<p>In connection with Henriksdals wastewater treatment plant (WWTP) a smaller plant is situated called Sjöstadsverket where new methods for wastewater treatment are tested and evaluated in different process lines. On one of the lines experiments with enhanced biological phosphorous removal (EBPR), have been carried out to evaluate if it is a good alternative to traditional chemical phosphorus removal. This thesis evaluates the results from the experiments conducted during fall 2005.</p><p>The incoming water from Hammarby Sjöstad consists of only household wastewater, which gives a wastewater with high concentrations of nutrients and organic carbon. This is partly positive, because one of the limiting factors for effective biological phosphorus removal is the lack of easily biodegradable organic carbon. The high concentrations of ammonium and phosphorus demand a high reduction to achieve the requirements of outgoing concentration.</p><p>To optimize the process experiments with different recirculations and different aeration techniques have been made. The experiments have shown that it is possible to obtain good results, with periods of very low outgoing phosphorus concentrations below 0,15 mg/L. It was, however, hard to obtain a stable process and to keep a good sludge quality during the period.</p><p>Primary sludge was hydrolysed to increase the amount of easily degradable organic material into the biological step of the process. The hydrolyse had a high efficiency during the test period, but with big variations. The most desirable fraction of organic material, VFA, increased to approximately 1500 mg/L during the best periods. This is only 9 % of the amount VFA in the primary sedimentation, but could be increased with a higher flux.</p><p>When the bioP sludge is fermented as a part of sludge treatment, a supernatant from digester sludge with high concentrations of phosphorus is received. To avoid to return phosphor into the activated sludge process and to recycle phosphorus, experiments with phosphorus precipitation were made. By using struvite precipitation up to 92 % of the phosphorus in the supernatant was reduced and precipitated. This was 12 % of the total amount of incoming phosphourus and was achieved at a pH just over 9 in the experiment tank and a Mg:P quote of 1:1.</p> / <p>I anslutning till Henriksdal’s reningsverk ligger Sjöstadsverket som är ett mindre reningsverk där nya reningsmetoder testas och utvärderas i på ett antal olika försökslinjer. På en av linjerna har försök med biologisk fosforrening, även kallat BioP, utförts för att undersöka om det är ett alternativ till konventionell kemisk rening av fosfor. Detta arbete sammanfattar resultaten från de experiment som utförts under hösten 2005.</p><p>I Hammarby Sjöstad, som förser Sjöstadsverket med avloppsvatten, separeras dag och spillvatten, vilket bidrar till ett näringsrikt vatten med en hög halt organiskt material. Detta är delvis positivt, då en av de begränsande faktorerna för en effektiv biologisk fosforrening är bristen på lättillgängligt organiskt material. De höga halterna inkommande fosfor och kväve kräver dock en högre reningsgrad för att de stränga utsläppsmålen ska nås. För att optimera processen har försök med olika inställningar på recirkulationsgrader genomförts och försök med olika luftningsstrategier. Försöksperioden har visat att det går att få mycket bra resultat, med periodvis utgående fosfathalter under 0,15 mg/L. Det har dock varit svårt att få en stabil process och behålla en bra slamkvalitet under hela försöksperioden.</p><p>Primärslam från försedimenteringen har hydrolyserats för att öka mängden lättillgängligt organiskt material in till det biologiska reningssteget. Hydrolysen fungerade bra under hela försöksperioden, dock med stora variationer. Den mest önskvärda fraktionen lättillgängligt organiskt material, VFA, hade under de bästa perioderna ökat till ca 1500 mg/L i hydrolysen. Detta utgör approximativt 9 % av mängden VFA i försedimenteringen, men skulle kunna ökas vid ett större flöde.</p><p>Då BioP-slammet rötas som en del av slambehandlingen fås ett fosforrikt rejektvatten. För att undvika att få in fosfor till aktivslamprocessen och för att ta till vara på fosfor som näringsämne har försök med fosforåtervinning från rejektvatten gjorts. Genom att använda sig av struvitfällning kunde upp till 92 % av fosforn i rejektvattnet reduceras och fällas ut. Detta motsvarar 12 % av den totala inkommande fosforhalten och uppnåddes vid pH strax över 9 i struvitfällningstanken och med en Mg:P kvot på 1:1.</p>

