Scielo RSS <![CDATA[Water SA]]> http://www.scielo.org.za/rss.php?pid=1816-795020160002&lang=en vol. 42 num. 2 lang. en <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Influence of phase separator design on the performance of UASB reactors treating municipal wastewater</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200001&lng=en&nrm=iso&tlng=en The objective of anaerobic sewage treatment is to maximize the fraction of influent organic material that is transformed into methane, thus minimizing the COD fractions that are discharged with the effluent or in the excess sludge production. Experimental data in this paper show that in the case of application of a UASB reactor for sewage treatment, the phase separator design has an important influence on digestion efficiency. An efficient phase separator leads to retention of a larger sludge mass, which means that the mean solids retention time is increased. The data show that the mean solids retention time or sludge age is the fundamental operational parameter that determines the efficiency of the anaerobic treatment. A simple way to improve the phase separator performance is to apply parallel plates in the settling section of the UASB reactor, above the conventional phase separator design of triangular prisms with an open base. <![CDATA[<b>Assessment of water quality based on diatom indices in a small temperate river system, Kowie River, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200002&lng=en&nrm=iso&tlng=en This study aimed to assess the impact of land use patterns on water quality and benthic diatom community structure and to test the applicability of diatom indices developed in other regions of the world to a small temperate southern African river system. Sampling was conducted at eight study sites along the length of the river on four separate occasions. Multivariate data analyses were performed on the diatom community dataset to specify the main gradients of floristic variation and to detect and visualize similarities in diatom samples in relation to land-use patterns within the catchment. One hundred and twelve (112) diatom species belonging to 36 genera were recorded during the study. Canonical correspondence analysis (CCA) demonstrated that variations in the benthic diatom community structure were best explained by ammonium, nitrate, conductivity, pH, temperature, resistivity and water flow. OMNIDIA was used for calculation of selected diatom water quality indices. A number of the indices, e.g., the trophic diatom index (TDI), eutrophication/pollution index and biological index of water quality (BIWQ), either under- or over-estimated the water quality of the system. With few exceptions, there were no significant correlations (p> 0.05) between the diatom indices' values and the nutrient variables. The absence of any significant correlations between the diatom indices' values and selected physico-chemical variables suggests that indices developed in other regions of the world may not be suitable for temperate southern African rivers. <![CDATA[<b>A spatial assessment of stream-flow characteristics and hydrologic alterations, post dam construction in the Manyame catchment, Zimbabwe</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200003&lng=en&nrm=iso&tlng=en The global hydrologie regime has been intensively altered through activities such as dam construction, water abstraction, and inter-basin transfers. This paper uses the Range of Variability Approach (RVA) and daily stream flow records from nine gauging stations to characterize stream-flow post dam construction in the Manyame catchment, Zimbabwe. We identify which variables continue to be altered, upstream and at different distances downstream, to distinguish sections with the highest potential for ecological disruption and to understand how hydrological alterations dissipate downstream of dams. Our results indicate that different sections of the same river have different stream-flow characteristics post dam construction. The most adverse effects of dams were on downstream stretches of the river which were characterized by low flows, extreme low flows and an increased number of zero-flow days. These differences reflect the operation rules of the Manyame catchment dams. While the change in stream-flow characteristics is apparent in the 0-10 km range, it is slightly felt in the 11-20 km range and totally disappears at distances >20 km downstream of dams. These changes in stream characteristics, and that damming is only restricted to the upper third of the catchment, make the hydrologic fragmentations in the catchment minor. However, the continued hydrologic alterations post dam construction raise important concerns about the interactions of hydrology with other factors like sediment deposition upstream of dams and climate change. We recommend that catchment