Research Publications (Engineering and Built Environment)

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39th Johannesburg International Conference on “Chemical, Biological and Environmental Engineering” (JCBEE-23) Nov. 16-17, 2023 Johannesburg (South Africa)
(International Institute of Chemical, Biological & Environmental Engineering (IICBEE), 2023-11-16) Chetty, Manimagalay; Rathilal, Sudesh; Tetteh, Emmanuel; Singh, Nikita
Abstract—Recent energy demand and environmental concerns associated with fossil fuels makes algae biomass a desirable energy source. Algal biomass has a high organic content and a variety of metabolic properties that make it a promising resource for managing wastewater and sequestering CO₂, in addition to producing profitable biobased products. However, the operation and valorization of algae biomass on a large scale are accompanied by significant costs and setbacks. Therefore, the transition towards a biobased economy requires this study to examine emerging technologies that could utilize algae biomass as an industrialized feedstock from the wastewater settings. A comprehensive analysis of various green technologies of producing high-value products (lipids and hydrocarbons) from algae biomass was reviewed. The fundamental principles that limit the cultivation , extraction, and conversion of different types of algae biomasses for commercialization are discussed. Furthermore, the challenges, future research directions and potential opportunities of valorizing algae biomass was highlighted. It was noted that, exploring algae biomass towards sustainable waste management with resources recovery is viable for industrialization.
Anaerobic treatment of slaugterhouse wastewater: evaluating operating conditions
(WIT Press, 2019-12-11) Chollom, Martha Noro; Rathilal, Sudesh; Swalaha, Feroz Mahomed; Bakare, Babatunde F.; Tetteh, Emmanuel K.
The aim of the study was to elucidate the effect of process parameters on the performance of an upflow anaerobic sludge blanket reactor (UASB) that was treating slaughterhouse wastewater. The UASB reactor was operated continuously under mesophilic conditions to evaluate its performance with respect to the removal of organics and, at the same time, monitor biogas production. Organic loading rate (OLR) was varied while keeping the hydraulic retention time (HRT) constant. Chemical oxygen demand (COD) removal efficiency higher than 75% was achieved at an OLR of 9 kg.COD.m-3.d-1, with a HRT of 12 h. Bulking sludge problems were not observed during the reactor operation period. Stability of the treatment process was achieved by the natural buffering of the system due to the produced alkalinity and also due to the characteristics of the wastewaters which was found to be rich in proteins and fatty acids.
The applicability of nanofiltration for the treatment and reuse of textile reactive dye effluent
(AJOL, 2015) Chollom, Martha Noro; Rathilal, Sudesh; Pillay, Visvanathan Lingamurti; Alfa, Dorcas
The main aim of the study was to test the feasibility of using nanofiltration (NF) processes for the treatment of reactive dye-bath effluents from the textile industry, in order to recover the water and chemicals (salts) for reuse purposes. The study of the reusability of nanofiltered water for dyeing has been given little or no attention. About 30% of reactive dyes remain unfixed on fibres; the unfixed dyes are responsible for the colouration in effluents. Membrane processes were employed to treat reactive dye-bath effluents to recover the salts and water. Investigations were conducted firstly with ultrafiltration (UF) used as a pre-treatment for NF. Secondly, evaluations were performed for 2 types of NF membranes (SR90 and NF90), in terms of quality of permeate produced and fluxes achieved for 2 different samples of effluent. The effect of cleaning on membrane performance was assessed. A reusability test was carried out on both permeate samples for dyeing light and dark shade recipes. The use of UF as pre-treatment to NF resulted in rejection of colloidal substances > 90% and a 15% flux improvement. Permeate from NF90 had a conductivity of 76 µS/cm and total organic carbon (TOC) of 20 mg/ℓ, as compared to SR90 which had a conductivity of 8.3 mS/cm and a TOC of 58 mg/ℓ. Light shade from NF90 gave satisfactory results on dyeing, with no colour difference. However a variation in colour was noticed when the medium sample was used to dye the light shade. Both NF permeates gave satisfactory results when used to dye the dark shades. Permeate from NF90 was within the accepted range for reuse, while permeate from SR90 had a higher salt recovery. Chemical cleaning resulted in 80% flux recovery. From the reusability test it was concluded that permeate from NF90 met the reuse criteria for feed water to the dye bath.
