An alum coagulation treatment facility employing mixing, flocculating, and settling units, designed by criteria commonly used in the design of water treatment facilities, was operated to determine whether or not it could effectively remove algae and other suspended matter from raw sewage stabilization lagoon effluent. Algal sludge produced by the treatment facility was investigated: (1) to evaluate its potential as a soil conditioner; (2) to determine whether a stabilization lagoon could be used for algal sludge disposal; and (3) to determine whether or not sludge recirculation would reflect a chemical savings. The experimental lagoons and treatment facility, owned by Sanitary District No. 1 of Pima County, Arizona, were located near Tucson, Arizona. It was found, in a field study, that mixing, flocculating, and settling units commonly used for water treatment were efficient in clarifying lagoon effluent and produced a water with the appearance of tap water. Active photosynthesizing algae, producing high oxygen concentrations in lagoon effluent, caused flotation of alum coagulated algal sludge; however, by selecting lagoon effluent low in dissolved oxygen content, algal sludge flotation in the treatment facility was prevented. Algal sludge with Less than one percent total solids was readily dewatered in three days by sand bed drying. Resuspension of air dried algal sludge resulted in a maximum moisture uptake of 50 percent of the final wet weight. Dry algal sludge contained 47 to 61 percent volatile solids, 1.6 to 5.2 percent total phosphorus, and 3.6 to 4.9 percent organic nitrogen. No significant amount of ammonia nitrogen or nitrite-nitrate nitrogen was present in the sludge. The composition and characteristics of dry algal sludge indicate applicability as an aid to soil conditioning. For three months the characteristics of a lagoon used for algal sludge disposal were compared with a control lagoon operated in parallel; it was found that the returned algal sludge was not detrimental to the stabilization process. Acid treated and non-acid treated algal sludge produced from completely treated lagoon effluent had a clarifying value when reused with alum to coagulate effluent, but neither acid treated nor nonacid treated sludge produced from partly treated effluent caused additional clarification when returned with the same coagulant dose that initially produced the sludge. None of the different types of return sludge investigated had a clarifying value when returned under operating conditions necessary to obtain a coagulant savings.

No description available.

<font face="Times New Roman"><font face="Times New Roman"> <p align="left">The popularization and health benefits associated with the &ldquo / Mediterranean diet&rdquo / saw a world wide increase in the production and consumption of processed olives and olive oil. During the brining of table olives large quantities of processed olive waste water is seasonally generated. This blackish-brown, malodours liquid is rich in organic and phenolic compounds, which cause environmental problems upon discarding. Currently, processed wastewater is discarded into large evaporation ponds where it poses serious environmental risks. The biodegradation of organic substrates present in the olive wastewater is inhibited by the high concentrations of phenolic compounds. <font face="Times New Roman">In order to identify organisms which could potentially be used in the bioremediation of olive wastewater, 36 microbial strains were isolated from evaporation ponds in the Boland region of South Africa. Twenty five isolates were capable of growth on 50% olive wastewater and their bioremediation potential as well as their ability to produce valuable intermediate compounds were subsequently characterized. Based on the RPHPLC results, which showed that a number of chemical intermediates were produced in fermentation of olive wastewater, isolate AS-35 was selected for further analysis. Strain AS-35, identified as a </font><font face="Times New Roman"><em>Bacillus megaterium,</em> </font><font face="Times New Roman">was significantly influenced by the exposure to olive waste. The total cellular protein profile, generation time and cellular morphology of this isolate were dramatically affected by the introduction of olive waste. <font face="Times New Roman">This study investigated the differential gene display of </font><font face="Times New Roman"><font face="Times New Roman"><em>Bacillus megaterium</em></font> </font><font face="Times New Roman">following exposure to olive wastewater. Proteomic and transcriptomic differences of the organism cultured in nutrient rich LB and olive wastewater were compared. These results indicated that AS-35 expressed genes involved in glycolysis, tryptophan and nucleotide synthesis as well as the chaperones GroEL and DnaK during its growth in LB. In contrast, genes induced following the abolishment of glucose dependent catabolite repression, genes involved in biotin synthesis and &szlig / -oxidation of fatty or organic acids as well as a gene whose expression is regulated by stress induced s</font><font face="Times New Roman" size="1">B</font><font face="Times New Roman">-dependent regulon were expressed during olive waste growth.</font></font></p> </font></font>

