The Swedish water sector faces many challenges in terms of climate change, worn out facilities and distribution systems as many of them were built in the 50-, 60- and 70s, but also increased cyber security concerns. Collaborations between different actors are therefore required to address these challenges. This thesis work's purpose is to examine the opportunities a collaboration between water treatment plants could bring for the water sector to achieve a more sustainable drinking water production. The purpose is also to examine the most efficient way to establish a collaboration between them through digital means. A workshop and several interviews with representatives from different water treatment plants were conducted to gather information on possibilities of data/information sharing between them, but also to make a security classification of data/information generated at the water treatment plants. The representatives included process engineers, process technicians, security associates and an associate at Svenskt vatten, an interest organization for the water sector. The result showed that data/information sharing is already taking place in the sector under limited conditions. Smaller VA organizations have more challenges due to lack of skilled workers, partners and time. It is difficult for many in the sector to know where to turn to when in need of help, particularly for smaller VA organizations who usually are the ones with fewer contact networks. It is not to say that only smaller VA organizations are affected but they are more likely to lack contact with other water organizations. The majority of water treatment plants agree on that data/information on treatment processes would be allowed to share under limited conditions. The information classification is a matter for each plant due to different security realities which determines the information classification. This makes it difficult to decide on what parameters could be shared by every water treatment plant. This needs to be investigated further in order to determine what data/information could be shared by most water treatment plants on a platform. Most participants thought that a platform of some kind would be the best solution to simplify data/information sharing between water treatment plants. The suggested platform is a good start for making contacts between water treatment plants and has the potential to enable storage and sharing of data/information in the future. / Den svenska VA sektorn står inför många utmaningar så som klimatförändringar, slitna anläggningar och distributionsnät då många av dem byggdes under 50-, 60- och 70-talet. Även oron kring cybersäkerheten ökar. Samarbeten mellan olika aktörer krävs för att lösa dessa utmaningar. Syftet med examensarbetet är att undersöka de möjligheter som samarbeten mellan vattenverk skulle medföra för att nå en mer hållbar dricksvattenproduktion. Syftet är också att undersöka det mest effektiva sättet att få till ett samarbete mellan vattenverken med digitala medel. En workshop och flertalet intervjuer genomfördes med olika representanter från vattenverk för att samla information om möjligheten med att dela data/information mellan dem. Men också för att göra en säkerhetsklassning av data/information som genereras på vattenverken. Representanterna inkluderade processingenjörer, processtekniker, säkerhetsansvariga samt en medarbetare från Svenskt vatten, en intresseorganisation för vattensektorn. Resultatet visade att delning av data/information redan sker inom sektorn, dock under begränsade former. Mindre VA organisationer har fler utmaningar på grund av brist på anställda med rätt kompetens, samarbetspartners och tid. Många inom sektorn har utmaningar när det kommer till att söka och få hjälp, särskilt för de mindre VA organisationerna som vanligtvis har färre kontakter. Men de är inte bara de små som är påverkade av detta problem, men det är vanligare att de inte har kontakter med andra VA organisationer. De flesta vattenverken ansåg att data/information från reningssteg skulle vara möjligt att dela under begränsade former. Informationssäkerhetsklassning är en enskild fråga för varje vattenverk som baseras på de hot som varje vattenverk står inför. Detta medför att det är svårt att bestämma vilken data/information som kan delas av varje vattenverk. Detta område behöver vidare utredas innan ett beslut kan fattas om vilken data/information alla vattenverk ska dela på en plattform. De flesta deltagarna tyckte att en plattform av något slag skulle vara lösningen för att förenkla delning av data/information mellan vattenverken. Den föreslagna plattformen är en bra start för vattenverk att skapa kontakter och har potentialen att möjliggöra lagring och delning av data/information i framtiden.

