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    Removal of copper, chromium and arsenic from the tannery and timber treatment effluents and remediation of chromium of contaminated soil : a thesis presented in partial fulfillment of the requirements for the degree of Master of Applied Science at Massey University
    (Massey University, 1997) Thiagarajan, Subramani
    Tannery and timber treatment effluents are considered to be the major source of Copper (Cu), Chromium (Cr) and Arsenic (As) heavy metal contamination into the environment. Chromium is used in tanneries for the treatment of hides and skins whereas, copper, chromium, and arsenic (CCA) solution is used as the timber treatment chemical. Chromium is used as Cr (III) in tannery industry and as Cr (VI) in timber treatment industry. Arsenic and Cr (VI) which are present in the timber treatment effluent are highly toxic and carcinogenic. An initial survey has indicated that some tannery industries in New Zealand have not developed pre-treatment practices to reduce the heavy metal concentration before discharging the effluent into soil or waterways. The heavy metal pollution due to timber treatment industries may occur from the drips, leaks and spills due to poor handling of CCA solution while treating timber. In this project, the potential value of industrial waste materials, such as Pinus radiata bark, fluidised bed boiler ash (FBA), flue gas desulphurisation gypsum (FGDG) and natural resources, such as zeolite, peat soil, and two soils (Tokomaru and Egmont soils) to reduce heavy metal concentration in tannery and timber treatment effluents was examined. The value of these materials in the remediation of soil contaminated with Cr was examined using a growth experiment. The effect of pre-treatment of Pinus bark with acid, alkali of formaldehyde/acid on the retention of Cr was examined. Pre-treatment of Pinus bark increased the heavy metal retention only at low heavy metal concentration and did not significantly improve the heavy metal retention at high concentration. The extent of adsorption increased with an increase in surface area of Pinus bark material. Speciation of Cr indicated that Cr (VI) is reduced to Cr (III) and adsorbed onto the Pinus bark. FBA was found to be most efficient in reducing the Cr (III) concentration from tannery effluent and As and Cu concentrations in the timber treatment effluent. In the case of Cr (VI), the highest retention was shown by the Pinus bark and the peat soil. The increased retention of Cr (III), Cu and As by FBA was due to the precipitation of Cr (III) as chromium hydroxide, Cu as cupric hydroxide and As as calcium arsenate. A combination of FBA + Pinus bark or FBA + peat soil was efficient in reducing all the three heavy metal (Cu, Cr (VI) and As) concentration from the timber treatment effluent. The effluents contaminated with Cu, Cr and As can be passed through a column containing FBA and Pinus bark or peat soil. A growth experiment using sun flower (Helianthus annus) was set-up to examine the effectiveness of FBA, lime and Pinus bark to immobilise Cr in contaminated soil. FBA and lime amended soils were effective in establishing a normal plant growth of sun flower in Cr (III) contaminated soil even at high Cr (III) levels (3200 mg/kg soil). Incorporation of lime or FBA in Cr (III) contaminated soils causes precipitation of Cr (III) and thereby reduces the bioavailabilty of Cr for plants uptake. Only Pinus bark amended soil was found to be effective in remediating Cr (VI) contaminated soil even at 3200 mg/kg soil. Pinus bark material effectively retained the Cr (VI) present in the soil solution and thus reducing the toxicity and bioavailability of Cr (VI) to plants.
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    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, Judith
    In 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.
