Field tests were conducted and historical operating data were evaluated to assess the performance of the Monterey WWTP utilizing subsurface flow (SF) constructed wetlands. Previous work with SF wetlands has demonstrated adequate, but variable removal of organic matter, suspended solids, and nitrogen. Few research studies have observed the generation of compounds in the wetlands that affect other treatment processes, specifically reduced compounds that contribute to the chlorine demand. This study attempts not only to distinguish the factors leading to the inadequate performance of the SF wetlands in removing organic matter and nitrogen, but also to identify the cause of the frequent occurrences of a nondetectable chlorine residual in the chlorine contact tank at the Monterey WWTP. Collection and analysis of historical operating data from January 1998 to May 2000 revealed a constantly decreasing removal of carbonaceous biochemical oxygen demand (CBOD5) by the SF wetlands and a poor removal of ammonia-N throughout the system. The decreasing removal of CBOD5 appeared to be caused by clogging of the wetland bed media by accumulated solids. The inability to remove the accumulated solids by pumping was shown. Analysis of field data also showed that the SF wetlands removed 88% of the influent TSS and 71% of the influent CBOD5, while experiencing a 18% increase in ammonia-N. Bisulfide produced in the anaerobic wetland beds accounted for 95% of the chlorine lost in contact tank. The variable production of sulfide is the cause of the frequent nondetectable chlorine concentrations observed. The results of this study suggest that chemical costs of chlorine and sulfur dioxide may be greatly reduced if bisulfide can be removed before chlorination. Also, the use of large rocks as media in SF wetland beds may significantly reduce the physical and biological removal of organic matter. / Master of Science

Microalgae are photosynthetic organisms considered to be one of the most promising high-value chemicals and biofuel-producing organisms. However, there are several challenges for the widespread implementation of industrial processes using microalgae. The work presented in this dissertation proposes solutions to the different challenges involving the use of microalgae as microbial cell factories. To investigate the application of anaerobic digestion as a way to generate nutrients for microbial growth, salmon offal was used as substrate for anaerobic digestion, and soil from a flooded run-off pond on the Virginia Tech campus in Blacksburg, VA. A fast reduction in volatile solids and the short-chain fatty acid production profile is favorable for the growth of microalgae. A novel algae strain Scenedesmus sp. A6 was isolated from a decorative waterfountain in a hotel in Madison, IN. Mixotrophic growth trials were conducted using wastewater from the salmon offal digestion, that demostrated the A6 isolate grows six times faster in the wastewater then autotrophically. Bioassays of ethanolic cell extracts of A6 cultures demonstrated antimicrobial activity against E. coli cells at concentrations above 50 µg/ml. Genome sequencing and assembly revealed multiple copies of genes involved with acetate and ammonia metabolism, and several genes involved with secondary metabolite synthesis. An alternative to the high capital investment of photobioreactors for the cultivation of microalgae is the use of open-source and open-hardware bioreactor controller. Here, the concept of an open-hardwate bioreactor control called ``BioBrain'' is introduced. The BioBrain device is based on the Arduino Mega micro-controller board, and is capable of monitoring and controlling culture conditions during simple strain characterization studies, with an estimated construction cost of less than $800 USD. Finally, a new primer design tool for the ligation-independant cloning technique 𝜆-PCR was developed called lambdaPrimeR. The contributions of this work are the discovery and development of different tools that can overcome the challenges of the use of microalgae as microbial cell factories in industrial processes. / Ph. D. / Microalgae are single-celled organisms capable of photosynthesis and have the potential to revolutionize fuel and high-value chemical production. However, the high process costs involving the cultivation and biomass harvesting of these organisms limits the number of industrial applications of microalgae. Therefore, reduction of the overall costs of any process involving microalgae is vital for the widespread use of these organisms in industry. On this dissertation, I explore different approaches to tackle the challenges of using microalgae as a high-value chemicals cell factories. First, the use of anaerobic digestion of salmon offal to generate low-cost nutrients for algae growth is successfully demonstrated, with the discovery of a novel algae isolate Scenedesmus sp. A6, capable of very robust growth on the anaerobic digestion wastewater. Further characterization of this novel isolate showed that it has antimicrobial activity against E. coli cells. Therefore, the Scenedesmus sp. A6 isolate has the potential to be used as a high-value chemical cell factory. Reduction in equipment and instrumentation costs was also achieved by the design and construction of an open-hardware and open-source bioreactor controller device called the “BioBrain”, and a low-cost modular bubble column photobioreactor called “The Big Large Tube”. Together, these two devices represent a significant reduction in equipment costs for the cultivation of microalgae. Finally, an open-source Bioinformatics tool called “lambdaPrimeR” was developed to facilitate the use of a novel Genetic Engineering technique called λ-PCR, that has the potential to make genetic engineering of microalgae much easier.