managers target enhancing the natural flow variability of the river instead of meeting target flows. <![CDATA[<b>Effects of greywater irrigation on germination, growth and photosynthetic characteristics in selected African leafy vegetables</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200004&lng=en&nrm=iso&tlng=en The reuse of greywater, wastewater from sources other than toilets, could enable low-income households to save potable water for drinking and cooking. Greywater irrigation of food crops is widely practised but its effects on African leafy vegetables (ALVs), which hold potential for cultivation to improve food security, are unknown. This study investigated the effects of synthetic greywater irrigation on germination in three ALVs, viz., Amaranthus dubius, Cleome gynandra and Solanum nigrum, and subsequent seedling growth in A. dubius and S. nigrum. Seeds and seedlings were treated with chlorinated and dechlorinated greywater and tap water, supplemented with nutrients. Greywater application decreased germination capacity (by 23-25%) when assessed in Petri dishes in A. dubius only. However, greywater application was less harmful to A. dubius seeds sown in soil. Vigour was compromised in greywater-treated seeds of all three species but greywater can be used to irrigate freshly-sown seeds of A. dubius without reducing percentage seedling production. However, greywater irrigation reduced capacity (by 21-23%) and rate of shoot emergence in S. nigrum, and growth and chlorophyll content in both species. These negative effects were accompanied by increased soil electrical conductivity (after 21 d) and pH (after 14 d). The reduced growth under greywater irrigation was most likely based on a reduction in light-harvesting capacity and/or nutrient availability. Overall, S. nigrum seedlings were significantly more sensitive to the negative effects of greywater, possibly due to increased transpirational water loss under greywater irrigation. The effects of greywater were largely independent of chlorine content. Applying greywater in excess of plant requirements and/or alternating greywater irrigation events with freshwater watering events could promote leaching of salts found in greywater. The effects of greywater irrigation on soil water and nutrient availability demand further investigation for ALVs. <![CDATA[<b>The strontium isotope distribution in water and fish within major South African catchments</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200005&lng=en&nrm=iso&tlng=en Strontium has 4 naturally-occurring isotopes (84Sr, 86Sr, 87Sr, 88Sr) all of which are stable (Faure, 1986). The correlation between the 87Sr/86Sr isotope ratio of lake water and fish fin spine tissue was investigated in 23 lakes within 4 major South African catchments. Data showed that fish within a specific lake all have the same Sr isotope ratio in their fin spine tissue regardless of species, age, sex and condition. The origin of the dissolved Sr fraction in lake water can be either from the natural weathering of upstream geological units or from an upstream anthropogenic source. The Sr isotopic ratios of the water samples were, however, constant over a multi-year period suggesting that the main source may be the more consistent geological environment. The Sr isotope ratio of river and lake water generally increases along the course of the rivers within the tertiary catchments of the areas investigated. In large rivers like the Vaal, where pollution also plays a role, the pattern is much more complicated. In the Olifants River catchment, Lake Middelburg, Lake Witbank and Lake Doornpoort have a similar Sr isotope ratio, which is distinct from Lake Bronkhorstspruit. Lake Loskop which is downstream from these lakes has a Sr isotope ratio between these two extremes, indicating mixing of water from upstream sources. Similarly Lake Arabie (Flag Boshielo), which is even further downstream, shows a Sr isotope composition between the composition of Lake Loskop and the lakes in the Elands River. <![CDATA[<b>Analysis of auto-purification response of the Apies River, Gauteng, South Africa, to treated wastewater effluent</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200006&lng=en&nrm=iso&tlng=en The assimilative capacity of water bodies is an important factor in the integrated management of surface water resources. The current study examined the auto-recovery processes of the Apies River from wastewater discharged into it from a municipal wastewater treatment facility, using a series of equations, including the modified Streeter-Phelps equation. Field data obtained include dissolved oxygen (DO), temperature, stream velocity, depth, and width. Water samples were also obtained at 10 sampling stations for the determination of biochemical oxygen demand (BOD) using standard methods. It was observed that the DO and