Until recently, the management of milking parlour effluent has received very little attention. The wastewater produced by milking operations comprises mainly milk solids and manure and can impose environmental threats to nearby water bodies if not properly treated before disposal. In this study, three bench-scale Sequencing Batch Biological Reactors were used to treat the UBC dairy barn milking centre wastewater. The experiment was designed to investigate the treatment efficiency of the reactors under different operating temperatures and different numbers of cycles employed per unit daily flow (for the same hydraulic retention time). Parameters studied included BOD₅, COD, Total Suspended Solids, NH₃-N, N0₂-NO₃-N and dissolved oxygen uptake. It was concluded that very high and consistent treatment efficiency can be achieved by using a Sequencing Batch Biological Reactor to treat milking centre wastes. Over 90% BOD₅ removal was observed in the room temperature and 30°C reactors. Even in low operating temperatures of 3.7 and 10.5°C, over 70% BOD₅ removal was attained. Removal of the other pollutional parameters studied was similarly excellent. Uncontrolled denitrification also occured to various degrees in all three reactors. It was also concluded that within the range studied in this experiment (4 to 8 cycles per day), changing the number of cycles employed per unit daily flow did not have any significant effect on the treatment efficiency of the reactors. / Applied Science, Faculty of / Chemical and Biological Engineering, Department of / Graduate

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 179-186). / xix, 215 leaves, bound ill. 29 cm

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: Due to the growing demands for fresh and clean water, the investigation into the treatment, reuse and recycling of wastewater from all industries are becoming more of a priority, both globally and in South Africa where as much as 62 % of the total water used per year is used by the agricultural sector. The investigation into the recycling and reuse of wastewater in the agricultural sector (especially the dairy farming industry) is therefore no exception. The water usage in five typical South African milking parlours was estimated in this study and ranged from 15 to 51 L.cow-1.day-1. However, the water used for the cleaning in place (CIP) washing of the milking equipment were rather similar in all five milking parlours and ranged between 4.9 and 6.4 L.cow-1.day-1. The possibility of handling and treating the CIP wastewater separately from the rest of the milking parlour wastewater has been considered in the past by other researchers. Anaerobic digestion, as a means of treating wastewater from the dairy industry, has been employed successfully in both full scale and laboratory scale projects. The wastewater from equipment washing of milking parlours is assumed to have similar characteristic to that generated from dairy factories. The anaerobic sequencing batch reactor (ASBR) system is gaining popularity as a wastewater treatment technology lately due to its simplicity, ease of operation and compact design and is therefore expected to be a suitable and practical solution for dairy farmers in treating milking parlour wastewater from equipment washing. Investigation into anaerobic treatment at lower temperatures than the conventional mesophilic range is also becoming of interest due to lower energy requirements. The aim of this study was to determine whether the ASBR technology could be considered as a suitable technology for treating wastewater from the CIP washing of milking parlour equipment. To support this study, the water usage and CIP effluent generated at typical South African milking parlours were firstly verified. Subsequently, laboratory work entailed: • Assessing the sensitivity of the ASBR process (at mesophilic temperature of 35 °C) to fluctuations in the concentration of the detergents in synthetic CIP milking parlour wastewater; and • Evaluating the performance of the ASBR process at 22.5 and 35 °C when treating real wastewater from the CIP washing of milking equipment. Chemical oxygen demand (COD) removal efficiencies between 89 and 98 % were achieved when the synthetic wastewater (similar to wastewater from the CIP washing of milking equipment with COD concentrations ranging between 12 600 and 13 400 mg.L-1) was treated in an ASBR. The results showed that an increase in the CIP detergent concentration up to four times the concentration normally used in milking parlours did not significantly affect the ASBR performance in terms of methane productivity, methane yield and COD removal efficiencies when OLRs between 0.6 and 5.2 g COD.L-1.day-1 were applied. The results also showed that COD removal efficiencies between 92 and 