The effect of high organic liquid wastes on the overall performance of anaerobic bioreactor landfills is not known. In this study three different liquid wastes were added to mix of office paper, newspaper, cardboard and plastic in 3 different concentrations under anaerobic conditions to determine their effect on degradation of organics. The addition of buffer chemicals was found to improve degradation compared to data from an earlier study done without the addition of initial buffering. Paint waste with a COD 237,500 mg/L added at a concentration of 10% did not show any negative effect on the overall performance. The distillation waste with a COD of 812,500 mg/L added at 5% and higher concentration resulted in accumulation of volatile fatty acids and strong inhibition. The surfactant waste added at concentrations up to 1500 mg/L showed some inhibition but the overall performance was good. The surfactant waste also appeared to improve lignin degradation. / Master of Science

Anaerobic digestion is widely used for stabilization of solids in sewage sludges. Recent changes in the priorities and goals of digestion processes are focusing more attention on the efficiency of these processes. Increasing hauling cost and restrictions for land applications are two factors which are driving the increased attention to digestion efficiency. Noxious odor production from the land applied biosolids is another important issue related to digestion efficiency. Existing anaerobic digestion or aerobic digestion processes failed to provide simultaneous solution to biosolids related problems i.e. simultaneous VS reduction, better dewatering of biosolids and lesser odors from the biosolids. Studies done by Novak et al. (2004) using different activated sludges show that anaerobic-aerobic digestion and aerobic-anaerobic digestion both increase volatile solids reduction compared to a single digestion environment. They proposed that there are 4 VS fractions in sludges: (1) a fraction degradable only under aerobic conditions, (2) a fraction degradable only under anaerobic conditions, (3) a fraction degradable under both anaerobic and aerobic conditions, and (4) a non degradable fraction. It has also been found (Akunna et al., 1993) that anaerobic-aerobic sequential treatment of wastewater can help in achieving substantial nitrogen removal. These results suggest that sequential anaerobic-aerobic digestion can address multiple biosolid related problems. This study was designed to understand the effect of sequential anaerobic-aerobic digestion on the properties of resulting effluent biosolids. The study was carried out in two operation phases and during both phases one digester was maintained at thermophilic conditions and the other at mesophilic temperature conditions. In first operation phase (Phase-I) thermophilic digester was operating at 20 day SRT and mesophilic anaerobic digester was at 10 day SRT. The aerobic digesters following anaerobic digesters were operating at 6 day SRT. In second operation phase (Phase-II), both thermophilic and mesophilic anaerobic digesters were operating at 15 day SRT and both had two aerobic digesters operating in parallel at 3 day and 6 day SRTs. In addition, batch experiments were also conducted to measure the performance of aerobic-anaerobic digestion sequence. Another study was carried out to understand the nitrogen removal mechanism during aerobic digestion of anaerobic digested sludge. The feed sludge was spiked with four different concentrations of nitrate and nitrite. It was observed during the study that aerobic digestion of anaerobic sludge helps in achieving higher Volatile solid reduction (~65% vs ~ 46% for mesophilic digestion and ~52% for thermophilic digestion). This result supports the hypothesis concerning the different fractions in volatile solids. Experimental results also show that the increase in VSR upon increasing anaerobic digestion SRT (more than 15 days) is less than the increase in the VSR due to the same increment of aerobic digestion SRT. Reduction in COD and VFA were also measured to be more than 50% during aerobic digestion. Investigation of nitrogen fate during the sequential anaerobic-aerobic digestion show more than 50% total nitrogen removal. Higher nitrogen removal was in thermophilic anaerobic – aerobic digester combination than that in mesophilic anaerobic–aerobic combination. The most probable reason for the removal was simultaneous nitrification and denitrification. Higher concentration of readily available VFA from thermophilic anaerobic digested sludge provide advantage in denitrification in following aerobic digester. The resulting biosolids