Masters Thesis / Un-sewered settlements are provided with the basic water and sanitation systems that comprise, in most cases, of dry sanitation and standpipes. Substantial amounts of wastewater (including greywater) generated from households are discarded untreated into streets, open spaces between shacks, streams and rivers due to the lack of adequate disposal or treatment infrastructures. The negative impacts from unsafe disposal of greywater generated in un-sewered settlements affect both human health and the general environment. Several treatment technologies ranging from the simplest to the more sophisticated have been developed and made available for consideration to deal with the adverse impacts caused by the unsafe discharge of greywater. Some of these treatment technologies have been implemented successfully in certain developing countries worldwide. Amongst these is the anaerobic up-flow batch reactor (AnUBR) which was successfully used for the first time to treat greywater from sewered areas in Jordan, Lebanon and Sri Lanka. The AnUBR has emerged as a localised greywater treatment technology alternative to conventional treatment methods in areas not served by sewer networks. This technology holds promise because of its simplicity of design, high pollutant removal efficiency, absence of energy or chemical consumption, ease with which it can be implemented, cost effectiveness, and low operation and maintenance costs. This technology was originally developed for treating sewage and high strength greywater from hotels. Recently it was further pioneered by INWRDAM (Inter-Islamic Network on Water Resources Development and Management) in the treatment of greywater from sewered areas of developing countries. This technology has not been tested in un-sewered settlements of developing countries which are characterised by the lack of disposal infrastructures despite being suitable for tropical countries. This treatment system is able to produce effluent that meets the quality standard for discharge and irrigation. However, new applications of the AnUBR require further investigation in order to ascertain its feasibility and evaluate its performance in the un-sewered settlement context. Given the promising results reported for the AnUBR application for greywater treatment, this study aims to investigate the performance of the AnUBR as an alternative technology for the treatment of greywater generated in un-sewered settlements and its application in developing countries. A laboratory scale plant encompassing the AnUBR was designed, constructed and investigated using influent greywater collected from two selected case study settlements representing sewered and un-sewered areas. The plant was operated for 20 consecutives days using greywater from both selected sites separately. The influent greywater was analysed prior to feeding the plant and fed intermittently by batch as per designed feeding schedule. The performance of the AnUBR was evaluated mainly by analysing the quality of effluent produced, while the typical application was recommended based on the ability of the plant to produce effluent complying with local regulations and ability to treat greywater regardless of its source. The daily characteristics of influent greywater from both sites during the period of investigation were found to be as follows: temperature: 24 – 29ºC, pH: 7.1 – 7.2, TSS: 117.72 – 2,246.6mg/l, TN: 5.66 – 12.29mg/l, TP: 12.27 – 116.46mg/l, COD: 223.17 – 1,135.32mg/l, BOD5: 98.0 – 383.6mg/l, O&G: 52.22 – 475.29mg/l, e-coli: 8.87x104 – 2.17x107cfu/100ml, and Faecal coliform: 1.49x105 – 2.41x107cfu/100ml. The AnUBR managed to treat greywater to a quality that comply with the general standards for discharge into natural water resources. The final effluent showed a significant decrease in the level of pollutants from the initial values presented above to the following: temperature: 27 – 29 ºC, pH: 7.1 – 7.2, TSS: 5.12 – 12.82mg/l, TN 0.91 – 1.09mg/l, TP: 0.93 – 7.47mg/l, COD: 24.67 – 40.45mg/l, BOD5: 8.59 – 16.0mg/l, O&G: 1.15 – 1.72mg/l, e-coli: 213.3 – 1.12x103cfu/100ml, and Faecal coliform: 461.6 – 1.5x103cfu/100ml. Results obtained showed that the quality of influent greywater (from un-sewered settlements) is similar regardless of the water and sanitation technology. Following the operation of the AnUBR, significant removal of pollutants was observed in all processes. The overall removal efficiency averaged 80 to 95% for O&G and TSS respectively and 50 to 85% for TN and TP. The COD and BOD5 removal averaged 70 to 85% while that of micro-organisms averaged 90 to 99%. However, despite the high removal efficiency recorded the AnUBR may still require a post treatment step in order to improve the quality of effluent. It was concluded that the AnUBR is a viable alternative greywater treatment technology for un-sewered settlements, households or businesses such as hotels and restaurants. The AnUBR is able of treating high polluted greywater to effluent of quality that meets the standards for discharge or reuse provided a post treatment to ensure the complete killing of pathogenic organisms. The result of this study confirms the performance of the AnUBR for the treatment of greywater and provides an understanding of its concept as an alternative to conventional treatment and its application in un-sewered settlements based on local practical investigations.