Application of organic coagulants in water and wastewater treatment
(IntechOpen, 2019-04-03) Tetteh, Emmanuel Kweinor; Rathilal, Sudesh
Coagulation is an essential mechanism that occurs in most conventional water and wastewater treatment plants. This occurs in a physical purification unit involving transport processes and the addition of coagulants for chemical reactions, charge neutralization, and formation of smaller flocs to agglomerate into larger flocs. This enhances the effective removal of recalcitrant contaminants by downstream processes. However, poor treatment of wastewater might have a high negative impact on biodiversity and the environment in general. This chapter seeks to address the limitation of employing inorganic coagulants by evaluating the efficiency of organic coagulants and exploring the factors and mechanism governing coagulation in a physiochemical treatment process of water and wastewater resources. The effect of pH, coagulant type and dosage to ease the high sludge production and discharge of residual metals into the downstream waters is addressed. The emerging of organic coagulants and technology to mitigate the performance and recovery of mineral coagulants from wastewater treatment residual is been proposed.
Characteristics of greywater from different sources within households in a community in Durban, South Africa
(IWA Publishing, 2017) Bakare, Babatunde F.; Mtsweni, Sphesihle; Rathilal, Sudesh
The reuse of greywater is steadily gaining importance in South Africa. Greywater contains pollutants that could have adverse effects on the environment and public health if the water is not treated before reuse. Successful implementation of any greywater treatment process depends largely on its characteristics in terms of the pollutant strength. This study investigated the physico-chemical characteristics of greywater from different sources within 75 households in a community in Durban, South Africa. The study was undertaken to create an understanding of greywater quality from different sources within and between households. Greywater samples were collected from the kitchen, laundry and bathing facilities within each of the households. The samples were analysed for: pH, conductivity, turbidity, total solids, chemical oxygen demand (COD) and biological oxygen demand (BOD). There was a signiﬁcant difference in the parameters analysed between the greywater from the kitchen compared with the greywater from the bathtub/shower and laundry. It was also observed that the characteristics of greywater from the different households varied considerably. The characteristics of the greywater obtained in this study suggest that the greywater generated cannot be easily treatable using biological treatment processes and/or technologies due to the very low mean BOD : COD ratio (<0.5).
Cleaner technology systems for surface ﬁnishing : evaporative coolers for close circuiting low temperature plating process
(Elsevier, 2013-12-10) Munsamy, Megashnee; Telukdarie, Arnesh; Zhang, W.
In the electroplating process, the rinse system generates large quantities of wastewater requiring treatment prior to disposal to municipal systems. The use of conventional water treatment systems is a challenge due to the presence of hazardous components. In addition, this does not solve the problem of the generation of rinse wastewater, but only treats it. Thus the focus was on point-source reduction technologies, speciﬁcally the application of a three-stage low ﬂow counter current rinse for recovery of the rinse water in the plating bath, enabling close circuiting of the plating bath rinse system. However, recovery of the rinse water into the plating bath is impeded by the low rates of evaporation, especially in the low temperature plating baths. Alternative methodologies to heating were investigated to facilitate evaporation, with evaporative cooling being identiﬁed as the most feasible option. Evaporative cooling facilitates evaporation, whilst maintaining the plating bath temperature within the operational limits. For the recovery of the rinse water in the plating bath, the rate of evaporation in the plating bath must be equivalent to the fresh make-up water requirements of the rinse tanks. The Closed Circuit Plating System (CCPS) model was developed to enable the proper design and/or implementation of an evapo-rative cooler; whereby the user speciﬁed inputs are evaluated in achieving the required evaporation rates for the recovery of the rinse water in the plating bath. The key characteristic of the CCPS model is the minimum requirement of proprietary plating solution speciﬁc information. The inputs for the model are chemical composition of the plating solution, ﬂowrates, temperature and height of the cooling tower. The outputs from the model are evaporation rates and equilibrium temperatures of the plating bath and cooling tower. The primary limitation of the CCPS model is that it is based on an airewater system. Single and multiple variable sensitivity analyses were performed on the plating plant operational pa-rameters to determine their inﬂuence on close circuiting of the rinse plating system: plating solution composition and operational temperature; ambient air temperature; air ﬂow rate and the surface area of the packing in the cooling tower. The results from the model indicated the upper limit plating solution opera-tional temperature, high air ﬂow rates, low ambient air temperature and large surface area of packing facilitated water evaporation rates and lower equilibrium temperatures in the plating bath and cooling tower. The sensitivity analyses will allow the electroplater to optimise the operating conditions to achieve the required evaporation rates for recovery of the rinse water into the plating bath, while simultaneously maintaining the outputs of the electroplating plant and reducing the rinse wastewater generation to almost zero.