An experimental study was carried out to evaluate the performance of pilot scale constructed wetlands for the treatment of domestic wastewater in Addis Ababa, Ethiopia. Three parallel sets of constructed wetlands; consisting of one Horizontal Flow (HF), one Vertical Flow (VF) and one hybrid of HF and VFconstructed in series were built in Addis Ababa. The wetland systems had identical wetland fill media and macrophytes but with different wastewater flow types. The total surface area of the wetland systems was 72 m2 /24 m2 for each/ and designed to treat 3.15 m3 of domestic wastewater per day. Triplicate grab samples were taken from the influent and effluents every 15 days for one year and analyzed within 24 hours. Temperature, pH, DO and EC were measured onsite and the nutrient content of macrophytes was determined twice during the monitoring period. During the first 12 months monitoring period, the average removal efficiencies of the HFCW, VFCW and hybrid CW were: BOD (89.1%, 92.2% and 93.4%), COD (80.6%, 82.1% and 84.0%), TSS (89.1, 83.8% and 84.7%), NH4 + (58.6%, 66.2% and 65.4%), NO3 - (64.0%, 71.5% and 73.5%), TN (49.1%, 54.9% and 58.7%), PO4 3- (45.4%, 50.3% and 48.4%), TP (58.0%, 51.7% and 54.4%) and FC (98.6%, 96.6% and 96.5%), respectively. The hybrid system showed relatively higher removal efficiencies for most pollutants. Again, the wetland systems showed relatively higher percent reduction during the dry seasons /from Dec - May/. The areal removal rate constants of BOD5, TN, PO4 3- and TP were higher than the literature values while the values of COD and TSS were lower compared to the literature values. Concerning the nutrient content of the wetland plant, the average TN contents of the below-ground and above-ground plant part were 1.56% and 2.27% for the HFCW, 1.75% and 2.74% for the VFCW and 1.80% and 2.63% for the hybrid system, respectively. Meanwhile, the average TP contents of the belowground and above-ground plant part were 0.139% and 0.064% for the HFCW, 0.167% and 0.067% for the VFCW and 0.115% and 0.065% for the hybrid systems, respectively. In general, the results showed that properly designed constructed wetland systems could be used as effective wastewater treatment method in Ethiopia. / Environmental Sciences / Ph. D. (Environmental Sciences)

Lau Wai Kee Albert. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 2000-01, design report." / On double leaves. / Includes bibliographical references. / Chapter Chapter 1 --- Prologue --- p.1 / Definition of the unseen space --- p.2 / Unseen space in the city --- p.3 / Chapter Chapter 2 --- Justification of selected unseen space --- p.4 / Definition of nullah --- p.6 / Surface transformation of the nullah --- p.8 / People perception of the nullah --- p.10 / People perception of wastewater --- p.12 / Chapter Chapter 3 --- Justification of site selection --- p.15 / Site analysis --- p.18 / Transportation character --- p.22 / Chapter Chapter 4 --- Physical identity of nullah --- p.25 / Intrinsic meaning of nullah --- p.26 / Chapter Chapter 5 --- Philosophy of nullah --- p.30 / Concept --- p.34 / Project mission --- p.38 / Conceptual strategy --- p.39 / Chapter Chapter 7 --- Philosophical meaning of water --- p.46 / People perception to water --- p.50 / Basic concept in water space design --- p.52 / Chapter Chapter 8 --- Precedent study --- p.56 / Urban rivers --- p.57 / Local rivers --- p.66 / Chapter Chapter 9 --- Design ideas --- p.68 / Appendix / Water quality of Kai Tak nullah --- p.75 / Annual rainfall --- p.76 / "Interview with Dr. Chung, Dept. of Biology, CUHK" --- p.78 / Biblography --- p.80

Industrial effluents with high concentrations of heavy metals are widespread pollutants of great concerns as they are known to be persistent and non-degradable. Continuous monitoring and treatment of the effluents become pertinent because of their impacts on wastewater treatment plants. The aim of this study is to determine the correlation between heavy metal pollution in water and the location of industries in order to ascertain the effectiveness of the municipal waste water treatment plant. Heavy metal identification and physico-chemical analysis were done using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and multi-parameter probe respectively. Correlation coefficients of the measured values were done to investigate the effect of the industrial effluents on the treatment plants. Heavy metal resistant bacteria were identified and characterised by polymerase chain reaction and sequencing. Leeuwkuil wastewater treatment plants were effective in maintaining temperature, pH, and chemical oxygen demand within South Africa green drop and SAGG Standards whereas the purification plant was effective in maintaining the values of Cu, Zn, Al, temperature, BOD, COD, and TDS within the SANS and WHO standard for potable water. This findings indicated the need for the treatment plants to be reviewed.The industrial wastewater were identified as a point source of heavy metal pollution that influenced Leeuwkuil wastewater treatment plants and the purification plants in Vaal, Vereenining South Africa. Pseudomonas aeruginosa, Serratia marcescens, Bacillus sp. strain and Bacillus toyonensis that showed 100% similarity were found to be resistant to Al, Cu, Pb and Zn. These identified bacteria can be considered for further study in bioremediation. / Environmental Sciences / M. Sc. (Environmental Science)

