable due to an incomplete knowledge of the hydraulic characteristics. Current design methods idealise constructed wetlands as plug flow reactors ignoring the existence of longitudinal dispersion, short-circuiting and stagnant regions. The overall effect will be a reduction of treatment efficiency at the outlet. This thesis investigates the hydraulic characteristics of a subsurface flow wetland using a fluorescence dye tracer so as to determine the difference between theoretical and actual retention times and their effect on treatment efficiency. A thorough review of the literature is undertaken, firstly examining wetland systems and their treatment mechanisms, it then reviews their hydraulic characteristics and design considerations while finally discussing dye tracing studies. A series of dye tracing trials were undertaken on a pilot scale gravel bed wetland with a theoretical retention time of four days. The results from this research are presented as plots of dye concentration versus time at the outlet. These results are analysed in terms of chemical reactor theory and their implications on performance of various treatment mechanisms is discussed.Item Effects of carbon dioxide addition on algae and treatment performance of high rate algal ponds : a thesis presented in partial fulfilment of the requirements of the degree of Master of Engineering in Environmental Engineering at Massey University(Massey University, 2006) Heubeck, StephanWaste stabilisation ponds have been used for treating a great variety of wastewaters around the world for many decades. More advanced systems combine anaerobic or advanced facultative ponds with high rate algal ponds (HRAP) followed by a number of algae settling ponds and maturation ponds to achieve enhanced and more reliable removal of wastewater pollutants, while yielding possibly valuable by-products such as biogas and algal biomass. In recent years a growing number of scientists and engineers have proposed the use of HRAP treating domestic wastewater for carbon dioxide (CO2) scrubbing from biogas and CO2 sequestration. The experiments presented in this thesis sought to determine if the treatment performance of HRAP is affected by the addition of CO2 and subsequent reduction of pond pH. Experiments with algae cultures grown on domestic wastewater in laboratory microcosms, outside mesocosms and outside pilot-scale HRAP were conducted. Carbon dioxide addition to algae wastewater cultures restricted the maximum pH level to ~8. Key wastewater quality parameters of CO2 added cultures, were compared to control cultures without CO2 addition. The wastewater quality parameters monitored include temperature, pH, and concentrations of total suspended solids (TSS), ammoniacal-nitrogen (NH4-N), dissolved reactive phosphorus (DRP), filtered biochemical oxygen demand (fBOD5) and the faecal indicator Escherichia coli (E. coli). Carbon dioxide addition to algae wastewater cultures was found to promote algal growth and increased the TSS concentrations. Over 8 day culture length CO2 addition in laboratory and outside batch experiments increased algal growth (indicated by TSS) by up to 76% and 53%, respectively. During semi-continuous outside experiments CO2 addition increased algal growth by ~20% in comparison to the control cultures. Despite enhancing algal growth (TSS), CO2 addition appeared to have little effect on algae cell morphology, species composition and zooplankton activity in the algae wastewater cultures. Monitoring of the key nutrients NH4-N and DRP in cultures with and without CO2 addition indicated that CO2 addition can lead to an increase or a decrease in nutrient removal. Under culture conditions which allowed the control cultures to achieve high day-time pH levels CO2 addition, and subsequent pH restriction, appeared to reduce overall nutrient removal. Only slight changes or an increase in nutrient removal as a result of CO2 addition were observed under culture conditions which allowed only for a moderate or small elevation of the control culture pH. However, the increases in algal biomass, observed in all CO2 added cultures indicate a greater potential for the reclamation of potentially valuable wastewater nutrients in the form of algal biomass. Monitoring of fBOD5 levels during several outside experiments showed that CO2 addition had no effect on the fBOD5 removal by the algae wastewater cultures under those conditions. During several outside batch experiments (of up to 8 day culture length) the removal of the faecal indicator bacteria E. coli was monitored. It was shown that CO2 addition reduced E. coli removal by 1.4 to 4.9 log units compared to control cultures. Basic modelling of carbon flows indicated that under New Zealand conditions the CO2 volumes required for the changes described above would be available from the biogas produced in a wastewater pond system treating wastewater with a volatile solids (VS) concentration of ~ 500 mg/L. In systems treating weaker wastewaters additional CO2 could be made available through the onsite combustion of biogas. In summary, the obtained results suggest that CO2 addition to a field-scale HRAP could increase algal biomass growth year-round and slightly enhance nutrient removal during winter, but might reduce nutrient removal during summer, and reduce E. coli removal year-round, while having no effect on fBOD5 removal. The reduction in nutrient treatment performance during summer, and especially the losses in E. coli removal resulting form CO2 addition may require more sophisticated downstream processing of the HRAP effluent, like increase retention times in maturation ponds. Such remedial measures have to be evaluated on a case by case basis, and are dependent on the given regulations and discharge regimes of the system. This study indicates that in general HRAP can be employed for biogas purification and provide a useful sink for CO2 rich waste streams. The beneficial effects of CO2 addition to HRAP do not appear to allow for any design or management changes within the system, while it was indicated that most detrimental effects of CO2 addition could be accommodated without major alternations, although in some cases significant remedial measures may be required for correcting the losses in disinfection and nutrient removal performance.Item COD removal and nitrification of piggery wastewater in a sequencing batch reactor : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Technology in Environmental Engineering(Massey University, 1998) Wong, Wing NgaPiggery wastewaters are particularly problematic when released untreated into the environment. They contain high levels of chemical oxygen demand (COD) and also nutrients such as nitrogen and phosphorus which can cause eutrophication in surface waters. The sequencing batch reactor is a form of biological treatment in a completely mixed reactor with aerobic and anoxic periods to facilitate nutrient removal. In this study nitrogen removal of piggery wastewater in a SBR by nitrification and denitrification was investigated. Screened raw piggery effluent was used in this study. Average non filtered feed contained a chemical oxygen demand of 12,679 mg/l. The average of the non filtered feed TKN was 1103 mg/l with its largest component being ammonia having an average concentration of 681 mg/l (non filtered feed). Initial experiments with solids retention time (SRT) of 15 days and the hydraulic retention time (HRT) was 5 and 3.3 days for 9 and 4 weeks respectively during Stage 1. No significant nitrification activity was observed during this period. The reactor cycle time was then increased to 2 days which effectively increased the SRT to 30 days and HRT to 6.7 days (Stage 2). The new environment allowed the nitrifying population to develop and nitrification was observed with the formation of nitrite and nitrate. The heterotrophic kinetic constants determined the yield coefficient as 0.49. The maximum specific growth rate (μ max) was 6.8 day-1 and half saturation constant (Ks) was 293.6 mg/l. The COD removal of the feed in the SBR started from around 70% in weeks 6-10 during Stage 1 and reached 92.7% in week 29. Ammonia removal was not significant in the first 17 weeks due to no significant nitrification activity during that time. After initiating a 2 day reactor cycle, ammonia removal rates increased to over 90%. Batch tests indicated that most of the ammonia needed to be removed in the first aerobic period. This allows nitrite and nitrate concentrations to build up and be removed by the subsequent anoxic period. This was when there was enough readily degradable COD as not to inhibit denitrification. The reactor cycle time which achieved full nitrification and the highest nitrate removal by denitrification was observed in the batch test on day 256. The first 6 hour aerobic period removed 81.1% of the ammonia. Subsequent anoxic periods reduced the nitrate concentration in the effluent to 11.0 mg N/l. The nitrification rates increased in the reactor over time as the nitrifying population acclimatised to the piggery effluent. In fact the highest nitrate formation and ammonia oxidation rate was 15.5 mg N/l. h and 24.6 mg N/l.h measured during the last test on day 270. Nitrite formation rates peaked at 11.5 mg N/l.h. The SBR biomass population was able to remove nitrate efficiently as batch tests showed that denitrification rates could reach 22.1 mg N/l.h. The relationship between effluent nitrate levels and COD: ammonia concentration ratio was assessed in order to determine the importance of these chemical characteristics important in controlling the nitrification and denitrification activity in the SBR. Results showed that as the COD: ammonia concentration ratio increases, the effluent nitrate levels decreases. The study found that the SBR was suitable in removing COD and