A total of 34 sewage sludge samples were collected from South African provinces: KwaZulu- Natal, Gauteng, North West and Western Cape province. The samples were analysed for mineral ions and polynuclear aromatic hydrocarbons (PAH). The methods used for sample preparation were US-EPA 3050B and 3540C for mineral ions and PAHs respectively. The moisture content was also analysed. A minimum of 4.5 % and maximum of 99.5 % moisture were detected in the samples. The sludge that had stayed longer in their sampling points had low moisture contents than those that were sampled immediately after production. A total of 22-minaral ions were detected in the samples. When these were quantified an abundance trend that was found to be most common was: P>Ca>Fe>Al>Mg>K>Zn>Na>Mn>Cu>Ba>Cr>Pb>Si>Se>Sr>B>Ni>Mo>Co>Cd>Be. Phosphorous was the most abundant mineral ion in most of the samples apart from calcium, which was found to be abundant in a few cases. Comparing these results to the South African guideline limits, it emerges that most of the sewage works are compliant with the guidelines. The mineral ion that was found to be above the set limit in most occasions was selenium. The current South African guidelines were found to compare favourably to those of other countries. In the study 16 PAHs were also analysed, based on frequency of occurrence these were found to be: benzo(b)fluorathene ~ benzo(k fIuoranthene> phenanthrene> acenaphthylene> fluorine> naphthalene> benzo(a)anthracene> chrysene> acenaphthene> benzo(a)pyrene> fluoranthene> anthracene ~ pyrene> benzo(g,h,i)perylene> indeno(l ,2,3-cd)pyrene> dibenzo(a,h)anthracene Dibenzo(a,h)pyrene was below the detection limit in all the samples analysed while benzo(b)fluoranthene and benzo(k)fluoranthene were the most abundant compounds. All the samples analysed had concentration of benzo(a)pyrene below the South African limit of 2.53 mg kg"1. Comparing these guidelines with other international countries, South Africa specifies a single compound for monitoring while in other countries more than one compound is monitored. Thus South African guidelines need to be put in line with those of major EU countries such as Germany and Denmark with respect to PAH limits. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

A comprehensive literature survey looking at different aspects of organic contaminants in sewage sludge is incorporated in the thesis. It is clear from the data available that plants do not take up most of the organic pollutants. However, a risk of contamination of the food chain exists when sludge is spread directly onto crops that are to be consumed raw or semi-cooked. The major source of human exposure to sludge-borne organic pollutants is through the consumption of animal products such as meat and milk through the bioaccumulation of compounds such as polychlorinated dibenzo-p-dioxins and -furans (PCDD/Fs), polychlorinated biphenyls (PCBs) or polynuclear aromatic hydrocarbons (PAHs). This is due to the ingestion of soil and sludge by livestock due to the spreading of sludge on the land used for grazing. Currently little is known about the plant uptake of phthalates and nonylphenols, which are present in relatively high levels in sludge. Included in the literature survey is a list of the most common methods normally used for extraction of organic compounds and the possible methods of analysis. What is noted is that there is no universally accepted and validated analytical method for analysing most of the organic compounds. In addition, data concerning levels of organic pollutants is scarce worldwide. The methods selected for this project were EPA Methods 35IOC (Liquid-liquid extraction) and 3540C (Soxhlet extraction) for the aqueous and solid sewage sludge respectively. These two methods were chosen because they are simple, inexpensive and effective. The chosen purification method was the sulfur clean-up process (EPA Method 3660B). This is because sulfur precipitates were observed in most of the concentrated extracts, especially from the solid samples. A total of 109 samples from 78 sewage works were extracted, using Soxhlet extraction for solids and liquid-liquid extraction for liquid samples. All the extracts were analysed using GC-MS. The identification of the organic compounds was made possible by the use of GC-MS Wiley library. A total of 712 organic compounds were identified in the South African sewage sludge. These included Phenols, Pesticides, PAHs, Phthalates, PCBs, Furans, Amines, Aldehydes, Esters, Acids, Chlorinated Hydrocarbons, Alcohols, Hydrocarbons and Others (all sorts of organic compounds that did not belong to the named categories). The extraction efficiency and reproducibility using a "clean" sludge matrix was carried out. The results showed that the method chosen for extraction i.e. Soxhlet method had an efficiency of over 80% and the results were reproducible. A total of 14 samples were selected for the quantification of p-cresol, nonylphenol and pesticides listed in the current legislation. The results showed negative results for pesticides, confirming that the pesticides listed in the legislation are not the compounds that need to be regulated as far as organic pollutants are concerned. The reasons for this are most likely due to the fact that most of the pesticides listed are banned or their use is severely restricted. The results for the quantification of p-cresol and nonylphenol, when comparing the liquid and the solid extracts of the liquid sludge, show that 99% of p-cresol is concentrated in the liquid phase. The opposite is true when looking at nonylphenol where 90% of it is trapped in the solid matrix leaving 10% in the liquid phase. It is also noted that liquid sludge contains high concentrations of both p-cresol and nonylphenol when compared to the solid sludge. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006.

