What is eWQMS?

Emanti Management's Water Quality Management System (eWQMS) can be used to guide the tracking, reviewing and improving of water quality.

Ammonia

Ammonia forms part of the Nitrogen Cycle. Under normal conditions, low concentrations of ammonia are generally recorded in drinking water supplies.

Effect and possible implications of failure

  • Operational

High concentrations of ammonia measured in drinking-water may indicate the presence of untreated sewage and animal waste pollution. Consumption thereof could result in other health effects associated with consumption of sewage contaminated waters. In addition, ammonia can compromise disinfection efficiency, result in nitrite/nitrate formation in distribution networks, cause the failure of filters for the removal of manganese and cause taste and odour problems.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <1.0 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 1.0 - 2.0 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: No limit

Possible reason/s for failure

  • Source water has high ammonia (e.g. groundwater source is naturally high in ammonia, no source protection, pollution from pit latrines or animal waste around source)
  • No ammonia removal process at treatment plant (e.g. no ion exchange, no forced aeration)
  • Resins require replacement (e.g. breakthrough achieved)
  • No chemicals available for bed regeneration
  • Incorrect/inappropriate chemicals (e.g. chemicals used damage bed)
  • Poor process control (e.g. no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from sources of waste)
  • Lack of maintenance (e.g. ineffective regeneration of bed)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Calcium

Calcium is an alkaline earth metal occurring naturally in varying concentrations in most water and, together with magnesium, is one of the main components of water hardness. Soft waters contain low calcium concentrations, while hard waters contain high calcium concentrations.

Effect and possible implications of failure

  • Aesthetic
  • Operational

Low concentrations of calcium can indicate a soft and acidic water, which could lead to corrosion of metals and aggression of cement concrete. High concentrations of calcium impair the lathering of soap, and can lead to staining on enamelled surfaces such as baths and hand basins.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <150 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 150 - 300 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 7 years

Possible reason/s for failure

  • Source water has low or high calcium (e.g. source water is soft and acidic or hard)
  • For soft waters - No stabilisation/pH adjustment process at treatment plant (e.g. no lime dosing equipment, no limestone contactors)
  • For hard waters - No softening process at treatment plant (e.g. no nanofiltration, no cation exchange, no chemical precipitation)
  • No chemicals for stabilisation/pH adjustment (e.g. lime not available)
  • Incorrect/inappropriate chemicals for stabilisation (e.g. chemicals used not suitable for water type)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • Poor process control (e.g. ineffective chemical dosages, inconsistent dosing, no monitoring and remedial intervention, no jar tests to optimise chemical dosages, problem with process control/SCADA system)
  • Contamination (e.g. dissolution of calcite from new cement concrete pipes, infiltration or seepage from other water sources)
  • Lack of maintenance (e.g. blocked lime dosers/limestone contactors, ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system, dead ends in distribution network)
  • Sabotage/vandalism

Chloride

Chloride is the negatively charged or anionic component of table salt (NaCl). Elevated chloride levels therefore impart a salty taste to water.

Effect and possible implications of failure

  • Aesthetic

High chloride concentrations can cause nausea and vomiting, will impart a salty taste to water and will accelerate the corrosion of iron.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <200 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 200 - 600 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 7 years

Possible reason/s for failure

  • Source water has high salt content (e.g. groundwater source has natural high salinity, no source protection, sea water infiltration at coast)
  • Treatment plant cannot reduce salt content (e.g. no reverse osmosis, no electrodialysis, no distillation, no ion exchange)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • Poor process control (e.g. no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from industry, sea water)
  • Lack of maintenance (e.g. ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Fluoride

Fluoride is the most electro-negative element and readily forms complexes with many metals.

Effect and possible implications of failure

  • Health

The presence of fluoride in drinking water reduces the occurrence of dental caries in adults and children. A small amount of fluoride is necessary for proper hardening of dental enamel and to increase resistance to attack on tooth enamel by bacterial acids. An excess intake of fluoride, however, can damage the skeleton, causing a hardening of the bones and making them brittle.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <1.0 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 1.0 - 1.5 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 1 year

Possible reason/s for failure

  • Source water has high fluoride (e.g. groundwater source is naturally high in fluoride)
  • No fluoride removal process at treatment plant (e.g. no activated alumina, no reverse osmosis, no ion exchange)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • No chemicals available for membrane cleaning/bed regeneration (e.g. no base and acid available for regeneration)
  • Incorrect/inappropriate chemicals (e.g. chemicals used are harsh and damage membranes)
  • Poor process control (e.g. ineffective chemical dosages, inconsistent dosing, no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from other water sources)
  • Lack of maintenance (e.g. ineffective regeneration of bed, ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Magnesium

Magnesium is an alkaline earth metal which reacts with oxygen and water to form magnesium oxide and magnesium hydroxide respectively. Magnesium, together with calcium, is a measure of hardness in water (hard water causes scaling in distribution systems and appliances).

Effect and possible implications of failure

  • Aesthetic
  • Health

The most common health effect of excess magnesium intake is diarrhoea. High concentrations of magnesium also impart a bitter taste to water. High concentrations of magnesium causes scaling (together with calcium) in distribution systems and appliances.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <70 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 70 - 100 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 7 years

Possible reason/s for failure

  • Source water has high magnesium (e.g. source water is hard)
  • No softening process at treatment plant (e.g. no nanofiltration, no lime softening, no ion exchange, no chemical precipitation)
  • No chemicals (e.g. lime not available)
  • Incorrect/inappropriate chemicals (e.g. chemicals used not suitable for water type)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • Poor process control (e.g. ineffective chemical dosages, inconsistent dosing, no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from other water sources)
  • Lack of maintenance (e.g. blocked lime dosers, ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Nitrate/Nitrite

Nitrate is a plant nutrient and is the end product of the oxidation of ammonia and nitrite.