BOD level (5.59 mg/L and 8.5 mg/L respectively) of the effluent from the wastewater treatment facility indicated better water quality than the Apies River background DO level (5.42 mg/L) and BOD level (13 mg/L). Also, at 270 m downstream of the effluent discharge point, another effluent stream (Skinnerspruit) adversely impacted on the Apies River with DO and BOD levels of 6.5 mg/L and 9.0 mg/L, respectively, compared to the Apies River background values of 6.81 mg/L and 8.0 mg/L, respectively. The stream, however, recovered well from both the background and imposed pollution sources as it had a computed positive auto-recovery factor of 1.74. Furthermore, the measured DO deficit was plotted against predicted DO deficit. The plot revealed a close match between the measured and predicted DO deficit, indicating that the model could be used for predicting DO deficit along other segments of the river. To further improve on the natural auto-recovery processes of the Apies River, it was recommended that flow along the Skinnerspruit should be enhanced by clearing the observed aquatic plants growing within the channel. Also, suspected pollution activities taking place further upstream on the Apies River should be investigated and appropriately addressed. <![CDATA[<b>Climate influences on Vaal River flow</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200007&lng=en&nrm=iso&tlng=en A study of climatic influences on Vaal River discharge, near Johannesburg, South Africa, finds that peak summer flows in the period 1979-2014 coincide with ocean-atmosphere interaction in the east Atlantic. The analysis has three parts: inter-annual influences by correlation of summer discharge with climate fields, atmosphere and ocean composites of 14 peak flow months, and a case study flood in January 2010 and its regional scale forcing. Inter-annual links are established with low pressure over the east Atlantic and an eastward equatorial ocean current and suppressed upwelling in the northern Benguela. During the January 2010 flood in the Vaal River, flow increased to 2 801 m³/s. There was a low salinity plume and warm sea temperatures off Angola > 29°C. A terrestrial vegetation fraction > 0.6 and corresponding latent heat fluxes enriched NW-cloud bands over the Vaal River catchment, during the flood case study of January 2010. Comparison of (Pacific) Southern Oscillation and east Atlantic influence on Vaal River discharge reveals the former drives evaporative losses while the latter provides an advance warning of flow variability. <![CDATA[<b>Evaluation of models generated via hybrid evolutionary algorithms for the prediction of <i>Microcystis </i>concentrations in the Vaal Dam, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200008&lng=en&nrm=iso&tlng=en Cyanobacteria are responsible for many problems in drinking water treatment works (DWTW) because of their ability to produce cyanotoxins that potentially can have an adverse effect on consumer health. Therefore, the monitoring of cyanobacteria in source waters entering DWTW has become an essential part of drinking water treatment management. Managers of DWTW rely heavily on results from physical, chemical and biological water quality analyses, from grab samples, for their management decisions. However, results of water quality analyses may be delayed from 3 h to 14 days depending on a magnitude of factors such as sampling, distance and accessibility to laboratory, laboratory sample turnaround times, specific methods used in analyses, etc. Therefore, the benefit to managers and production chemists to be able to forecast future events of high cyanobacterial cell concentrations in the source water is evident. During this study, physical, chemical and biological water quality data from samples taken from 2000 to 2009 in the Vaal Dam, supplying South Africa's largest bulk drinking water treatment facility, were used to develop models for the prediction of the cyanobacterium Microcystis sp. in the source water (real-time prediction together with 7, 14 and 21 days in advance). Water quality data from the Vaal Dam from 2010-2012 were used to test these models. The model showing the most promising results for incorporation into a 'Cyanobacterial Incident Management Protocol' is the one predicting Microcystis sp. 7 days in advance. This model showed a square correlation coefficient (R²) of 0.90 when tested with the testing dataset (chosen by bootstrapping from the 2000-2009 input dataset) and a R²of 0.53 when tested with the 3-year 'unseen' dataset from 2010-2012. <![CDATA[<b>A comparison of mollusc diversity between the relatively pristine Marico River and the impacted Crocodile River, two major tributaries of the Limpopo River, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200009&lng=en&nrm=iso&tlng=en A study of the freshwater mollusc diversity was conducted