Regulatory standards and guidelines for piped drinking water in SingaporeA/P Hu JiangyongDiv. Of Env. Sci. & Engr.National University of Singapore

Outline Introduction Piped drinking water Regulatory framework for piped drinking water in Singapore Major legislation administered by PUB Major legislation administered by NEA

INTRODUCTION

Glossary/use of the terms Drinking water Potable water Bottled/packaged water

Drinking water Water that is safe for drinking or human consumption. Can be consumed without the risk of any immediate or long term harm. Contaminated drinking water can lead to: Large-scale outbreaksCrypto outbreak in Wisconsin, USA, in 1993, which made 403,000 people ill, and resulted in estimated 69 deaths. Adverse short or long term health effects, such as cancer, birth defects, liver and kidney damage.

Potable water Another term for water that is suitable for drinking. Usually supplied through pipes/public water systems, in which case, it is also called tap water. Also used for cooking or preparation of food (including culinary ice and drinks), rinsing of mouth/gargling, showering, and other domestic use.

Bottled/packaged water Drinking water sealed in bottles or other containers/packages.

Bottled/packaged waterInternational guidelines for bottled water include those prescribed by: Codex Alimentarius Commission (CAC)International Bottled Water Association

Overview In Singapore:Piped drinking water is regulated by statutory boards under the Ministry of the Environment and Water ResourcesPUB (Public Utilities Board)NEA (National Environment Agency) Bottled/packaged drinking water is regulated by AVA (Agri-food and Veterinary Authority of Singapore) Sale of potable water to shipping community is regulated by MPA (Maritime and Port Authority of Singapore)

PIPED DRINKING WATER

Water supply Singapore consumes about 1.3-1.4 million M3 of piped water every day. PUB is the major water supplier in Singapore. Small water suppliers include those that operate on off-shore islands. They usually produce 1,000 M3 of piped water per day.

Water supply PUB has implemented a Four National Taps strategy to diversify its raw water resources.

Water supply Local Catchment Water: There are separate systems to collect rainwater and used water. Rainwater is collected through a network of drains, canals, rivers, storm-water collection ponds and reservoirs. Reservoirs include MacRitchie, Kranji, Upper Peirce, Bedok, etc. Most waterworks/plants use chemical coagulation, gravity filtration, chlorination and addition of ammonia for chloramination. Some plants also use ozone and membrane filtration.

Water supply Imported Water: Singapore has been importing water from Johor, Malaysia, under the 1961 and 1962 Water Agreements. The agreements will expire in 2011 and 2061.

Water supply NEWater: It is high-grade reclaimed water produced from treated used water that is further purified using advanced membrane technologies and ultra-violet disinfection. Currently, there are 5 NEWater plants. NEWater meets 30% of Singapore's total water demand. By 2060, PUB plans to triple the current capacity so that NEWater can meet 50% of Singapores future water demand. NEWater is supplied to wafer fabrication, electronics and power generation industries for process use as well as commercial and institutional complexes for air-con cooling purposes. PUB also blends a small percentage of the NEWater with the reservoir water.

Water supply Desalinated Water: Singapore has one of Asias largest seawater RO plant, which produces about 136,000 M3/d to meet about 10% of Singapores water needs. By 2060, PUB intends to ramp up desalination capacity by almost 10 times so that desalinated water will meet at least 30% of water demand in the long term.

REGULATORY FRAMEWORK FOR PIPED DRINKING WATER IN SINGAPORE

PUB PUB is the national water agency in Singapore. It looks after issues such as raw water resources, water sustainability, etc.NEA NEA is the national environmental agency in Singapore. It looks after issues such as environmental protection and environmental public health. Quality of piped drinking water supplied by PUB and other water suppliers is regulated by NEA.

Piped Drinking WaterMAJOR LEGISLATION ADMINISTERED BY PUB

Public Utilities Act Public Utilities (Water Supply) RegulationsPublic Utilities (Reservoirs and Catchment Areas) Regulations Sewerage and Drainage Act

Public Utilities Act Approval of new suppliers: Any person (/organization) wanting to supply piped water for human consumption must first obtain an approval from PUB, and comply with requirements, standards and codes of practice prescribed by PUB.

Public Utilities Act Any person responsible for maintenance of water service installations (e.g. in any residential, commercial or industrial premises) must ensure that the installations are properly maintained, and kept in a fit and safe condition. A person who lays or repair any pipe in the vicinity of another pipe must, if one of the pipes is used to convey water for human consumption, ensure that the pipes do not become connected/cross-connected to each other.

Public Utilities Act Allows PUB to charge price and fix tariffs for water supplied by PUB. Current charges:

Public Utilities Act Provides powers to PUB employees to enter premises to which water is supplied by PUB, to examine pipes and meters. Provides powers to PUB to construct in any street or place such works as are necessary for purposes connected with supply of water.

