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Item An investigation into measuring ammonia loss during the operation of a freestall dairy barn : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University, Palmerston North, New Zealand(Massey University, 2020) Malik, KhadijaThe dairy sector in New Zealand (NZ) has undergone rapid intensification and transformation over the past few decades: the traditional pasture based grazing systems are continuously being replaced by high supplement feed input system like feed pads, herd homes and wintering barns. Practising duration controlled grazing; using temporary housing systems (naturally ventilated barns) can reduce urinary load to paddocks and N loss to water. There is concern that ammonia (NH3) loss to the atmosphere during housing, manure storage and re-application to pasture simply results in pollution swapping i.e. decreasing N loss to water while increasing the greenhouse gas emission footprint of dairying. The main objective of this research was to develop cost effective techniques to monitor, mitigate and minimise the NH3 gas emissions from a duration controlled grazing system in the Manawatu region of NZ. The main components of dairy cattle (DC) grazing systems are feed, housing, storage and slurry reapplication to land. The first study focused on developing techniques to identify the hotspots contributing to gas emissions from all stages of the manure management chain. The efficiency of two commonly used techniques namely active and passive NH3 gas sampling was evaluated and modified. Commonly used 7 L dynamic chambers and large vacuum pumps were replaced by small 50 ml PVC tube acid scrubbers and small aquarium pumps. The acid scrubbers were successfully deployed for NH3 gas emission measurements from storage pond and slurry re-application to land. Simple diffusion sampling tubes (DSTs) were also developed and calibrated for long term measurements from storage ponds. The second set of laboratory experiments aimed at studying the losses associated with the feed component. The effect of diet on urine N content excreted by dairy cows and the influence of urea N content of urine on the magnitude of NH3 emissions was studied by simulating excreta deposition on a barn floor in 1 L Agee jars. In NZ dairy cows are fed on pasture based production system, however when the pasture becomes limiting during summers then cows are fed on high supplement feed inputs like maize and hay silage. It was hypothesised that dietary manipulation would impact N excretion and NH3 emissions from excreta. For this experiment, a total of fifty four dairy cows were used. They were split into three groups (each group containing 18 cows) and fed on high crude protein (HCP, 25%), medium crude proteins (MCP, 18.5%) and low crude proteins (LCP, 13.5%) diets. Urine and dung samples were collected separately from each group of the cows. NH3 emissions from the slurry mixture were measured in vitro in a laboratory set up at room temperature (18 ºC - 24 ºC) for 6 days. The laboratory set up consisted of 11 Agee jars (1 L) with passive acid traps (10 ml 0.5 M H2SO4) contained in 50 ml pink tops. The slurry mixture was reconstituted at a standard rate of excretion by dairy cows at a ratio of 1 : 1.3 (dung: urine) by mixing the freshly collected urine and dung [(w/v); wet basis] in urine containers. The cumulative NH3 losses were reported based on the urea N applied and total Kjeldahl N applied to each Agee jar. The results showed that NH3 emissions reduced by 13 - 20% with decrease in dietary crude protein. It was concluded that manipulating the CP level in diet can reduce urinary N excretion from dairy cows and hence lower NH3 emissions. A subsequent series of laboratory experiments were conducted using 1 L Agee jars to quantify NH3 losses from various hotspots in a naturally ventilated dairy cow barn to study the factors affecting NH3 emissions. The main sources of NH3 losses from the barn are excreta deposited on laneways, scraper lanes and slurry collection pits located underneath the barn. In Study 1, aged slurry samples were taken from different positions in the slurry pathway from channel grate to the storage pond. In Experiment 2 of study 1 (Ex-situ measurements), sources of fresh slurry were created (by mixing urine and dung) to represent the different depths of fresh slurry deposited in the free-stall barn’s laneways and under the grates in the transport channel. The NH3 emission rate from all slurry samples were measured in closed chambers. In study 2 (In situ measurements), a 3D sonic anemometer and NH3 acid traps were used to measure airflow rates and NH3 concentrations in the barns ventilation pathways. The barn’s estimated NH3 emissions calculated from