at selected sites in the relatively pristine Marico River and the impacted Crocodile River, the major tributaries of the Limpopo River. Four surveys were conducted, two in an early (May 2013 and 2014) and two in a late (November 2013 and 2014) low-flow period. Semi-quantitative surveys were done by sampling the vegetation, as well as the substratum, with a standard SASS net for approximately 15 min each. Environmental parameters including water temperature, electrical conductivity (EC) and pH were measured at each site. Molluscs were identified up to species level, sorted, counted, and the presence of juvenile specimens recorded. Historical data for the 1/16th degree square grids (loci), in which each of the sampling sites of the current study was located, were extracted from the National Freshwater Snail Collection at the Unit for Environmental Sciences and Management, Potchefstroom Campus of the North-West University. During this study, 20 and 9 species were recovered from the Marico and Crocodile Rivers, respectively, as compared to 13 and 12 species on record for these loci, respectively. Juvenile specimens were present during the four surveys at most of the sites. Canonical correspondence analyses were applied which revealed that biotopes, water temperature and EC played the most significant role in the distribution and abundance of species. The relatively high mollusc diversity and the fact that juveniles were present throughout the study, demonstrated that current habitat and environmental conditions were suitable to promote recruitment and the sustainability of diverse mollusc populations in the Marico River and its tributaries. However, in contrast to this, the exploitation of and habitat transformation in the Crocodile River has resulted in the decrease of biotopes which eventually could have led to the decrease in diversity and the establishment of P. acuta, an exotic invader species. <![CDATA[<b>Coming to the party of their own volition: Interest groups, the Lesotho Highlands Water Project Phase 1 and change in the water sector</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200010&lng=en&nrm=iso&tlng=en Interest groups are omnipresent phenomena of most political societies. They are present because of their attempts to influence public policy and their representation role. These roles are fundamental agential roles. Through these roles interest groups can bring about changes in the water policy arena. This paper will look at some of these changes using the Lesotho Highlands Water Project Phase 1 as a case study. Through their actions to bring about change, interest groups are drivers of water politics. Interest groups can enhance water policies when they highlight the inherent deficiencies of policies and suggest alternatives for the betterment of policies concerning the welfare of individuals or groups as well as the environment. Water resource managers and decision-makers should therefore be aware of these actors and the roles they are likely to play when influencing aspects of water infrastructure projects. Interest groups can influence water policies even if they are only involved on an informal basis. In other words, governments do not have to go out of their way, so to speak, to involve interest groups; interest groups will come to the party, on their own volition. Said differently, interest groups usually become involved in water policy matters on a voluntary basis whether water policy makers like it or not. <![CDATA[<b>Laboratory-scale simulations with hydrated lime and organic polymer to evaluate the effect of pre-chlorination on motile <i>Ceratium hirundinella </i>cells during conventional water treatment</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200011&lng=en&nrm=iso&tlng=en Algal genera such as Carteria, Chlamydomonas, Chlorogonium, Cryptomonas, Ceratium, Peridinium and Euglena are motile and may disrupt unit processes and cause water treatment problems. Algal species belonging to these motile algal genera are known to interfere with coagulation and flocculation unit processes which are the main processes for algal removal. These cells are well adapted, by means of their motile structures, morphological shapes and storage products, to remain in the supernatant (by swimming or floating) until it is carried over to sand filters, where cells may cause filter-clogging problems. When organic material is released from algal cells as a result of physical-chemical impacts on the cells, it may result in taste-and odour-related problems or the formation of harmful organic products such as trihalomethanes (THM). The aims of this study were to: (i) determine chlorine concentrations required to immobilise C. hirundinella cells; (ii) determine the removal efficiencies of pre-chlorination; (iii) investigate the integrity of C. hirundinella cells; and (iv) identify