Anionic surfactants are wildly used in many industrial and household applications. Because anionic surfactants are used so widely, significant attention has focused on the removal of these contaminants from wastewater. Among various treatment techniques, biofiltration, such as trickling filter technologies, has been employed in many wastewater treatment plants (WWPTs) to remove anionic surfactants. However, current knowledge of the efficacy of trickling filter to remove anionic surfactants from wastewaters is limited. The present study characterized the performance of a high rate (i.e. roughing) trickling filter to remove anionic surfactants both at lab-scale and pilot-scale. Lab-scale tests investigated the biodegradation of anionic surfactants under controllable conditions were compared with those from previous studies by others. Pilot-scale tests investigated the efficacy of a trickling filter at removing anionic surfactants from a wastewater over an extended period of time. The data from the pilot-scale tests were used to model the performance of trickling filter at removing anionic surfactants from the wastewater, using first order and modified Velz models. The lab-scale tests indicated that high molecular weight anionic surfactants degrade faster than the low molecular weight surfactants. The biodegradation rates observed in the present study were similar to those from pervious studies by others. The pilot-scale tests indicated that roughing trickling filter could remove 11% to 29% of anionic surfactants and 4% to 22% of COD from the wastewater. Higher molecular weight anionic surfactants were more degradable. The experimental data could be accurately modeled using the modified Velz model (R² value more than 0.9). The degradation rates of modified Velz model for total anionic surfactants, high molecular weight anionic surfactants and COD were 0.053±0.0057, 0.088±0.0048 and 0.119±0.0111 (mIs)0.5 respectively. The pilot-scale test results indicated that a high rate (i.e., roughing) trickling filter was not capable of effectively removing anionic surfactants in the primary effluent at Lions Gate WWTP because a relatively large trickling filter area would be required to achieve the required surfactant removal efficiency.

Anionic surfactants are wildly used in many industrial and household applications. Because anionic surfactants are used so widely, significant attention has focused on the removal of these contaminants from wastewater. Among various treatment techniques, biofiltration, such as trickling filter technologies, has been employed in many wastewater treatment plants (WWPTs) to remove anionic surfactants. However, current knowledge of the efficacy of trickling filter to remove anionic surfactants from wastewaters is limited. The present study characterized the performance of a high rate (i.e. roughing) trickling filter to remove anionic surfactants both at lab-scale and pilot-scale. Lab-scale tests investigated the biodegradation of anionic surfactants under controllable conditions were compared with those from previous studies by others. Pilot-scale tests investigated the efficacy of a trickling filter at removing anionic surfactants from a wastewater over an extended period of time. The data from the pilot-scale tests were used to model the performance of trickling filter at removing anionic surfactants from the wastewater, using first order and modified Velz models. The lab-scale tests indicated that high molecular weight anionic surfactants degrade faster than the low molecular weight surfactants. The biodegradation rates observed in the present study were similar to those from pervious studies by others. The pilot-scale tests indicated that roughing trickling filter could remove 11% to 29% of anionic surfactants and 4% to 22% of COD from the wastewater. Higher molecular weight anionic surfactants were more degradable. The experimental data could be accurately modeled using the modified Velz model (R² value more than 0.9). The degradation rates of modified Velz model for total anionic surfactants, high molecular weight anionic surfactants and COD were 0.053±0.0057, 0.088±0.0048 and 0.119±0.0111 (mIs)0.5 respectively. The pilot-scale test results indicated that a high rate (i.e., roughing) trickling filter was not capable of effectively removing anionic surfactants in the primary effluent at Lions Gate WWTP because a relatively large trickling filter area would be required to achieve the required surfactant removal efficiency.