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    Modeling and microbiology of a New Zealand dairy industry activated sludge treatment plant : a thesis presented in partial fulfillment of the requirements for the degree of Master of [Technology in] Environmental Engineering at Massey University
    (Massey University, 1997) Rule, Glenys Jane
    An extended aeration activated sludge plant treating dairy factory wastewater was studied. The effectiveness of organic and nutrient removal was investigated in conjunction with the causes of existing foaming and bulking problems. Excellent removal efficiencies of 99.7% BOD5, 98.8% COD, and 96.9% TKN were achieved thoughout the period studied. The removal of total phosphorus however, was only 33.8% and this may become an issue that requires attention in the future. The dominant filamentous organisms in the sludge were identified as Type 0914, Type 0092, Nocardia pinensis, Nocardia amarae-like organisms, and Nostocoida limicola III. It was determined that these organisms were the major cause of the bulking and foaming conditions at the Waste Treatment Plant, although the use of surfactants in the factories and nitrogen and iron deficiencies were probably also contributing. All of the dominant filaments identified have been previously found to exist in large numbers in low food to organism ratio/high sludge age conditions. It was therefore recommended that the sludge age be reduced and the F/M ratio increased by increasing the amount of sludge wasted from the treatment plant. Existing kinetic coefficients were used, together with the Activated Sludge SIMulation programme utilising Activated sludge Model No. 1, to successfully model the existing system. This model can now be used by treatment plant employees (with some training required) to predict the results of alterations to plant operation and/or configuration.
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    Nitrogen and phosphorus removal from dairyshed effluent using a sequencing batch reactor : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Applied Science at Massey University
    (Massey University, 1997) Ellwood, Brian
    It is apparent that present dairyshed effluent treatment systems are not capable of complying with regulations generated by Regional Councils implementing the Resource Management Act 1991. This has created a need for research into dairyshed effluent treatment. To develop an improved treatment system for dairyshed effluent, research was conducted with two main study objectives; to characterise effluent from the dairyshed holding yard and anaerobic pond, and to develop a sequencing batch reactor (SBR) for the removal of nitrogen and phosphorus. The carbon characterisation showed that there was a large difference between dairyshed effluent and domestic effluent in the proportion of carbon in each fraction. When treating dairyshed wastewater to reduce BOD, nitrogen and phosphorus concentrations it was not possible to treat either the yard effluent or the anaerobic effluent without addition of external materials. The BOD reaction rate constant for the yard effluent at 0.2 d -1 was similar to a typical domestic wastewater value of 0.23 d -1 . The anaerobic pond effluent BOD reaction rate constant of 0.16 d -1 was lower than the yard effluent value indicating that the anaerobically treated effluent was hard to treat aerobically. A pilot scale SBR treating dairyshed effluent was operated for 75 days. Startup procedure used a 50/50 mixture of anaerobic pond and aerobic pond effluents which was successful in establishing a biomass capable of nitrifying anaerobic pond effluent. The startup time to establish a nitrifying population was 17 days. The sludge was found to settle well, with a maximum sludge volume index of 54 ml/g measured during the SBR operation. Sludge bulking was not seen as a problem. Nitrification performance a large proportion of the bacteria were lost took only 5 days to recover. With the addition of alkalinity nitrification reliably reduced the effluent ammonia concentration to 5 mg/l. From the cycle analysis the first order reaction rate constants for nitrification were; ammonia reduction 0.7 hr -1 , TKN reduction 0.4 hr -1 and nitrate formation 0.2 hr -1. These constants could be used in future work to optimise stage times. KEYWORDS: Sequencing Batch Reactor; Dairyshed effluent characterisation; readily available carbon; nitrogen and phosphorus removal; activated sludge; venturi aerator; Sludge Volume Index.