Comparative analysis and case study to evaluate conventional designs and environmentally sensitive infrastructure design solutions
(SAICE, 2016-08) Saroop, Shian Hemraj; Allopi, Dhiren
Globally the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming and other negative consequences. In the area of sustainability there is an urgent need to apply technologies and methods which deliver more sustainable performance in a way that is cost-effective. Sustainable, adaptive and mitigating approaches to climate change in the design of infrastructure are therefore important steering elements (FIDIC 2009)
Conceptual framework of environmental sustainable interventions with the use of green infrastructure design criteria on projects
(2014) Saroop, Shian Hemraj; Allopi, Dhiren
This paper presents a conceptual framework that incorporates eco-efficiency on Infrastructure projects with the use of the environmentally sustainable criteria on infrastructure projects. Mainstreaming environmental aspects and incorporating the eco-efficiency concept into various stages of infrastructure development have not been considered as much as they should have been. Engineers need to look at greener technologies rather than just using traditional engineering solutions. This paper aims to develop a framework that enables a project to be designed in accordance with environmentally sustainable criteria. The key aim of the framework was to create a more socially, economically, and environmentally sustainable neighbourhood, which focused on combating flooding, waste management, water recycling and enhancing biodiversity.
Creating eco efficient township infrastructure projects with the use of green engineering solutions and sustainability criteria
(Institute of Municipal Enginering of South Africa, 2015) Saroop, Shian Hemraj; Allopi, Dhiren
Globally, the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming, and other negative consequences (Harvey and Wayne, 20084). As we face significant planetary issues such as global warming, it is clear that the engineering profession has a significant part to play in affecting the future of our planet. In order to stay competitive and to meet upcoming stricter environmental regulations and customer requirements, designers have a key role in designing civil infrastructure so that it is environmentally sustainable. These and other factors have compelled the engineer to design with greater care and in more detail. The changing roles of engineers will be highlighted, in order to react to changes in climate. Mainstreaming environmental aspects and incorporating the eco-efficiency concept into various stages of infrastructure development have not been considered as much as they should have been. Engineers need to look at greener technologies rather than just using traditional engineering solutions. This paper looks at the effects of climate change on infrastructure and the changing role of engineers. It aims to demonstrate the use of sustainability criteria on infrastructure projects. The use of the proposed criteria would ensure a sustainable design for township infrastructure services through the consideration of scare resources, ecological sensitivity in the design and planning of infrastructure projects. This paper focuses on the concept of eco-efficiency in infrastructure design that promotes the use of the greener engineering options, enabling him/her to choose the one likely to yield the best performance with the least environmental impact. It looks at a number of recommended green practices on infrastructure services design, that are environmentally sound placing, fewer burdens on the environment.
