Treatment technologies for recycle liquors :nutrient removal, mass balances, and potential recovery at wastewater treatment plants

PhD thesisRecycle liquors (RLs) from anaerobic digesters at wastewater treatment plants (WWTPs) can be a challenge to WWTP operations, but also a source of nutrient recovery. For example, Northumbrian Water Ltd.’s Bran Sands WWTP has historically had elevated NH4-N levels and accumulation of PO4-P within its works, primarily due to the recycling of nutrient-rich RLs from its sludge treatment process to its activated sludge (AS) units. This has led to chronic scaling problems (as struvite), fluctuations in AS process stability, and increased operational costs (i.e. increased maintenance, chemical and energy costs). In order to tackle these issues, this thesis performed a mass balance on NH4-N and PO4-P around the WWTP to understand the material flow across plant operations, which led to various NH4-N and PO4-P treatment and recovery studies. Relative to PO4-P removal and struvite reduction, the addition of MgCl2 (and pH adjustment) were examined to assess their value in removing P and N from the soluble phase (i.e. in RLs) in AD and post-AD units. NH4-N and PO4-P removal/recovery increased as Mg2+ and pH increased when added to both locations. However, NH4-N and PO4-P removal/recovery was most efficient in post-AD applications (i.e. ~49 ± 0.17% and ~83 ± 0.25%, respectively, at pH 8 with 150 mg/L of added Mg2+). A simple cost benefit analysis shows this could potentially offset 83% of the annual cost of dealing with scaling problems on site, and ~£321,000/yr can be generated from the sale of the recovered PO4-P. The AD experiments also showed increase volatile solids removal and biogas production as Mg2+ and pH increased. To further reduce NH4-N in RLs, the thesis investigated the suitability of aerobic, nitrifying granule bioreactors for NH4-N removal. Up to 95% NH4-N removal (mean influent NH4-N = 300 mg/L) was observed at NH4-N loading rate of 0.6 gNH4-N L-1.d-1, which was most efficient when nitrite-oxidising bacteria abundances were comparatively higher in the granules relative to ammonia-oxidizing bacteria. Overall, the work shows that a combination of Mg2+ addition for PO4-P removal and aerobic granule bioreactors for NH4-N removal could reduce nutrient levels in RLs, although work is still needed to translate this potential into actual enhanced NH4-N and PO4-P recovery.Northumbrian Water Ltd, NWL

A stochastic modeling of recurrent measles epidemic

A simple stochastic mathematical model is developed and investigated for the dynamics of measles epidemic. The model, which is a multi-dimensional diffusion process, includes susceptible individuals, latent (exposed), infected and removed individuals. Stochastic effects are assumed to arise in the process of infection of susceptible individuals. Using the best currently available parameter values, the intrinsic variability in response to a given initial infection is examined by solving the stochastic system numerically. The results of the simulation seem to agree with the historical pattern of measles in Nigeria. Keywords: Stochastic model, measles, epidemiology, Wiener process, Euler scheme

Gamma Radiation Hazard Associated with Tin Mining on Jos Plateau

Tin miners may be exposed to gamma radiation due to radio nuclide contaminants associated with the tin. In this work, 10 samples of soil were collected from different mining sites on the Jos Plateau of North central Nigeria and were analyzed by measuring the concentrations (Bq/kg) of the three radio nuclides 40K, 238U and 232Th which are associated with the tin; and calculating the absorbed dose rates per year. The gamma ray measurements were achieved through the use of gamma ray spectrometer coupled to a NaI(Ti) scintillation detector. Estimation of the absorbed dose rates using the Beck and Decmopo formula showed the maximum absorbed dose rate in one of the ten locations as 4.704 mSv/y and an average of 2.718 mSv/y was obtainedfor the ten locations. These are within the range given by ICRP, the maximum permissible dose per year for a radiation worker, which is about 20 mSv/y. Thus the mining of tin on the Jos Plateau poses no serious danger to lives

Phytochemistry and Antimicrobial Activity of the Leaf of cassia alata LINN.