produced during sequential digestion process were also analyzed for dewatering properties and odor production. Proteins and polysaccharides concentrations were observed to decrease during aerobic digestion for thermophilic anaerobic - aerobic digestion combination, while in another combinations polysaccharide concentrations increases at aerobic phase with 3 day digestion. The concentration of polysaccharides decreases at higher digestion period of 6 and 9. The result of decrease in polysaccharide and protein was reflected by the reduction in the polymer dose consumption and decrease in the optimum CST for the biosolids resulting from the sequential anaerobic aerobic digestion. Experimental results from odor experiments show that odor production potential of the biosolids decreases with increase in both anaerobic phase SRT and aerobic phase SRT. Thermophilic biosolids produces comparatively low odors but for longer periods, while mesophilic biosolids produces higher magnitude of odors during storage but only for comparative shorter period. Aerobic digestion of anaerobic sludge helps in reducing more than 50% odor production, but freeze-thaw cycle experiment shows that in both anaerobic and sequential anaerobic – aerobic digested sludges have higher potential for odor production. Higher aerobic digestion SRTs (6 days and above) shows more potential of reducing odors, but more experimental work is required to be done. / Master of Science

This study was conducted to isolate and characterize bacteria that have the capacity to degrade both carbofuran and dicamba. The pathways of degradation for both pesticides were elucidated. An aerobic, carbofuran-degrading bacterium was isolated from a high concentration carbofuran bioreactor. The isolate degrades carbofuran at the upper limit of carbofuran solubility (approximately 700 mg L⁻¹), to carbofuran phenol. In aqueous mineral salts medium with carbofuran as Furadan 4F (6 g L⁻¹ a.i.), degradation of carbofuran to undetectable levels required approximately 100 days. Although carbofuran phenol was not completely degraded, the cells remained viable in the presence of unusually high concentrations of both surfactant and carbofuran phenol. Additional nutrient sources had little effect upon the rate of degradation of carbofuran in pure culture. A dicamba-degrading consortium enriched from wetland soil, using the batch culture method, was used to elucidate the pathway of dicamba degradation under anaerobic conditions. The consortium consisted of one sulfate reducing bacterium, one fermenter, and three methanogens. The sulfate reducing bacterium was isolated from the consortium using sulfate as a terminal electron acceptor and 2-bromoethanesulfonic acid was added to inhibit the growth of the methanogens. Since the fermenter is dependent upon the methanogens, elimination of these organisms caused the elimination of the fermenter. Three methanogens (Methanothrix, Methanosarcina and Methanospirillum sp) were isolated with acetate and headspace gas consisting of H₂-CO₂. Degradation of dicamba proceded through an initial demethylation reaction yielding 3,6-dichlorosalicylic acid, as determined by high performance liquid chromatography (HPLC) analysis of aqueous medium. This was followed by a reductive dehalogenation reaction at the meta position of 3,6-dichlorosalicylic acid forming 6-chlorosalicylic acid. The metabolites were isolated using thin layer chromatography. Confirmation of metabolite identity was achieved using HPLC, and mass spectrometry. It appears that the fermenter was responsible for mediating the demethylation reaction. The consortium was unable to mineralize the aromatic ring. The substrate specificity of the dicamba-degrading consortium was investigated. The consortium was found to have the capacity to mediate the reductive dehalogenation of both 3-chlorosalicylic acid and 2,5-dichlorobenzoic acid at the meta position. The consortium was unable to dehalogenate either 3-chlorobenzoic acid, 4-chlorosalicylic acid, 5-chlorosalicylic acid, or 2,5-dichlorophenol. Addition of the reducing agent cysteine (0.025% and 0.050%) to a yeast extract amended (0.04%) mineral salts medium containing 3-chlorosalicylic acid reduced the rate of dehalogenation compared to medium containing sodium sulfide as the reducing agent. Only limited dehalogenation of 3- chlorosalicylic acid and 2,5-dichlorobenzoic acid was observed when the sulfate reducing bacterium was cultured alone in a yeast extract amended medium, suggesting that the mutualistic efforts of a mixed population of anaerobes were necessary to efficiently mediate reductive dehalogenation. / Ph. D.