Anionic surfactants are wildly used in many industrial and household applications. Because anionic surfactants are used so widely, significant attention has focused on the removal of these contaminants from wastewater. Among various treatment techniques, biofiltration, such as trickling filter technologies, has been employed in many wastewater treatment plants (WWPTs) to remove anionic surfactants. However, current knowledge of the efficacy of trickling filter to remove anionic surfactants from wastewaters is limited. The present study characterized the performance of a high rate (i.e. roughing) trickling filter to remove anionic surfactants both at lab-scale and pilot-scale. Lab-scale tests investigated the biodegradation of anionic surfactants under controllable conditions were compared with those from previous studies by others. Pilot-scale tests investigated the efficacy of a trickling filter at removing anionic surfactants from a wastewater over an extended period of time. The data from the pilot-scale tests were used to model the performance of trickling filter at removing anionic surfactants from the wastewater, using first order and modified Velz models. The lab-scale tests indicated that high molecular weight anionic surfactants degrade faster than the low molecular weight surfactants. The biodegradation rates observed in the present study were similar to those from pervious studies by others. The pilot-scale tests indicated that roughing trickling filter could remove 11% to 29% of anionic surfactants and 4% to 22% of COD from the wastewater. Higher molecular weight anionic surfactants were more degradable. The experimental data could be accurately modeled using the modified Velz model (R² value more than 0.9). The degradation rates of modified Velz model for total anionic surfactants, high molecular weight anionic surfactants and COD were 0.053±0.0057, 0.088±0.0048 and 0.119±0.0111 (mIs)0.5 respectively. The pilot-scale test results indicated that a high rate (i.e., roughing) trickling filter was not capable of effectively removing anionic surfactants in the primary effluent at Lions Gate WWTP because a relatively large trickling filter area would be required to achieve the required surfactant removal efficiency. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Dissolved organics in wastewater samples were separated into three size fractions (0-1,000 amu, 1,000-10,000 amu, and 10,000 amu-0.22 m) using ultrafiltration (UF) membranes. The mass distribution within each fraction was adjusted by using a new permeation coefficient model to account for membrane rejection. Dissolved organic and soluble BOD (sBOD) removals in a trickling filter were studied for the different size fractions. The Logan trickling filter model was recalibrated and used to generate predicted removals by size fraction of sBOD, dissolved organic carbon (DOC), and biodegradable DOC (bDOC) for a given influent. Although there was moderate agreement between observed and predicted removals, more investigation is needed to explain shifts in material between different size fractions. Of the three parameters, bDOC may offer a better parameter for modelling trickling filter performance than sBOD.

The feasibility of using bench-scale biotrickling filter reactors inoculated with the fungus UBAF004, isolated from soil in Tahuapalca, for treatment of water contaminated with cypermethrin was investigated. Wood chips, gravel and ceramics were tested as packing materials for the reactors in batch experiments in small glass flasks. Wood proved to be the material on which the fungus grew best and was thus chosen as the packing material for the reactors. It was determined that UBAF004 had quite low competitive strength compared to other microorganisms when growing on wood and gravel but not necessarily on ceramics. UBAF004 grew slowly in the reactors leading to poor degradation performance. The results obtained indicate that it will be challenging to use UBAF004 for treatment of water contaminated with cypermethrin in Tahuapalca. The single largest issue is to find a way to establish a stable population of the fungus in the reactor and to protect it from being out competed by other microorganisms. / <p>Opponent: Veronika Granat</p>

The purpose of this investigation was to study the aerobic digestion of trickling filter humus and the relationship between digestion and the subsequent filterability of the sludge. Five individual, ten liter, batch-type digestion studies were conducted at 20°C for detention periods ranging from 22 to 38 days. Various water quality parameters were monitored during the three digestion runs of trickling filter humus, one digestion run of a 70% primary and 30% trickling filter sludge (by volume), and one digestion run of waste activated sludge completed during this investigation. Results of the investigation showed that trickling filter humus responds to the aerobic digestion process in a manner similar to that of waste activated sludge. Significant total and volatile solids reductions along with consistent mixed liquor BOD₅ reductions were noted for digestion periods of 22 days. Using the concept of specific resistance, the filtration characteristics of the aerobically digested humus were determined to be poorer than those usually obtained for aerobically digested waste activated sludge. The degree of filterability was observed to deteriorate during periods of prolonged endogenous respiration. The primary-trickling filter sludge mixture was observed to adapt to the aerobic digestion process in a manner strikingly similar to that of the purely biological trickling filter humus. / Master of Science