the two contrasting studies were compared. There is limited NZ data on NH3 gas emissions from a slurry storage pond receiving slurry from a wintering barn. NH3 gas emissions were monitored in the winter of 2017 (2nd June to 16th August) by modified integrated horizontal flux (IHF) methodology. The gas emission flux was measured using diffusion sampling tubes (DSTs) placed at sampling heights (0.25 m to 3.5 m) on an aluminium tower. The towers were mounted at 4 banks (N, S, E, W) of the pond and DSTs were changed every 72 or 94 h. The gas emission flux was found to be positively correlated to daily evapotranspiration rate (ETR) (R2=0.80) and this relationship was used to predict gaseous emission from a static pond. The slurry is usually stored up-to 3 months before re-application to land. NH3 gas emission from the final stage of manure management was measured on two occasions; Summer 2015 and Autumn 2016. Slurry was incorporated in land through slurry surface spray and injection and losses were measured using IHF methodology. Slurry was applied at 81 kg N ha-1 for surface spray and 73 kg N ha-1 was injected into the soil through injection. Similarly the application rate for autumn application was 252 kg N ha-1 for surface spray and 233 kg N ha-1 for injection application. The percentage NH3-N losses were 2% from slurry surface spray and 1.4% from slurry incorporation through injection for summer application and 3% from slurry surface spray and only 1% from injected application of slurry in autumn. On completion of NH3 loss measurements at all stages of manure management it was possible to construct a partial NH3 loss budget to illustrate the relative NH3 losses associated with the temporary housing of cows in a freestall barn, manure storage and reapplication to land. This simple analysis illustrated that the largest loss of NH3 can occur if there is a long storage phase of effluent in a open pond. Future research to mitigate NH3 losses created by housing cows should focus on the reduction of NH3 loss from ponds.Item Treatment of refinery crude oil tank sludge : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Environmental Engineering at Massey University(Massey University, 1999) Guan Hing, Jose BThe treatment and disposal of oil refinery tank sludge is a critical issue among oil refineries. This is because of the hazardous nature of the sludge due to high levels of oil and heavy metals, which must be removed prior to disposal. This study was carried out to investigate the removal of crude oil and heavy metals to allow the design of an appropriate disposal treatment that could meet the environmental regulations for this type of waste. A typical emulsified crude oil tank sludge, produced from tank cleaning operations was characterised and was shown to contain approximately 41%, 16%, 25%, and 8% of solids (sand), oil, water and volatile materials, respectively. The sludge also contained high level of metals, of which more than 98% resided in the solids fraction. The heavy metals analysed were copper, nickel and zinc with average values of 3,955mg/kg, 443 mg/kg and 13,851 mg/kg of raw sludge, respectively. The crude oil fraction of the sludge was removed by solvent washing with kerosene which resulted in emulsion breakdown. A model which optimises the removal of crude oil was developed and validated against experimental data. The model predictions agreed well with experimental trials using kerosene as the solvent. A 2:1 solvent to sludge ratio is adequate to remove the oil (> 98%) in the sludge after two washing stages. This resulted in oil-free/metal-rich solids. Kerosene washing reduced the volume by 76% and mass by 59%, which allows easier handling and disposal. Heavy metals reduction was achieved by acid washing using 8N nitric acid and a 10:4 mixture of 2.4N hydrochloric and 8N nitric acids. Approximately 99% of the metals were removed using a 10:1 acid to solids ratio, at pH <1 and ambient conditions, making the sludge suitable for land application and meeting the appropriate disposal guidelines for oil and metal levels. The solvent washing process was shown to be industrially feasible for volume and mass reduction of the sludge. However, heavy metal reduction by acid washing requires further optimisation before it can be applied on an industrial scale.Item Nutrient accumulation in soils under long-term farm dairy effluent application : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Applied Science in Soil Science at Massey University, Palmerston North, New Zealand(Massey University, 2005) Cox, JulietLand-based application of farm dairy effluent (FDE) has been encouraged by regional councils since the introduction of the resource management act (RMA) in 1991. The problems associated