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2005. / The Up-flow Anaerobic Sludge Blanket Reactor (UASB) provides a state-of–the-art solution to effluent treatment by anaerobic digestion: sludge production is dramatically lower than in other digestion processes, and energy is gained from the system if the produced biogas is converted to electricity and/or heat. The UASB is a modified fluidised bed reactor, with the solid state ‘catalyst’ being granulated anaerobic sludge, and the liquid phase the effluent that needs to be treated. A gas cap is installed to serve as a carbon dioxide and methane collector. This biogas (carbon dioxide and methane) is produced by the stepwise decomposition of complex carbohydrates and proteins via a consortium of micro-organisms living in a symbiotic environment known as a granule. A typical UASB reactor has an organic removal rate of 89-93% Chemical Oxygen Demand (COD) and operates optimally at loadings of 9.8-11 kg COD/ m3 reactor volume/day. Unfortunately, one major problem hampers the efficiency of this reactor to such an extent that the unit is only economically viable in exceptional cases; if the reactor is inoculated with un-granulated anaerobic sludge, start-up times of up to 12 months can be expected. The lengthy start-up times motivated the search for an artificial way to cultivate USAB granules. Early research (done on lab-scale, 400ml vessel volumes) proved that, under a specified set of environmental conditions, granule growth can occur in an artificial environment. Yet these laboratory-scale vessels did not facilitate scale-up or the study thereof. This led to the main problem statement of this research project: namely to design, commission, and optimise benchscale bioreactors that will generate granulated anaerobic sludge in an incubation period of 20 days. These units should also facilitate in the determining of parameters that will assist in the design of a scale-up to a UASB granule producing reactor of economically viable size. Two bench-scale reactors were initially designed specifically to “mimic” the motion found in the laboratory-scale vessels. The results from these initial reactors proved that granulation cannot only be enhanced, but granules can actually be cultivated from dispersed anaerobic sludge in a larger artificial environment over an incubation period of only 20 days. The results were still far from satisfactory, as the granules produced were irregular in shape and the yield of usable granules (2.2 kg/m3 reactor volume) insufficient. A third test reactor was designed to “mimic” roller table movement and baffles were included. These results were much better and the yield was 4.4 kg/m3 reactor volume at a baffle tipspeed of 0.0055 m/s. The optimisation was extended further to include the inoculation sludge and the feed medium. A C:N:P ratio of 10:1:4 proved to yield the best results. Monovalent anions, hydrogen concentration and a pH-level outside the 6.5 to 7.2 range evidently had an inhibitory effect on the granulation rate. After the optimisation study the third test unit produced a usable granule yield of 15.2 kg/m3 reactor volume over the 20-day incubation period. The incubation period can be separated into 3 distinct phases, namely the acidification, stabilisation and growth phases. From the mass balance it was found that most of the COD and nutrients were used for ECP production in the acidification phase. During the stabilisation phase, the COD and nutrients were mostly used for nucleus formation, and finally in the growth phase the COD was used for granule growth. To study the effect the internal surface area of the reactor has on the granulation process, 3 scale-down versions of the third test unit were constructed. Within the studied range, a yield of usable granules of 40 kg/m2 reactor internal surface area was obtained.

