Unprotected Wells Research Articles

Small town water quality

This paper examined water-quality monitoring in two small towns’ water supply systems and unprotected wells in some selected communities. The systems were Bekwai and Juaso in the Ashanti Region. Water samples collected were tested to determine basic water-quality parameters. The main problem identified was the presence of bacteriological parameters; Escherichia coli, Salmonella and coliforms indicating the presence of micro-organisms in the water that are potentially harmful to human health. All physical and chemical parameters except iron were within the limits of theWHO guidelines. It is highly recommended that all small piped water supply schemes receive some form of post-chlorine treatment. Source protection should be done and hygienic conditions of the point sources improved.

Assessment of drinking water quality of Mtopwa village in Bangwe Township, Blantyre

The water quality from open hand-dug wells in Mtopwa village in Blantyre was assessed over a period of four months. The research entailed conduction of experiments using recommended methods to analyse selected water quality parameters. Interviews were also conducted with the Blantyre City Assembly (BCA) personnel on the role of the assembly to eliminate scarcity of potable water and also with the residents on how they are affected by the scarcity of potable water. Results showed that suspended solids and coliforms exceeded the recommended guideline values for drinking water according to World Health Organisation, Malawi Bureau of standards and Ministry of Water development. Turbidity, pH and total dissolved solids (TDSs) were within acceptable limits for all the well water samples tested. The scarcity of potable water and poverty forces the residents to consume water from unprotected hand-dug wells, streams and rivers without any form of treatment.

Diarrhoea and acute respiratory infections prevalence and risk factors among under-five children in Iraq in 2000

BackgroundDiarrhoea and acute respiratory conditions are common medical conditions among under-five children in resource-limited and conflict situations. The present study was conducted to estimate the prevalence and associated factors for acute respiratory conditions and diarrhoea among children under the age of five years in Iraq in 2000.MethodsData for the Iraqi Multiple Indicator Cluster Survey were obtained from UNICEF. We estimated the prevalence of acute respiratory conditions and diarrhoea. Assessment of the associations between these two medical conditions on one hand and socio-demographic and environmental variables on the other was done using logistic regression analysis. Weighted analysis was conducted to account for complex survey design.ResultsA total of 14,676 children under the age of 5 years were reported by their mothers in the study. Of these 50.4% were males. About half (53.9%) of the children had complete vaccination status. Overall, 21.3% of the children had diarrhoea, and 6.9% had acute respiratory infection (ARI) in the last two weeks. In multivariate analysis, diarrhoea was associated with age of child, area of residence, maternal education, source of water, toilet facility, disposal of children' stool and disposal of dirty water. Compared to children aged 48–59 months, children in the age groups 6–11 months and 12–23 months were 2.22 (95%CI [2.02, 2.44]) and 1.84 (95%CI [1.71, 2.00]) times more likely, respectively, to have diarrhoea. Children whose mothers had no formal education were 11% (AOR = 1.11, 95%CI [1.04, 1.18]) more likely to have diarrhoea compared to children with mothers who had attained secondary level of education. Compared to children who belonged to households with unprotected well or river as the main source of water, children who belonged to households with piped water were 32% (AOR = 1.32, 95%CI [1.17, 1.48]) more likely to have diarrhoea while those who belonged to households with protected well were 26% (AOR = 0.74, 95%CI [0.62, 0.89]) less likely to have diarrhoea. Age of child, toilet facility, wealth, and sex of child were significantly associated with ARI.ConclusionIn a study of under-five children in Iraq in 2000, we found that history of diarrhoea and ARI were negatively associated with lower socio-economic status, adequate disposal of children's stool and dirty water, but the results were inconsistent in terms of access to potable water and sanitation facilities possibly due to non-functioning of water and sewage plants after the war. Improvement in water quality and sanitation are vital in the reduction of diarrhoeal diseases.