with FDE irrigation are high levels of nitrate in ground and surface waters which can lead to human health issues where the groundwater is used as drinking-water and environmental degradation of streams, rivers and lakes. Regional councils impose nitrogen loading limits to reduce the likelihood of environmental problems from nitrate leaching. Long-term data investigating FDE application and the associated soil changes over time is currently unavailable and the nutrient budgeting tool OVERSEER® Nutrient Budgets 2 is validated against only short-term trials. Therefore, assumptions made in the model for long-term FDE application areas may not be correct. The project investigated the soil chemical characteristics of six long-term (>6 years) farm dairy effluent paddocks and matched non-effluent paddocks in the Waikato and Bay of Plenty. Fieldwork involved the removal of five core samples from each paddock, with each core yielding six sub-samples of 75 mm depth. Soil analyses included bulk density calculations, cation exchange capacity, total carbon, nitrogen and phosphorus determination and Olsen P. It was found that two sites had the same total cation exchange capacity in the effluent and non-effluent paddocks, but the proportions of the individual cations were different. A significant (α = 0.05) difference in the exchangeable potassium concentration existed between the pairs of paddocks with much greater potassium found in the areas irrigated with FDE. No discernable difference in the concentrations of carbon and nitrogen was found between the topsoil of the effluent and non-effluent paddocks. This was due to the highly variable nature of the effluent and the soils themselves, and the large pool of nutrients in the soil, requiring a large change before a noticeable difference occurred. The total nitrogen and phosphorus levels found in the soil profiles (0-450 mm) of the effluent and non-effluent paddocks were very similar, and reflects the large additions of fertilisers to non-effluent paddocks. The OVERSEER® Nutrient Budgets model was used to produce nutrient budgets for farms from the Waikato and Bay of Plenty and predictions of accumulation of nutrients over time. Comparisons made between the OVERSEER® results and soil chemical analyses revealed that with the exception of potassium, it was not possible to accurately predict the nutrient concentration in the soil by extrapolation of OVERSEER® data. This was due to changes in management practices over time and the inherent variability of soils. If the model is to be used as a regulatory tool, accurate fertiliser records must be kept, along with frequent pasture and soil analysis. It is also advisable that a soil map of the farm area is completed in order to most accurately use the model.Item Decolourization of wood-ethanol stillage using a granular activated carbon packed anaerobic expanded-bed reactor : a thesis presented in partial fulfilment of requirements for the degree of Master of Technology in Biotechnology at Massey University /(Massey University, 1984) Tan, Soon HoeThe anaerobic treatment (including decolourization) of wood-ethanol stillage from the Forest Research Institute (FRI) wood-hydrolysis pilot plant at Rotorua has been investigated using granular activated carbon (GAC) packed expanded-bed reactors. Specifically, bioregeneration of the GAC in the reactors in terms of organic and colour removal has been considered. Two 7.2 1 anaerobic expanded bed (AEB) reactors were designed and built. Reactor One (R1) was used for the anaerobic digestion of raw wood-ethanol stillage and Reactor Two (R2) for the decolourization of anaerobic lagoon pretreated wood-ethanol stillage. For R1, a desulphated stillage feed (to 500 mg.1-1sulphate) was used. Depending on the organic loading rate (OLR), the additions of nitrogen (N), phosphorus (P) and alkalinity reagent ranged from 240-350 mg.l-1, 80-250 mg.l-1 and 2.5- 4.5 ml 20% w/v NaOH per litre feed respectively. Only N and P feed supplements were used for R2 at 240 and 80 mg.l-1 respectively. The reactors' performance and stability were closely monitored through analyses of volatile fatty acid's, pH, alkalinity, colour, chemical oxygen demand (COD), sulfide, biogas production rate and methane composition, solids concentrations, N and P. After operating R1 for 227 days, it was demonstrated that this system, is superior to the previous systems reported for the treatment of a similar stillage. A non-maximal OLR of 29.0 kg tCOD.m-3.d-1 at 0.85 d hydraulic retention time (HRT) with total and soluble COD (tCOD and sCOD) removals of 74.5 and 83.5% respectively were achieved. Digestion stability was excellent with acetate at 160 mg.l-1, propionate at 490 mg.l-1 and a gas methane composition of 61.0%. The