scholarly journals Investigating the occurrence of algae in the drinking water supply system of Harare, Zimbabwe

2020 ◽  
Vol 10 (2) ◽  
pp. 179-190
Author(s):  
Pardon Dandadzi ◽  
Zvikomborero Hoko ◽  
Tamuka Nhiwatiwa
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Water Supply ◽  
Distribution System ◽  
Quality Parameters ◽  
Supply System ◽  
Water Quality Parameters ◽  
Residual Chlorine ◽  
Raw Water

Abstract This study assessed the quality of drinking water in the water supply system for the City of Harare (Zimbabwe) by investigating the occurrence of algae and other water quality parameters that affect its growth. At Morton Jaffray Water Treatment Works (MJWTWs), samples were collected from the raw water inlet and treated water outlet points. In the distribution system, samples were collected from selected sites and grouped into four zones (1, 2, 3 and 4). The algal taxonomic groups that were found in both raw and treated water comprised of Cyanophyceae, Chlorophyceae, Bacillariophyceae, Euglenophyceae and Dinophyceae. It was found out that Microcystis aeruginosa followed by Anabaena were the most abundant species in both raw water and in the distribution system. All measured water quality parameters were within the Standards Association of Zimbabwe and WHO guideline values except for chlorine which had an average residual chlorine concentration that was lower than the WHO recommended lower value of 0.2 mg/L in parts of Zone 2. Morton Jaffray Water Treatment Works does not completely remove algae, and there is a carry-over of algae into the distribution system. Boosting of chlorine is recommended for Zone 2 that had residual chlorine less than the WHO minimum threshold of 0.2 mg/L.

scholarly journals Limnology of lake Surinsar, Jammu, J&K: Part II – Water chemistry

2009 ◽  
Vol 1 (2) ◽  
pp. 159-165
Author(s):  
D. Slathia ◽  
S. P. S. Dutta
Keyword(s):  
Water Quality ◽  
Electrical Conductivity ◽  
Drinking Water ◽  
Quality Parameters ◽  
International Standards ◽  
Water Quality Parameters ◽  
Total Hardness ◽  
Human Consumption ◽  
Raw Water ◽  
Detectable Limit

Water quality parameters viz. air temperature (15.21 0 C -36 0 C/16.71 0 C - 39.42 0 C), water temperature (13 0 C-32.42 0 C/15 0 C-32.8 0 C), depth (42cm-69.08cm/ 25cm-121.92cm), turbidity (3.88-46.27NTU/3.67-69.39 NTU), salinity (0.10-0.31ppt/ 0.10-0.37ppt), electrical conductivity (0.101-0.172mS/cm/0.114-0.279mS/cm), TDS (49.63-111.78 mg/l/57.64-177.01mg/l), pH (7.92-9.82/7.80-9.09), free CO2 (0-19.22mg/l/0-15.32mg/l), DO (6.82-9.90mg/l/4.65-9.40mg/l), carbonate (0-18.38mg/l/0-20.63mg/l), bicarbonate (60.99-170.70mg/l/77.62-168.70mg/l, chloride (7.41-12.35mg/l/9.59-19.60mg/l), calcium (6.85-38.50mg/l/11.81-140.49mg/l), magnesium (4.62-7.22mg/l/3.86-39.05mg/l), total hardness (40.29-125.50 mg/l/56.61-511.05mg/l), BOD (3.12-5.79mg/l/1.31-16.21 mg/l), COD (17.74-75.42 mg/l/ 26.57-73.03mg/l), sodium (14.2-22.5mg/l/12.2-30.9mg/l), potassium (1.83-4.17mg/l/2.25-6.21mg/l), phosphate (0.048-0.233mg/l/0.008-0.603mg/l), nitrate (0.13-1.3mg/l/0.11-4.08mg/l), sulphate (1.60-19.19mg/l/1.36-15.70mg/l), silicate (0.14-4.23mg/l/0.27-7.05mg/l), iron (0-0.65/0-0.40mg/l), copper (below detectable limit) and zinc (below detectable limit), of lake Surinsar-the only source of drinking water to the inhabitants of the Surinsar village, have been reported monthly, during the year 2002-03/2003-04. WQI range falls from poor (70.45, December; 73.55, October; 74.4, November and 74.56, September/ 74.52, January and 75.36, September), very poor(82.54, February; 89.25, May; 80.76, August and 78.86, January/ 80.89, February; 98.25, April; 80.03, June; 82.26, July; 86.55, October and 83.03, November) to unfit (100.44, June; 101.9, July; 103.86, April and 119.5, March/ 103.73, May; 108.28, March; 122.56, August and 103.72, December). Comparison of range of various water quality parameters of Surinsar lake water, with national and international standards has also revealed that most of these parameters are beyond permissible limits. This clearly indicates the unsuitability of raw water, generally consumed by local inhabitants, for human consumption.