Biosorption is a property of certain type of inactive, microbial biomass to bind and concentrate heavy metals from even very dilute aqueous solutions. Biomass exhibits this property, acting just as a chemical substance, as an ion exchanger of biological origin. It is particularly the cell wall structure of certain algae that is found responsible for this phenomenon. In these experiments, the rate and extent for removal of copper is subjected to parameters such as pH, initial metal concentration, biosorbent size, contact time, temperature and the ability of the biomass to be regenerated in sorption-desorption experiments. The metal adsorption was found to be rapid within 25 minutes. The maximum copper uptake of 30 mg of copper / g of biomass has been observed, in the following conditions: 100 mg / L, 0.1 g of biomass, pH 4 and at temperature of 25°C. From this study, it was found that copper uptake is increasing with increase in pH, with optimum being pH 4. Copper uptake increases substantially from 0 to 25 minutes. Metal biosorption behaviour of raw seaweed Sargassum in six consecutive sorptiondesorption cycles were also investigated in a packed-bed column, during a continuous removal of copper from a 35 mg/l aqueous solution at pH 4. The sorption and desorption was carried out for an average of 85 and 15 hours, respectively, representing more than 40 days of continuous use of the biosorbent. The weight loss ofbiomass after this time was 13.5%. The column service time decreased from 25 hrs in the first cycle to 10 hrs for the last cycle. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2005.

Salts in solution should be removed by desalination techniques to prevent equipment fouling and corrosion. Common desalination technologies are energy intensive such as Multi Stage Flash (MSF) distillation which requires 14.5 J/m3 (Ribeiro. J, 1996) of energy. Desalination technologies produce purified water and a concentrated salt solution, where the salt concentration is dependent on the desalination technology used. This work investigates gas hydrate technology as a possible desalination technology. Hydrates are composed of guest molecules and host molecules. Guest molecules may be in the form of a liquid or gas. During hydrate formation, host molecules, water, form a cage enclosing the guest molecule. Common hydrate formers or guest molecules such as; methane, ethane, propane and carbon dioxide are currently being investigated in literature, for use in gas hydrate desalination technology. Common hydrate formers form hydrates at low temperatures; below 288 K and high pressures; above 2 MPa. To increase the temperature and reduce the pressure at which gas hydrates form, commercially available hydrofluorocarbon hydrate formers such as R14, R32, R116, R134a, R152a, R218, R404a, R407c, R410a and R507 are preliminarily investigated in this work. The criteria for choosing the most suitable fluorine-based formers require the former to be: environmentally acceptable where it is approved by the Montreal Protocol; non-toxic where it has a low acute toxicity; non-flammable; chemically stable; a structure II hydrate to simplify the washing process; available in commercial quantities; low cost in comparison to other hydrate formers; compatible with standard materials and contain a high critical point for a large heat of vaporisation (McCormack and Andersen, 1995). Taking all these criteria into account, R134a was chosen for further investigation as a possible hydrate former. In this work, hydrate-liquid-vapour phase equilibrium measurements are conducted using the isochoric method with a static high pressure stainless steel equilibrium cell. The Combined Standard Uncertainty for the 0-1 MPa pressure transducer, 0-10 MPa pressure transducer and the Pt100 temperature probes are ±0.64 MPa, ±5.00 MPa and ±0.09 K respectively. Vapour pressure measurements for Hydrofluoropropyleneoxide, CO2, R22 and R134a were measured to verify the pressure and temperature calibrations. Hydrate test systems for R22 (1) + water (2) and R134a (1) + water (2) were measured to verify calibrations, equipment and procedures. New systems measured included R134a (1) + water (2) + {5wt%, 10wt% or 15wt%} NaCl (3). For the system R134 (1) + water (2) at 281 K the dissociation pressure is 0.269 MPa. However, addition of NaCl to the system resulted in a shift of the HVL equilibrium phase boundary to lower temperatures or higher pressures. The average shift in temperature between the system R134a (1) + water (2) containing no salt and the systems containing {5, 10 and 15} wt% NaCl are -1.9K, -4.8K and -8.1K respectively. In this work, the measured systems were modelled using two methods of approach. The first method is where hydrofluorocarbon hydrate former solubility is included, (Parrish et al., 1972) and the second is where hydrofluorocarbon hydrate former solubility is ignored, (Eslamimanesh et al., 2011). From these models, it is found that hydrofluorocarbon solubility could not be neglected. In this work, the hydrate phase was modelled using modifications of the van der Waals and Platteeuw model, (Parrish et al., 1972). The liquid and vapour phases are modelled using the Peng- Robinson equation of state with classical mixing rules (Peng, 1976). The electrolyte component is modelled using the Aasberg-Peterson model (Aasberg-Petersen et al., 1991) modified by Tohidi (Tohidi et al., 1995). The percent absolute average deviation (%AAD) for the systems, which includes solubility, is 0.41 for R22 (1) + water (2) and 0.33 for R134a (1) + water (2). For the system R134a (1) + water (2) + {5 wt%, 10 wt% or 15 wt%} NaCl (3) the % AAD is 5.14. Using the hydrate former, R134a, is insufficient to ensure gas hydrate technology is competitive with other desalination technologies. Hydrate dissociation temperature should be increased and pressure decreased further to ambient conditions. As evident in literature, promoters, such as cyclopentane, are recommended to be added to the system to shift the HLV equilibrium phase boundary as close to ambient conditions as possible. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