This study is a component of a research project on the economic costs of eutrophication in the Vaal River system. Its objective is to investigate the relationship between raw water quality and the chemical costs of producing potable water at two water treatment plants: Zuikerbosch Station #2 (owned by Rand Water) in the Upper Vaal Water Management Area (UVWMA), and Balkfontein (owned by Sedibeng Water) in the Middle Vaal Water Management Area (MVWMA). Time series data on raw water quality and chemical dosages used to treat raw water were obtained for Zuikerbosch Station #2 (hereafter referred to as Zuikerbosch) for the period November 2004 – October 2006 and for Balkfontein for the period January 2004 to December 2006. Descriptive statistics reveal that raw water in the Vaal River is of a poorer quality at Balkfontein compared to that at Zuikerbosch. Furthermore, the actual real chemical water treatment costs (measured in 2006 ZAR) averaged R89.90 per megalitre at Zuikerbosch and R126.31 at Balkfontein, indicating that the chemical water treatment costs of producing potable water tend to increase as raw water quality declines. Collinearity among water quality (WQ) variables at both water treatment plants was analysed using Principal Component Analysis (PCA). The dimensions of water quality identified in the analysis are similar to those reported in Pieterse and van Vuuren’s (1997) study of the Vaal River. For both water treatment plants, Ordinary Least Squares (OLS) regression was used to identify the relationship between real chemical costs of water treatment and the dimensions of water quality identified through the respective Principal Components Analyses. The estimated regression models account for over 50.2% and 34.7% of variation in real chemical water treatment costs at Zuikerbosch and Balkfontein, respectively. The coefficient estimated for PC1 at Zuikerbosch is statistically significant at the 1% level of probability with high negative loadings of total alkalinity and turbidity. Increases in the levels of total alkalinity and turbidity in raw water treated at Zuikerbosch is negatively related to the chemical costs of water treatment. An increased total alkalinity level was found to reduce the chemical costs of treating potable water. PC2 is statistically the most important variable in the estimated explanatory model for Balkfontein. The estimated regression coefficient for PC2 is statistically significant at the 5% level of probability. The estimated relationship between chemical water treatment costs and PC2 shows that there is a positive relationship between the raw water temperature and chemical water treatment costs. However, increases in the levels of chlorophyll and pH in raw water treated at Balkfontein is negatively related to the chemical costs of water treatment. Total hardness, magnesium, calcium, sulphate, conductivity, and chloride, being the highest positive loadings in PC1, relate negatively to the chemical cost of treating water. For predictive rather than explanatory purposes, a partial adjustment regression model was estimated for each of the two water treatment plants. Using this model, real chemical water treatment costs were specified as a function of real chemical water treatment costs in the previous time period, and of raw water quality variables in the current period. The R2 statistics for the two regression models were 61.4% using the data for Zuikerbosch and 59.9% using the data for Balkfontein, suggesting that both models have reasonable levels of predictive power. The chemical cost of water treatment for Zuikerbosch and Balkfontein are predicted at R96.25 and R90.74 per megalitre per day respectively. If raw water nitrate in the UVWMA increases by 1% per megalitre a day while other factors remain constant, chemical water treatment costs at Zuikerbosch can be expected to increase by 0.297% per megalitre and the cost accompanied this change is (R0.285*1998ML*365days) R207,841.95 provided that Zuikerbosch treats an average of 1998 megalitres per day. Likewise, if Zuikerbosch maintains its daily average operating capacity and is able to maintain an optimal level of total alkalinity in UVWMA, the estimated saving on chemical water treatment cost will be R150.063.78 per annum. At Balkfontein, chemical water treatment cost is expected to increase on average by 0.346% per megalitre per day for a 1% per megalitre per day increase in the level of chlorophyll-a, and the cost accompanied this change is R41,128.20 per annum. The prediction also shows a 2.077% per megalitre per day increase chemical water treatment cost for a 1% increase in turbidity and this accompanied with a chemical water treatment cost of R 249,003 per annum, provided that Balkfontein operates at its full capacity (i.e., 360 megalitres per day). / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