scholarly journals Water quality trend analysis in a citywide water distribution system

2021 ◽  
Author(s):  
Keya Chowdhury ◽  
Aysha Akter
Keyword(s):  
Water Quality ◽  
Distribution System ◽  
Water Distribution ◽  
Oxygen Demand ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Residual Chlorine ◽  
Secondary Source ◽  
Pipe Material ◽  
Rapid Urbanization

Abstract Rapid urbanization poses challenges to meet the increased water supply demands. Apart from the quantity, the distributed water quality often fails to meet the permissible level. This study aimed to conduct a citywide spatio-temporal variation of water quality parameters. Water sampling points were selected by applying the Analytical Hierarchical Process (AHP) technique using ArcGIS considering pipe leakage, source water quality, pipe age, and pipe materials. The Chattogram city comprises 397 km of pipes; pipe material distribution shows 71.28% PVC, 20.94% asbestos, 5.16% mild steel, 2.17% ductile, and 0.45% cast iron. The citywide pipe network was established in 1963; 20.87% of pipes aged over 30 years, 15.07% 20–30 years, 26.38% 10–20 years, and 37.68% pipelines are relatively new, i.e., within 0–10 years. Eight water quality parameters, i.e., pH, temperature, turbidity, biochemical oxygen demand after five days (BOD5), total coliform, fecal coliform, chloride, and residual chlorine, were collected from the secondary source cross-checked by field survey. Computation of the Water Quality Index (WQI) was interpolated using Inverse Distance Weighted (IDW) method to generate a WQI map. Thus, this study could be a basis to improve the treatment system and proper distribution network maintenance.

scholarly journals Assessment of Bacteriological and Physicochemical Quality of Drinking Water from Source to Household Tap Connection in Nekemte, Oromia, Ethiopia

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Gonfa Duressa ◽  
Fassil Assefa ◽  
Mulissa Jida
Keyword(s):  
Drinking Water ◽  
Water Supply ◽  
Water Samples ◽  
Distribution System ◽  
Tap Water ◽  
Quality Parameters ◽  
Residual Chlorine ◽  
Faecal Coliforms ◽  
Cross Sectional ◽  
Drinking Water Standards

In Ethiopia, access to improved water supply and sanitation has been very low and hence majority of the communicable diseases are associated with unsafe and inadequate water supply. Thus, the aim of this study was to assess physicochemical and bacteriological characteristics of water from sources to household connection in Nekemte town. A cross-sectional study was conducted from November 2015 to March 2016. Water samples were collected in triplicates from selected 30 sampling points from source, disinfection point, main distribution system tank, and household taps. All samples were analysed for bacteriological, chemical, and physical quality parameters using standard procedures. The results showed that temperature, pH, turbidity, total dissolved substances, and electrical conductivity of the water samples were varied between 16.9 and 22°C, 6.8–7.0, nil-12 NTU, 50–70 mg/l, and 40–46 µS/cm, respectively. Phosphate and nitrate concentrations of the water samples also ranged between 0.65 and 1 mg/l and 2.2–6.5 mg/l, respectively. Free residual chlorine concentration in the majority of the water samples was less than 0.5 mg/l. All samples were positive for total coliform with counts ranging from 12 to 120 CFU/100 ml, whereas faecal coliforms were detected in only 37% of tap water samples. In general, the majority of the tested parameters were within the permissible range of both the WHO and Ethiopian drinking water standards. However, Fe, Mn, faecal coliforms, total coliforms, and temperature did not conform to both WHO and Ethiopian drinking water standards. Based on the results, we can conclude that water quality deterioration was both at the sources and in the supply networks. Hence, proper drainage, sewage disposal systems, and sufficient disinfection of water with chlorine are of prime importance to deliver safe drinking water to the residents of Nekemte town.