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.

M. Tech. (Civil Engineering, Faculty of Engineering and Technology), Vaal University of Technolog / Textile industry effluents are carcinogenic and highly recalcitrant hence difficult to degrade especially through biological methods. Abattoir effluents are classified under high-strength wastewaters because of their characteristic high organic load hence highly biodegradable. Anaerobic co-digestion is the concept of degrading two effluent streams with complementary characteristics in order to improve the substrate removal rate. The feasibility of co-digesting abattoir and textile wastewater in a UASB reactor was evaluated at mesophilic and ambient temperature conditions. Preliminary experiments were conducted in 500 ml batch reactors to evaluate the optimum abattoir to textile synthetic wastewater ratio. The effect of COD, TVFA, alkalinity and pH on biogas yield was examined at both ambient and mesophilic temperatures. Anaerobic co-digestion of abattoir to textile wastewater in the ratio determined in the batch process was carried out in a 3 L UASB reactor by a continuous process. The continuous biodegradation process was executed at three different HRTs (22, 18 and 14 hrs) over a 60 day operation period. UASB reactor efficiency was achieved at organic loads ranging from 3.0 – 10.8 gCOD L-1 day-1. Continuous mode experiments were carried out at influent flow rates which corresponded to HRTs ranging between 1 to 8 days in order to evaluate the steady state operating parameters for the co-digestion process. The abattoir to textile effluent ratio was found to be 60:40 respectively. The COD, TVFA, alkalinity and pH and biogas yield followed a similar pattern over time at both mesophilic and ambient temperature conditions. Experimental data adequately fit the Grau first order kinetic model and average COD removal efficiencies of 85% and BOD5 of around 96% were achieved. The average biogas yield remained essentially constant, around 0.19 L/g CODremoved. The co-digested mixture was found to be biodegradable judging from the BOD:COD ratio of 0.53. TCOD removal efficiency decreased from 93% to 16% as HRT decreased from 8 days to 1 day. The kinetics of a UASB reactor co-digesting the mixture of synthetic abattoir and textile wastewater was evaluated in this study using Grau second order multicomponent substrate removal kinetic model. The Grau second order kinetic model, whose kinetic coefficient (ks) was 0.389, was found to be suitable for predicting the performance of a lab-scale UASB reactor.

Foram operados dois reatores UASB de bancada (volumes de 39,0 e 10,5 L) instalados em série, alimentados com águas residuárias de suinocultura com concentração de sólidos suspensos totais (SST), no primeiro reator, em torno de 5000 mg/L, com temperatura controlada (de 25 a 30 graus Celsius) e com tempo de detenção hidráulica (TDH) no primeiro reator de 62 a 16 h e no segundo de 16 a 4 h. O objetivo foi avaliar o desempenho e caracterizar física e microbiologicamente o lodo dos reatores UASB operados em dois estágios. Os resultados obtidos no ensaio 1, com TDH de 62 h no primeiro reator e SST no afluente de 5240 mg/L, mostraram eficiências de remoção de DQO total de 86% e 59% e SST de 82% e 57%, no primeiro e segundo reatores, respectivamente. A eficiência de remoção de DQO total e SST no sistema, no ensaio 1, foi de 95% e 94%. No ensaio 2, com TDH de 31 h no primeiro reator e SST de 5000 mg/L no afluente, observou-se eficiência de remoção de DQO total de 86% e 43% e SST de 85% e 58%, no primeiro e segundo reatores, respectivamente. A eficiência de remoção de DQO total e SST no sistema, no ensaio 2, foi de 92% e 94%. No ensaio 3, com TDH de 16 h no primeiro reator e SST de 5490 mg/L no afluente, observou-se eficiência de remoção de DQO total de 73% e 23% e SST de 65% e 20%, no primeiro e segundo reatores, respectivamente. A eficiência de remoção de DQO total e SST no sistema, no ensaio 3, foi de 79% e 73%. A TCOV aplicada no primeiro reator, no ensaio 1, foi de 4,55 kg DQO total/\'M POT.3\'.d, no ensaio 2 de 8,75 kg DQO total/\'M POT.3\'.d e no ensaio 3 de 18,65 kg DQO total/\'M POT.3\'.d. A produção