The Influence Of Environmental Sanitation Practices And Hygiene On The Incidence Of Diarrhoea – The Case Of Koforidua Municipality, Ghana

A case-control study was done using a convenience sample of 100 pairs of mothers and children (less than five years old) divided into two groups; the first group made of children with diarrhoea and their mothers (case group) and the second group made up of mothers and children who did not have diarrhoea (control). A structured interview schedule and review of routine data were used to collect data. Only 12.5% of children less than six months in the case group were exclusively being breastfed compared with 75% of the control group. 56% of the cases used water from unprotected wells for domestic activity while 70% of the control group used pipe- borne water. Also 24% of the case group did not cover stored water while 76% of the control group covered stored water. This demonstrated poor food and water safety. Only 10% of cases had access to flushing water closets for human excreta disposal while the remaining 90% either used pit latrines or disposal into surrounding bushes. It was recommended that good amenities for the disposal of refuse in the communities be provided by the government and the delivery of pipe-borne water be made more regular to the inhabitants Further, appropriate education in simple language is to be offered by health personnel especially at Ante-Natal Clinic and on radio stations and mothers are to be encouraged to put into practice what they learn about the treatment and prevention of diarrhoea.African Journal of Clinical and Experimental Microbiology Vol. 10 (1) 2009: pp. 56-63

A short-term intervention for the treatment of severe malnutrition in a post-conflict country: results of a survey in Guinea Bissau

To determine (i) the extent of malnutrition and the risk factors for severe malnutrition in Guinea Bissau, a post-conflict country experiencing long-term consequences of civil war; and (ii) the feasibility and effectiveness of a short-term intervention characterized by outpatient treatment with locally produced food for the treatment of severe malnutrition during the rainy season. Social, clinical, nutritional information were collected for children reaching the paediatric outpatient clinic of the Hospital 'Comunità di Sant'Egidio' in Bissau, Guinea Bissau, from 1 July to 12 August 2003. Severely malnourished children (weight-for-age <-3sd) in poor health status were admitted for daily nutritional and pharmacological treatment until complete recovery. Social and health indicators were analysed to define risk factors of severe malnutrition. In total, 2642 children were visited (age range: 1 month-17 years). Fever, cough and dermatological problems were the main reasons for access. Social data outlined poor housing conditions: 86.4 % used water from unprotected wells, 97.3 % did not have a bathroom at home, 78.2 % lived in a mud house. Weight-for-age was <-2sd in 23.0 % of the children and <-3sd in 10.3 %; thirty-seven children (1.4 %) were severely malnourished and admitted for day care. All recovered with a weight gain of 4.45 g/kg per d, none died or relapsed after 1 year. Severely malnourished children were mainly infants, part of large families and had illiterate mothers. Short-term interventions performed in post-conflict countries during seasons of high burden of disease and malnutrition are feasible and successful at low cost; day-care treatment of severe malnutrition with locally produced food is an option that can be tested in other settings.

Vulnerability of headwater catchment resources to incidences of 210Pb excess and 137Cs radionuclide fallout

Recent identification of elevated excess 210Pb (≤302.6 mBq L−1) and 137Cs (≤111.3 mBq L−1) activity in drinking water wells up to 20 m depth indicates some transport of airborne radionuclide fallout beyond soils in the Shaker Village catchment, Maine. Estimated airborne mass loading 210Pbex fluxes of about 0.9 mBq m−3, canvass this headwater catchment and may be sufficient to pose risks to unprotected shallow wells. Inventories of 210Pbex and 137Cs in pond sediments indicate maximum median activities of 943 mBq g−1 and 40.0 mBq g−1, respectively. Calculated 210Pbex fluxes in the catchment soils range from 0.62–0.78 Bq cm−2 year−1 and yield a mean residence time of near 140 years. Measured 137Cs activity up to 51.1 mBq g−1 occurs in sediments at least to 5 m depth. Assumed particle transport in groundwater with apparent 85Kr ages less than 5 years BP (2005) may explain the correlation between these particle-reactive radionuclides and elevated activity in some drinking water wells.