The provision of clean drinking water typically involves treatment processes to remove contaminants. The conventional process involves coagulation with hydrolysing metal salts, typically of aluminium (‘alum’) or trivalent iron (‘ferric’). Along with the product water this also produces a waste by-product, or sludge. The fact of increasing sludge production — due to higher levels of treatment and greater volume of water supply — conflicts with modern demands for environmental best practice, leading to higher financial costs. A further issue is the significant quantity of water that is held up in the sludge, and wasted. / One means of dealing with these problems is to dewater the sludge further. This reduces the volume of waste to be disposed of. The consistency is also improved (e.g. for the purpose of landfilling). And a significant amount of water can be recovered. The efficiency, and efficacy, of this process depends on the dewaterability of the sludge.In fact, good dewaterability is vital to the operation of conventional drinking water treatment plants (WTP’s). The usual process of separating the particulates, formed from a blend of contaminants and coagulated precipitate, relies on ‘clarification’ and ‘thickening’, which are essentially settling operations of solid–liquid separation.WTP operators — and researchers — do attempt to measure sludge dewaterability, but usually rely on empirical characterisation techniques that do not tell the full story and can even mislead. Understanding of the physical and chemical nature of the sludge is also surprisingly rudimentary, considering the long history of these processes. / The present work begins by reviewing the current state of knowledge on raw water and sludge composition, with special focus on solid aluminium and iron phases and on fractal aggregate structure. Next the theory of dewatering is examined, with the adopted phenomenological theory contrasted with empirical techniques and other theories.The foundation for subsequent analyses is laid by experimental work which establishes the solid phase density of WTP sludges. Additionally, alum sludges are found to contain pseudoböhmite, while 2-line ferrihydrite and goethite are identified in ferric sludges. / A key hypothesis is that dewaterability is partly determined by the treatment conditions. To investigate this, numerous WTP sludges were studied that had been generated under diverse conditions: some plant samples were obtained, and the remainder were generated in the laboratory (results were consistent). Dewaterability was characterised for each sludge in concentration ranges relevant to settling, centrifugation and filtration using models developed by LANDMAN and WHITE inter alia; it is expressed in terms of both equilibrium and kinetic parameters, py(φ) and R(φ) respectively.This work confirmed that dewaterability is significantly influenced by treatment conditions.The strongest correlations were observed when varying coagulation pH and coagulant dose. At high doses precipitated coagulant controls the sludge behaviour, and dewaterability is poor. Dewaterability deteriorates as pH is increased for high-dose alum sludges; other sludges are less sensitive to pH. These findings can be linked to the faster coagulation dynamics prevailing at high coagulant and alkali dose.Alum and ferric sludges in general had comparable dewaterabilities, and the characteristics of a magnesium sludge were similar too.Small effects on dewaterability were observed in response to variations in raw water organic content and shearing. Polymer flocculation and conditioning appeared mainly to affect dewaterability at low sludge concentrations. Ageing did not produce clear changes in dewaterability.Dense, compact particles are known to dewater better than ‘fluffy’ aggregates or flocs usually encountered in drinking water treatment. This explains the superior dewaterability of a sludge containing powdered activated carbon (PAC). Even greater improvements were observed following a cycle of sludge freezing and thawing for a wide range of WTP sludges. / Further aspects considered in the present work include deviations from simplifying assumptions that are usually made. Specifically: investigation of long-time dewatering behaviour, wall effects, non-isotropic stresses, and reversibility of dewatering (or ‘elasticity’).Several other results and conclusions, of both theoretical and experimental nature, are presented on topics of subsidiary or peripheral interest that are nonetheless important for establishing a reliable basis for research in this area. / This work has proposed links between industrial drinking water coagulation conditions, sludge dewaterability from settling to filtration, and the microstructure of the aggregates making up that sludge. This information can be used when considering the operation or design of a WTP in order to optimise sludge dewaterability, within the constraints of producing drinking water of acceptable quality.