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    Application of biochar technologies to wastewater treatment : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science, Massey University, Palmerston North, New Zealand
    (Massey University, 2013) Hina, Kiran
    A review of wastewater treatment options and the properties of biochar (charcoal made from biomass with the intention of carbon sequestration in soil) indicated the potential application of biochar for removal of ammonium-N (NH4+-N) and various organic and inorganic pollutants from wastewaters. This thesis investigates (i) the capacity of alkaline activated and non-activated Pine and Eucalyptus biochars to retain N and P from wastewaters, and (ii) the potential use of these nutrient-rich materials as slow-release fertilisers in soil, thus assisting the recycling of nutrients from waste streams. The retention of NH4+-N on different materials, pine bark, pine biochar (produced from wood chips at 550 °C) and zeolite was investigated. When shaken with a 39 mg NH4+-N L-1 influent solution, Zeolite proved to be the best sorbent of NH4+-N, followed by pine biochar and pine bark; 0.71> 0.38 > 0.27 mg NH4+-N g-1 sorbent, respectively. Ways of increasing the CEC (cation exchange capacity) and NH4+-N sorption capacity of biochar were investigated by (i) alkaline activation by tannery waste or (ii) physical activation using steam as pre and post treatment of biochars, respectively to increase their CEC. Washed alkaline activated biochars (Pine and Eucalyptus) showed a significant (p < 0.05) increase in the NH4+-N sorption capacity over corresponding non-activated biochars. Steam activation increased the internal surface area of biochars but did not prove increased retention of NH4+-N. The efficiency of NH4+-N removal from synthetic NH4+ solutions and urban and dairy wastewaters by alkaline activated and non-activated Pine and Eucalyptus biochars was evaluated and compared using batch and column studies under different flow rates and retention times. Greater NH4+-N sorption was observed in alkaline activated Pine biochar from both the synthetic solution and urban wastewater in column studies @ 2.40 mg N g-1 and 2.17 mg g-1 NH4+-N biochar, respectively. Inclusion of Okato tephra with alkaline activated pine biochar proved effective in removing both P and N from urban wastewater. Finally, the activated pine biochar and tephra loaded with N and P from wastewater treatment were incorporated into two soils (Kiwitea and Manawatu) and the bioavailability of N and P was tested by growing ryegrass in an exhaustive Standford and Dement bioassay. The recovery of N and P was very low and this indicated that it was not economical to use biochar in wastewater treatment for subsequent use as a fertiliser.
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    The fate of methane in a New Zealand pulp and paper mill wastewater treatment system : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Environmental Technology & Sustainable Energy at Massey University, Palmerston North, New Zealand
    (Massey University, 2011) Manzano, John Mark Lalunio
    The wastewater produced by Carter Holt Harvey’s Kinleith pulp and paper mill in Tokoroa is currently treated by a series of aerobic ponds, designed to remove organic pollutants. The treatment system has experienced increases in Biological Oxygen Demand (BOD, a measure of organic pollution strength) at the outlet. The increases in BOD happened when no significant changes in wastewater influent flow and/or characteristics were recorded. The surge in BOD has caused the outlet discharge limit to be exceeded in the past. Based on previous studies, we believe that aerobic oxidation of methane (CH4), by microorganisms called methanotrophs, can cause the generation of methanol (a compound that can cause an increase in BOD load in waste streams), under conditions that repress the further conversion of methanol into biomass and carbon dioxide (CO2). The overall objectives of this project therefore were: ? To determine if the biosynthesis of CH4 can occur in the treatment system ? To determine if the subsequent biological aerobic CH4 oxidation to methanol can occur in the treatment system ? Whether enough methanol can be generated to affect the treatment system’s performance in terms of BOD removal. Evidence was found that confirmed CH4 was formed in the pond sediments across the entire treatment system (with rates significantly higher near the inlet). CH4 is therefore available in the treatment system for aerobic CH4 oxidation. The presence of aerobic conditions and the absence of dissolved CH4 in the water column (part of the pond where wastewater flows above the sediment), showed that aerobic CH4 oxidation can occur in the water column of the treatment system (except at the oxygen limited inlet). Laboratory testing also confirmed that aerobic CH4 oxidation can occur and methanotrophs are present (albeit in small numbers) in the water column. A model was used to determine if aerobic CH4 oxidation to methanol can cause the BOD increase at the outlet. The model found that the rates (CH4 production in the sediment and CH4 oxidation in the water column) needed to cause the surge in BOD was significantly higher than the maximum rates calculated from laboratory tests ofsamples collected from the treatment system. Aerobic CH4 oxidation was therefore unlikely to cause the BOD increase at the outlet. It is possible that the BOD increase is due to benthic feedback (anaerobic sludge layer becomes buoyant, suddenly releasing soluble compounds into the aerobic water column of a pond). The BOD increase experienced at the outlet followed similar characteristics associated with benthic feedback (event was random, occurred at a pond with an oxygen limited sludge layer and aerobic water column). If the cause of the BOD increase needs to be determined in the future, further investigation into benthic feedback is recommended. To conclude, aerobic CH4 oxidation to methanol can occur in the treatment system, but is unlikely to cause the BOD increase at the outlet of the treatment system. The technical capabilities and knowledge developed during the project will likely benefit those in the pulp mill industry. Methods and techniques have been developed to investigate the generation and fate of CH4 within a pulp mill aerated pond.