98 % could be achieved in the ASBR process operated at 35 °C when treating real CIP milking parlour effluent (with COD concentrations ranging between 14 900 and 28 800 mg.L-1) when applying OLRs up to 6.6 g COD.L-1.day-1, without nutrient control. Therefore, the ASBR process is suitable to treat real milking parlour wastewater with OLRs above 6 g COD.L-1.day-1 at mesophilic temperatures. At an operating temperature of 22.5 °C, the ASBR achieved TCOD removal efficiencies between 86 and 98 % when treating real CIP effluent. Despite these high COD removal efficiencies, the reactor failed at an OLR of 2.9 g COD.L-1.day-1. As such, the ASBR process appears to be susceptible to failure (due to overloading) when the OLR is increased too rapidly at this low operating temperature. This is most probably due to the fact that methanogenic bacteria do not acclimatise and operate as well at temperatures below the mesophilic range. However, during a second attempt at 22.5 oC, the ASBR achieved COD removal efficiencies between 89 and 97 % when the OLR was increased less rapidly, up to 3.3 g COD.L-1.day-1. These results show that the ASBR process can indeed treat real milking parlour wastewater at 22.5 °C without nutrient control at OLRs above 3 g COD.L-1.day-1. The COD concentration in the effluent from the ASBRs when the maximum OLRs were applied were always below 1 000 mg.L-1. This is notably lower than the South African legal limit for irrigation of up to 50 m3 of wastewater per day. However, this is significantly higher than the South African legal limit of 75 mg.L-1 for safe disposal into a fresh water body. / AFRIKAANSE OPSOMMING: Die wêreldwye toename in die aanvraag na vars, skoon water het tot gevolg dat die ondersoek in die behandeling, hergebruik en herwinning van afvalwater tans groot aandag geniet. Nie net wêreldwyd nie, maar ook in Suid-Afrika waar tans 62 % van die water wat gebruik word per jaar, aangewend word vir die lanbou sektor. Daarom is die ondersoek na besparing van water in lanbou aktiwiteite (veral melkboerderye) geen uitsondering nie. Die watergebruik tydens melktyd in 5 verskillende melkerye is ondersoek en dit blyk dat die watergebruik in die 5 melkery drasties van mekaar verskil. Dit strek van ‘n minimum van 15 litres per koei per dag tot ‘n maksimum van 51 liters per koei per dag. Die volume water wat gebruik word vir die outomatiese was van die melktoerusting het nie so baie gevarieer nie en het gestrek tussen 4.9 en 6.4 liter per koei per dag. Die moontlikheid om die afvalwater wat gegenereer word tydens die outomatiese was van die melktoerusting apart te hou van die res van die afvalwater, is in die verlede deur ander navorsers oorweeg. Afvalwater van suiwelfabrieke is in die verlede al deur middel van anaerobiese vertering in ‘n groot aantal laboratorium- en volskaalse anaerobiese aanlegte behandel. Daar word aangeneem dat die afvalwater wat gegenereer word tydens die was van melktoerusting min of meer dieselfde samestelling sal hê as die afvalwater van suiwelfabrieke. Die anaerobiese opvolgende lot reaktor (AOLR) word al hoe meer gewild in anaerobiesewaterbehandeling as gevolg van die eenvoudige en maklike werking en kompakte ontwerp. Dit word verwag dat hierdie tegnologie ‘n gepaste en praktiese oplossing sal wees om die afvalwater van die was van melktoerusting te behandel. Die anaerobiese behandeling van afvalwater by temperature laer as die normale mesofiliese temperature word ook al hoe meer gewild as gevolg van minder hitte wat benodig word. Die doel van hierdie studie was om te bepaal of die AOLR tegnologie ‘n gepaste tegnologie is om afvalwater wat gegeneer word tydens die outomatiese was proses van melkery toerusting te behandel. Ter ondersteuning van die doel, is die watergebruik in ‘n paar tipiese, Suid- Afrikaanse melkerye eers bevestig. Daaropvolgend, het die laboratoriumwerk die volgende behels: • The bepaal of die AOLR proses (wat by mesofiliese temperatuur van 35 °C bedryf was) sensitief is vir veranderinge in die konsentrasie van sepe in sintetiese waswater wat na ‘n AOLR gevoer word; en • Om die werking van die AOLR proses te ondersoek wanneer regte afvalwater van melkery by onderskeidelik 22.5 en 35 °C behandel word. Chemiese suurstof behoefte (CSB) verwydering van 89 to 98 % is bereik toe sintetiese afvalwater wat gelykstaande aan afvalwater gegenereer tydens die was van melk toerusting is (met CSB konsentrasies tussen 12 600 en 13 400 mg.L-1) in ‘n AOLR behandel is. Die resultate het getoon dat daar geen aanmerklike verskil in die werking van die AOLR in terme van metaanproduksie, metaanopbrengs en CSB verwyderingseffektiwiteit was met a toename tot en met so hoog as vier maal die normale seepkonsentrasie in die afvalwater was toe organiese ladingstempo’s (OLTs) tussen 0.6 en 5.2 g