Public Utilities (Water Supply) RegulationsAllows PUB to prescribes requirements for: Quality and standard of water fittings (including plumbing materials, hydrostatic pressure they should withstand, etc.) Fitting should not be made of lead/lead alloy.Installation of water service installations, and hot water apparatus/heaterTesting of water fittingsMaintenance and security of water storage tanks, including annual cleaning and disinfection

Public Utilities (Water Supply) RegulationsAllows PUB to prescribes requirements for: Licensing of plumbers/water service workers Water metersConservation of water and installation of water saving devicesFlushing cisterns and flush valves (e.g. those serving urinals and water-closet pans)

Public Utilities (Reservoirs and Catchment Areas) RegulationsAllows PUB to prescribe requirements for: Activities permitted in a catchment area park and central water catchment area, e.g. driving of lorries, fishing, camping, etc.Prohibited activities, e.g. washing and bathing in any reservoir, and defecating in the grounds.Operating of any vessels or watercraft

Sewerage and Drainage ActThe Act primarily covers sewerage and drainage systems. However, it also provides powers to PUB to prohibit any person from constructing any works for taking or intercepting water from any place or sea, without having the approval from PUB. Example - rainwater, ground water, etc.

Piped drinking waterMAJOR LEGISLATION ADMINISTERED BY NEA

Environmental Public Health Act Environmental Public Health (Quality of Piped Drinking Water) Regulations Came into effect on 1 August 2008 Supplemented by a Code of Practice on Piped Drinking Water Sampling and Safety Plans

Environmental Public Health ActPART IXCONTROL OF PURITY OF WATER SUPPLIES

States that no person shall sell or offer for sale water intended for human consumption which is polluted or unwholesome.

EPH (Quality of Piped Drinking Water) Regulations Suppliers are required to comply with the water quality standards prescribed within the regulations. The standards include about 100 health-based and aesthetic parameters. Comprises parameters: Physico-chemical (pH, colour, turbidity)Microbial (E. coli)Radiological (Gross Alpha, Beta, and Rn-222)Chemical parameters (e.g. pesticides, heavy metals, etc.)

Physico-chemical parametersColour: Max. 15 True Colour UnitsTurbidity*: Max. 5 NTU at consumers tappH: 6.5-9.5

* For treated water leaving the plant, turbidity should not exceed 1 NTU (even after addition of lime). Particular consideration should also be given to any abnormal increase in the turbidity levels. This is to minimize the risk of cryptosporidium .

E. Coli (or alternatively,: shall not be detectable thermotolerant coliform) in 100 ml sample

Other parameters that may need to be monitored as a part of operational monitoring, depending upon the findings of the water safety plan:

Colony counts (or heterotrophic plate count) Cryptosporidium Legionella bacteria Clostridium perfringens (e.g. for ground water)Microbial parameter

Radiological parametersThe above standards are for screening purpose. In case of any specific contamination, further analysis of water may become necessary to identify the presence of the radionuclide.Gross Alpha: Max. 0.5 becquerel/litreGross Beta: Max. 1.0 becquerel/litreRadon 222: Max. 100 becquerel/litre

Operational parameters that may need to be monitored, depending upon the findings of the water safety plan.

The limits should be set, depending upon the historical results of water testing. Chloride Conductivity, TDS Hardness Iron Manganese Odour Taste Total organic carbon Sulphate Zinc

Contaminants from treatment chemicalsContaminants from pipes and fittingsCyanotoxinDisinfectantDisinfection byproductsInorganic chemicals, including heavy metalsOrganicsPesticides used for public health purposesPesticides used for agricultural purpose

Chemical Parameters (mg/l)

(A) Contaminants from treatment chemicals*

Acrylamide 0.0005Epichlorohydrin 0.0004

(B) Contaminants from pipes and ttings

Antimony 0.02Benzo[a]pyrene 0.0007Copper 2Lead 0.01Nickel 0.07Vinyl chloride 0.0003* For Aluminium, the guideline values for operational monitoring is 0.1 for large plants and 0.2 for small plants.