A survey of bacteriological quality of drinking water in North Gondar

Background: The high prevalence of diarrheal disease among children and infants can be traced to the use of unsafe water and unhygienic practices. The over all concept adopted for microbiological quality is that no water intended for human consumption shall contain E. coli in 100 ml sample. But, a 1-10 E.coli count per 100 ml is acceptable that needs regular sanitary checks for un chlorinated water. Objectives: To assess the extent of bacterial contamination among protected and unprotected water sources. Methods: A cross-sectional study on drinking water quality in North Gondar region was conducted from May to June 2000. Water samples were taken for bacteriological analysis. Results: Analysis of protected springs, protected wells and water lines showed that 35.7%, 28.6% and 50% of the water samples had E. coli, respectively. On the other hand, 50% of the unprotected wells and springs had a fecal coliform count of 180 and above. Conclusions: The majority of the drinking water sources are either of unacceptable quality or grossly polluted. Regular quality control mechanisms need to be in place to ensure safety of drinking water. [Ethiop.J.Health Dev. 2004;18(2):112-115]

Realising the maximum health benefits from water quality improvements in the home: a case from Zaka district, Zimbabwe

The provision of good quality household drinking water is often regarded as an important means of improving health. There are however indications that the microbiological quality of water deteriorates between source and point of use in the home. The notion that providing clean water sources could be the solution to the rural water supply problem might therefore not be correct. This paper presents the findings from a survey that sought to investigate the quality of water in the home post-collection and any factors that were contributing to the quality. The 24 households that participated in the study were selected randomly from two villages. Water samples were collected from the households and from the drinking water sources. These were tested for total coliforms and Escherichia coli. Greater contamination was detected in the water drawn from unprotected wells than in that drawn from protected ones. For protected sources, there was an increase in the numbers of pathogens in the stored water relative to the source water. In a few instances there was a decrease in indicator bacteria numbers following water collection. This could have been due to a natural die off of the pathogens. There however did not seem to be a significant correlation between the microbiological quality of water in the home and the length of time the water has been stored. These findings indicate that there is some deterioration in the microbiological quality of water post-collection and it appears the phenomenon may be attributable to water handling and hygiene behaviours in the home. Water was collected frequently and rarely treated after collection. Only one household out of the 24 reported treating their water after collecting it. Home water treatment or safe storage may be an appropriate intervention in this community to reduce diarrhoeal disease.

Determinants of drinking water quality in rural Nicaragua.

One hundred and fifty-three water samples from rural Nicaragua were examined for the presence of faecal coliforms during both wet and dry periods. A linear model was fitted by analysis of covariance with the logarithm of the faecal coliform count as the dependent variable. As expected, traditional water sources were grossly contaminated at all times whereas piped water sources were much cleaner. Hand-dug protected wells had significantly higher levels of faecal contamination than unprotected riverside wells and springs during the dry season. The possible reasons for this unexpected finding are discussed. A close association between rainfall and faecal contamination was demonstrated but the effect of rainfall depended on the type of water source. An association between water quality and the size of the community served by the source was also detected. The finding that stored water was usually more contaminated than fresh water samples is consistent with the results from other studies. Since it is unusual for water quality to be inversely correlated with accessibility, this study site would be suitable for investigating the relative importance of water-borne versus water-washed transmission mechanisms in childhood diarrhoea.

Distribution of ostracods in the groundwater of the North Western Coast of Euboea (Greece)

Freshwater fauna from 20 wells located 15-200 m from the seashore as well as marine interstitial fauna from the coastal zone around the village Aghios Georghios (Cape Likhada) have been investigated. Freshwater hypogean ostracods live mainly in protected wells having clean bottom and little particulate organic matter from which the water is moderately pumped. Epigean freshwater ostracods dominate in unprotected wells with large amounts of organic matter on the bottom. There is a sharp difference between the ostracod fauna living in fresh groundwater (mainly Cypridids) and those living in coastal marine interstitial habitats (marine Cytherids and Polycopids). It is suggested that in the Mediterranean realm the hypogean fauna could be found easily in protected wells with little organic matter accumulation, where water is moderately pumped.