Data pre-processing for process optimization at a drinking water treatment plant in Ugu District Municipality, South Africa
(Business Perspectives, 2015) Magombo, James; Dzwairo, Bloodless; Moyo, Sibusiso; Dewa, Mendon
When testing and recording water quality data from treatment plants, errors arise. The errors are in the form of re-cordings left blank (missing values), obvious errors in writing or typing, or they can be as a result of values being very small to detect and are therefore censored. The censored values are known to be below the limit of detection (LOD). In statistical analysis, the blank cells can be filled with a certain value. Censored values are often corrected by substituting with a constant value throughout. This value will be a fraction of the limit of detection and most commonly used frac-tions are, half the limit of detection, the limit of detection divided by the square root of 2, or multiplying the limit of detection by 0.75. The direct substitution method for handling missing and values below the limit of detection results in a uniform distribution for values below the limit of detection, and a true distribution for those above. As a result, treat-ment of the values below the limit of detection is dependent upon their percentage in the sample size. An alternative method used will mimic the characteristic of the distribution pattern of the values above the limit of detection to esti-mate the values below it. This can be done with an extrapolation technique or maximum likelihood estimation. In this study, data from the Umzinto Water Treatment Plant was used to develop a data pre-processing program using Visual Basics for Applications (VBA) and Microsoft Excel 2013. The procedure involved 4 stages: data preparation, data pre-processing for blanks and non-detects, data pre-processing for the censored values and finally the identifica-tion of the outliers. The developed program was then used to pre-process raw water quality data, which resulted in satisfactory process time and data conversion. The methodology used can be borrowed for the pre-processing of data driven environmental models and hence it has a great influence on sustainability of water treatment plants.
Development and evaluation of a small scale water disinfection system
(IWA Publishing, 2016-07-08) Alfa, Dorcas; Rathilal, Sudesh; Pikwa, Kumnandi; Chollom, Martha Noro; Pillay, Visvanathan Lingamurti
Provision of microbiologically safe drinking water for people living in the rural areas of developing countries remains a major challenge to date. A simple gravity-driven membrane point of use system was developed based on woven fabric microﬁltration (WFMF) membranes. The WFMF is a loose type of membrane (0.45 μm). However, complete disinfection is not achieved with the WFMF, hence it was incorporated with two disinfectants. This study aimed to combine the WFMF with two disinfectants (Water guard and bromochlor tablets) to bring the water to the accepted quality for drinking. Four different types of water were sourced, considering two factors; E. coli and turbidity content. The WFMF demonstrated excellent filtration performance by producing permeates with turbidity less than 1 NTU for feed turbidity ranging between 10 and 200 NTU. There was 95–99.8% E. coli removal for raw feeds with influent E. coli ranging between 500 and 44,500 CFU/100 mL. Total disinfection was achieved with both disinfectants, however, the effectiveness of the chemical disinfectants in E. coli removal was affected by the quality of water to be disinfected. The study showed that turbidity plays a major role in disinfection performances by increasing chlorine demand on water sources with high turbidity levels.
Development and evaluation of woven fabric microﬁltration membranes impregnated with silver nanoparticles for potable water treatment
(Elsevier, 2014-02-06) Mecha, C.A.; Pillay, Visvanathan Lingamurti
Access to clean and safe drinking water is a fundamental human need, which is commonly lacking in remote rural areas. A simple gravity-fed water treatment unit was developed based on woven fabric microﬁltration (WFMF) membranes. However, since these membranes are loose micro-ﬁlters, the unit has to be used in conjunction with a disinfectant. This paper explores combining the WFMF membranes with silver nanoparticles (AgNPs) using a modiﬁed chemical reduction method. The originally white membranes turned brown–yellow due to the surface plasmon resonance of silver; however, there was no signiﬁcant difference in the morphology of the membranes after the impregnation with 0.0117 wt%AgNPs. The coated membranes were more hydrophilic and had higher water permeability (po0.05). Filtration of turbid water (40–700 NTU) showed that both membranes produced clear permeate (o1 NTU). Treatment of water spiked with bacteria (2500–77,000 CFU/100 mL Escherichia coli) showed that the removal efﬁciency of uncoated membranes was 84–91% and that of coated membranes was 100%. Accordingly, the coated membranes depicted great potential for water treatment. To the best of our knowledge, this is the ﬁrst study that investigated the incorporation of AgNPs in WFMF membranes and characterized their properties.