Effect and possible implications of failure

  • Health

High concentrations of nitrates/nitrites in drinking-water are generally associated with methemoglobinaemia in infants ("blue-baby syndrome"). In addition, nitrate/nitrite can cause tiredness and fatigue.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <10 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 10 - 20 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 7 years

Possible reason/s for failure

  • Source water has high nitrate/nitrite (e.g. groundwater source is naturally high in nitrate/nitrite, no source protection, pollution from pit latrines or animal waste around source)
  • No nitrate/nitrite removal process at treatment plant (e.g. no reverse osmosis, no ion exchange, no electrodialysis)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • No chemicals available for membrane cleaning/bed regeneration
  • Incorrect/inappropriate chemicals (e.g. chemicals used are harsh and damage membranes)
  • Poor process control (e.g. ineffective chemical dosages, inconsistent dosing, no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from other water sources)
  • Lack of maintenance (e.g. ineffective regeneration of bed, ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Potassium

Potassium is an alkali metal which always occurs in association with anions (including chloride, sulphate, bicarbonate and nitrate). Potassium is the main intracellular cation in living tissues and is an essential dietary constituent. High concentrations of potassium may occur in runoff from irrigated lands, from fertilizer production and domestic wastes). Metabolically, potassium interacts with sodium.

Effect and possible implications of failure

  • Operational
  • Health

High concentrations of potassium can impart a bitter taste to water and can result in nausea and vomiting. Exposure to excessive concentrations of potassium can be dangerous to infants or persons with renal disease.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <50 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 50 - 100 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 7 years

Possible reason/s for failure

  • Source water has high potassium (e.g. runoff from irrigated lands, fertilizer production near source, no source protection from domestic wastes)
  • Treatment plant cannot reduce potassium content (e.g. no reverse osmosis, no electrodialysis, no distillation, no ion exchange)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • Poor process control (e.g. no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from industry)
  • Lack of maintenance (e.g. ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Sodium

Sodium is the alkali metal constituent of table salt (sodium chloride). Sodium is an essential dietary element needed to maintain electrolyte balance in the body. Sodium levels are generally low in areas with high rainfall and high in arid areas (low rainfall). Metabolically, sodium interacts with potassium.

Effect and possible implications of failure

  • Aesthetic
  • Health

Excessive intake of sodium can lead to nausea and vomiting, place a strain on the kidneys and the heart, and lead to salt imbalances in the body. High sodium concentrations will give rise to an unacceptable salty taste.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <200 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 200 - 400 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 7 years

Possible reason/s for failure

  • Source water has high sodium content (e.g. groundwater source has natural high salinity, no source protection, sea water infiltration at coast)
  • Treatment plant cannot reduce sodium content (e.g. no reverse osmosis, no electrodialysis, no distillation, no ion exchange)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • Poor process control (e.g. no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from industry, sea water)
  • Lack of maintenance (e.g. ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Sulfate

Sulfate is the oxy-anion of sulphur in the +6 oxidation state. Sulfates occur in numerous minerals and are often used in the chemical industry.

Effect and possible implications of failure

  • Health

Consumption of excessive amounts of sulfate in drinking water usually results in diarrhoea. Sulfate also imparts a bitter or salty taste to water.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <400 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 400 - 600 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 7 years

Possible reason/s for failure

  • Source water has high sulfate content (e.g. groundwater source has natural high sulfate level, no source protection from acid mine wastes, tanneries, textile mills)
  • Treatment plant cannot reduce sulfate content (e.g. no reverse osmosis, no electrodialysis, no distillation, no ion exchange, no precipitation with calcium or barium salts with settling and filtration)
  • Membranes/resins require replacement (e.g. membrane life exhausted, breakthrough achieved)
  • No chemicals for sulfate removal (e.g. calcium or barium salts not available)
  • Incorrect/inappropriate chemicals for sulfate removal (e.g. chemicals used not suitable for water type)
  • Poor process control (e.g. no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from industry)
  • Lack of maintenance (e.g. ineffective cleaning of membranes)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Zinc

Zinc is a grey metal, relatively resistant to corrosion, and therefore often used in galvanising to protect iron from corrosion. Therefore the presence of zinc in drinking water may indicate the corrosion of galvanised plumbing and fittings.

Effect and possible implications of failure

  • Aesthetic
  • Health

High concentrations of zinc will impart a milky appearance and bitter taste in water. In addition, gastro-intestinal irritation, nausea and vomiting may occur.

SANS 241 Standards

  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 3, Class I (recommended operational limit): <5.0 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 4, Class II (max. allowable for limit duration): 5.0 - 10.0 mg/L
  • SANS 241 Table 2 (Physical, organoleptic and chemical requirements) Column 5, Class II water consumption period, max: 1 year

Possible reason/s for failure

  • Source water has high zinc content (e.g. from industries including galvanizing processes and manufacture of paints, cosmetics, pharmaceuticals, dyes and insecticides)
  • Treatment plant cannot reduce zinc content (e.g. no pH adjustment above 9.5 and precipitation with lime settling and filtration)
  • No chemicals for zinc removal (e.g. lime not available)
  • Incorrect/inappropriate chemicals for zinc removal (e.g. chemicals used not suitable for water type)
  • Poor process control (e.g. no monitoring and remedial intervention, problem with process control/SCADA system)
  • Contamination (e.g. infiltration or seepage from industry into distribution network)
  • Lack of maintenance (e.g. flocculation channels/sedimentation tanks not cleaned/de-sludged)
  • Poor design (e.g. inappropriate treatment system)
  • Sabotage/vandalism

Back

© 2011, Emanti Management