CSB.L-1.dag-1 aangewend was nie. Die resultate het ook getoon dat die CSB van regte afvalwater van melkerye (met CSB konsentrasies tussen 14 900 en 28 800 mg.L-1) met 92 tot 98 % verminder kan word wanneer dit in ‘n AOLR (wat by 35 °C bestuur word) en OLTs tot so hoog as 6.6 g CSB.L-1.dag-1 aangewend word, sonder dat die nutrientinhoud in die afvalwater beheer was. Hierdie AOLR proses wat is dus gepas om afvalwater van melkery te behandel met OLTs bo 6 CSB.L-1.dag-1 by mesofiliese temperature. Die AOLR wat by ‘n temperatuur van 22.5 °C bedryf was, het CSB verwydering tussen 86 en 98 % behaal. Ondanks die hoë CSB verwydering het die reaktor misluk by ‘n maksimum OLT van 2.9 g CSB.L-1.dag-1. Dit het getoon dat die AOLR proses meer geneig is om vatbaar te wees vir mislukking (as gevolg van ‘n oorlading) wanneer die OLT te vinnig verhoog word by laer temperature. Dit is moontlik as gevolg daarvan dat die metanogeniese bakterieë nie so goed aanpas en werk by temperature laer as mesofiliese temperature nie. Nietemin, tydens ‘n tweede probeerslag by 22.5 °C, het die AOLR CSB verwydering tussen 89 en 97 % behaal tydens ‘n stadiger toename in die OLT tot en met 3.3 g CSB.L-1.dag-1. Hierdie resultate dui aan dat die AOLR proses wat by ‘n temperatuur van 22.5 °C bedryf word ook gepas is om afvalwater van melkerye te behandel, sonder nutrient beheer by OLTs hoër as 3 g CSB.L-1.dag-1. Die CSB konsentrasies in die afvloeisel van die AOLR’e in die studie tydens die aanwending van die hoogste OLTs, was altyd laer as 1 000 mg.L-1. Dit is merkbaar laer as die limiet vir besproeiing van tot en met 50 m3 per dag in Suid-Afrika. Maar, dit was nogtans regdeur hoër as die limiet van 75 mg.L-1 vir veilige storting in ‘n varswaterbron.

Increases in herd size and enforcement of water quality regulations have created an effluent disposal problem for the New Zealand dairy industry. Spray disposal to land and lagooning are commonly used but mechanical failures, management requirements and pressure on land have limited their suitability in many situations. This project was established to consider an alternative system. Initial studies revealed that anaerobic treatment in unmixed, non-insulated tanks, followed by trickling filter aeration, might be suitable. Two laboratory scale and one field treatment plant (1/15 - 1/20 full scale) were constructed to investigate the system. A factorial experimental design allowed investigation into three anaerobic treatment levels with a 3 x 3 aerobic treatment interaction nested within each anaerobic treatment. Anaerobic residence times of 5, 7.5 and 10 days provided loading rates of 1.35 - 0.63 kg COD/m3-day and 1.36 - 0.67 kg T S/m3-day. Removals between inlet and outlet averaged 71% and were insensitive to loading rate. Total solids accumulation rates of 40-50% TS input rate suggests that anaerobic tank design should be based on solids accumulation rate and cleaning frequency. The stone media trickling filter was loaded at approximately 0.61 kg COD/m3-day. Aeration periods of 1, 2 and 3 days and hydraulic loads of 2.8, 10.1 and 18.2 m3/m2-day were studied to determine their influence on treatment efficiency. Multiple regression analysis indicated that the longer residence times and higher recycle rates improved treatment efficiency. Removals varied with the measured parameters but ranged from 42-66% for COD. Design alterations to allow the final discharge to be taken from the bottom of the filter, after settling, would increase aerobic treatment efficiency above 75% COD removal. Prediction of treatment efficiencies beyond the monitored operating conditions suggested that only marginal improvements could be made. The TS accumulation rate in the aerobic phase was approximately 13% of the TS input rate or 56% of the BOD removal rate. Overall plant treatment efficiencies of 80-89% were obtained. Removals in excess of 92% could be achieved with minor design alterations. Maintenance and operational requirements were minimal. The only problem with the system was an average 15 fold increase in NO3-N and 4 fold increase in DIP under conditions for optimum removal of the other parameters. Intermittent land disposal could reduce this problem. Treatment comparison between similar laboratory plants, and between laboratory and field plants which varied by a scale factor of 56, suggests that identically designed plants would give a similar performance and that there is little scale effect. Increasing the scale only improved treatment efficiencies under unstable aerobic conditions, i.e., high recycle rates and low residence times. Increasing scale gave some decrease in maintenance and operational problems. Design of a full scale plant, based on daily pollution loads from a 250 cow dairy shed, suggests that the system is a viable proposition.