<p>This study was made as a part of a feasibility study on a polishing wetland at Rimbo wastewater plant (wwp) in Norrtälje municipality. The wwp had to decrease the nitrogen discharge to reach the limit 15 mg tot-N/l. The nitrogen in the outlet was mainly in the form of nitrate, hence the wetland mainly ought to support denitrification. The proposed area for the wetland was situated right next to the wwp and was already in the municipalitys posession. One aim of this study was to examine what spieces of plants needed to achieve highest possible denitrification. Some different plant spieces for providing a good and interesting environment for birds and people were also proposed. Furthermore a massbalance model was developed for studying the important exchange processes in a wetland, to study the impact of an uneven streambed on the hyporheic water exchange and for trying to predict the wetlands nitrogen removal capacity. Proposed plants to support denitrification was different reeds such as Common reed (Phragmites australis), Bulrush (Typha), Reed Sweet-grass (Glyceria maxima) och Reed Canry-grass (Phalaris Arundinacea). Common reed is a durable species who can survive in deeper water up to 2 metres while the others need a shallower water about 0,5 m of depth. For the good of the birdlife, different spieces of Sedges (Carex) were chosen due to their ability to produce large amounts of nutrient rich seeds. Measurment in sediment cores from Ekeby wetland in Eskilstuna gave a potential denitrification capacity of 3,31 mg NO3-N m^-3 _sed s^-1. The denitrification capacity was then used in a massbalance model were the theory of advective pumping in an uneven bedsurface also was implemented. Evaluation of the model results showed that an uneven bedsurface did not contribute to an increased nitrogen removal from the wetland, possibly due to a far too low advection and flow of the water. This was also a reason to why the distribution between denitrification from the water- and plant community vs the sediment was unbalanced. The model results showed that less than 1 % of the reduced nitrogen came from the sediment part, in contrast to current knowledge that says about 50%. The model and the participating exchange processes need to be further evaluated before the models prediction of nitrogen removal can be used in design of a wetland. Calculations and comparisons with other wetlands showed that with a well estimated, grown up and maintained wetland, there should be no problems in achieving the goal of nitrogen removal in Rimbo wetland. Such a wetland should also provide a good habitat for birds and animals and also be a good recreationarea for people to visit, properties that were appreciated as important effects in other wetlands studied in this work.</p> / <p>Detta arbete gjordes som en del av en förstudie för anläggande av en efterpolerande våtmark till reningsverket i Rimbo, Norrtälje kommun. Reningsverket behövde sänka sitt utsläpp av kväve till riktvärdet 15 mg tot-N/l. Huvuddelen av kvävet i utloppsvattnet förelåg i nitratform, varför denitrifikationen borde förstärkas genom att anlägga en våtmark. Det tilltänkta området för våtmarken ligger i anslutning till reningsverket och ägs idag av kommunen. I detta arbete undersöktes vilken växtlighet i våtmarken som var lämpligast för syftet att få en så bra denitrifikation som möjligt. Även olika växtarter för att ge en intressant miljö för fåglar och människor togs fram. Dessutom utvecklades en massbalansmodell som användes för att studera de utbytesprocesser som är viktiga i en våtmark, frågan hur en ojämn bottenmorfometri påverkar det hyporheiska vattenutbytet samt om det går att förutsäga reningskapaciteten i Rimbo våtmark. Lämpliga växter för denitrifikationen ansågs vara vassbildande växter, och då främst främst bladvass (Phragmites australis), men även kaveldun (Typha), jättegröe (Glyceria maxima) och rörflen (Phalaris Arundinacea). Bladvass är en mycket tålig växt som klarar stort vattendjup, medan de andra vassorterna behöver en grundare våtmark på ca 0,5 m. För fågellivets bästa ansågs starrväxter (Carex) vara viktiga arter då de producerar stora mängder frön. Mätning av denitrifikationspotentialen i sediment från Ekeby våtmark gav en hastighet för denitrifikationen i sedimentet på 3,31 mg NO3-N m^-3 _sed s^-1. Denitrifikationen från sediment användes sedan i en massbalansmodell där även även teorin om advektivt pumputbyte vid ojämn bottenform implementerades. En utvärdering av modellresultaten kunde avgöra att en ojämn eller vågig bottenmorfometri inte skulle förbättra reningen i våtmarken. Detta beroende på bland annat för låg advektionshastighet och flöde. Detta låga flöde ned i sedimentet bidrog även till att fördelningen av kväveborttag från sediment respektive vatten- och växtdelen blev snedfördelad. Enligt modellen var det mindre än 1% av kvävet som togs bort från sedimentet medan all vetenskap tyder på närmare 50%. Modellen och de ingående utbytesprocesserna bör utvärderas och utvecklas ytterligare innan den kan användas som verktyg för att beräkna kvävereningen från en våtmark. Beräkningar och jämförelser med andra våtmarker visade dock att en väl beväxt, utförd och beskickad våtmark inte skulle ha några problem att sänka nitrathalten till riktvärdet. En våtmark skulle även utgöra en bra uppehållsmiljö för fåglar, djur och människor vilket anses som viktiga mervärden i våtmarker på andra platser i Sverige.</p>