trihalomethanes that are formed. Source water samples enriched with C. hirundinella cells were exposed to a pre-determined chlorine concentration range (0.05-0.45 mg/L). This study found that the half-maximal inhibitory concentration (IC50-values) for chlorine < 0.20 mg/L is sufficient to render C. hirundinella cells immobile, while cells remain intact. Pre-chlorination did not have an impact on C. hirundinella removal when hydrated lime was used as a coagulant or coagulant aid. However, when organic polymer only was used as coagulant, removal efficiencies were improved by 20%. Chlorine by-products were measured, but posed no specific health risks to drinking water consumers due to the low concentration levels measured. Algal removal challenges that occur in water treatment plants when dosing organic polymers can be resolved by implementation of effective pre-chlorination strategies. <![CDATA[<b>Development and implementation of a monitoring programme for South African estuaries</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200012&lng=en&nrm=iso&tlng=en This study designed and implemented a national estuarine monitoring programme for South African estuaries. The National Water Act (Act No. 36 of 1998) mandates the Department of Water and Sanitation (DWS) to undertake monitoring for the protection of water resources. Monitoring also forms an integral component of estuarine management plans which are a requirement of the Integrated Coastal Management Act (Act No. 24 of 2008). The design of the programme was based on a review of international best practice, a critical evaluation of existing national monitoring programmes implemented by DWS and workshop input from a group of national experts. The National Estuary Monitoring Programme has three tiers. Tier 1 focuses on basic data, Tier 2 makes use of the methods used for determining estuarine freshwater inflow requirements, and Tier 3 is usually of a short temporal scale and dependent on the issue at hand, such as a sewage spill or fish kill. Tier 1 monitoring commenced on 21 priority estuaries between 2012 and 2014 in collaboration with government conservation authorities, conservation forums and local and district municipalities. Available financial and human resources guided the selection of the priority estuaries. Analysis of the implementation of the programme showed that collaboration between all relevant role-players was central to the successes achieved during the first 3 years of the programme and will continue to be critical for the success of the programme, although funding remains a challenge. <![CDATA[<b>Public-private partnership conceptual framework and models for the funding and financing of water services infrastructure in municipalities from selected provinces in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200013&lng=en&nrm=iso&tlng=en This paper presents public-private partnership (PPP) framework models for funding and financing of water services infrastructure at local government (municipalities) level (sphere) in South Africa. Data were assembled from various stakeholders, viz., private and public sector institutions in the Gauteng and Limpopo Provinces of South Africa. The framework for PPPs identified three models, viz. state, hybrid and private sector models. In the 'state model' the water services value chain is 100% government funded and owned infrastructure. Government i s a key player in infrastructure investment and inefficiencies within the public expenditure management systems are particularly detrimental, e.g., there are significant problems in spending of infrastructure budgets. In the 'private model' harnessing the significant potential for capital markets to finance water infrastructure, particularly local bond markets, is contingent on their strengthening and further development. Well-functioning and appropriately institutional investors (pension funds, insurance companies, etc.) would be natural sources of long-term financing for water services infrastructure because liabilities would better match the longer terms of water infrastructure projects. The 'hybrid model' is in the middle of the water services value chain, i.e., a partnership between government and the private sector. The use of this framework is essential in the including of the private sector in the implementation of water infrastructure development projects. The research results highlight the underlying principles that underpin, support, determine and confirm the success of the PPP models and value chain framework for local government water infrastructure in South Africa. Twelve key parameters were identified that would drive the success of any water services infrastructure PPP model. Even though PPP is an alternative procurement vehicle, PPP models are considered to be used as vehicles for addressing institutional