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Item Transformation and loss of excretal nitrogen under winter management systems : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Soil Science at Massey University, Palmerston North, New Zealand(Massey University, 2007) Qui, WeiwenExcreta from cattle animals contain large amounts of nutrients, particularly nitrogen, which could lead to substantial gaseous losses of ammonia and nitrous oxide to the atmosphere, as well as nitrogen leaching. These losses are greatest during wet conditions in winter. However, the situation could be improved through moving cows off grazing paddocks to a stand-off pad or housing system. Therefore, it is necessary to quantify ammonia emissions and evaluate denitrification potential (which leads to emission of N₂O) through various winter management systems in order to determine methods and technologies for efficient and effective mitigation of gaseous emissions. To understand the mechanism of nitrogen transformation and of reduction on gaseous emission from excreta in various winter management systems, a series of incubation studies and a field study were carried out investigating the suitability of several natural materials with absorbent properties, as media to reduce gaseous emission of ammonia and nitrous oxide. The incubation studies were undertaken using cow excreta that consisted of a 1:1 (v:w) mixture of fresh urine and dung collected from a dairy farm. A lab incubation study was conducted using excreta, and excreta amended with soil and sawdust treatments. A further lab incubation study was carried out using different levels of natural materials. The field study consisted of two stand-off pads in which crushed pine bark or sawdust were used as bedding materials. In the incubation study, ammonification was rapid in the case of excreta, compared to excreta amended with addition of natural materials. Whereas nitrification was very slow in the all treatments, only a small amount of nitrate ions could be detected till the end of incubation study. In the incubation study, both soil and sawdust appeared to significantly reduce ammonia emission. In comparison to excreta, amendment with soil (excreta: soil=1:2, w:w) and sawdust (excreta: sawdust=1:2, w:v) reduced ammonia loss by 32.9% and 19.5%, respectively. Excreta amended with a combination of soil and sawdust (1:1:1, w:w:v) was most effective, reducing ammonia emission by 34% under aerobic conditions. Nitrate concentration was found to be the crucial limiting factor affecting the denitrification rate in the incubation studies. When KNO₃ was added to the excreta, the denitrification rate was 43.8µg N₂O-N/g excreta/hour. However, the denitrification rate of the excreta amended with both glucose-C and KNO₃ was 114.4µg N₂O-N/g excreta/hour. Denitrification potential followed: excreta> excreta with sawdust> excreta with soil. On a field-scale stand-off pad, the carbon-rich natural materials pine bark and sawdust were shown to retain nitrogen effectively. After nine months of use, the bark retained 78% of the deposited excreta-N, while the sawdust pad retained 51%. Therefore, it can be concluded that reduction of nitrogen losses can be achieved by using stand-off pad or housing systems (herd homes) which incorporate the use of a carbon rich natural material or soil in winter.Item Response of short rotation forestry to dairy farm-pond effluent irrigation : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Agricultural Engineering at Massey University(Massey University, 1999) Peña Obando-Tungcul, Rebecca delaA growing concern to protect the environment has prompted Regional Councils in New Zealand to monitor compliance under the Resource Management Act (1991) covering the discharge of wastewater into waterways. To meet the desired standards, application of wastewater onto high dry matter producing short vegetation forests offers opportunity for the beneficial use of nutrients while renovating the wastewater. A field trial was established near Palmerston North to determine the response of nine Salix clones and one Eucalyptus short rotation forest (SRF) species to dairy farm effluent irrigation and to determine their water and nutrient uptake potential. A micro sprinkler irrigation system was designed to operate at 100 kPa and supply each plot of 16 trees with either 7.5 mm. 15 mm, or 30 mm of dairy farm effluent every two weeks. Twenty-four applications were made covering two growing seasons with a break over winter. A control treatment of 7.5 mm of water + 187.5 kg N haˉ¹ yearˉ¹ was included, being equivalent to the nitrogen addition from the lowest effluent application rate. The three SRF species, Salix matsudana x alba (NZ 1295). Salix kinuyanagi (PN 386) and Eucalyptus nitens were selected for more detailed analysis than the other seven Salix clones. This included the measurement of evapotranspiration rates and a pot trial