Nitrogen from piggery wastewater.Item Characterizing the removal of antibiotics in algal wastewater treatment ponds : a case study on tetracycline in HRAPs: 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, New Zealand(Massey University, 2016) Norvill, ZaneAntibiotics are ubiquitous pollutants in wastewater, owing to their usefulness in both animal and human treatment. Antibiotic pollution is a growing concern because of the risk of encouraging antibiotic resistance in wastewater treatment (WWT) systems and downstream of effluent discharge. The aim of this thesis was to investigate the fate of antibiotics in algal WWT ponds, which have unique ecological and environmental characteristics (e.g. presence of algae; diurnal variation in pH, dissolved oxygen, and temperature) compared with conventional biological WWT. The research in this thesis focused on a case study of the fate of tetracycline (TET, an antibiotic) in high rate algal ponds (HRAP). Indoor lab scale HRAP studies were used to investigate the fate of TET under several operating conditions. Outdoor pilot scale studies (900 L and 180 L HRAPs) under Oceanic and Mediterranean climates were used to validate the lab scale findings. Results showed that high removal (85% to >98%) of TET was possible in the lab and pilot scale HRAPs with HRTs of 4 and 7 days. Sorption was consistently a low contributor (3-10% removal by sorption) during continuous HRAP studies, based on the amount of TET extracted from biomass. Batch experimentation was used to further distinguish mechanisms of TET removal. The majority of TET removal was caused by photodegradation. Indirect photodegradation of TET was dominant over direct photolysis, with 3-7 times higher photodegradation observed in wastewater effluent than for photodegradation in purified water during batch tests incubated in sunlight. Under dark conditions sorption was the dominant removal mechanism, and biodegradation was negligible in batch tests since aqueous TET removed was recovered (± 10%) by extraction of sorbed TET from the biomass. Irreversible abiotic hydrolysis was not observed during TET removal batch tests in purified (MQ) water. A kinetic model was developed and used to predict TET removal in the pilot HRAPs, based on parameters derived from batch experiments. The model predictions for aqueous TET concentrations were successfully validated against initial TET pulse tests in the 180 L pilot scale HRAP. However TET removal decreased in subsequent pulse tests in the pilot HRAP, resulting in over-prediction of TET removal by the kinetic model. This decrease in TET removal was associated with decrease in pH, dissolved oxygen concentrations, and biomass settleability, but causal relationships between TET removal and these variables could not be quantified. Until the predictive kinetic model is developed further, this model may serve as a preliminary estimate of TET fate in algal WWT ponds of different design and operation. Future research should also investigate the potential formation and toxicity (including antibiotic efficiency) of TET degradation products, but this was outside the scope of this thesis. Predictions from the model were sensitive to the daily light intensity, suggesting that TET removal would be reduced in the winter months.Item Prefermentation and sequencing batch reactor treatment of farm dairy effluent for biological nutrient removal : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Applied Science, Massey University(Massey University, 1998) Mulcahy, JudithIn order to meet the requirements of regional councils' Water Quality Plans implemented under the Resource Management Act (1991), many farmers in New Zealand are now irrigating effluent farm dairy effluent. However there are situations where irrigation is not practicable and it is considered that a sequencing batch reactor (SBR) treatment system may provide a highly treated effluent able to be discharged directly to waterways. The objectives of this research were to develop an SBR operating strategy to optimise biological nutrient removal from farm dairy effluent, monitor the effectiveness of a pilot-scale SBR at removing nitrogen and phosphorus, and assess whether the untreated effluent could be made more readily biodegradable by prefermentation. An operating strategy was designed to enable biological nutrient removal, with the aim of achieving low phosphorus, ammonia and nitrate effluent concentrations. The SBR operating strategy is Fill, Anaerobic, Aerobic I, Anoxic, Aerobic II, Settle, and Decant. Phosphorus is released in the anaerobic phase, using the readily biodegradable carbon. The first aerobic phase is used tor nitrification and phosphorus uptake. Remaining readily biodegradable carbon is also oxidised thus the denitrification occurring in the anoxic phase depends entirely on endogenous carbon. The final aerobic phase operates as a polisher. The results show that