scholarly journals EVALUASI KINERJA INSTALASI PENGOLAHAN AIR PADA SISTEM PENYEDIAAN AIR MINUM (SPAM) DI DESA JEJANGKIT TIMUR, KALIMANTAN SELATA

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Rony Riduan ◽  
Arif Dhiaksa
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Water Treatment ◽  
Treatment Plant ◽  
Quality Parameters ◽  
Supply System ◽  
Water Quantity ◽  
Technical Aspects ◽  
E Coli ◽  
Drinking Water Supply System

Desa Jejangkit Timur wilayahnya merupakan daerah Rawa. Di Desa Jejangkit Timur telah dibangun Sistem Penyediaan Air Minum (SPAM) secara swadaya yang mengolah air rawa menjadi air bersih. Penelitian ini bertujuan untuk mengevaluasi kinerja dan memberikan rekomendasi untuk meningkatkan kinerja Instalasi Pengolahan Air SPAM Jejangkit Timur. Sebelumnya telah dilakukan kajian Kinerja terhadap SPAM tersebut, namun sebatas terhadap 6 parameter kualitas air (TDS, pH, Fe, Mn, MPN Coliform, dan E. Coli) dan aspek non teknis. Evaluasi kinerja pada penelitian ini ditinjau pada aspek teknis terkait dengan kuantitas air dan kualitas air yang diproduksi Instalasi Pengolahan Air (IPA) dengan parameter lebih lengkap. Metode yang digunakan adalah melalui studi literatur, uji laboratorium, dan observasi lapangan. Dari hasil kajian, diperoleh informasi bahwa kinerja IPA SPAM ditinjau dari aspek teknis parameter kuantitas air adalah mampu memenuhi kebutuhan pokok air minum pelanggan.  Kinerja IPA SPAM pada parameter kualitas air fisika dan kimia yang diuji telah sesuai dengan standar, namun pada parameter biologi belum sesuai. Rekomendasi untuk meningkatkan kinerja IPA SPAM antara lain adalah pemasangan alat pengukur debit, pembangunan unit pengolahan air baku, peningkatan sistem input bahan tambah, penambahan tutup IPA, pembangunan unit pengolahan limbah, dan pemeriksaan kualitas air secara berkala, Kata kunci: Air minum, rawa, sistem penyediaan air minum.  The village of Jejangkit Timur is located in the swamp area. A drinking water supply system (SPAM) has been developed independently by processing swamp water into clean water. This research was conducted to analyze and provide recommendations to improve  the performance of Water Treatment Plant (WTP) SPAM in Jejangkit Timur Village. Previously, a study of the performance of the SPAM was conducted, but limited to 6 water quality parameters (TDS, pH, Fe, Mn, MPN Coliform, and E. Coli) and non-technical aspects. Study of the performance is reviewed from technical aspects related to water quantity and quality of water produced by WTP with more complete parameters. The method used is through literature studies, laboratory tests, and field observations. From the results of the study, information was obtained that the performance of the SPAM in terms of the technical aspects of the water quantity parameter was able to meet the basic needs of drinking water for all customers. The performance of the SPAM on the physical and chemical water quality parameters tested were in accordance with the Drinking Water Quality Standards, but the biological parameters were not appropriate. recommendations to improve the performance of WTP SPAM include the installation of discharge gauges on input and output of WTP, construction of raw water treatment unit, improvement of input additive material input systems, addition of IPA cover, construction of residual waste treatment plant unit, and continuous water quality check records. Keywords: A drinking water supply system, drinking water, swamps.