The efficiency of chitosan as a coagulant in the treatment of the effluents from the Sugar Industry
(2015) Pambi, Ritha-Lorette Luti; Musonge, Paul
Chitosan has been used as a coagulant for industrial wastewater treatment. However, no attention has been given to the coagulation of sugar effluents using this polymer. Two effluent streams from a local sugar refinery, namely the final effluent (FE) and the resin effluent (RE) were treated using chitosan prepared by dissolution in aqueous hydrochloric acid. The optimum chitosan dosage was found to be 138 mg/l and 7.41 mg/l for RE and FE respectively, beyond which, the efficiency of the coagulant decreased. The efficiency of the chitosan was higher under acidic conditions and using sodium hydroxide to adjust the pH negatively affected the performance of the chitosan. The treatment of FE yielded better removal efficiency (97% total suspended solids, 61% colour and 35% chemical oxygen demand) than RE (68% total suspended solids, 30% colour and 15% chemical oxygen demand). This coagulant can be used to pre-treat turbid water for further treatment.
Evaluation of flux stabilisation using Bio-UF membrane filter on KZN Rivers, South Africa
(Techno-Press, 2016) Thoola, Maipato Immaculate; Rathilal, Sudesh; Pillay, Lingham V.
South Africa recognises piped water as the main source of safe drinking water supply. Remote areas do not have access to this resource and they rely solely on surface water for survival, which exposes them to waterborne diseases. Interim point of use solutions are not practiced due to their laboriousness and alteration of the taste. Bio-ultra low pressure driven membrane system has been noted to be able to produce stable fluxes after one week of operation; however, there is limited literature on South African waters. This study was conducted on three rivers namely; Umgeni, Umbilo and Tugela. Three laboratory systems were setup to evaluate the performance of the technology in terms of producing stable fluxes and water that is compliant with the WHO 2008 drinking water guideline with regards to turbidity, total coliforms and E.coli. The obtained flux rate trends were similar to those noted in literature where they are referred to as stable fluxes. However, when further comparing the obtained fluxes to the normal dead-end filtration curve, it was noted that both the Umbilo and Tugela Rivers responded similarly to a normal dead-end filtration curve. The Umgeni River was noted to produce flux rates which were higher than those obtainable under normal dead-end. It can be concluded that there was no stabilisation of flux noted. However, feed water with low E.coli and turbidity concentrations enhances the flux rates. The technology was noted to produce water of less than 1 NTU and 100% removal efficiency for E.coli and total coliforms.
Fouling and cleaning in osmotically driven membranes
(InTechOpen, 2018-03-06) Chollom, Martha Noro; Rathilal, Sudesh
Fouling is a phenomenon that occurs in all membrane processes. It is a complex problem, which limits the full operation of this technology. Fouling in pressure-driven membranes (PDMs) has been studied extensively, and the occurrence is well understood in that methods of mitigation have been proposed; however, limitations still occur for their full implementation. The use of osmotically driven membranes (ODMs) for water treatment is an emerging technology, which has shown some advantages such as low hydraulic pressure operation, high solute rejection and high recovery over PDMs. However, like in PDMs, fouling still presents a challenge. This chapter is aimed at evaluating the impact of fouling on the ODM performance, exploring the factors and mechanisms governing the fouling behaviour, developing approaches for mitigating fouling, elucidating the effect of membrane fouling and providing mitigation strategies as well as the causes of fouling in ODMs.