This dissertation presents a series of studies relating to optimization of kinematics and consumables during chemical mechanical planarization processes. These are also evaluated with the purpose of minimizing environmental and cost of ownership impacts.In order to study diamond micro-wear and substrate wear during planarization processes, a series of static etch tests and wear tests were performed using different types of diamond discs and subjected to various treatments. Scanning Electron Microscopy (SEM) and Inductively Coupled Plasma Membrane Spectroscopy (ICPMS) were used to estimate the extent of diamond micro-wear and substrate wear.Next, the impact of various factors (type of slurry abrasive, pH, abrasive content and abrasive concentration) on pad wear rate during planarization process was studied. Another study in this dissertation focuses on the development of a novel technique of using coefficient of friction (COF) data to distinguish between good and bad diamond discs. This study made use of the innovative tool diamond disc dragging device (DDD-100) designed and developed for the purpose of this study.It is known that the performance of chemical mechanical planarization depends significantly on the polishing pad grooving type and the kinematics involved in the process. Variations in pad grooving type as well as pressure and sliding velocity can affect polishing performance. One study in this dissertation investigates the effect of pressure and sliding velocity on the polishing performance. The study is conducted on multiple pressure and sliding velocity variations to understand the characteristic of each condition. A subsequent study focuses on the impact of pad grooving type on polishing performance.The greatest contribution of this dissertation involves development of the novel slurry injector to optimize the utilization of slurry during planarization processes. Slurry is a critical component in chemical mechanical planarization processes and accounts for approximately 50 percent of the cost of ownership (CoO). The novel injector apart from reducing the consumption of slurry, also contributed in addressing problems associated with foaming, reduced the number of defects and achieved better within wafer non-uniformity (WIWNU).

The characteristics of dissolved aquatic organic matter present in four natural water sources, as well as corresponding treated waters derived from eight water treatment plants, is described. An assessment is made of the performance of direct filtration, conventional treatment, and lime softening in removing trihalomethane (THM) precursors from a diverse array of water sources. A comparison is made between conventional treatment and direct filtration in removing THM precursors from a common natural water source, the Colorado River. In addition, the effect of selected initial conditions and operating parameters on the direct filtration process are evaluated by using a synthetic water/bench-scale apparatus. Important characteristics of the organic matter, including molecular weight (MW) distribution, carboxylic acidity and humic substances content, appear to affect the removal of this organic material. As a general rule, THM reactivity or yield (ug THM/mg C) increases with MW. The <10,000 MW range was found to be the most consistent reactive fraction of aquatic organic matter. All of the various treatments preferentially removed the most reactive fraction of precursor present in each MW range. None of the various treatments proved to be very effective in removing precursor material below a MW of <500. Humic molecules, with the highest carboxylic acidity and hence highest charge density, are generally more difficult to remove by alum coagulation. All of the various treatment processes studied preferentially removed hydrophobic over hydrophilic aquatic organic matter. None of the source related conditions (fulvic acid, kaolinite, pH) nor process-related conditions (flocculation velocity gradient, mixing time, prechlorination, preozonation) evaluated under the same experimental conditions exerted a major impact upon the performance of the bench-scale direct filtration process. Larger sized particles may be easier to remove by bench-scale treatment, but removal of the smaller particles may result in better removals of organic matter as quantified by NVTOC and UV Absorbance.