The leaves of cassia alata Linn were successively extracted with n-hexane and ethylacetate using the soxhlet method. Preliminary phytochemical screening of the extracts revealed the presence of free anthraquinones, flavonoids, steroids and saponins. The n-hexane crude extract exhibited some anti – bacterial activity against Yersinnia enterocolitica, streptococcus pneumonia and salmonella typhi. Anti–fungal activities against Microsporum audouini and Trichophyton meritagrophyta were also exhibited. A synergic test of n–hexane and ethylacetate extracts showed an improved sensitivity against shigella sormei and strep. pneumonia. A confirmatory phytochemical analysis performed on the most mobile tlc isolate (Rf 0.94) from the n-hexane extract revealed the presence of steroidal saponin. This was found to be active against strep. pneumonia. Key words: Cassia alata, Phytochemistry,Steroids and Antimicrobial activit

On some properties of the block linear multi-step methods

The convergence, stability and order of Block linear Multistep methods have been determined in the past based on individual members of the block. In this paper, methods are proposed to examine the properties of the entire block. Some Block Linear Multistep methods have been considered, their convergence, stability and order have been determined using these approaches. Keywords: Annuity, Amortisation, Sinking Fund, Present and Future Value Annuity, Maturity date and Redemption value

Profil epidemiologique et anatomo-clinique des malade du centre d'oncologie de Doula:Une analyse sur neuf ans

Les auteurs présentent une étude rétrospective et analytique, sur neuf ans et sept mois (19 juin 1999 au 1er février 2008) réalisée sur les malades reçus en consultation au Centre d’Oncologie de Douala pendant cette période. L’objectif est d’étudier le profil épidémiologique de ces malades, en particulier le sexe, l’âge, et les localisations tumorales observées pour chaque patient. 4775 patients ont été reçus en consultation durant la période d’étude, comprenant 3065 femmes (64%) et 1710 hommes (36%). Les âges varient de un à 90 ans, avec une moyenne de 41,3 ans. La distribution des fréquences selon la localisation montre une très nette prédominance des localisations gynécologiques et mammaires (2151 cas, soit 45,05%), suivies des lymphomes (845 cas, soit 17,7%) puis des sarcomes de Kaposi (720 cas représentant 15% de l’effectif total). Ainsi, sur 840 tumeurs malignes du sein répertoriées, 90 patientes (11%) sont d’emblée métastatiques, et cent patientes (12%) présentent des mastites carcinomateuses très souvent ulcérées. Quatre cents cancers du col utérin sont dénombrés, dont seulement 50 (12,50%) étaient encore à un stade clinique inférieur ou égal au stade II de la FIGO. L’on relève également que sur 720 cas de sarcomes de Kaposi reçus, seulement 10 patients (1 ,40%) étaient indemnes de l’infection à VIH. Des tentatives d’explications sont amorcées, dans la recherche de perspectives porteuses pour l’avenir.MOTS CLES: Epidémiologie-Localisations-Oncologie–Douala–Cameroun

Terrestrial and fluvial carbon fluxes in a tropical watershed: Nyong basin, Cameroon

The Nyong watershed, with an area of 27 800 km2 and a mean annual discharge of 390 m3 s−1, is the second largest river in Cameroon. The Nyong watershed serves as an outstanding study area for the examination of carbon fluxes in humid tropical environments because of its limited anthropogenic impact and homogeneous silicate bedrock. Between April 2005 and April 2007, we sampled water at seven stations, from the small watershed of the Mengong (0.6 km2) to the Nyong at Edea (24 500 km2), and monitored temperature, pH, dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) contents, as well as the isotopic composition of DIC (δ13CDIC)andDOC(δ13CDOC).We estimated terrestrial net ecosystemproductivity in theNyong River watershed and measured fluvial fluxes of carbon to the ocean and the atmosphere. The Nyong River basin sequesters significant amounts of carbon on an annual basis: ~7 920 000t C year−1 (300 g C m−2 year−1). The combined dissolved organic, dissolved inorganic and atmospheric fluxes of carbon from the Nyong River only export 3% of this flux fromthe basin on an annual basis. This includes a minimumCO2 outgassing of 1487 g Cm−2 year−1, comparable to 115% of the annual flux of DOC and four times greater than the flux of DIC