colour loading rate was 4.7 kg chloroplatinate.m-3.d-1 with a 75% colour removal. Higher colour and COD removals may be obtained by operating at a longer HRT (e.g. the percentage colour and sCOD removals were 90.6 and 91.8% respectively at a 2 d HRT). Previously, no significant colour removal for the anaerobic digestion of wood-ethanol stillage has been reported. In this study, only approximately 9% w/v of the chromophoric materials present in the wood-ethanol stillage are particularly recalcitrant to anaerobic degradation. The methane gas yield was near to that predicted by theory (99.7% at 2 d HRT) with a very low sludge yield (2.8% based on 91.8% sCOD removal). Consequently, the AEB reactor had a very low nutrient requirement for effective treatment. In terms of reactor stability, it can accomodate very high hydraulic loading rates (less than 0.85 d) without problems of cell washout. The use of activated carbon medium also provides a toxicity sequesting potential against biological inhibitors present in the wood-ethanol stillage. Continuous bioregeneration of the GAC in R1 has also been demonstrated using sCOD and colour breakthrough curves for GAC adsorption with and without biological activity. Microbial degradation of the chromophoric species has been confirmed using UV-visible spectrophotometric scans. Little methanogenic activity was observed in R2 in its 191 days of operation due to the recalcitrant nature of the anaerobic lagoon pretreated stillage. Only approximately 20% bioregeneration of GAC in terms of colour removal was achieved at a colour loading rate of 1.2 kg chloroplatinate.m-3.d-1. This study has demonstrated that the GAC packed expanded-bed reactor (R1) provides a very effective treatment of wood-ethanol stillage (including decolourization) while recovering a very significant portion (89%) of the stillage energy. Considerable capital and operating cost savings are possible using the AEB system since effective treatment can be achieved in a single step utilizing a relatively small reactor with minimal nutrient, sludge disposal and GAC regeneration or replacement costs. The only disadvantages of the system are the carbon cost, a long start-up period of 5 months and a recycle energy cost to maintain an expanded-bed. It is believed that they can partly be reduced by using a GAC carrier with a smaller particle size. Anaerobic digestion, utilizing a GAC packed expanded-bed reactor, thus represents a cost effective and commercially attractive option for the utilization/disposal of wood-ethanol stillage.Item Composting of high moisture dairy manure using sawdust or mixed paper as amendments and wood chips as the bulking agent : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Environmental Engineering at Massey University(Massey University, 2002) Mollah, Md. ShahjahanThe agricultural industry in New Zealand is a major source of waste generation and about 84% of the country's point source pollution comes from dairy sector alone. Dairy farm effluent in New Zealand is most commonly treated via waste stabilization ponds. Two-pond systems which are frequently used, are not sufficient to make the dairy shed effluent suitable for discharging to surface water, thus there is a need for investigation and development of treatment/disposal technologies, especially where land treatment is not a practical option. Composting is a process whereby the heat that is liberated from the decomposition of organics drives the evaporation of water. By reducing the large amount of water in the slurry, its mass, bulk weight & volume through composting, there is a large potential to reduce associated transportation and handling costs of disposal as well as minimising the area of land required for manure application. Composting can further reduce the risk of pollution from runoff, odour, and nitrate contamination of ground water. A passively aerated composting system was used to treat high moisture (90%) dairy manure slurry. Both sawdust and mixed paper were investigated as amendments with wood chips as the bulking agent. Two identical piles (1,2m× 1.2m× 1,2m) for the sawdust investigation and another two for the mixed paper experiment were established. Passive aeration was achieved with three horizontal aeration pipes in the base of each pile. The piles were monitored for about 70 days for all the experiments. During the active phase of composting, piles reached above 60°C and thermophilic temperatures were sustained for more than three weeks. The importance of pile cooling because of excessive wind flow was demonstrated suggesting the advisability of a wind barrier to protect piles Moisture content in the piles decreased over the period of study. Initial moisture content varied from 67% to 71% but