In-based III-V compound semiconductors have higher electron mobilities than either Si or Ge and direct band gaps. These properties could enable the fabrication of low power, high-speed n-channel metal oxide semiconductor field effect transistors (MOSFETs) and optoelectronics combining MOS technology with photonics. Since thermal and native oxides formed on III-V surfaces exhibit large current leakage and high densities of trap states, a key to incorporating these materials into advanced devices is the development of processing steps that form stable interfaces with dielectric layers. In this thesis, a processing flow consisting of native oxide removal using HF chemistries and deposition of high dielectric permittivity films using atomic layer deposition was investigated. Understanding the reaction mechanisms of these processes could provide the means of controlling composition and structure, yielding a desired electronic behavior. Quantitative X-ray photoelectron spectroscopy analysis of surfaces was coupled with electrical measurements on MOS capacitors of the interface quality in order to understand the nature of high-k/III-V interface defects and their repair. Ex situ liquid phase HF etching removed InSb, InAs, and InGaAs(100) native oxides and produced an Sb- or As-enriched surface, which oxidized when exposed to air. A 5 to 22 °A thick As- and Sb-rich residual oxide was left on the surface after etching and < 5 min of air exposure. The results showed that group V enrichment originated from the reduction of group V oxides by protons in the solution and the preferential reaction of HF with the group III atom of the substrate. A sub-atmospheric in situ gas phase HF/H2O process removed native oxide from InSb, InAs, and InGaAs(100) surfaces, producing an In or Ga fluoride-rich sacrificial layer. A 50 to 90% oxide removal was achieved and a 10 to 25 °A-thick overlayer consisting of mainly In and Ga fluorides was produced. The composition and morphology of the sacrificial layer were controlled by the partial pressure of H2O as well as the ratio of HF to H2O used. Water played a critical role in the process by directly participating in the etching reaction and promoting the desorption of fluoride etching products. Accumulation of thick fluoride layer at high HF to water partial pressure ratios prevented adsorption and diffusion of etchant to the buried residual oxide. When oxide was removed, HF preferentially reacted with In or Ga atoms from the substrate, enriching the surface with group III fluorides and producing approximately one monolayer of elemental group V atoms at the interface. Interface reactions occurred during atomic layer deposition of Al2O3, in which trimethylaluminum (TMA) removed surface oxides and fluorides. Chemically sharp InSb/Al2O3 and InGaAs/Al2O3 interfaces were achieved for gas phase HF-etched InSb and liquid phase HF-etched InGaAs. A ligand transfer mechanism promotes nucleation of Al2O3 and removal of III-V atoms from the sacrificial oxide and fluoride layers as volatile trimethyl indium, gallium, arsenic, and antimony. These reactions have been explained by the relative bond strength of surface and precursor metal atoms with O and F. Interaction of a InSb(100) surface with TiCl4 as a model for metal halide ALD precursors showed that similar ligand transfer reactions occured. Adsorbed chlorine from the dissociative adsorption of TiCl4 on the InSb surface at elevated temperature, however, preferentially etched In atoms from the substrate and produced a roughened surface. The quality of InGaAs/Al2O3 interfaces prepared by solvent cleaning and liquid phase HF were assesed electrically using capacitance-voltage and conductance measurements. Surface recombination velocity (SRV) values were extracted from the measurements to represent the net effect of interface defects, which includes defect density and capture cross section. The InGaAs/Al2O3 interface prepared by solvent cleaning consisted of interfacial native oxides while that etched in liquid phase HF consisted of submonolayer arsenic oxide. The two chemically contrasting interfaces, however, gave similar SRV values of 34.4±3.7 and 28.9±13.4 cm/s for native oxide and liquid phase HF prepared samples, respectively. This suggests that the presence or absence of oxides was not the only determining factor. Post Al2O3 deposition annealing in forming gas and NH3 ambient significantly improved the electrical quality for both surfaces, as shown by SRV values between 1 to 4 cm/s which is comparable to that of an ideal H-terminated Si surface. XPS analysis showed that the contribution from elemental As and Ga2O3 at the interface of both surfaces increased after annealing in forming gas and NH3, likely due to thermal or hydrogen-induced reaction between interfacial As oxide and Ga atoms in the substrate. There was no correlation between the atomic coverages of interfacial elemental As and oxides to the SRV values. High activity defects at III-V/Al2O3 interfaces are associated with interfacial dangling bonds which were passivated thermally and chemically by annealing in forming gas and NH3.