Emek pıyasasında göç ve prekarite : İstanbul'da Kamerunlu göçmenler üzerıne bır araştırma

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Göç medyada, politik ortamda her zamankinden daha önemli bir sorun haline gelmiştir. Nitekim 2015 yılı bir dizi önemli göç krizlerinin yılı olmuştur. Birleşmiş Milletler Nüfüs Fonu (UNFPA 2015) 244 milyon kişinin, ya da dünya nüfusunun yüzde 3,3'ünün kendi kaynak ülkeleri dışında yaşadığını göstermektedir. Göçmenlerin bir kısmı daha iyi ekonomik ve sosyal fırsatların arayışı içinde sınırları aşarken, bir kısmında ülkelerindeki çeşitli krizlerden kaçmaya zorlanmaktadır. 2015 yılı itibariyle, Türkiye'de yaşayan sadece Suriyeli göçmen sayısı 3 milyon yakındır. Türkiye, sadece Suriyeli göçmenlerin uğrak alanlarından biri değildir. Aynı zamanda çok sayıda Afrika ülkesinden çeşitli şekillerde ve oranlarda göç almaktadır. Bu çalışmanın örneklem seçim alanını oluşturan Kamurunlu göçmenler de çeşitli nedenler ve şekillerde Türkiye'yi uğrak alan haline getiren Afrikalı göçmenlerdendir. Türkiye, özellikle bir çok Afrikalı göçmen açısından ekonomik olarak para kazanabilecekleri, iş ve fırsatları onlara sunan bir ülke olarak görünmektedir. Bu durum Türk İşgücü piyasasında, göçmen işgücü temelinde prekariteye yol açan bir takım etkilerin ortaya çıkmasına neden olmaktadır. Bu çalışmanın amacı da bahsedilen bu durumla ilgilidir. Çalışmanın temel amacı, Türk işgücü piyasasında göçmen işgücü temelinde ortaya çıkan prekarite olgusunu göçmen işgücü üzerinden hareketle analiz etmektir. Bu amaç çerçevesinde çalışmada ilk olarak Kamerunlu göçmenlerin Türkiye'ye göç etme nedenleri, Türkiye'deki çalışma ve yaşam koşulları, göçmenlerin demorafik özellikleri ve Kamerun'daki sosyal ekonomik pozisyonları tespit edilmeye çalışılmıştır. İkinci olarak ise, Kamerunlu göçmen işgücünün Türkiye'deki meslek ilişkileri, yasal statüleri, işe alınma yolları, yabancı işgücü olarak yaşadıkları güvensizlik ve hak sorunlarına ilişkin bir inceleme yapılarak, Türkiye işgücü piyasasının göçmenler için güvencesizlik düzeyi tespit edilmeye çalışılmıştır. Böylece göçmen işgücü temelinde prekaritenin boyutları ve düzeyleri ortaya çıkarılmaya çalışılmıştır. Çalışmada ihtiyaç duyulan veriler 18-23 Mart 2016 tarihleri arasında 16 Kamerunlu göçmenle yapılan mülakatlar neticesinde toplanmıştır. Mülakat sonuçları, göçmen işgücü temelinde yoğun prekaritenin varlığına işaret etmekle birlikte, bunun giderek derinleşeceğine dair kuvvetli imalarda bulunmaktadır.Migration has become more than ever an important issue on the medias, on political sphere and object of several academic works. The year 2015 was punctuated by a series of migration crises, the United Nations Population Fund (UNFPA, 2015) reported that 244 million people, or 3.3 per cent of the world's population, lived outside their country of origin. The majority of migrants cross borders in search of better economic and social opportunities, others are forced to flee crises. By the year of 2015 the number of Syrians refugees registered by the Government of Turkey in their territory is around 3 milion. Nevertheless, Turkey is also attracted by other migrants from different countries such as Cameroon. This phenomenon impacts on the Turkish labor market leading to precarity. This paper is set to look at migration and precarity concepts in Turkish labour market. Previous researches focused on Africans in general migrating to Turkey but this research tackles the specific case of Cameroonians. The main purpose is to perceive the working condition of Cameroonian migrants workers in Istanbul. This article provides an insight on the rush of Cameroonian migrants to Turkey and contributes in understanding the precarious nature on the Turkish labor market. This involves the social, economic and legal framework of Cameroonian workers. It has been designed to investigate specific aspects such as their educational backgrounds, working conditions, ways of recruitment, professional inter-relations, legal status, challenges and vulnerability as foreign workers. The fieldwork took place from the 18th of March to 23rd, 2016. Through an empirical study 16 structured and semi structured interviews were conducted in various districts in Istanbul