diminished to between 47% and 58% by the conclusions of the experiments. Results of these studies suggest that composting can remove water by virtue of the biologically produced heat. The results of this study also suggest that the amount of heat energy generated from composting depends on the amount of volatile solids degraded. Energy rich feed materials were shown to be converted to energy poor materials due to reduced volatile solids degradation and energy poor feed materials emerged as energy rich due to the greater amount of volatile solids degradation. In this study from 47.2% to 76% of produced heat was lost as latent heat through convective (evaporative drying). From the comparison of results using two different amendments, mixed paper was found better than sawdust as an amendment in terms of biodegradability, heat development, heat accumulation, evaporative drying, moisture removal, volume reduction and weight reduction. The results of this study also indicated that the required extent of total coliforms destruction was not achieved within the period of composting using the materials and method undertaken. A longer maturation or curing phase may be helpful in achieving the recommended level of total coliform inactivation.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 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, SubramaniTannery 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.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 The production of lactic acid from whey by continuous culture as a possible means of waste disposal : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Biotechnology at Massey University(Massey University, 1972) Marshall, Kevin RaymondA study was made of the fermentation of lactose in lactic casein whey to lactic acid using a strain of Lactobacillus bulgaricus. Both batch and continuous culture were used. A culture vessel capable of being operated under controlled conditions was designed and built for this study. Temperature, pH, gas atmosphere, degree of agitation and medium flow rate could be altered and controlled. A meter was developed for the continuous measurement of lactic acid production. The meter used a capacitance probe to measure the volume of alkali added to the culture to maintain a constant pH. The kinetics of lactic acid production in a batch culture of whey were characterized by : dP/dt = (αdN/dt + βN) Pm - P/Kp + Pm - P The kinetics of bacterial cell growth were consistent with the normally accepted Monod equation but no direct verification of this was made. A notable feature of the production of lactic acid in a batch culture was the considerable amount of lactic acid formed by non-dividing bacterial cells. More than 50 percent of the acid produced during a batch culture was synthesised while the cell population was in a stationary growth phase. The maximum cell number was not limited by the concentration of lactose. Supplementation with tryptophan, casamino acids and a number of vitamins increased the cell population and the rate of acid production and decreased the batch time. Sodium caseinate was a good source of essential and stimulatory nutrients. The optimum heat treatment of the whey involved heating to 69°C. In unsupplemented whey the removal of suspended material by centrifuging and filtration prevented the formation of acid. To maintain maximum acid formation rates the impeller Reynolds number had to be greater than 10,000. The presence of oxygen prevented the growth of the bacterial cell population, but once the maximum cell population had been reached oxygen did not effect the acid synthesis. In a single stage continuous culture reactor the concentration of lactic acid was given by : P = N (α + β/D) Pm - P/Kp + Pm - P The constants were determined from batch culture data. A single stage continuous culture is not suitable for the conversion of all the lactose in the whey to lactic acid. If lactic acid production by continuous culture is to be considered as a means of waste disposal it will be necessary to use feed back of cells to a single - stage reactor or multi-stage stirred tanks. In continuous culture studies it was shown that the optimum temperature for the fermentation of lactic casein whey was 46°C. A pH in the rage 5.4 - 6.0 was best. Outside this range, productivity and yield were decreased. It can be concluded that though continuous production of lactic acid from whey is feasible, multi-stage continuous reaction systems and/or cell feedback are necessary to reduce the lactose concentration to an acceptable level. The whey should be supplemented with a source of amino acids.Item 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 LalunioThe 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.