to determine the tolerance level of seedlings to higher levels of effluent application. Application of up to 90 mm of effluent per fortnight increased the biomass production and nutrient accumulation of potted PN 386 and E. nitens. whereas the NZ 1295 produced optimum biomass and accumulation of nutrients at 60 mm of effluent application per fortnight. At the end of the first growing season, the above ground biomass of the ten tree species in the field trial was assessed using a non-destructive method followed by a destructive harvest at the end of the second growing season. Dry matter production in these short rotation forest crops varied with species and clones and with the amount of dairy farm-pond effluent applied. Salix NZ 1296. PN 386 and NZ 1295 irrigated with the highest application rate of 30 mm of effluent per fortnight produced the highest biomass yields of 37.91, 37.87 and 37.58 ODt haˉ¹ yearˉ¹ respectively. NZ 1296 irrigated with 30 mm of effluent per fortnight accumulated 196 kg N haˉ¹ yearˉ¹, 37.6 kg P haˉ¹ yearˉ¹, and 103.6 kg Mg haˉ¹ yearˉ¹ in its above ground biomass. E. nitens irrigated with 15 mm of effluent per fortnight produced a comparable above ground oven dry biomass yield of 36.33 ODt haˉ¹ yearˉ¹ and accumulated the highest amount of potassium and calcium in its above ground biomass giving 145.4 and 148.1 kg haˉ1 yearˉ¹, respectively. Transpiration monitoring during the second growing season using a heat pulse technique showed that under the highest application rate (30 mm per fortnight) on a cloud-free day. 15 month old NZ 1295 trees each transpired the highest cumulative amount of 6.38 mm day ˉ¹ compared to 2.71 mm dayˉ¹ for trees irrigated at the lowest rate (7.5 mm per fortnight). Results of this study overall suggest that increasing the rate of effluent irrigation will increase the soil pH. nitrates and exchangeable potassium, calcium and magnesium concentrations throughout the soil profile. Total nitrogen and total phosphorus levels decreased throughout the soil profile after the second growing season. The cation exchange capacity of the soil decreased with increased rate of effluent after the second growing season. The soil-SRF treatment system renovated the nutrients in the effluent. The soil-E. nitens treatment system renovated the highest percentage of total nitrogen (17.21t haˉ¹ mˉ¹ depth) equivalent to 96.45% of total nitrogen supplied by both the soil and the 30 mm of effluent applied per fortnight. The soil-PN 386 treatment system renovated the highest percentage of total phosphorus (6.4 t haˉ¹ mˉ¹ depth) equivalent to 92.72% of the total phosphorus available in the soil and supplied by the 7.5 mm of effluent treatment. The soil-NZ 1295 treatment system renovated the highest percentage of potassium (99.5%). calcium (98.74%) and magnesium (95.63%) supplied by both the soil and the 30 mm of effluent treatment. The capacity of the three SRF species to renovate total nitrogen, phosphorus and potassium from the effluent decreased with increasing rates of application. PN 386 irrigated at 7.5 mm of effluent renovated the highest percentage of 99.45% of total nitrogen (114.25 kg haˉ¹ over two growing seasons) and 79.18% of total phosphorus (35.60 kg haˉ¹ over two growing seasons). The amounts of calcium and magnesium renovated by the SRF species were more than the amount supplied by even the highest rate of effluent (30 mm per fortnight). Salix PN 386. NZ 1295 and E. nitens are recommended SRF species to grow in a land treatment scheme for dairy farm pond-effluent when applied at a rate of 30 mm per fortnight over the growing period on to a silt loam soil. Pot trials showed higher volumes of effluent renovation on to PN 386 and E. nitens may be applicable when applied up to 90 mm of effluent per fortnight but further evaluation is needed before this can be recommended.Item Effects of increasing cow urine deposition area on soil mineral nitrogen movement and pasture growth on a recent soil in the Manawatu region, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Environmental Management at Massey University, Manawatū, Palmerston North, New Zealand(Massey University, 2017) Romero Ramírez, Stefanía YaninaThe cow urine patch is a major source of nitrate (NO₃⁻) leaching from grazed dairy pasture farms. Increasing the urine deposition area is a direct way of reducing the potential risk of this cause N leaching losses. Research is required to quantity the effectiveness of this mitigation across a range of different soil and climatic conditions. The objective of this study was to determine the effect of increasing the cow urine deposition area on NO₃⁻ leaching risk and short-term pasture accumulation on Recent soil in the Manawatu Region, New Zealand. A field trial was conducted, which consisted of three treatments evaluated on pasture plots: Urine (1 m2), Urine (0.2 m2) and No-urine. The two urine treatments received the same