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2018. / The sugar industry contributes to the development of the economy in many countries, including South Africa. The wastewater generated by this industry has a high pollution load, and therefore requires treatment before discharge to the environment. The primary aims of this study were to determine the performance of an upflow anaerobic sludge blanket (UASB) reactor treating sugarcane molasses and to develop an empirical model to predict the behaviour of the UASB in terms of chemical oxygen demand (COD) removal and biogas production. A UASB (46 L working volume) was inoculated with granular sludge from the brewery industry and was used to investigate the treatment of synthetic sugar industry wastewater with an average COD of 4101 mg/L. The experiments were designed using Design-Expert® Software Version 10. The analysis of variance for the models and the optimisation of reactor temperature and feed carbon to nitrogen (C/N ratio) were carried out using response surface methodology. The UASB was operated at constant hydraulic retention time and organic loading rate of 2.04 days and 2.01 kg/m3.d, respectively. A start-up period of 22 days was required to reach steady-state. The developed empirical models for total COD removal efficiency and biogas production rate were found to be statistically significant with Prob > F values of 0.0747 and 0.0495 and the determination coefficients (R2) were found to be 0.80 and 0.65, respectively. The optimal conditions were found to be at a temperature of 38oC and C/N ratio of 22 mgTOC/mgTN. The corresponding removal efficiencies in terms of total COD, five day biological oxygen demand, total nitrogen, total phosphorus, and sulphate was 77.7, 85.9, 99.2, 44.4 and 57.2%, respectively. Biogas was produced at a rate of 0.832 L/L.d with a methane, carbon dioxide and molecular oxygen content of 65.2, 32.8 and 0.6%. Results suggest that UASBs may offer a feasible option for reducing the organic strength of sugar industry wastewater, while simultaneously generating methane-rich biogas.

Currently at the Savannah River Site (SRS), there are fifteen single-shell, 3.6-million liter tanks containing High Level Waste. To close the tanks, the sludge must be removed. Mechanical methods have had limited success. Oxalic acid cleaning is now being considered as a new technology. This research uses sample results and chemical equilibrium software to develop a preferred flowsheet and evaluate the acceptability of the system impacts. Based on modeling and testing, between 246,000 to 511,000 l of 8 wt% oxalic acid were required to dissolve a 9,000 liter Purex sludge heel. For SRS H-Area modified sludge, 322,000 to 511,000 l were required. To restore the pH of the treatment tank slurries, approximately 140,000 to 190,000 l of 50 wt% NaOH or 260,000 to 340,000 l of supernate were required. When developing the flowsheet, there were two primary goals to minimize downstream impacts. The first was to ensure that the Resultant oxalate solids were transferred to DWPF, without being washed. The second was to transfer the remaining soluble sodium oxalates to the evaporator drop tank, so they do not transfer through or precipitate in the evaporator pot. Adiabatic modeling determined the maximum possible temperature to be 73.5°C and the maximum expected temperature to be 64.6°C. At one atmosphere and at 73.5°C, a maximum of 770 l of water vapor was generated, while at 64.6°C a maximum 254 l of carbon dioxide were generated. Although tank wall corrosion was not a concern, because of the large cooling coil surface area, the corrosion induced hydrogen generation rate was calculated to be as high as 10,250 l/hr. Since the minimum tank purge exhaust was assumed to be 5,600 l/hr, the corrosion induced hydrogen generation rate was identified as a potential concern. Excluding corrosion induced hydrogen, trending the behavior of the spiked constituents of concern, and considering conditions necessary for ignition, energetic compounds were shown not to represent an increased risk Based on modeling, about 56,800 l of Resultant oxalates could be added to a washed sludge batch with minimal impact on the number of additional glass canisters produced. For each sludge batch, with 1 to 3 heel dissolutions, about 60,000 kg of sodium oxalate entered the evaporator system, with most collecting in the drop tank, where they will remain until eventual salt heel removal. For each 6,000 kg of sodium oxalate in the drop tank, about 189,000 l of Saltstone feed would eventually be produced. Overall, except for corrosion-induced hydrogen, there were no significant process impacts that would forbid the use of oxalic acid in cleaning High Level Waste tanks. / MATHEMATICAL SCIENCES / M. Tech. (Chemical Engineering)

The survival of three enteroviruses (polio 1, coxsackie B3 and echo 1) and a rotavirus (SA-11) was studied under laboratory conditions. The effects of temperature, dissolved oxygen, detention time, sludge source and virus type on virus inactivation were determined. Temperature was the single most important factor influencing the rate of virus inactivation. No significant differences were found for virus inactivation rates at dissolved oxygen levels between 0.9 and 5.8 mg/l. However, the inactivation rate of the viruses under aerobic conditions was found to be significantly greater than the inactivation rate under anaerobic conditions (−0.77log10/day vs −0.33 log10/day). Sludge source, detention time and virus type did not significantly influence the rate of virus inactivation.