Automatische Melksysteme (AMS) sind in weiten Teilen Europas bereits sehr verbreitet und werden von verschiedenen Herstellern weltweit angeboten. Die Gewährleistung einer hohen Milchqualität ist eine der Hauptanforderungen beim Übergang vom konventionellen zum automatischen Melken. Ziel dieser Arbeit war es den Einfluss des mechanischen Stresses, der durch mehrere AMS-Elemente induziert wird, auf die Milchqualität zu untersuchen. Dafür wurden zwei Labor-Melkstände (LMP) mit den melktechnischen Hauptkomponenten zweier AMS entwickelt und die Versuche unter standardisierten Laborbedingungen durchgeführt. Für die Analyse der Effekte einzelner technischer Komponenten oder Einstellungen wurden verschiedene Modifikationen vorgenommen, die zum Teil von den realen Einsatzbedingungen in der Praxis abweichen. Zur Bewertung der Milchqualität wurden folgende Merkmale herangezogen: freie Fettsäuren (FFA), Fett-, Eiweiß-, Laktose- und Harnstoffgehalt, Zellzahl, pH, und Gefrierpunkt. Für einen Teil der Untersuchungen konnte darüber hinaus auch das Fettsäureprofil in der Milch analysiert werden. Der Einfluss der folgenden Komponenten wurde analysiert: Das Pulsationsverhältnis, LMP, die Melkbecher, die Auslegung der LMP-Technik, und die Durchflussrate. Allgemeine Korrelationen zwischen einzelnen technischen Elementen und der Milchqualität festgestellt, signifikante Ergebnisse wurden eindeutig beim FFA- und Fettgehalt beobachtet. Die seit einiger Zeit routinemäßig bestimmbaren Fettsäureprofile bieten einen aussichtsreichen Ansatz für Ursache-Wirkung-Analysen in neuer Qualität. Die nachgewiesenen Signifikanzen in den Änderungen von Eiweiß- und Laktosegehalt sowie des Gefrierpunktes bedürfen tiefergehender Betrachtungen und kausaler Analysen. Insgesamt wurde deutlich, dass mechanische Belastungen von Milch bereits auf dem Weg vom Kuheuter zum Milchsammeltank zu Veränderungen chemischer und physikalischer Produkteigenschaften führen, auch wenn hier unter Laborbedingungen gearbeitet wurde. / Automatic milking systems (AMS) have been common in large parts of Europe and are offered by various manufacturers worldwide. Ensuring high milk quality is one of the primary requirements when transition from conventional milking to AMS. The aim of the present thesis was to investigate whether the mechanical stress induced by multiple AMS elements and settings affect the parameters of cow milk. To this end, two laboratory milking parlors (LMP) were developed to imitate an actual AMS. Under standardized laboratory conditions, the main milking technical components were installed by two different AMS companies for the analysis of the effects of single technical elements or settings on milk parameters. The following parameters were used to evaluate milk quality: free fatty acids (FFA), fat, protein, lactose, urea, somatic cell count (SCC), pH, and freezing point (FP). For some of the investigations, the milk fatty acid profile (MFAP) was also analyzed. The influence of following components: pulsation ratio, LMP, teat cup, the layout of the LMP technique, and flow rate was analysed. General correlations were identified between singular technical elements and milk quality, significant results were observed clearly on FFA and fat content. Milk fatty acid profiles (MFAP) have been routinely determinable for some time now and can offer an interesting approach for cause-and-effect analyses of a new quality. The demonstrated significances in the changes of protein and lactose content as well as freezing point require deeper consideration and causal analysis. Overall, it became clear that mechanical stresses on milk already lead to changes in chemical and physical product properties on the way from the cow's udder to the milk collection tank, even if the work was carried out under laboratory conditions.