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    Activated sludge treatment of dairy processing wastewaters : the role of selectors for the control of sludge bulking : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University
    (Massey University, 1996) Leonard, Anne M.
    The typical wastewater from a milk processing facility producing butter and milk powder was treated in a modified activated sludge system in order to establish process characteristics and investigate operational problems. A synthetic wastewater was developed with similar average physical and chemical characteristics to that from a full scale facility. The relative biodegradability of the wastewater fractions was assessed and basic microbial growth parameters also determined. A laboratory scale activated sludge reactor configuration was then established and its performance monitored. Although effective treatment was achieved in terms of suspended and soluble organic matter removal, the use of a completely mixed reactor resulted in the system becoming inoperable due to the excessive growth of filamentous microorganisms, with Type 0411 being the dominant filament. In order to inhibit filamentous bulking, various selector reactor configurations were trialed. As nitrification of feed stream proteins had been indicated, unaerated selectors were used with the intention of effecting anoxic substrate removal in the initial selector zone; but due to the limited supply of oxidised nitrogen, insufficient substrate removal occurred in the selectors to prevent filamentous bulking, with Type 021N becoming dominant. The next series of trials used aerated selectors, with some configurations demonstrating the ability to both prevent and cure filamentous bulking. The unsuccessful trials resulted in the proliferation of Haliscomenobacter hydrossis. From selector trials conducted it was established that the requirements for successful suppression of filamentous growth were the incorporation of an initial selector zone in which greater than 95% of removable soluble substrate was removed and the bulk solution was maintained in a fully aerobic state. Serial selector configurations demonstrated improved performance over a single selector. From observations of the physical conditions and substrate concentrations in the reactor configurations employed, a correlation of filament type to environmental condition can be tentatively made: Types 0411 and 021N were indicated to be low organic loading type filaments, whereas H. hydrossis was indicated to be a low dissolved oxygen filament. Rapid substrate removal rates were attributed to biosorption, accumulation and storage mechanisms, increasing as the selector configuration trials progressed. In general floc formers possessed a higher specific growth rate and substrate affinity than the filamentous microorganisms. Filament Type 021N was indicated to lack biosorptive capacity, however H. hydrossis was indicated as having a greater biosorptive capacity than the floc formers present. The highly degradable nature of the substrate and high substrate concentration gradients imposed by the selector configuration caused rapid oxygen uptake rates; resulting in aerobic, anoxic and anaerobic substrate removal mechanisms all occurring in the initial selector zone. The occurrence of simultaneous nitrification, denitrification and phosphorus accumulation resulted in significant nutrient removals from the aerated selector reactor system, with influent nitrogen and phosphorus levels each reduced by up to 96% in the effluent stream. This study found that an activated sludge process was an appropriate method for the effective treatment of milk processing wastewaters, as effluent suspended solids of less than 10 g.m-3 and soluble COD of less than 30 g.m-3 were consistently obtained, however a modified configuration would be required to prevent the growth of filamentous microorganisms and attendant operability problems. Due to the nature of dairy processing wastewaters, a selector reactor configuration could be employed not only to overcome potential filamentous bulking problems, but also to provide an opportunity for biological nutrient removal without the inclusion of dedicated anoxic / anaerobic reaction steps or the complex flow regimes conventionally employed for nutrient removal activated sludge systems.