Research and evaluation of effect of traditional (iron salts) and alternative iron source (ochre) on anaerobic digestion of sludge mixture process have been made in dissertation. Research has been made in two European countries: Lithuania and Sweden. Sludge mixture used for the experiments was from biological phosphorus removal plants; ochre originated from groundwater treatment plants. Case study, laboratory and pilot-scale experiments have been made for the complex evaluation of impact of ochre on sludge digestion process. Standard and specific methodics were used for the evaluation of results. Based on results technology for using of ochre for the improving of the anaerobic digestion process at the treatment plants with biological phosphorus treatment has been proposed. / Disertacijoje nagrinėjamas ir vertinamas tradicinio (geležies druskų) ir alternativaus geležies šaltinio (geležies paplavų) poveikis anaerobinio dumblo mišinio pūdymo procesui. Tyrimai buvo atlikti dviejose Europos Sąjungos šalyse: Lietuvoje ir Švedijoje. Tyrimams dumblo mišinys imtas iš biologinio fosforo šalinimo įrenginių; geležies paplavos – iš požeminio vandens gerinimo įrenginių. Siekiant kompleksiškai įvertinti geležies paplavų įtaką dumblo pūdymo procesui, buvo atlikti natūriniai, laboratoriniai ir pusiau gamybiniai tyrimai. Darbe panaudotos standartinės ir specifinės pūdymo proceso kokybės nustatymo metodikos. Remiantis gautais rezultatais buvo pasiūlyta technologinė geležies paplavų panaudojimo dumblo apdorojimo ūkyje, skirta nuotekų valymo įrenginiams su biologiniu fosforo šalinimu.

Disertacijoje nagrinėjamas ir vertinamas tradicinio (geležies druskų) ir alternativaus geležies šaltinio (geležies paplavų) poveikis anaerobinio dumblo mišinio pūdymo procesui. Tyrimai buvo atlikti dviejose Europos Sąjungos šalyse: Lietuvoje ir Švedijoje. Tyrimams dumblo mišinys imtas iš biologinio fosforo šalinimo įrenginių; geležies paplavos – iš požeminio vandens gerinimo įrenginių. Siekiant kompleksiškai įvertinti geležies paplavų įtaką dumblo pūdymo procesui, buvo atlikti natūriniai, laboratoriniai ir pusiau gamybiniai tyrimai. Darbe panaudotos standartinės ir specifinės pūdymo proceso kokybės nustatymo metodikos. Remiantis gautais rezultatais buvo pasiūlyta technologinė geležies paplavų panaudojimo dumblo apdorojimo ūkyje, skirta nuotekų valymo įrenginiams su biologiniu fosforo šalinimu. / Resarch and evaluation of effect of traditional (iron salts) and alternative iron source (ochre) on anaerobic digestion of sludge mixture process have been made in dissertation. Research have been made in two European countries: Lithuania and Sweden. Sludge mixture used for the experiments was from biological phosphorus removal plants; ochre originated from groundwater treatment plants. Case study, laboratory and pilot-scale experiments have been made for the complex evaluation of impact of ochre on sludge digestion process. Standard and specific methodics were used for the evaluation of results. Based on results technology for using of ochre for the improving of the anaerobic digestion process at the treatment plants with biological phosphorus treatment have been proposed.