Sustainable Energization of Rural Areas of Developing Countries – A Comprehensive Planning Approach

AbstractAccess to modern energy services in developing countries (DC) is a double-faced challenge. About 1.3billion people do not have access to electricity; 2.6 billion rely on traditional use of biomass for cooking. Solutions to this energy challenge can neither be through isolated promotion of individual technologies nor fuel switching alone. A “system approach” towards a more comprehensive energy access strategy is required. Such access strategy would comprise of the supply of alternative energy carriers and planning of complete energy solutions via a more comprehensive and sustainable Rural Energy Planning (REP) i.e. Sustainable Energization (SE). Existing procedures to SE do not account for the existing energy balance and have not been demonstrated in the context of rural areas. The study aimed to propose and consolidate a more comprehensive REP procedure for SE of rural areas of DC. A seven-step procedure is proposed and its relevance and validity demonstrated through a field case study. The proposed procedure takes into account the existing energy balance and integrates energy drivers in the energy services supply network. Application of the procedure in a rural context showed a great improvement in the quantity, quality, and variety of accessible and affordable energy services for a more sustainable development of rural areas

Antifungal properties of methanolic extracts of some medical plants in Enugu, south east Nigeria

Objective: The current study evaluated the anti-fungal activities of methanolic extracts of the leaves and fruits of some medicinal plants of health value in Enugu, southeast Nigeria.Materials and methods: Volumes of the different extracts into molten Sabouraud Dextrose Agar to make up for concentrations of 25 mg/ml, 50 mg/ml and 100 mg/ml respectively. Concentrations of 125 μg/ml, 250 μg/ml and 500 μg/ml of Miconazole were incorporated to serve as a positive control while 0.5 ml of DMSO served as a negative control. The plants extracts employed were from Azadirachta indica (Neem), Anacardium occidentale (Cashew), Euphorbia hirta (Asthma weed), Jatropha curcas (Physic nut), Acantus montanus (Mountain thistle) and Picralima nitida (òsúigwe in Igbo). A 2 mm agar disc cut out from the margin of actively growing cultures of each dermatophyte (Trichophyton soudanense, T. mentagrophytes, Cladosporium sp, T. rubrum and Fusarium sp) were inoculated on the agar plates containing varying concentrations of the different plant extracts, the standard antifungal agent and negative control in triplicates and incubated at 28 ºC.Results: All the extracts exhibited antifungal activities of varying degrees with radial growth inhibitions (RGIs) ranging from 0-0.45 mm radius. Fifty percent (50 %) of the plants extracts comprising of Picralima nitida, Euphorbia hirta and Acantus montanus exhibited complete inhibition at 100 mg/ml against all the clinical isolates under investigation (p < 0.05). Picralima nitida seed was the only plant extract with complete inhibition at 25 mg/ml against T. soudanense and T. rubrum. Picralima nitida was the closest in activity to miconazole. Azadirachta indica (Neem) did not exhibit complete inhibition against any of the clinical isolates at 100 mg/ml yet exhibited a significantly lower RGI at the lowest concentration of 25 mg/ml better than others.Conclusion: Antifungal activities showed that leaves extract of fruits plants against the clinical isolates are good source of medicinal applicationsKeywords: Antifungal agents, medical plants, Enugu, Nigeri