MENVSC / Department of Ecology and Resource Management / Fluoride is one of the anionic contaminants which is found in excess in groundwater because of geochemical reaction or anthropogenic activities such as the disposal of industrial wastewaters. Among various methods used for defluoridation of water such as precipitation, ion-exchange processes, membrane processes, the adsorptions process is widely used. It offers satisfactory results and seems to be a more attractive method for the removal of fluoride in terms of cost, simplicity of design and operation. In this work, the preparation of clay polymer nanocomposites (CPNCs) used in defluoridation began by modifying the original natural Mukondeni clay to render the layered silicate miscible with the chosen polymer, microcrystalline cellulose. Clay polymer nanocomposites (CPNCs) were synthesized using the melt intercalation method. Mukondeni black clay with microcrystalline cellulose as polymers was melt mixed at 220 °C for 10 minutes in an extruder for exfoliation of the resulting composite. Physicochemical characteristics and mineralogical characteristics of the CPNC was determined using XRD, XRF, BET, FTIR and SEM. Batch adsorption experiments were conducted to determine the efficiency of CPNCs in defluoridation of groundwater. The pH, EC, TDS and fluoride concentration of field water was determined using the CRISON MM40 multimeter probe and the Orion versastar fluoride selective electrode for fluoride concentration. Elemental analysis revealed that CPNC 1:1 is mainly characterized of cellulose, Quartz and Albatite as the major minerals with traces of Montmorillonite, Ednite and Magnesium as minor minerals constituting CPNC 1:1. The structure of 1:4 CPNC was partially crystalline and partially amorphous showing increased cellulose quantity (1:4 clay to cellulose) as compared 1:1 CPNC, 1:2 CPNC and 1:3 CPNC. Maximum adsorption of fluoride was attained in 10 minutes using 0.5g of 1:4 CPNC removed 22.3% of fluoride. The initial fluoride concentration for the collected field groundwater was 5.4 mg/L, EC 436 μS/cm, and TDS 282 mg/L. The regeneration potential of CPNCs was evaluated through 3 successive adsorption desorption cycles. Fluoride removal decreased after the first cycle for all ratios of CPNCs, a continued decreased can be observed following the second cycle. CPNC 1:2 decreased from 9.32 % at the 1st cycle to 2.84 % and 0.56 % on the 2nd and 3rd cycle respectively. CPNC 1:4 decreased from 8.22 % at the 1st cycle to 4.80 % and 0.72 % on the 2nd and 3rd cycle respectively. The fluoride-rich Siloam groundwater had a slightly alkaline pH of 9.6. iv The low adsorptive characteristic displayed by all 4 CPNCs can be deduced from the BET analysis that revealed low surface area, pore volume, and pore size, it is evident from the BET analysis that less fluoride will be absorb as adsorption sites will be limited. Based on the findings of this study, recommendations are designing of correct preparation techniques to obtain nanocomposites with desirable properties, polymer melting points and evaporation point of the binder should be taken into consideration. / NRF