challenges in local government. However, in most cases it has been indicated that lack of technical and financial skills and monitoring of the private operator are serious challenges. <![CDATA[<b>Exploratory use of a Bayesian network process for translating stakeholder perceptions of water quality problems in a catchment in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200014&lng=en&nrm=iso&tlng=en Water resource management is complex, and should ideally be a co-operative, stakeholder-driven problem-solving process. Bayesian networks (BNs) are one participatory tool being increasingly used to facilitate this process. The upper Mgeni catchment in the province of KwaZulu-Natal, South Africa, is a key water resource area with looming water quality problems. The high number of stakeholders involved in a catchment management forum provided an environment for testing the development of a BN showing relationships between water quality problems and stakeholders in this area. Through engagement with stakeholders at quarterly meetings during 2011, and collation and analysis of water quality time-series, qualitative and quantitative data were successfully translated into a BN for water quality improvement in the study area. The model demonstrated that certain water quality variables (for example, compliance of wastewater treatment works; increase in housing developments) were more likely to be the cause of problems than others (such as discharges from farm dams or accidental spills). The value of involving stakeholders in a co-operative process is highlighted, and it is argued that the robustness of such a model would be enhanced further if applied within a formal participatory approach using conditional probability values endorsed by all stakeholders. <![CDATA[<b>Assessment of sorghum-cowpea intercrop system under water-limited conditions using a decision support tool</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200015&lng=en&nrm=iso&tlng=en Intercropping can improve crop productivity through increased water use efficiency (WUE). However, limited information exists to support its adoption and subsequent management. In such instances, crop models can be used as decision support tools to complement data from field trials. The Agricultural Production Systems Simulator Model (APSIM) was used to develop best management practices for improved yield and WUE for a sorghum-cowpea intercrop system for 5 sites in KwaZulu-Natal, South Africa: Richards Bay, Umbumbulu, Deepdale, Wartburg and Ukulinga. Each site represented 1 of 5 different bio-resource units. Planting dates (trigger season climate method, modelling and fixed date approaches), fertilizer rates (0, 50 and 100% recommended N rate), plant population (50% less and 50% more, for either sorghum or cowpea) and irrigation (deficit irrigation and rainfall-based approaches) were considered. In Deepdale, planting dates generated by the model gave high (952.2±85 and 326.3±68 kg-ha-1) and stable yields for sorghum and cowpea, respectively. Adding 100% fertilizer improved both yield and WUE of the intercrop by 18.5 and 5.1%, respectively, in Umbumbulu and Wartburg. Across all environments, sorghum and cowpea plant populations of 39 000 and 13 000 plants-ha-1, respectively, increased yield (26.11%) and WUE (15.54%) of the intercrop system. Deficit irrigation was more effective resulting in yield (12.84%) and WUE (11.09%) improvements. It is concluded that APSIM can be used to develop best management practices to assist in developing guidelines for improving productivity of intercrop systems under water-scarce conditions. <![CDATA[<b>Trace element accumulation and human health risk assessment of <i>Labeo capensis </i>(Smith, 1841) from the Vaal Dam reservoir, South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200016&lng=en&nrm=iso&tlng=en This paper aimed to determine the trace element concentrations within water, sediment and tissues of the Orange River mudfish Labeo capensis (Smith, 1841) collected from the Vaal Dam reservoir, and to assess potential risks associated with the consumption of L. capensis muscle tissue. The study was undertaken in March 2013; 22 L. capensis were collected with the aid of gill nets. Water and sediment samples were collected on site, and additional water analysis data for the sampling period were received from Rand Water Analytical Facility in Vereeniging. Analysis of water revealed trace elements were present at trace levels. The comparison of trace element concentrations between the water, sediment and fish tissues revealed that the sediment contains the highest concentrations, followed by fish tissues and water. This trend exists as a result of the underlying geology of the Vaal Dam, the physiological and biological characteristics of L. capensis, and the physico-chemical state of the water. The risk assessment