scholarly journals Occurrence of trihalomethane in relation to treatment technologies and water quality under tropical conditions

2018 ◽  
Vol 1 (1) ◽  
pp. 69-83
Author(s):  
A. A. G. D. Amarasooriya ◽  
S. K. Weragoda ◽  
M. Makehelwala ◽  
R. Weerasooriya
Keyword(s):  
Water Quality ◽  
Water Supply ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Residual Chlorine ◽  
Treatment Technology ◽  
Tropical Conditions ◽  
Treatment Technologies ◽  
Resident Time ◽  
By Products

Abstract Distribution of most prevalent disinfection by-products, trihalomethanes (THMs) in relation to treatment technology and common water quality parameters (turbidity, conductivity, color, pH, and residual chlorine) was examined for two water supply schemes (WSS) in Sri Lanka (locations: Greater Kandy-WSS (GKWSS) (80.56–80.66 °E, 7.28–7.38 °N) and Kandy South-WSS (KSWSS) (80.49–80.63 °E, 7.21–7.30 °N). In both treatment plants, only CHCl3 and CHCl2Br were detected in appreciable concentrations and total THMs (TTHMs) values were well below the WHO limits (80 μg/L). TTHMs variations ranged from 0 to 16 μg/L and 0 to 54 μg/L in GKWSS and KSWSS, respectively. Highest TTHM value (54 μg/L) was found in KSWSS which employs pulsation treatment technology. Correlations between CHCl3 and CHCl2Br in both water schemes are noteworthy, but THM levels relate to most of the water quality parameters ambiguously. However, a distinct relationship is observed between THM levels and degree of chlorination, resident time, pipeline corrosion, and temperature. THM formation increased towards the boundaries of most of the sub-water supply schemes (SWSS).

A national approach to risk assessment for drinking water catchments in Australia

2005 ◽  
Vol 5 (2) ◽  
pp. 123-134 ◽  
Author(s):  
R. Miller ◽  
B. Whitehill ◽  
D. Deere
Keyword(s):  
Water Quality ◽  
Risk Assessment ◽  
Land Use ◽  
Drinking Water ◽  
Water Supply ◽  
Supply System ◽  
Drinking Water Quality ◽  
Water Utilities ◽  
Quality Data ◽  
Water Quality Data

This paper comments on the strengths and weaknesses of different methodologies for risk assessment, appropriate for utilisation by Australian Water Utilities in risk assessment for drinking water source protection areas. It is intended that a suggested methodology be recommended as a national approach to catchment risk assessment. Catchment risk management is a process for setting priorities for protecting drinking water quality in source water areas. It is structured through a series of steps for identifying water quality hazards, assessing the threat posed, and prioritizing actions to address the threat. Water management organisations around Australia are at various stages of developing programs for catchment risk management. While much conceptual work has been done on the individual components of catchment risk management, work on these components has not previously been combined to form a management tool for source water protection. A key driver for this project has been the requirements of the National Health and Medical Research Council Framework for the Management of Drinking Water Quality (DWQMF) included in the draft 2002 Australian Drinking Water Guidelines (ADWG). The Framework outlines a quality management system of steps for the Australian water industry to follow with checks and balances to ensure water quality is protected from catchment to tap. Key steps in the Framework that relate to this project are as follows: Element 2 Assessment of the Drinking Water Supply System• Water Supply System analysis• Review of Water Quality Data• Hazard Identification and Risk Assessment Element 3 Preventive Measures for Drinking Water Quality Management• Preventive Measures and Multiple Barriers• Critical Control Points This paper provides an evaluation of the following risk assessment techniques: Hazard Analysis and Critical Control Points (HACCP); World Health Organisation Water Safety Plans; Australian Standard AS 4360; and The Australian Drinking Water Guidelines – Drinking Water Quality Management Framework. These methods were selected for assessment in this report as they provided coverage of the different approaches being used across Australia by water utilities of varying: scale of water management organisation; types of water supply system management; and land use and activity-based risks in the catchment area of the source. Initially, different risk assessment methodologies were identified and reviewed. Then examples of applications of those methods were assessed, based on several key water utilities across Australia and overseas. Strengths and weaknesses of each approach were identified. In general there seems some general grouping of types of approaches into those that: cover the full catchment-to-tap drinking water system; cover just the catchment area of the source and do not recognise downstream barriers or processes; use water quality data or land use risks as a key driving component; and are based primarily on the hazard whilst others are based on a hazardous event. It is considered that an initial process of screening water quality data is very valuable in determining key water quality issues and guiding the risk assessment, and to the overall understanding of the catchment and water source area, allowing consistency with the intentions behind the ADWG DWQM Framework. As such, it is suggested that the recommended national risk assessment approach has two key introductory steps: initial screening of key issues via water quality data, and land use or activity scenario and event-based HACCP-style risk assessment. In addition, the importance of recognising the roles that uncertainty and bias plays in risk assessments was highlighted. As such it was deemed necessary to develop and integrate uncertainty guidelines for information used in the risk assessment process. A hybrid risk assessment methodology was developed, based on the HACCP approach, but with some key additions and modifications to make it applicable to varying catchment risks, water supply operation needs and environmental management processes.