Fouling mitigation on a woven ﬁbre microﬁltration membrane for the treatment of raw water
(Institution of Chemical Engineers, 2017-06) Chollom, Martha Noro; Pikwa, Kumnandi; Rathilal, Sudesh; Pillay, Visvanathan Lingamurti
The main source of drinking water in rural areas of South Africa is surface water. Improving drinking water and sanitation facilities alone does not completely solve the problem of waterborne diseases. A novel simple gravity driven ﬁltration unit incorporated with the woven ﬁbre microﬁltration (WFMF) membranes was developed for the treatment of raw water for drinking purposes. However, these membranes are susceptible to fouling which reduces ﬂux permeation. This paper focused on evaluating the fouling mitigation strategies to improve on performance of the woven ﬁbre membrane ﬁltration unit with respect to fouling and ﬂux recovery. The study found that the WFMF membrane fouled both internally by pore plugging and externally by adsorption and deposition on the membrane. As a result, a single ﬂux enhancement strategy proved insufﬁcient to maintain high ﬂux successfully. A combination of strategies gave the best optimum conditions for ﬂux production. Backwashing with a combination of brushing yielded the highest recovery of 187%. Soaking the membranes in 0.2% hypochlorite for an hour and thereafter by brushing them yielded 93% ﬂux recovery. Mechanical cleaning however yielded the best result with 97% ﬂux recovery. It was concluded that the selected strategies were the most successful strategies to prevent a sharp decline in ﬂux due to fouling and giving high average ﬂux for the ﬁltration period.
Green roofs and stormwater runoff quality in the urban landscape in South Africa
(National Research Council Canada, 2021-06-20) Sucheran, Arisha; Sucheran, Reshma
A number of sustainable urban drainage systems (SuDS), such as green roofs, are being developed and implemented in cities around the world to help reduce stormwater runoff and improve stormwater runoff quality. This study compares the water quality of green roofs with that of conventional roofs in the eThekwini region, South Africa. Samples of stormwater runoff from the different green roof systems on the eThekwini Green Roof Pilot Project were collected to test their level of contaminants and pollutants. The tests focused on all physical, aesthetic, chemical, and microbiological determinants pertaining to stormwater runoff. For all tests, the level of contaminants and pollutants were measured against the South African Water Quality Guidelines Volume 7 for Aquatic Ecosystems. The data revealed significant variations in pollutant concentrations between the green roofs and the conventional roof. Moreover, runoff water quality varied across the various roof types, which may indicate that the substrate composition has the greatest impact on green roof performance regarding rainwater quality. Overall, the results suggest that these green roof systems do not have the ability to filter pollutants out of stormwater runoff, but rather increase their levels of concentration.
Hydrological characterization of twelve water catchments in Nigeria
(AJER, 2014-01) Afolayan, S.O.; Adeyemo, Josiah; Otieno, Fredrick Alfred O.; Ojo, Olumuyiwa I.
Twelve water catchments (WCs) in Ogbomosho, south west of Nigeria were evaluated for their hydrological characterization with respect to domestic and irrigation activities. Both physiochemical and biological parameters (limnological properties) were determined which include pH, total alkalinity (TA), CO32-, HCO3-, NO3-N, SO42-, N, P, K, Na, Ca, Mg, dissolved oxygen (DO), electrical conductivity (ECw), biochemical oxygen demand (BOD), total solids (TS), total dissolved solids (TDS), chlorophyll a,b,c and phaeophytin. Temperature fluctuation of the water catchments was measured in-situ to avoid samples coming into contact with the surrounding air using mercury in glass thermometer. Soil samples collected from the bottom of the water catchments were determined for chemical properties such as N, P, K, Na, Ca, Mg, and SO4-2 following recommended procedures. These parameters were investigated based on the perceived research consent of their efficacy in characterizing water catchments hydrologically along safety and pollution divides. The limnological properties were configured into ranking compared with standards to evaluate the degree of contamination or suitability of the WCs for domestic and irrigation purposes. Results obtained indicated pH values of the catchments ranging from 5.8 to 7.4 with corresponding TA between 0 and 296 mgL-1 suggesting high level of