volume of 2.1 L urine/patch. Urine treatments were applied on the 6th of March 2017, and soil inorganic N was measured on three occasions; 15, 36 and 53 days after urine application (DAUA). At the third soil sampling time, which was 24 days after the drainage season was estimated to have commenced, the net inorganic N (inorganic N in the urine treatment minus the value for the No-urine treatment) in the 45-120 cm soil depth was 1.08 g net inorganic N/patch for the Urine (1 m2) treatment compared to 2.97 g net inorganic N/patch for the Urine (0.2 m2) treatment. Therefore, the Urine (1 m2) treatment resulted in a 63.6% reduction in the quantity of net inorganic N that was highly susceptible to leaching, compared to the more typical urine patch area of 0.2 m2. At a paddock scale, when net inorganic N from the urine treatments is multiplied by an estimate of the quantity of urine patches per hectare in a single grazing, this equates to a reduction of 2.53 kg N/ha from a single autumn grazing. It is expected that increasing urine deposition area at multiple grazings would result in greater reductions in the annual NO₃⁻ leaching risk. Over the two pasture harvests conducted in the trial, the pasture DM accumulation for the No-urine treatment produced an average of 3220 kg DM/ha. The two urine patch treatments achieved a similar level of pasture DM accumulation to that of the No-urine treatment. The lack of a pasture growth response from the added urine could have been influenced by the high clover content (35.9%) of the pasture, and in addition, there may have been adequate background soil mineral N levels, which together could have contributed to N not being growth limiting during the trial. This research has demonstrated that increasing cow urine deposition area in autumn has potential to be an effective mitigation for decreasing N leaching losses from grazed dairy pastures. Further research is required to investigate the effects of increasing cow urine deposition area at multiple grazings, in order to determine the effect of this mitigation option on annual NO₃⁻ leaching and pasture production.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 Dairy wintering systems in southern New Zealand : quantification and modelling of nutrient transfers and losses from contrasting wintering systems : a thesis submitted 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, 2017) Chrystal, JaneTraditional dairy wintering practice in the lower South Island of New Zealand has been to graze brassica crops in situ. This practice has been under increasing scrutiny from local Regional Councils due to the relatively high nitrogen (N) leaching losses from this component of the whole farm system. Alternative wintering options to reduce N leaching losses that are currently available to farmers (such as barns and permanent wintering pads) are high cost and involve a large capital investment. In this work a new wintering system (termed a 'portable pad’) was developed for use on support blocks (which can be located many kilometres from the milking platform) as an interim measure for reducing N leaching losses that is low cost and low input. This system is designed as a mitigation strategy that is available for use immediately while research investigates more permanent solutions. This system is a hybrid of the traditional crop grazing system and an off-paddock system, where effluent is captured. It makes use of the advantages of each of the original systems utilising the low cost feed source of the brassica crops, grazed in situ, while also utilising the benefits of duration controlled grazing with its associated effluent capture and irrigation at low rates. The aim of the research was to generate whole system N leaching loss values for each of the three farm systems investigated (crop wintering, deep-litter wintering barn, and portable pad). Field and laboratory research was conducted to fill identified knowledge gaps such that system N loss values could be estimated. OVERSEER Nutrient Budget software tool was used in conjunction with measured and modelled (APSIM) data to simulate whole farm N leaching loss values for the three farm systems investigated. Nitrogen leaching losses from the portable pad and barn systems were between 5 and 26 % and between 13 and 26 % lower, respectively, than the crop wintering system.Item Dairy waste treatment by high-rate trickling filtration, with particular reference to nitrogen : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Biotechnology(Massey University, 1970) Bennett, Rodney JackThe effective disposal of dairy factory waste is becoming increasingly important in New Zealand. Treatment by high-rate trickling filtration is a successful method in use overseas. For New Zealand conditions, a 'roughing' treatment removing 60 - 90% of the BOD of the waste should be adequate. One objective of this research was the development of a filter capable