(C) Cyanotoxin

Microcystin-LR 0.001 For total microcystin-LR (free plus cell-bound)(D) Disinfectant

Chlorine 5*Monochloramine 3

* For effective disinfection, there should be residual free chlorine of 0.5 mg/litre after at least 30 min contact time at pH

(E) Disinfection byproducts

THMsBromodichloromethane 0.06 Bromoform 0.1 Chloroform 0.3Dibromochloromethane 0.1 THM ratio (sum of the ratio of the 1 concentration of each THM to its limit)

OthersBromate 0.01Chlorate0.7Chlorite 0.7

(E) Disinfection Byproducts

Cyanogen chloride 0.07 for cyanide as total cyanogenic compoundsDibromoacetonitrile 0.07Dichloroacetate 0.05 Dichloroacetonitrile 0.02Monochloramine 3Monochloroacetate 0.02Trichloroacetate 0.2Trichlorophenol, 2,4,60.2

(F) Inorganic chemicals, including heavy metals

Antimony 0.02 Arsenic 0.01 Barium 0.7 Boron 0.5 Cadmium 0.003 Chromium, in all forms as a total 0.05 Copper 2 Cyanide 0.07 Fluoride 0.7 Lead 0.01 Manganese 0.4

(F) Inorganic chemicals, including heavy metals

Mercury, in inorganic form 0.006 Molybdenum 0.07 Nickel 0.07 Nitrate (as NO3-) 50 Nitrate plus nitrite ratio 1 Nitrite (as NO2-) 3 Selenium 0.01 Uranium 0.015

(G) Organics

Benzene 0.01Carbon tetrachloride 0.004Di(2-ethylhexyl)phthalate 0.008Dichlorobenzene, 1,21 Dichlorobenzene, 1,4 0.3Dichloroethane, 1,20.03Dichloroethene, 1,20.05Dichloromethane 0.02Dioxane, 1,40.05Edetic acid (EDTA) 0.6Ethylbenzene 0.3

(G) Organics

Hexachlorobutadiene 0.0006Nitrilotriacetic acid (NTA) 0.2Pentachlorophenol 0.009Styrene 0.02Tetrachloroethene 0.04Toluene 0.7Trichloroethene 0.02Xylenes 0.5

(H) Pesticides used for public health purposes

Chlorpyrifos 0.03DDT and metabolites 0.001Permethrin 0.3Pyriproxyfen 0.3

(I) Pesticides used in agriculture

Alachlor 0.02Aldicarb 0.01(applies to aldicarb sulfoxide and aldicarb sulfone)Aldrin and dieldrin 0.00003 (For combined aldrin plus dieldrin)Atrazine 0.002Carbofuran 0.007Chlordane 0.0002Chlorotoluron 0.03Cyanazine 0.00062,4-D (2,4-dichlorophenoxyacetic acid, free acid 0.032,4-D Butyric acid 0.091,2-Dibromo-3-chloropropane 0.0011,2-Dibromoethane 0.0004 1,2-Dichloropropane (1,2-DCP) 0.04 1,3-Dichloropropene 0.02Dichlorprop 0.1Dimethoate 0.006Endrin 0.0006

(I) Pesticides used in agriculture

Fenoprop 0.009Isoproturon 0.009Lindane 0.002MCPA 0.002Mecoprop 0.01Methoxychlor 0.02Metolachlor 0.01Molinate 0.006Pendimethalin 0.02Simazine 0.0022,4,5-T 0.009Terbuthylazine 0.007Triuralin 0.02Methoxychlor 0.02Metolachlor 0.01Molinate 0.006Pendimethalin 0.02Simazine 0.0022,4,5-T 0.009Terbuthylazine 0.007Triuralin 0.02

EPH (Quality of Piped Drinking Water) Regulations The standards are based on WHO Guidelines.

The standards have undergone review by the Technical Committee on National Drinking Water Quality Standards, which comprises local and overseas experts.

Water quality PUBs typical values for the treated water quality.

EPH (Quality of Piped Drinking Water) RegulationsThe suppliers are required to: Submit to NEA details on water treatment processes, and chemicals and materials used in the production and distribution of water. Prepare and implement water sampling plan and water safety plans (WSPs) approved by NEA. WSPs should include hazard assessment and risk characterization, and should be prepared in accordance to the prescribed format and Code of Practice.

EPH (Quality of Piped Drinking Water) RegulationsThe suppliers are required to: Submit test results to NEA in accordance to the approved water sampling plans. Ensure that measures are put in place to prevent contamination or adulteration of water samples. Carry out testing of water in an approved (accredited) lab.

EPH (Quality of Piped Drinking Water) RegulationsThe suppliers are required to: Ensure that site test kits are checked for calibration, and maintained in good working condition. Notify NEA within 24 hours in case of failure to comply with the water quality standards, and should also take appropriate remedial actions. Keep records for 5 to 10 years.

Thank You !

The Regulations include requirements for the suppliers to conduct sampling and testing of piped drinking water that they supply, and to carry out water safety plans to minimize the likelihood of any piped drinking water failing to comply with the water quality standards prescribed under the Regulations. *varied fields such astoxicology, water treatment, microbiology, medicine, corrosion, andphysical, analytical, legal and social sciencesdifferent organizations such as NUS, NEA, NTU, MOH, AVA, PUB, HSA.*So far the regulatory framework works well. There is no outbreak in last several years.*