Deep Well Casing Cathodic Protection Requirements

ABSTRACT Failures of well casings as a result of external corrosion on bothcathodically protected and unprotected wells in the South Swan Hills Unit havebeen investigated. Previous testing indicated that an instantaneously appliedcurrent of 30.0 amperes would not provide adequate protection throughout thecorrosive Wabamun D-1 water-bearing zone which exists throughout the unit atdepths ranging between 1,676 m (5,500 ft) and 2,195 m (7,200 ft). A four-well pilot project was initiated in early 1977 to determine if 30.0amperes and polarization would provide adequate cathodic protection throughoutthe D-1 zone. The results of the pilot project indicated that cathodicprotection with 30. 0 amperes and polarization is possible throughout thecorrosive zone and that cathodic protection currents can be successfullyprojected below high-resistance zones. Introduction The South Swan Hills Unit is located approximately 225 km (140 miles)northwest of Edmonton, Alberta (Fig. 1). The field was discovered in 1961 andwas placed on production the following year. The total daily Unit production isapproximately 9,540 m3 (60,000 barrels) of oil and 9,540m3 (60,000 barrels) of water from 161 producing wells. The Unitcontains a total of 228 wells. A typical downhole diagram of a South Swan Hill Unit well is depicted in Figure 2. The average total depth of the wells in the Unit is 2,469 m (8,100ft) and the average calculated cement top is 1,280 m (4,200 ft). The wellsproduce from the Beaverhill A and B formations. A total of 13 leaks attributed to external corrosion have been experiencedin Unit wells since 1966. As shown in Figure 2, the leaks have occurred in twodistinct ranges: 8 between 894 m (2,900 ft) and 1,340 m (4,400 ft) on wellsdrilled with low-pH gyp starch mud, and 5 between 1,890 m (6,200 ft) 2,286 m(7,500 ft) on both non-gyp starch and gyp starch mud wells. The corrosionoccurring over the lower level is attributed to the water-bearing Wabamun D-1zone. Previous testing had indicated that cathodic protection over the D-1 zonemay not be possible in the South Swan Hills field.

Insulated Hot Oil-Producing Wells In Permafrost

An analysis is presented for the transient heat flow in and around production wells in which insulated casings may be used to reduce production wells in which insulated casings may be used to reduce permafrost thaw in the Alaskan North Slope. Results show that insulated permafrost thaw in the Alaskan North Slope. Results show that insulated casing systems can greatly restrict potential thawing of permafrost. Introduction A potential problem in the production of hot (180 to 200 degrees F) crude oil in unprotected wells on the Alaskan North Slope is the thawing of permafrost adjacent to the wells. Thawing of permafrost could result in soil consolidation, subsidence, and possible damage to the well. BP Alaska, Inc., and Arthur D. Little, Inc., have collaborated in developing a method to analyze the thermal performance of insulated wells in permafrost and in performing analyses of typical insulated well-casing systems. The ultimate objectives of this work were to understand permafrost thermal behavior under oil production conditions and to assist the design, development, and testing of an insulated well-casing system. The heat flow along and through the well casing and into the surrounding soil is quite complex. Standard, closed-form, or integral solutions available for melting in one or two dimensions are not applicable to the heat flow in the surrounding soil because of the complexity of heat exchange between the flowing hot oil and the ground, and the variation of thermophysical properties with temperature and depth. Previous studies for wellbore heat transmissions have neglected vertical beat flow in the soil and have not taken into account the effects of latent heat of fusion. Couch et al. have developed a mathematical model for thawing the soil surrounding unprotected wells that included the effects of latent heat of fusion of the soil. The effects of the latent heat were shown to be significant. Their analysis treated the well casing as part of the thermal resistance between the hot oil and the soil. Heat flow along the casing was not accounted for. In the present analysis, we have considered the details of the construction of the casing itself, as well as the heat flow in the casing, to evaluate the effects of "thermal shorting" across the insulation where casing joints are coupled. In addition, the model allows an examination of the effects of localized failure of one or several insulation joints. Analysis Problem Definition and Mathematical Models Problem Definition and Mathematical Models Fig. 1, a sketch of a typical configuration oil-producing well in a permafrost region, shows the flowstring for hot crude oil, a surrounding insulation system (extending only over a selected depth of the permafrost region) and casing, and a region of cement surrounding the well casing. Hot crude oil enters the flowstring at a depth significantly below the permafrost level and flows upward, transferring heat to the innermost pipe by convection. Heat is conducted along the pipe by convection. Heat is conducted along the flowstring, through the casing and insulation, through the cement, and into the surrounding permafrost and unfrozen soil. Since the well-casing components provide a thermal short circuit in the vertical direction, heat also may be conducted along the casing from warmer to colder regions. JPT P. 357