Currently at the Savannah River Site (SRS), there are fifteen single-shell, 3.6-million liter tanks containing High Level Waste. To close the tanks, the sludge must be removed. Mechanical methods have had limited success. Oxalic acid cleaning is now being considered as a new technology. This research uses sample results and chemical equilibrium software to develop a preferred flowsheet and evaluate the acceptability of the system impacts. Based on modeling and testing, between 246,000 to 511,000 l of 8 wt% oxalic acid were required to dissolve a 9,000 liter Purex sludge heel. For SRS H-Area modified sludge, 322,000 to 511,000 l were required. To restore the pH of the treatment tank slurries, approximately 140,000 to 190,000 l of 50 wt% NaOH or 260,000 to 340,000 l of supernate were required. When developing the flowsheet, there were two primary goals to minimize downstream impacts. The first was to ensure that the Resultant oxalate solids were transferred to DWPF, without being washed. The second was to transfer the remaining soluble sodium oxalates to the evaporator drop tank, so they do not transfer through or precipitate in the evaporator pot. Adiabatic modeling determined the maximum possible temperature to be 73.5°C and the maximum expected temperature to be 64.6°C. At one atmosphere and at 73.5°C, a maximum of 770 l of water vapor was generated, while at 64.6°C a maximum 254 l of carbon dioxide were generated. Although tank wall corrosion was not a concern, because of the large cooling coil surface area, the corrosion induced hydrogen generation rate was calculated to be as high as 10,250 l/hr. Since the minimum tank purge exhaust was assumed to be 5,600 l/hr, the corrosion induced hydrogen generation rate was identified as a potential concern. Excluding corrosion induced hydrogen, trending the behavior of the spiked constituents of concern, and considering conditions necessary for ignition, energetic compounds were shown not to represent an increased risk Based on modeling, about 56,800 l of Resultant oxalates could be added to a washed sludge batch with minimal impact on the number of additional glass canisters produced. For each sludge batch, with 1 to 3 heel dissolutions, about 60,000 kg of sodium oxalate entered the evaporator system, with most collecting in the drop tank, where they will remain until eventual salt heel removal. For each 6,000 kg of sodium oxalate in the drop tank, about 189,000 l of Saltstone feed would eventually be produced. Overall, except for corrosion-induced hydrogen, there were no significant process impacts that would forbid the use of oxalic acid in cleaning High Level Waste tanks. / MATHEMATICAL SCIENCES / M. Tech. (Chemical Engineering)

The crab processing industry of the Chesapeake Bay region has, until recently, been able to dispose of their processing wastewaters by discharging them, largely untreated, directly to the receiving waters along which their plants are located. With the upcoming implementation of new NPDES discharge limits, this practice will no longer be possible. This study investigated the potential of two different technologies for treating the processing wastewaters. Bench-scale anaerobic contact type reactors were studied for effectiveness in the removal of organics from the processor’s wastewaters, and a pilot-scale countercurrent air stripping tower was studied for ammonia removal. Two anaerobic reactors which were fed retort process wastewater at F/M ratios of 0.35 and 0.25 lb COD/1b MLVSS/day, were found to achieve organics removals (on a BOD₅ basis) of 88% and 94% respectively. Similarly, a second pair of anaerobic reactors were fed a mixed wastewater, representative of a mechanized processing plant’s total wastewater flow, at F/M ratios of 0.10 and 0.07 lb COD/1b MLVSS/day. These reactors were found to achieve organics removals (on a BOD₅ basis) of 79% and 83% respectively. All four of the reactors were eventually shut down after exhibiting signs of failure. These failures were attributed to possible sodium and ammonia toxicity problems. The effectiveness of the air stripping tower in the removal of ammonia from retort process wastewater was tested in relation to liquid flow rate, influent temperature, and influent pH. A maximum ammonia removal of 71% was observed when treating a waste, with an influent temperature of 580C and pH level of 12.2, at an air-to-water ratio of approximately 825 ft³/gal. Similarly, an ammonia removal rate of 67% was observed while treating a waste, with an influent temperature of 650°C and pH level of 11.0, at an air-to-water ratio of approximately 412 ft³/gal. / Master of Science