dissolved carbon dioxide (DCO2) and traces of untreated wastewater in most of the catchments. Based on ranking of the limnological properties of the WCs, WC4, WC5, WC6 recorded indices between 65 and 95 signifying that cumulatively these three WCs were more prone to pollution and could affect human health at consumption while WC2, WC3, WC 7 and , WC 10, aligned between 95 and 120 indicating mild to medium pollution and WC1, WC 11, and WC 12 oscillated between 120 to 145 picturing WCs approaching standards (132) while WC8 ranged between 145 and 170 revealing WC 8 as catchment with little or no tendency for hazards at drinking. Similarly, WC2, WC8, recorded soil reference (SR) between 50 and 60 suggesting possible interference of organic decomposition between the soil stratum and water in the catchment, however, WC1, WC4, WC5, WC6, WC7 and WC 12 recorded SR between 40 and 50 showing possible adjustment of the soils in the WCs of various salinity levels and WC 3, WC9, WC 11 revolving between 30 and 40 projecting the WCs with minimal pollution. Moreover, WC 10 only recorded value between 20 and 30, an inference of the soil stratum void of absolute contamination. Generally, WC2, WC8, appeared polluted both in limnological properties and basic soil conditions while WC9, WC10, WC11, and WC3 reflected high scale of ranking on limnological properties with low scale of SR possibly indicating little or no interaction between the soil base and the water in the catchments. Contrary wise, WC6 was high in SR but low in limnological properties. This trend suggests the presence of oxygen saturation in some of the WCs. Overall results indicated that WC4, WC5, WC6 require major water treatment prior to its usage for irrigation to avoid salt deposition at the crop root base, while WC2, WC3, WC7, WC9 and WC10 were considered relatively safe for drinking. WC1, WC11, WC2 requires some measure of precaution before drinking, however, WC12, and WC 8 could be consumed with little or no fear of infection.
Influence of effluent type on the performance of chitosan as a coagulant
(Akshar Publications, 2014) Pambi, Ritha-Lorette Luti; Musonge, Paul
The use of chitosan as a bio-polymeric coagulant has continued to attract interest in water treatment due to its biodegradability and non-toxicity. Its ability to treat effluents of high organic content has been investigated in some food processing industries. The focus of the present study is to compare results of the use of chitosan in the treatment of effluent from a Sugar Processing Plant (SPP), with those obtained from the treatment of wastewater from a Milk Processing Plant (MPP) and from a Brewery Processing Plant (BPP), in order to determine the influence of effluent type on the impurities removal efficiency. The treatment of the MPP provided the best removal efficiency (99% suspended solids removal and 70% COD removal) in comparison to the SPP (98% suspended solids removal and 11% COD removal) and BPP (95% suspended solids removal and 50% COD removal). The optimum pH value varied as a function of the type of effluent with BPP= 4.5, SPP = 4.5 and MPP =7. The results indicate that chitosan is not very efficient for the removal of dissolved matter. A relationship between total suspended solids (TSS) and total dissolved solids (TDS) has been developed.
Maximization of hydropower generation from Hazelmere Dam in South Africa
(Business Perspectives, 2015) Mashiyane, Thulasizwe Innocent; Olofintoye, Oluwatosin Onaopemipo; Adeyemo, Josiah
Harnessing more energy from existing water sources within the frontier of the country is germane in capacitating the South African Governmentâ€™s commitment to reduction of the countryâ€™s greenhouse gas emissions and transition to a low-carbon economy while meeting a national target of 3 725 megawatts by 2030. This study aims to determine the amount of energy that can be generated from Hazelmere Dam on the Mdloti River, South Africa. Behavioral analyses of the Hazelmere reservoir were performed using plausible scenarios. Feasible alternative reservoir operation models were formulated and investigated to determine the best operating policy and power system configuration. The optimi-zation models were formulated to maximize hydropower generation while keeping within the limits of existing irriga-tion demands. Differential evolution algorithm was employed to search feasible solution space for the best policy. Findings suggest that if the water resource in the dam is properly managed, about 558.54 MWh of annual energy may be generated from the reservoir under medium flow condition without system failure.