The absence of water catchment protection often results in contamination of drinking water supplies. Waters in South East Asia have been exploited to support extensive agriculture, industry, power generation, public water supply, fisheries and recreation use. Ammonia has been identified as a significant contaminant of drinking water because of its ability to affect the disinfection efficiency of chlorine. The interference of ammonia with chlorination is a prevalent and expensive problem faced by many water treatment plants (WTPs) located throughout South East Asia. The conventional approach for ammonia removal was to pre-chlorinate using high concentrations of chlorine, which has a number of disadvantages including the formation of disinfection by-products and high chlorine consumption. This thesis investigated the application of high rate nitrifying trickling filters (NTFs) as a means of ammonia removal from a polluted lowland water source as an alternative to pre-chlorination. NTFs are widely used for the biological remediation of ammonia rich wastewater, however their performance when required to operate under low ammonia concentrations for potable water applications was unknown. A NTF pilot facility consisting of one large-scale, and three small-scale NTFs were constructed at Hope Valley WTP in South Australia. The NTFs were operated to simulate the raw water quality of a polluted catchment identified in Indonesia (Buaran WTP), including variations in ammonia, biological oxygen demand (BOD5), and turbidity. Results confirmed that plastic-packed NTFs were able to operate equally successfully under low ammonia-N concentrations, some 10- to 50-fold lower that that of conventional wastewater applications, where complete conversion of ammonia to nitrate was consistently observed under these markedly reduced loadings. Results also showed that when operated under mass loads equivalent to typical ammonia loading criteria for wastewater NTFs, by increasing hydraulic flow¬, comparable apparent nitrification rates were achieved. These results confirmed that mass transport limitations posed by low ammonia-N concentrations on overall filter performance were insignificant. This thesis also investigated the impact of organic carbon quantity and biodegradability on the nitrification behaviour of the pilot NTF. Results demonstrated that organic carbon loading, rather than the C:N ratio, was an important regulator of filter nitrification capacity, where a linear decline in nitrification performance correlated well with sucrose and methanol augmented carbon loads. Extensive monitoring of inorganic nitrogen species down the NTF, to profile nitrification behaviour, showed sucrose-induced carbon loads greater than 870 mg sBOD5 m–2 d–1 severely suppressed nitrification throughout the entire filter bed. This study also confirmed that critical carbon loads for nitrification varied among carbon sources. In contrast to sucrose, when a more native-like carbon source was dosed (organic fertiliser), no significant decline in nitrification capacity was observed. This could be attributed to differences in carbon biodegradability. This research has provided new insights into the microbial ecology of a potable water NTF. The combination of fluorescent in situ hybridisation (FISH) and scanning electron microscopy (SEM) for in situ analysis of biofilms was successful in identifying the spatial distribution of ammonia oxidising bacteria (AOB), nitrite oxidising bacteria (NOB) and heterotrophs. When the NTF was operated under low organic loads, clusters of AOB and NOB were abundant, and were located in close proximity to each other. Uniquely, the study identified not only Nitrospira spp but also the less common Nitrobacter spp within the NTF biofilm. Biofilm analysis showed that the type of carbon source also strongly influenced the biofilms characteristics in terms of biomass ecology, morphology, and polysaccharide composition, which was correlated with NTF performance. Results showed that an increase in sBOD5 via the addition of sucrose promoted the rapid growth of filamentous heterotrophic bacteria and production of large amounts of polysaccharide. Stratification of nitrifiers and heterotrophs, and high biofilm polysaccharide concentrations were observed at all filter bed depths, which coincided with the impediment of nitrification throughout the entire filter column. High biofilm polysaccharide concentrations also coincided with a significant increase (40 %) in filter hydraulic retention time, as determined by hydraulic tracer experiments. In contrast to sucrose-fed biofilms, organic fertiliser-fed biofilms had a more uniform and dense ultra-structure dominated by many rod shaped bacteria, and was significantly lower in polysaccharide composition. This observation was coupled with superior nitrification performance. This study confirmed that a well functioning NTF is a viable, low cost alternative for ammonia removal from source water abstracted from poorly protected catchments found in many developing countries. Pre-treatment using NTFs has the potential to reduce the chlorine dose required for pre-chlorination. Thereby improving water quality by minimising the formation of disinfection by-products, and improving the control of chlorination. NTFs could also find ready application in other situations where ammonia interferes with chlorine disinfection.

Acrylonitrile (AN) is a major volatile waste generated in the production of acrylamide and often associated with aromatic contaminants (toluene and styrene) in plant effluents. We examined Rhodococcus rhodochrous DAP 96622 to determine if it could be adapted to efficient biodegradation of acrylonitrile (AN) in a bioreactor. A model bioreactor with granular activated carbon (GAC) as a substratum for Rhodococcus with AN as sole carbon or in combination with toluene was established. The kinetics of AN biodegradation by immobilized and planktonic cells were evaluated and compared. Inlet load and empty retention time were varied to test the removal efficiency in fed-batch and single-pass mode reactor. In addition, the three dimensional structure and characteristics of the biofilm were followed using confocal scanning laser microscopy (CSLM) and relative software. Immobilized cells in the bioreactor, at starting concentrations of AN up to 1150 mg l-1 in the presence of Tol, had at least 13 fold higher AN degradation rates than that seen of planktonic cells. A near steady state of AN degradation was maintained at 75-85% for AN and 80%-90% for Tol within the parameter of EBRT=8 min and AN and Tol inlet loads between 50-200 mg l-1 h-1 and 200-500 mg l-1h-1, respectively. However, when the inlet load of AN was increased to more than 200mg l-1 h-1 and 500 mg l-1 h-1 for Tol, a reduction in efficiency of AN degradation was observed. Biofilms with discrete microcolonies interspersed with voids and channels were observed. Precise measurement of biofilm characteristics agreed with the assumption that the biomass and thickness of the biofilm increased along the carbon column depth. With a porous attachment material like GAC, substrate diffusion is most likely not a limiting factor for AN degradation. Rhodococcus rhodochrous DAP 96622 in a non-sterile activated charcoal column showed efficient degradation of AN in the presence of Tol. The Rhodococcus bioreactor may provide a potential practical waste gas and water treatment system.