de \'CH IND.4\' no primeiro reator foi de 17,50 a 68,20 L \'CH IND.4\'/d e no segundo reator de 1,62 a 5,50 L \'CH IND.4\'/d com a diminuição do TDH. Os reatores UASB instalados em série foram eficientes na remoção da fração dissolvida e, principalmente, da fração devido à concentração de SST do afluente. Para TCOV de 4,55 kg DQO/\'M POT.3\'.d no primeiro reator, pôde-se obter eficiências de remoção de DQO total e de SST acima de 90% e de DQO dissolvida acima de 85%. Para TCOV de 18,65 kg DQO/\'M POT.3\'.d no primeiro reator, as eficiências de remoção de DQO total e de SST foram acima de 70% e DQO dissolvida acima de 75%. As maiores produções específicas de metano foram obtidas com TCOV de 2,55 kg DQO/\'M POT.3\'.d para o segundo reator e de 8,65 kg DQO/\'M POT.3\'.d para o primeiro reator. A operação dos reatores UASB com valores de concentração de SST no afluente em torno de 5000 mg/L foram prejudiciais ao processo de granulação do lodo. Os grânulos apresentaram distribuição dispersa das morfologias microbianas ao longo da parede, não caracterizando a divisão em camadas definidas. As arqueas metanogênicas predominantes foram as semelhantes à Methanosaeta. / Two bench scale UASB reactors (volumes of 39,0 and 10,5 L) were operated in sequence, fed with swine wastewater with total suspended solids (TSS) concentration around 5000 mg/L in the first reactor, with controlled temperature (from 25 to 30 Celsius degrees) and operating with hydraulic detention time (HDT) in the first reactor varying from 62 to 16 h and in the second reactor from 16 to 4 h. The objective was to evaluate the performance and to characterize physically and microbiologically the sludge from UASB reactors operated in two stages treating swine wastewater. The results obtained in phase 1, with HDT of 62 h in the first reactor and TSS in the influent of 5240 mg/L, presented total COD removal efficiencies of 86% and 59% and TSS reduction efficiency of 82% and 57%, in the first and second reactors, respectively. The removal efficiency of total COD and TSS in the system, in phase 1, was 95% and 94%, respectively. In the phase 2, using HDT of 31 h in the first reactor and TSS of 5000 mg/L in the influent, it was observed a total COD removal efficiency of 86% and 43% and TSS reduction efficiency of 85% and 58%, in the first and second reactors, respectively. The system removal efficiency of total COD and TSS in phase 2, was 92% and 94%, respectively. In phase 3, with a HDT of 16 h in the first reactor and TSS of 5490 mg/L in the influent, it was observed a total COD removal efficiency of 73% and 23% and TSS reduction efficiency of 65% and 20%, in the first and second reactors, respectively. The total COD removal efficiency and TSS reduction efficiency in the system, in phase 3, was 79% and 73%, respectively. The volumetric organic loading rate (VOLR) applied in the first reactor, in phase 1, was 4,55 kg total COD/\'M POT.3\'.d, in phase 2 was 8,75 kg total COD/\'M POT.3\'.d and in phase 3 was 18,65 kg total COD/\'M POT.3\'.d. The \'CH IND.4\' production in the first reactor was from 17,50 to 68,20 L \'CH IND.4\'/d and in the second reactor from 1,62 to 5,50 L \'CH IND.4\'/d decreasing the HDT in the experiment phases. The UASB reactor installed in sequence were efficient in the dissolved fraction removal and, mainly, to the fraction due to the TSS influent concentration. The total VOL value of 4,55 kg COD/\'M POT.3\'.d was measured in the first reactor, it was achieved TSS and total COD removal efficiencies above 90% and dissolved COD above 85%. For the OVL of 18,65 kg COD/\'M POT.3\'.d in the first reactor the TSS and total COD removal were above 70% and dissolved COD above 75%. The larger methane specific production was obtained with a total VOL of 2,55 kg COD/\'M POT.3\'.d in the second reactor and 8.65 kg COD/\'M POT.3\'.d in the first reactor. The UASB reactors operation with the TSS concentration values of 5000 mg/L in the influent was prejudicing the sludge granulation process. The granules present a microbial morphology disperse distribution that doesn\'t characterize a layers defined distribution. The predominant metonogenic archeas were similar to Methanosaeta.