of providing this treatment. Another objective was the resolution of the controversies between the theoretical and empirical performance-prediction relationships available for trickling filtration. Because nitrogen is receiving a greater emphasis as a pollutant, a third objective was the study of nitrogen removal in dairy waste trickling filtration. The experimental work primarily involved the use of a pilot-scale trickling filter. This was designed using conventional parameters. The filter column was an 18" diameter, 8' long concrete pipe, filled with river stone. An artificial waste compounded from whey and water was fed to the plant at a controlled rate, being diluted with flow from a 25 gallon recirculation tank prior to application to the column. The treated waste overflowed from the recirculation tank and was discharged. The plant was operated at the high organic loading intensities of 1.3 - 2.7 lb BOD/yd 3 day, and at the high recirculation ratios of 20 - 55 : 1. The levels of BOD and organic, ammoniacal, nitrite and nitrate nitrogen were measured in the feed and settled effluent at different recirculation ratios. Aqueous suspensions of biomass collected from the plant were incubated under aerobic and anaerobic conditions, in the presence of a variety of carbonaceous and nitrogenous additives. The nitrogen balance of these suspensions was studied. The plant fulfilled its design function of providing a 'roughing' treatment, as it removed 60 - 85% of the feed BOD. The experimental data did not support the available performance- prediction relationships, and hence the controversies between these relationships were not resolved. The pilot plant performance could be described by the equation Y = 17.778 + 3.079X - 0.0342 X2 where Y = % removal of applied BOD X = recirculation ratio This equation, specific to the pilot plant, predicts an optimum recirculation ratio of 45 : 1, which is considerably higher than the 10 : 1 ratio commonly used. Successful operation of the plant was achieved at BOD : nitrogen ratios in the feed of 21 - 27 : 1, which are higher than the 20 : 1 maximum generally recommended. Despite this high ratio, typically 30% of the feed organic nitrogen was present in the effluent. There was no evidence of nitrification. The nitrogen balance experiments provided evidence of net nitrogen loss from the suspensions, under aerobic conditions. Denitrification under anaerobic conditions followed normal routes.Item Understanding methanotroph ecology in a biofilter for efficiently mitigating methane emissions : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science (Biotechnology) at Massey University, Palmerston North, New Zealand(Massey University, 2016) Syed, Rashad AhmedIn New Zealand, the majority of the greenhouse gas (GHG), methane (CH4) emissions are from the agriculture sector (enteric fermentation, manure management) and the remainder from solid waste disposal, coal mining and natural gas leaks. A soil-based biofilter made from volcanic pumice soil (isolated from a landfill in Taupo, New Zealand) and perlite has been tested and promoted to mitigate high concentrations (3 300 ppm – 100 000 ppm) of CH4 emissions from a dairy effluent storage pond. This soil-perlite mixture exhibited excellent physical (porosity, water holding capacity and bulk density) characteristics to support the growth and activity of an active methanotroph community. Methanotrophs comprise a diverse group of aerobic alpha and gamma proteobacteria (type I and type II methanotrophs, respectively) that are present naturally in soils where CH4 is produced. However, there is little information on the methanotrophs community structure, population diversity and abundance in this soil-based biofilter. Understanding the activity of these diverse genera under varying soil conditions is essential for optimum use of biofiltration technology, and is the main aim of this thesis. This thesis describes a study to use molecular techniques (PCR, quantitative PCR, T-RFLP and molecular cloning) (Chapter 3) to reveal the population dynamics of methanotrophs (type I, type II and various genera – Methylobacter/Methylomonas/Methylosarcina, Methylococcus and Methylocapsa), in order to build a more efficient CH4 biofiltration system. Methanotroph population dynamics in two fundamentally different prototypes of volcanic pumice soil biofilters – a column and a floating/cover biofilter studied are presented in Chapters 4 and 5. The column biofilter study (Chapter 4) examined the performance of a previously used acidic soil-biofilter medium that was further acidified from pH 5.20 ± 0.20 to 3.72 ± 0.02 by H2S present in the biogas (from the dairy effluent pond).. The more acidic soil biofilter medium (volcanic pumice soil and perlite, 50:50 v/v) was reconstituted with optimal moisture content (110% gravimetric dry wt or ~ 60 % WHC) and achieved a maximum CH4 removal rate of 30.3 g m–3 h–1. In