Constructed wetlands are considered an inefficient technology for long-term phosphorus (P) removal. The P retention effectiveness of subsurface wetlands can be improved by using appropriate substrates. The objectives of this study were to: (i) use sorption isotherms to estimate the P sorption capacity of the two materials, masonry sand and light weight expanded shale; (ii) describe dissolved P removal in small (2.7 m3) subsurface flow wetlands; (iii) quantify the forms of P retained by the substrates in the pilot cells; and (iv) use resulting data to assess the technical and economic feasibility of the most promising system to remove P. The P sorption capacity of masonry sand and expanded shale, as determined with Langmuir isotherms, was 60 mg/kg and 971 mg/kg respectively. In the pilot cells receiving secondarily treated wastewater, cells containing expanded shale retained a greater proportion of the incoming P (50.8 percent) than cells containing masonry sand (14.5 percent). After a year of operation, samples were analyzed for total P (TP) and total inorganic P (TIP). Subsamples were fractionated into labile-P, Fe+Al-bound P, humic-P, Ca+Mg-bound P, and residual-P. Means and standard deviations of TP retained by the expanded shale and masonry sand were 349 + 169 and 11.9 + 18.6 mg/kg respectively. The largest forms of P retained by the expanded shale pilot cells were Fe+Al- bound P (108 mg/kg), followed by labile-P (46.7 mg/kg) and humic-P (39.8). Increases in the P forms of masonry sand were greatest in labile-P (7.5 mg/kg). The cost of an expanded shale wetland is within the range of costs conventional technologies for P removal. Accurate cost comparisons are dependent upon expansion capacity of the system under consideration. Materials with a high P sorption capacity also have potential for enhancing P removal in other constructed wetland applications such as stormwater wetlands and wetlands for treating agricultural runoff.

Submitted in fulfillment of the academic requirements for the Degree of Master of Technology: Biotechnology, Durban Institute of Technology, 2005. / The cumulative effects of pollution have led to increased public concern, which is resulting in strict legislation on the discharge of wastes in whatever state they are present, i.e. solid, liquid or gas. Currently, in South Africa, effluents with a high organic load are sent to landfills or marine outfall because the cost of discharge to sewer is prohibitive. In regions where there is a net surplus of rainfall, landfill sites have the potential to pollute the groundwater due to saturated soil conditions. Therefore, many landfill sites should not receive liquid effluents. If liquid wastes are disposed onto landfills, then an alternate sink is required for the treatment of the high volumes of leachate that are generated. These concentrated effluents could then be treated by biological, chemical or physical methods to reduce the pollution load in the natural water resources. In this study, anaerobic digestion has been identified as one of the biological processes that can be applied to treat high-strength or toxic organic liquid effluents, since a survey conducted by Sacks (1997) indicated that many anaerobic digesters in the KwaZulu-Natal region have spare capacity. However before high strength industrial wastes can be treated in existing anaerobic digesters, their impact on the digestion process, i.e. their toxicity and biodegradability under anaerobic conditions, needs to be determined. During this project, several high-strength or toxic industrial effluents were tested to assess their toxicity and biodegradability under anaerobic conditions. These include three synthetic textile size effluents from the textile industry (Textile effluent 1, 2, and 3) and three hazardous landfillieachates (Holfontein, Shongweni and Aloes). In addition, the components of a textile effluent, i.e., starch and wax, were tested to determine which / M

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