The kiln drying of wood produces huge amounts of vapour. The vapour is released to the environment when the process purges some of the saturated hot air. The main environmental issue regarding the use of kiln drying process are the release of the water vapour which contains organic contaminants. Some of them are hazardous to human health. In addition, there are some wood particles which may released with the water vapour purging process. In this research, the vapour is condensed and analysed for its organic contaminants and their biodegradability. The result showed that the dominant contaminants present in the condensate were ethanol and methanol with the concentration of approximately 65 mg/L and 25 mg/L respectively. The average COD concentration of the condensate was 159 ± 40 mg/L. The analysis also showed that the contaminants were biodegradable. In order to treat the wastewater, a trickling filter process using bark chips as a support medium was used to treat an artificial wastewater. The artificial wastewater contained the dominant contaminant present in the wood drying condensate. In the experiment, different sizes of bark chips were used. In addition, the loading rate of the treatment system was varied by changing the flow rate and contaminant concentration. The 30 cm long trickling filter using bark chips varying between of 2.8 – 4 mm diameter as the support medium gave a maximum removal of 36.4 % with removal capacity of 8.34 kg COD/m³bed•day at a flow rate of 2.8 cm/min and average inlet COD load of 20.4 kg COD/m3bed•day. The trickling filter with bark chips varying between 5.6 – 8 mm diameter as the support medium was operated using variations in contaminant concentration and flow rate. The operation using different inlet concentration gave the highest removal rate of 13.5 kg COD/m3bed•day at average initial load of 84.9 kg COD/m³bed•day, flow rate of 2.8 cm/min and theoretical initial concentration of 680 mg/L. The trickling filter operated with flow rate variation showed the highest removal rate of 10 kg COD/m³bed•day at an average inlet load of 53.3 kg COD/m³bed•day and flow rate of 7.1 cm/min. The removal rate of the contaminants in treatment was limited. There is a number of possible explanations. First is the active surface area, which indicating the area where the contact between the biofilm surface and feed happened. The active surface area increased as the flow rate increased. Second is the residence time of the feed in the bed. The residence time of the feed varied with the flow rate. It decreased as the flow rate increased. Third is the influence of the contaminants in the feed. The presence of methanol and methanol in the feed inhibited each other’s degradation. The dimention of a full-scale biotrickling filter to be used in actual kiln was also estimated. The estimation was made based on the maximum removal rate and optimum flow rate obtained in the experiments. The result of the estimation showed to obtain significant removal, the required bed would have to be 2.35 m in diameter and 160 in height.

The objective of this study is to remove turbidity originating from algae present in oxidation ponds effluents by an easy and inexpensive method. For this reason, a novel lab-scale Step Feed Dual Treatment (SFDT) process was constructed and the efficiency of trickling filter (TF) to remove algae and organic matter was investigated. SFDT process developed in this study is the unique, inexpensive and new system to scavenge algae from oxidation pond effluents. In this system, influent is first treated in a stabilization pond, and subsequently they directed to a TF, so as to provide a dual treatment. Moreover, some fraction of the raw influent was directly sent to TF to maintain a steady biofilm on the TF medium. Stabilization pond was not simulated in the experimental set-up as the main objective of the study is to observe TF ability to scavenge algae from pond effluent. To determine the magnitude of the effect of individual operational parameters (hydraulic loading rate, influent COD and chlorophyll-a concentration) and of their combinations on organics and particle removal efficacy an experimental design was followed. Experiments consistent with twolevel factorial design with three variables (23) were performed. Hydraulic loading rate (HLR) (0.5-2 m3/m2.day), influent COD (150-550 mg/l) and influent chlorophyll-a concentrations (Chl-a) (250-600 &micro / g/l) were selected as independent variables. The COD and algae removal (as Chl-a) were selected as dependent variables. Data obtained from the experiments showed that when HLR (m3/m2.day) was increased from 0.5 to 2, Chl-a, NTU, SS and COD removals were decreased, however, more than 85 % removal was attained in each case, except for COD. The lowest removal efficiencies were obtained for all the quality parameters when hydraulic loading was increased to 4 m3/m2.day. It was observed that in general removal percentages for turbidity, Chl-a, SS and COD increased considerably with the decreasing hydraulic loading rate. Highest removals were obtained at lowest HLR. The removal of algae in TF was presumably due to both flocculation (due to algal and bacterial EPS production) and degradation (through bacterial activity) of algae. In conclusion, trickling filter produced clear effluents, with less than 2 NTU, for most of the cases.