addition, the population of Methylocapsa-like methanotroph increased by 400 %, demonstrating the ability of these soil microorganisms to adapt and grow under acidic pH conditions in the biofilter. The results from this study indicated that (i) when primed with CH4, a soil biofilter can effectively regain efficiency if sufficient moisture levels are maintained, regardless of the soil acidity; (ii) changes in the methanotroph population did not compromise the overall capacity of the volcanic pumice soil to oxidise CH4; and (iii) the more acidic environment (pH 3.72) tends to favour the growth and activity of acid-loving Methylocapsa-like methanotroph while being detrimental to the growth of the Methylobacter / Methylococcus / Methylocystis group of methanotroph. In the floating biofilter (Chapter 5), original acidic soil biofilter medium (pH 5.20) as used in column study was assessed to remove CH4 from the effluent pond surface for a period of one year (December 2013 to November 2014). Field evaluation was supported with a concurrent laboratory study to assess their CH4-oxidising capacity, in addition to identifying and comparing the methanotroph community changes in the soil when exposed to field conditions. Results indicated that (i) irrespective of the season, the floating biofilters in the field were removing 67 ± 6% CH4 throughout the study period with a yearly average rate of 48 ± 23 g CH4 m-3 h-1; however, the highest CH4 removal rate achieved was 101.5 g m-3 h-1 CH4, about 300 % higher than the highest CH4 removal rate by the acidified column biofilter (Chapter 4); (ii) the acidity of the field floating biofilters increased from a pH value of 5.20 to 4.72, but didn’t suppress the genera of methanotrophs (particularly Methylobacter/Methylosinus/Methylocystis); (iii) the laboratory-based floating biofilters experienced biological disturbances with low and high CH4 removal phases during the study period, with an yearly average CH4 oxidation removal of 58%; and (iv) both type I and type II methanotrophs in the field floating biofilters were more abundant, diverse and even compared with the methanotroph community in the laboratory biofilters. This study has demonstrated the ability of the floating biofilters to efficiently mitigate dairy effluent ponds emissions in the field, without requiring any addition of nutrients or water; however, during very dry conditions, occasional addition of water might be needed to keep the biofilter bed moist (≥ 23±4 % dry wt). Earlier New Zealand studies and the current studies (Chapters 4 and 5) were based on the use of a particular volcanic pumice soil as biofilter medium. However, the limited availability of volcanic pumice soil and associated transportation costs limited the wider application of this technology within New Zealand and internationally. This necessitated the assessment of other farm soils and potentially suitable, economical, and locally available biofilter materials that could potentially be used by the farmers to mitigate CH4 emissions (Chapter 6). The potential biofilter materials, viz. farm soil (isolated from a dairy farm effluent pond bank area), pine biochar, garden waste compost, and weathered pine bark mulch were assessed with and without inoculation with a small amount of volcanic pumice soil. All materials supported the growth and activity of methanotrophs. However, the CH4 removal was high (> 80%) and consistent in the inoculated - farm soil and biochar, and was supported by the observed changes in the methanotroph community. The CH4 removal was further enhanced (up to 99%) by the addition of nutrient solution. Field evaluations of these potential materials are now needed to confirm the viability of these materials for recommending them for use on farms. Chapter 7 summarises the molecular results from all the above studies, and describes the future studies. Molecular techniques indicated that a very diverse (Shannon’s diversity, Hʹ = 3.9 to 4.4) group of type I and type II methanotrophs were present in the volcanic pumice soil, which assisted the biofilter materials to perform under varying abiotic conditions. Many novel species and strains of type I and type II methanotrophs were also identified in these soils. For long-term, low cost and efficient and stable CH4 removal, the presence of an even and abundant population (of type I and type II methanotrophs) is however essential. Nevertheless, biofilters offer much promise for mitigating CH4 emissions from dairy ponds, piggeries, and landfills, thereby contributing to the lowering of emissions of this potent greenhouse gas to mitigate the effects of climate change.Item The aerobic treatment of reverse osmosis permeate for reuse : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Technology in Environmental Engineering(Massey University, 1995) Bickers, Paul OliverThe reduction of effluent streams and the demand for freshwater intake in the dairy