Two surface water sources in the southwestern United States, Colorado River Water (CRW) and California State Project Water (SPW), were studied in bench-scale experiments examining two Trihalomethane (THM) precursor removal processes, activated carbon adsorption and ozone oxidation. Both source water contained bromide (Br-) ion leading to brominated THMs upon chlorination. Activated carbon removed THM precursors, as measured by dissolved organic carbon (DOC), while having little effect on bromide. The net result was an increase in the ratio of Br-/DOC and an increase in the relative abundance of brominated THMs. Ozone oxidized higher molecular weight precursor molecules into lower molecular weight by-products which were less reactive with chlorine. Moreover, ozonation transformed Br- to hypobromous acid (an "in-situ" oxidant), leading to an increase in the percentage of brominated THMs.

This thesis covers work carried out on algae bioreactors as a tertiary treatment process for wastewater treatment. The process was primarily assessed by the removal of Phosphorus and Nitrogen as an alternative to chemical and bacterial removal. Algal bioreactors would have the added advantage of carbon sequestration and a by-product in the energy rich algal biomass that should be exploited in the existing AD capacity. Laboratory scale bioreactors were run (4.5-30L) using the secondary treated final effluent from the local Loughborough sewage works. In a preliminary series of experiments several different bioreactor designs were tested. These included both batch feed and continuous flow feed configurations. The bioreactors were all agitated to keep the algal cells in suspension. The results demonstrated that the most effective and easy to operate was the batch feed process with the algal biomass by-product harvested by simple gravitational settling. Experiments also compared an artificial light source with natural light in outdoor experiments. Outdoor summer light produced greater growth rates but growth could not be sustained in natural UK winter light. Light intensity is proportional to productivity and algae require a minimum of around 97W/m2 to grow, an overcast winter day (the worst case scenario) was typically around 78W/m2, however this was only available for a few hours per day during Nov-Jan. The process would be better suited to areas of the world that receive year round sunlight. It was shown that phosphorus could be totally removed from wastewater by the algae in less than 24 hours depending on other operating variables. With optimisation and addition of more carbon, a HRT of 10-12 hours was predicted to achieve the EU WFD / UWWTD standard. It was further predicted that the process could be economically and sustainably more attractive than the alternatives for small to medium sized works. Biomass 3 concentrations of between 1-2g/L were found to best achieve these removals and produce the fastest average growth rates of between 125-150mg/L/d. The uptake rates of phosphorus and nitrogen were shown to be dependent on the type of algae present in the bioreactor. Nitrogen removal was shown to be less effective when using filamentous bluegreen algae whilst phosphorus removal was almost completely stopped compared to unicellular green algae that achieved a nitrogen uptake of 5.3mg/L/d and phosphorus uptake of 8mg/L/d. Soluble concentrations of Fe, Ni and Zn were also reduced by 60% in the standard 10 hours HRT. The predominant algae were shown to depend largely on these concentrations of phosphorus and nitrogen, and the strain most suited to that specific nutrient or temperature environment dominated. Nutrient uptake rates were linked to algal growth rates which correlated with the availability of Carbon as CO2. CO2 was shown to be the limiting factor for growth; becoming exhausted within 10 hours and causing the pH to rise to above 10.5. The literature showed this was a common result and the use of CO2 sparging would more than double performance making this process a good candidate for waste CO2 sequestration. Heat generated from combustion or generators with exhaust CO2 would also be ideal to maintain a year round constant temperature of between 20-25°C within the bioreactors. A number of possible uses for the algal biomass generated were examined but currently the most feasible option is wet anaerobic co-digestion. Further economic analysis was recommended on the balance between land area and complementary biomass generation for AD. It was also suggested given the interest as algae as a future fuel source, the process could also be adapted for large scale treatment and algal biomass production in areas of the world where land was available.