the SBR did not achieve biological nutrient removal: there was no apparent reduction in nitrogen and phosphorus levels in the effluent. The most likely reason for the SBR's failure to operate as expected is that it was operated on settled effluent rather than raw farm dairy effluent. The prefermentation trial aimed to increase the readily biodegradable carbon to improve phosphorus removal. The results showed that the optimal time for prefermentation of raw farm dairy effluent at 20°C was eight to ten days, when VFA oxygen demand peaked at about 2,100 mg/L. The prefermentation trial showed a lag phase of 0 to 2 days. The VFA proportions obtained in this experiment were 1.0 : 0.3 : 0.14 : 0.08 acetic : propionic : butyric : valeric acids. The SBR is likely to operate as part of a total treatment system, designed to enhance BNR and provide a high quality effluent. It is considered that screened farm dairy effluent would be held in a prefermentation pond with a hydraulic retention time of at least 8 to 10 days. Prefermented effluent would be treated in the SBR. The effluent would then be polished using wetlands. KEYWORDS: Sequencing batch reactor; prefermentation; farm dairy effluent; nitrogen removal; phosphorus removal; volatile fatty acids.Item Luxury uptake of phosphorus by microalgae in New Zealand waste stabilisation ponds : a thesis presented in partial fulfilment of the requirements for the degree of Masters in Engineering at Massey University, Manawatu, New Zealand(Massey University, 2015) Crimp, Aidan JeremyThe discharge of phosphorus to waterways within wastewater effluent causes significant environmental damage through microalgal blooms and eutrophication. This is a particular problem for wastewater treatment plants that rely on waste stabilisation ponds (WSPs) for the bulk of their treatment. While having simple designs and low running costs, WSPs are mostly ineffective at phosphorus removal, with only 15 – 50% removal achieved on average according to some studies. The luxury uptake phenomenon within microalgae has been identified as one mechanism that could improve WSP phosphorus removal. This occurs when microalgae store phosphorus beyond what is required for their metabolism as polyphosphate, leading to phosphorus contents above the standard 1 %P/g VSS for microalgae. However, studies on this subject in full scale WSPs to date have been limited to just two different ponds. To improve knowledge on this mechanism, this study aimed to assess the impact of environmental conditions, climatic region and pond type on microalgal luxury uptake, as well as determine which specific microalgal and cyanobacterial genera were best able to perform this mechanism. To achieve these objectives, a yearlong study was conducted on 13 different WSPs from 7 sites within various climatological regions within New Zealand, as well as two pilot scale High Rate Algal Ponds (HRAPs). From this study, it was found that luxury uptake was found to occur in 56% of the WSP, with a peak phosphorus content of 3.8 %P/g VSS. Conversely, only one sample taken from the HRAPs was found to exhibit luxury uptake. Total dissolved phosphorus (TDP) concentration and rainfall were found to have a significant effect on biomass phosphorus content at a 95% confidence level, while the WSP climate was found not have an influence. There were no significant differences between the biomass phosphorus contents in primary and secondary ponds, with averages of 1.31 %P/g VSS and 1.21 %P/g VSS respectively, while HRAPs (0.71 %P/g VSS) were significantly lower due to the low TDP concentrations experienced by these ponds. 22 of the 23 identified microalgal and cyanobacterial genera were found to perform luxury uptake, at varying frequencies. The cyanobacterium Planktothrix was most effective, storing polyphosphate as granules in 84% of the samples it was identified in. Scenedesmus, Pediastrum, and Schroederia were also effective, at frequencies of 73%, 82% and 79% respectively. There was some correlation between storage of phosphorus as polyphosphate and enhanced phosphorus contents in the biomass, with nearly all samples containing no visually identifiable polyphosphate granules exhibiting phosphorus contents below 1 %P/g VSS. However, there were only limited correlations between the amount of polyphosphate and the levels of the significant variables identified previously. This research provides valuable insight into the phosphorus uptake behaviour of microalgae and cyanobacteria, and shows that there is some potential for development of a new engineered process targeting improved phosphorus removal. If the phosphorus content of biomass in this new process could consistently attain a level of 3 %P/g VSS, phosphorus removal from wastewater for an average community of 500 people could be increased from 31% to 93%, thus greatly reducing the impact of wastewater discharge on the receiving environment.