O processamento anaeróbio da vinhaça se apresenta como uma alternativa para a recuperação de energia (biogás), e reaproveitamento das suas características nutricionais através da disposição no solo. Com o intuito de elevar a eficiência energética, o presente trabalho teve como objetivo estimular a produção de metano em reatores anaeróbios em batelada de lodo granular adaptado, alimentados com vinhaça de usina sucroalcooleira, por meio da adição de metais traço. Foram avaliadas as suplementações da vinhaça com Co, Zn, Mo, Ni, Mn e W. Na Fase 1 foram realizados 4 ensaios, os reatores foram analisados individualmente nas concentrações 200 μg.L-1, 350 μg.L-1, 500 μg.L-1 e 800 μg.L-1. Na Fase 2 verificou-se o comportamento dos metais em conjunto, à concentração de 350 μg.L-1 de cada micronutriente (Co, Ni, Zn, Mo, Cu e Mn). Os dados de produção acumulada de CH4 foram ajustados pelo modelo modificado de Gompertz, e foram obtidas as constantes cinéticas. Na Fase 1, verificou-se que a concentração de 200 μg.L-1 de Co foi a mais adequada aos experimentos e apresentou a maior velocidade máxima de produção de CH4, 121,30 mL.d-1 (aumento de 17% na taxa de produção de metano). Nesta mesma Fase, o W apresentou indícios de inibição à concentração de 800 μg.L-1, e os demais metais exibiram os melhores resultados nesta mesma concentração, a velocidade de produção (Rm) aumentou para o Mn (26%), Ni (25%), Cu (21%) e Mo (19%), e os rendimentos mais expressivos foram para Mo (0,267 mL CH4.mg-1 DQOrem), Zn (0,240 mL CH4.mg-1 DQOrem) e Ni (0,232 mL CH4.mg-1 DQOrem). A Fase 2 não apresentou resultados satisfatórios, as verificações não indicaram variação relevante entre os reatores do ensaio e controle. / Anaerobic processing of vinasse is presented as an alternative to energy recovery (biogas), and reuse of its nutritional characteristics through the provision on the ground. In order to increase energy efficiency, this study aimed to stimulate methane production in adapted anaerobic batch reactors with granular sludge fed with vinasse from sugarcane biorefineries, through the addition of trace metals. The supplementation vinasse were evaluated with Co, Zn, Mo, Ni, Mn and W. In phase 1 four essays were realized, and micronutrient were analyzed individually in concentrations of 200 μg.L-1, 350 μg.L-1, 500 μg.L-1 and 800 μ.L-1. In phase 2 it was observed the behavior of metal together, with micronutrients concentration of 350 μg.L-1 (Co, Ni, Zn, Mo, Cu e Mn). The data of methanes production were adjusted by Gompertz modified model and kinetics constants were obtained. In phase 1 it was verified that the concentration of 200 μg.L-1 of Co was optimal for the experiments and showed the highest maximum production velocity of CH4, 121,30 mL.d-1 (increase of 17%). In this phase W showed evidence of inhibition at a concentration of 800 μg.L-1, and other metals showed the best results in the same concentration. The velocity of production (Rm) increased to Mn (26%), Ni (25%), Cu (21%) e Mo (19%), and the most significant yields were to Mo (0,267 mL CH4.mg-1 DQOrem), Zn (0,240 mL CH4.mg-1 DQOrem) and Ni (0,232 mL CH4.mg-1 DQOrem). Phase 2 did not show satisfactory results.