industry, may be accomplished by the segregation and reuse of streams that can be readily treated. This study assessed the biodegradability and suitability for reuse of reverse osmosis (R/O) permeate from Kiwi Dairies Ltd processing factory (Hawera), using aerobic treatment. Analysis of the permeate showed that there was a direct relationship between chemical oxygen and lactose concentration. The chemical oxygen demand of R/O permeate from two reverse osmosis membrane plants operating in parallel varied widely during the period of study. This wide variation in permeate chemical oxygen was directly related to the membrane efficiency. Elemental analysis of the R/O permeate showed that iron and phosphorous would need to be supplemented to ensure balanced microbial growth. The biodegradability was characterised by a series of batch tests to determine the biokinetic constants µm, Ks, qsm and Yt. These tests showed that the biodegradability of reverse osmosis permeate is comparable to general dairy wastes. Batch tests were also performed on permeate from R/O membranes of varying performance efficiency, with different lactose and mineral concentrations. There were no conclusive variations in biokinetic constants between permeates from R/O membranes of varying performance efficiency. Operation of a model activated sludge pilot plant showed that soluble COD removal efficiencies of over 90% could be achieved at hydraulic retention times of 10 and 20 hours. The sludge settling characteristics were more favourable at a 10 hour hydraulic retention time. Sudden fluctuations in membrane efficiency caused shock loads resulting in a deterioration in treatment efficiency and sludge settling characteristics. Although the pilot plant achieved satisfactory reductions, soluble COD levels were not decreased to the level of 10 to 15 mg l -1 required to enable the reuse of the permeate. In order to determine if low substrate levels could be achieved when aerobically treating R/O permeate from an efficient membrane plant, a laboratory scale reactor was used to treat permeate with a COD of 200 mg l-1. It was established that R/O permeate could be aerobically treated to levels suitable for reuse, provided the previous membrane processes performed efficiently.Item Application of dissolved air flotation (DAF) to the treatment of dairy wastewaters : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology at Massey University(Massey University, 1993) Susarla, ParthasarathyAn investigative work was carried out to examine the process performance of dissolved air flotation to remove suspended solids and fat from dairy wastewaters. Suspended solids and fat inhibit advanced treatment systems and cause lot of problems like clogging etc. Traditionally dairy industry uses sedimentation and fat traps to remove solids and fat. Dissolved air flotation is a novel treatment method to purify dairy wastewaters. A laboratory bench scale flotation unit was used to carry out the flotation experiments. The wastewater was collected from a dairy factory manufacturing milk powder and butter. Two types of wastewater was collected, one type (Type-I) of wastewater was used when the plant was manufacturing only milk powder. Type-II wastewater contained discharge from butter plant, thus exhibiting a overall characteristics of the discharges from the plant. The effects of change in pH, temperature and the usage of coagulant alum were examined to assess the process performance of flotation. Experiments with changing the pH showed that pH plays an important role in the treatment of dairy wastewaters. When the pH was lowered to 4 from original pH of wastewater of 11.3, the solids and fat in the wastewater precipitated. High removal efficiencies were obtained at pH 4. Flotation tests were carried out at pH 4, 5, 7, 8 and original pH of wastewater. Considerable removal efficiencies were obtained at pH 7 and 8. This pH range is considered to be effective for further treatment like biological treatment. Temperature studies were carried out at pH 7 and 8. Removal efficiencies were average and were comparable to the removals with pH studies, at temperatures 25° C and 34° C. At a higher temperature of 48° C removal efficiency decreased considerably. Maximum removal efficiencies were obtained for solids and fat at a temperature of 34° C. Coagulant alum was used to increase the removal efficiency of solids and fat. Jar tests indicated that high dosage of alum was necessary to obtain optimum removal efficiencies. Alum was used in the concentrations of 150 mg/l to 400 mg/l. Removal efficiencies upto 92% were obtained for fat and solids. From the experiments it can be concluded that dissolved air flotation is a suitable method for the removal of fat and solids from the dairy wastewater. Scale up experiments can be undertaken before application for large scale treatment system.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.