performed on the muscle tissue revealed that As and Se had total hazard quotient (THQ) values greater than one, and that the levels of As and Se were above the safety threshold values for human consumption. <![CDATA[<b>Assessment of water quality in distribution networks through the lens of disinfection by-product rules</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200017&lng=en&nrm=iso&tlng=en Disinfection with chlorine is a common practice to ensure secured drinking water, but results in potentially harmful disinfection by-products (DBPs), when excess chlorination is done. The US Environmental Protection Agency (US EPA) has established Stage 1 and Stage 2 disinfection by-product Rules (DBP rules) to control DBP exposure. A modified version of the Canadian Council of Ministries of the Environment water quality index (CCME WQI) is used to assess water quality. CCME WQI is a globally accepted index to assess water quality, but is too generic to be used for DBP rules. The study developed a scheme to make the index suitable for DBP rules. A scoring method based on an analytic hierarchy process (AHP) is applied to assign weights based on DBP rules. A previously modified CCME WQI (Islam et al., 2014) is adapted along with the weights to perform the assessment at the distribution network (DN). A case study was performed on 7 sampling stations in a Québec City DN. The spatial water quality variations are presented using kriging - a geostatistical method, which identifies the regions with relatively poor water quality and highlights the potential locations for re-chlorination points. The proposed assessment formulation is flexible to handle situations with limited data, which makes it especially suited to smaller municipalities. <![CDATA[<b>The formulation of synthetic domestic wastewater sludge medium to study anaerobic biological treatment of acid mine drainage in the laboratory</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200018&lng=en&nrm=iso&tlng=en Requirements for successful biological treatment of acid mine drainage (AMD) rely on the reduction of sulphates by microorganisms using a suitable organic carbon source. Various carbon sources, such as domestic wastewater sludge, have previously been used in the semi-passive biological treatment of AMD. Domestic wastewater sludge is however highly variable in its composition, making laboratory experimentation difficult. Synthetic medium was therefore formulated based on the chemical oxygen demand (COD) and the biological degradable organic matter (BOD) of domestic wastewater sludge. Four synthetic media compositions were formulated consisting of different ratios of meat extract, vegetable extract, sodium chloride, potassium phosphate, urea, ammonium chloride, iron sulphate, magnesium sulphate and glucose. The media composition with BOD and COD measurements closest to that of anaerobic domestic wastewater sludge was selected for further studies. The combination of AMD to synthetic wastewater sludge in 3 ratios was determined for COD and sulphate reduction in bioreactors over a period of 90 d. The highest reduction of 86.76% in COD and 99.22% in sulphate content were obtained in a 1:1 AMD: synthetic domestic wastewater sludge (SDWWS) ratio that calculated to a COD/sulphate ratio of 3. <![CDATA[<b>Yao, Ren, Wei and Yue (2010) Biodegradation characterization and kinetics of <em>m</em>-cresol by <i>Lysinibacillus cresolivorans (Water SA </i>37 (1) 15-20)</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S1816-79502016000200019&lng=en&nrm=iso&tlng=en Requirements for successful biological treatment of acid mine drainage (AMD) rely on the reduction of sulphates by microorganisms using a suitable organic carbon source. Various carbon sources, such as domestic wastewater sludge, have previously been used in the semi-passive biological treatment of AMD. Domestic wastewater sludge is however highly variable in its composition, making laboratory experimentation difficult. Synthetic medium was therefore formulated based on the chemical oxygen demand (COD) and the biological degradable organic matter (BOD) of domestic wastewater sludge. Four synthetic media compositions were formulated consisting of different ratios of meat extract, vegetable extract, sodium chloride, potassium phosphate, urea, ammonium chloride, iron sulphate, magnesium sulphate and glucose. The media composition with BOD and COD measurements closest to that of anaerobic domestic wastewater sludge was selected for further studies. The combination of AMD to synthetic wastewater sludge in 3 ratios was determined for COD and sulphate reduction in bioreactors over a period of 90 d. The highest reduction of 86.76% in COD and 99.22% in sulphate content were obtained in a 1:1 AMD: synthetic domestic wastewater sludge (SDWWS) ratio that calculated to a COD/sulphate ratio of 3.