Permafrost Thawing Around Producing Oil Wells

Abstract A mathematical thermal model for predicting the time dependent temperature distribution surrounding a production well is described. The model provides for two-dimensional radially symmetrical and vertical heat conduction in the surrounding earth. Heat transfer from the produced fluids to the earth by conduction, convection and radiation is accounted for through an over-all heat transfer coefficient. The latent heat of fusion of water is included in the Model. The boundary of the melted zone at any time corresponds to the location of the 32 °F isotherm at that time. This boundary can be determined for various well completions either with or without insulation protection. Thus, the need for insulation can be determined as well as the effectiveness of various insulation schemes. Typical calculated results are presented for a well completed through 1,400 feet of permafrost with the top 700 feet of tubing insulated. INTRODUCTION THE DISCOVERY OF OIL IN ARCTIC REGIONS has introduced many new and unique problems which must be dealt with successfully before that oil can be brought to market. One anticipated difficulty is the thawing of the permafrost around the producing oil wells in these regions. This thawing is caused by the production of large volumes of hot fluids (possibly at 200 °F bottom-hole temperature) for extended periods of time. Any thawing that occurs at the cement-permafrost interface will destroy the cement bond. Thawing of the permafrost in the layers near the surface will result in sloughing of the soil around the wellbore. The ensuing mechanical stresses imposed on the casing could result in irreparable damage and necessitate premature abandonment of the well. In view of the tremendous drilling and completion expenses encountered in the Arctic, this is obviously undesirable. There are two possible approaches to solving this problem. One is to prevent thawing of the permafrost through a section thick enough to maintain a competent well completion. The other is to allow permafrost thawing and design a well completion which will be compatible with the adverse conditions resulting there from(1). For the first of these solutions there are again two possible means for accomplishing this goal. One method is to adequately insulate the production string through some portion of the permafrost zone. The second method is to refrigerate the casing string through some portion of the permafrost zone. In order to evaluate the alternatives of insulating the production string, a mathematical model giving a detailed description of the heat flow in and around the producing well is required. Previous models of wellbore heat flow(2,3) have neglected vertical heat flow in the earth surrounding the well, and the latent heat of fusion was not included in their energy balance. The use of these older models must be considered as only approximate solutions for the thawing problems treated here. A mathematical model has been developed which can predict the extent to which thawing will occur in unprotected wells and can evaluate the effectiveness of various schemes of insulating the production string.

THE BACTERIOLOGY OF FARM WATER SUPPLIES: A STUDY OF THE COLONY COUNT IN 48 HOURS AT 37°

SUMMARY: Colony counts in 48 hr. at 37° were much higher in farm water supplies derived from rivers, streams, canals and unprotected wells than in water from springs, protected wells, upland surface waters and chlorinated supplies. Relatively few of the upland surface waters had counts exceeding 102/ml., but the counts for unprotected shallow wells were as high as those for rivers, streams and canals.There was a general association between colony counts at 37° and presumptive coli‐aerogenes counts, but high 37° colony counts could not always be accepted as an indication of sewage or faecal pollution and obviously polluted waters sometimes had low colony counts at 37°.Irrespective of the magnitude of the colony count, the majority (63%) of the colonies were Gram‐negative rods, though they formed a higher proportion of the flora in high than in low count waters. Aerobic spore‐forming rods constituted nearly 20% of the colonies and micrococci 10%, while Gram‐positive rods which did not form spores were present in small numbers at all colony count ranges. Streptococci were relatively rare, forming less than 2% of the colonies.Approximately 25% of the 1,912 cultures isolated from colonies at 37° produced acid and gas in MacConkey's broth at 37°, but 7% of the 488 presumptive coli‐aerogenes cultures were aerobic spore‐forming rods. Typical coli‐aerogenes bacteria constituted 38% of the Gram‐negative rods and 24% of all the colonies examined. Surprisingly few colonies resembled Bact. coli type I in producing acid and gas in MacConkey's broth at 44°, and 13 (6.8%) of the 192 which did so were aerobic spore‐formers resembling Bacillus macerans.Slightly over a third of the cultures produced an acid or proteolytic reaction in litmus milk within 2 days at 22°.The results indicate that the colony count in 48 hr. at 37° does not contribute much useful information additional to that obtained from the presumptive coli‐aerogenes test at 37° and the Bact. coli test at 44°.