Submitted in partial fulfillment of the requirements for the degree in Masters of Technology: Chemistry, ML Sultan Technikon, Durban, 2003. / The pollution of water bodies by heavy metals is a serious threat to humanity. The technique known as phytoremediation is used to clean up these polluted water bodies. The accumulation of heavy metals by aquatic plants is a safer, . cheaper and friendlier manner of cleaning the environment. The aquatic plants -studied in this project are A.sessilis, P.stratiotes, R.steudelii and T.capensis. The accumulation of heavy metals in aquatic plants growing in waste water treatment ponds was investigated. The water, sludge and plants were collected from five maturation ponds at the Northern Waste Water Treatment Works, Sea Cow Lake, Durban. The samples were analysed for Zn, Mn, Cr, Ni, Pb and Cu using ICP-MS. In general it was found that the concentrations of the targeted metals were much lower in the water (0.002 to 0.109 mg/I) compared to sediment/sludge (44 to 1543mg/kg dry wt) and plants (0.4 to 2246 mg/kg dry wt). These results show that water released into the river from the final maturation pond has metal concentrations well below the maximum limits set by international environmental control bodies. It also shows that sediments act as good sinks for metals and that plants do uptake metals to a significant extent. Of the four plants investigated it was found that }t.sessi[ir (leaves, roots and stems) and }A.sessilis (roots and stems) are relatively good collectors of Mn and Cu respectively. These findings are described in the thesis. The concentration of heavy metals in the stems, leaves and roots of the three plants were compared to ascertain if there were differences in the ability of the plant at different parts of the plant to bioaccumulate the six heavy metals studied. / M

Lors du fonctionnement d’une machine de fusion, les interactions plasma-parois conduisent à des processus d’érosion des matériaux et à la production de particules. Ces poussières sont principalement composées de carbone et de tungstène. Pour des raisons de sureté et afin de garantir un fonctionnement optimum du réacteur, il est important de garder en quantité raisonnable les poussières dont la taille varie entre 10 nm et 100 $m. La mise en suspension de ces poussières est une étape préliminaire à leur récupération, et le laser est une technique prometteuse pour cette application. Afin d’optimiser le nettoyage, les mécanismes physiques à l’origine de l’éjection induite par laser de ces poussières ont été identifiés. Les agrégats sont directement ablatés par le laser et les gouttelettes métalliques sont éjectées intactes par une force électrostatique induite par les photoélectrons. Nous avons également caractérisé l’éjection des particules pour choisir un système de récupération adapté. / During tokamak operation, plasma-wall interactions lead to material erosion processand dusts production. These dusts are mainly composed by carbon and tungsten, with sizesranging from 10 nm to 100 $m. For safety reasons and to guarantee an optimum reactorfunctioning, the dusts have to be kept in reasonable quantity. The dusts mobilization is a firststep to collect them, and the laser is a promising technique for this application. To optimizethe cleaning, physical mechanisms responsible for dust ejection induced by laser have beenidentified. Some particles, such as aggregates, are directly ablated by the laser. The metaldroplets are ejected intact by an electrostatic force, induced by the photoelectrons. We alsocharacterized the particles ejection to choose an appropriate collection device.