scholarly journals First Derivative UV Spectra of Surface Water as a Monitor of Chlorination in Drinking Water Treatment

2001 ◽  
Vol 1 ◽  
pp. 39-43 ◽  
Author(s):  
V. Zitko
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Surface Water ◽  
Distribution System ◽  
Drinking Water Treatment ◽  
Uv Spectra ◽  
Free Chlorine ◽  
Residual Chlorine ◽  
First Derivative ◽  
Derivative Spectra

Many countries require the presence of free chlorine at about 0.1 mg/l in their drinking water supplies. For various reasons, such as cast-iron pipes or long residence times in the distribution system, free chlorine may decrease below detection limits. In such cases it is important to know whether or not the water was chlorinated or if nonchlorinated water entered the system by accident. Changes in UV spectra of natural organic matter in lakewater were used to assess qualitatively the degree of chlorination in the treatment to produce drinking water. The changes were more obvious in the first derivative spectra. In lakewater, the derivative spectra have a maximum at about 280 nm. This maximum shifts to longer wavelengths by up to 10 nm, decreases, and eventually disappears with an increasing dose of chlorine. The water treatment system was monitored by this technique for over 1 year and changes in the UV spectra of water samples were compared with experimental samples treated with known amounts of chlorine. The changes of the UV spectra with the concentration of added chlorine are presented. On several occasions, water, which received very little or no chlorination, may have entered the drinking water system. The results show that first derivative spectra are potentially a tool to determine, in the absence of residual chlorine, whether or not surface water was chlorinated during the treatment to produce potable water.

Suspended particles in the drinking water of two distribution systems

2001 ◽  
Vol 1 (4) ◽  
pp. 237-245 ◽  
Author(s):  
V. Gauthier ◽  
B. Barbeau ◽  
R. Millette ◽  
J.-C. Block ◽  
M. Prévost
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Organic Matter ◽  
Distribution System ◽  
Distribution Systems ◽  
Suspended Solids ◽  
Suspended Particles ◽  
Raw Water ◽  
Remote Locations ◽  
Dissolved Matter

The concentrations of suspended particles were measured in the drinking water of two distribution systems, and the nature of these particles documented. The concentrations of particulate matter were invariably found to be small (maximum 350 μg/L). They are globally in the very low range in comparison with dissolved matter concentrations, which are measured in several hundreds of mg/L. Except during special water quality events, such as turnover of the raw water resource, results show that organic matter represents the most important fraction of suspended solids (from 40 to 76%) in treated and distributed water. Examination of the nature of the particles made it possible to develop several hypotheses about the type of particles penetrating Montreal's distribution system during the turnover period (algae skeleton, clays). These particles were found to have been transported throughout the distribution systems quite easily, and this could result in the accumulation of deposits if their surface charge were ever even slightly destabilised, or if the particles were to penetrate the laminar flow areas that are fairly typical of remote locations in distribution systems.

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