Submitted in complete fulfillment for the degree of Doctor of Philosophy (Biotechnology) in the Department of Biotechnology and Food Technology, Durban University of Technology, Durban, South Africa, 2016. / Many households in developing countries are still without proper sanitation systems. The problems are even more prevalent in rural communities where there are no septic systems in place for the treatment of wastewater. This has resulted in the urgent need for the development and implementation of innovative wastewater treatment systems that are inexpensive, environmental friendly and are able to reduce contaminants to levels that pose no harm to the communities. Constructed rhizofiltration systems have been explored for this purpose. They have been used for many decades in many countries with varying degrees of success at the primary, secondary and tertiary levels of wastewater treatment. Poor optimization of this technology has been due to limited information available about the roles played by the whole system as well as by each component involved in the treatment technology. The current work elucidates the role played by macrophytes and microbial biofilms in the removal of nutrients in the rhizofiltration system. Factors affecting waste removal as well as environmental friendliness of the system were also investigated. The rhizofiltration system was constructed in Durban and was divided into planted (planted with Phragmites australis and Kyllinga nemoralis) and unplanted (reference) section. Dissolved oxygen (DO), pH, water temperature, total dissolved solids (TDS), electrical conductivity (EC) and salinity were monitored. The removal efficiency of nutrients was measured using spectrophotometric methods by measuring the concentration of ammonia, nitrate, nitrite, phosphate and orthophosphate in the wastewater pre- and post-treatment. The total organic carbon, chemical oxygen demand (COD), total Kehldjahl nitrogen, biological oxygen demand (BOD), ammonia, nitrate and the flow rate of wastewater into the system from the settling tank were used for the estimation of carbon dioxide, methane and nitrous oxide emitted from the rhizofilter using the 2009 EPA formulae. Both the planted and reference sections of the system removed nutrients with varying efficiencies. The reduction of nutrients in the rhizofilter was found to be seasonal, with most nutrients removed during the warm seasons. The system also retained more nutrients when wastewater containing low levels of nutrients was used. The unpaired t-test was used to determine the differences between nutrient removals between planted and reference sections. Higher reduction efficiencies of nutrients were obtained in the planted section. Up to 65% nitrite and 99% nitrate were removed while up to 86% total phosphorus was removed in a form of orthophosphate (86%). Removal of total nitrogen was shown to increase under high temperature conditions, while the same conditions decreased the total phosphorus removal. High temperatures also increased the performance of the system. The reduction of nutrients in the system corresponded to reduction of the chemical oxygen demand which also positively correlated to the dissolved oxygen concentration. Considering the discharge limits for all nutrients, the discharges in the effluent of the planted section were within the allowable limits as per South Africa’s Department of Water affairs and Forestry in 2012 but not in 2013. The results obtained in 2013 were due to increased nutrient loading introduced into the system. Diverse microbial communities occurred in the treatment system, with more diversity in the planted section. These organisms were supported by macrophytes in the planted section, and were responsible for nitrogen and phosphorus transformation. This explains why total nitrogen and phosphorus reduction was higher in the planted compared to the reference section. Both the planted and the reference sections of the rhizofiltration system produced the greenhouse gases. When the two sections were compared, the planted section produced more gases. Gases emitted by both sections were lower when compared to emission from sludge treatment reed beds and other conventional systems of wastewater treatments. These findings indicated that constructed rhizofiltration is a cleaner form of waste treatment, producing significantly less greenhouse gases and affecting less of a climate change. Findings of this work have revealed that rhizofiltration technology can be used as a low-cost alternative technology for the treatment of wastewater, using the combination of macrophytes and microbial biofilms. Macrophytes accumulated nitrogen and phosphorus as well as supported diverse microorganisms that metabolized and reduced nutrients in the rhizofiltration unit. / D