Avoid pollution, wastage to prevent water crisis

An aerial view of Lambir Water Treatment Plant.

PEOPLE can live a week without food but only a few days without water.

This underlines the importance of water as a life-sustaining resource.

Malaysia is blessed with an annual average of 324 billion cubic metres of rainfall. In this sense, water supply should not pose a problem but the opposite seems to be the case with water crisis being reported every year, affecting thousands of people.

This may be a sign that water resources are facing ‘pressure’ from development and planning that fail to take into account environmental limits for a natural recovery process.

Droughts are not the only factor causing the water crisis. These prolonged dry spells should be anticipated as part of a protracted hot weather cycle and be included in the contingency plan.

Deteriorating quality has also contributed to the water crisis in the country, making the water unsuitable not only for human consumption but also its long-term ecological roles.

Low water quality is due to the increasing number of contaminated rivers and destruction of water catchment areas through forest clearing and rapid development in the highlands.

People need fresh clean water for daily use as well agricultural and business activities. Water is also important for the environment to support biological processes and stabilise global temperatures.

The flocculator channel.

Contamination incidents

Various incidents of contamination have been reported as a result of waste disposal from the manufacturing, livestock, construction and plantation industries as well as oil spills and sand mining activities, all of which can affect water quality and cause most water treatment centres to close for losing the ability to treat highly-polluted water, ultimately leading to disruption of piped water supply.

In addition to pollution problems, inefficient water useage practices also contribute to the inadequacy of clean water supply. The pressure on water demand occurs because the useage rate exceeds the ability of the water to grow naturally through rainfall and underground sources — a problem further compounded by the El Nino phenomenon.

The inability of treatment centres to treat and process over-polluted water has also caused the pressure on supply to increase.

The huge aluminium chlorohydrate (ACH) tanks at the plant.

Treatment of Miri water

Recently, I joined a group of students from Madrasah As-Syibyan Miri on an educational tour of the Lambir Water Treatment Plant under Laku Management Sdn Bhd, a wholly-owned company of the state government, to learn about the source of our water supply and how it’s processed.

On hand to explain the treatment process and biological monitoring of raw water were the plant’s quality control executive Lizsberth Ngana and its production supervisor Clayvian Joshua.

The raw water for treatment in Miri comes from Sungai Liku, the primary source, capable of yielding about 80 million litres per day (MLD), Sungai Bakong, up to 120 MLD, and underground wells. Each cycle process takes about eight hours — from pumping raw water to becoming clear water.

Production supervisor Clayvian Joshua explaining the biological monitoring of raw water.

The water pumped from the river will undergo several treatment stages before being supplied to consumers. Although the supply sounds quite high, the costs of processing highly-contaminated raw water are also high. The chemicals used are getting more expensive.

After being pumped from the river, the raw water will go through an intake screening process for early filtration to isolate physical substances such as wood, sand, grass and others.

The raw water is then pumped into a cascade aerator where it’s exposed to the atmosphere to improve the oxygen content and remove odor and flavour through oxidation to oxidize iron and dissolve manganese into insoluble and precipitate conditions.

The floc formed during processing at the flocculator channel.

After ventilation, liquid aluminum sulphate (to bind the foreign particles together to form floc or solid material), and aluminum chlorohydrate (as a highly polymerised coagulant to bind foreign particles together to form floc) are used in the raw water for coagulation. The water then flows into the flocculation tank.

Polymers are used to coagulate suspended solids and produce large curds of solid materials and the flow in the tank of the coagulants is controlled to obtain optimum flocculation.

The floc formed will trap the bacteria and the colours present in the water and it’s important to note the dosage of the chemicals used needs to be precise to form a good floc and facilitate the settling process.

Different tanks

Water containing floc will then flow into the settling tank where the large and heavy floc will settle down at the sedimentation tanks, producing clear water which will then flow into the filtering tank.

Water that has been filtered will flow into the clean water tank where chlorine is added to kill germs and microorganisms for safe drinking.

Hydrated Lime, meanwhile, is used to ensure the pH value is within the desired range. The pH of the water becomes low during the curing process due to the addition of alum. Hydrated Lime is thus mixed into filtered water to raise the pH value to the desired level.

The appropriate pH value is needed because if acidic (low), it will erode the water supply pipe and if alkaline, will form sediments on the water supply system.

The clean water is stored in a clean tank before being distributed and water quality testing is carried out on samples of raw water, sediment and clean water.

The routine internal quality control is done by collecting and testing of water samples which are sent to Department of Chemistry for analysis. The quality is monitored by the Engineering Services Division of Ministry of Health.

The water complies with the National Standard for Drinking Water Quality set by the Ministry of Health based on World Health Organisation guidelines.

Lambir Treatment Plant Water quality control executive Lizsberth Ngana briefing the students on the water treatment process.

Chloramine use

In Miri, chloramine is used to disinfect drinking water before delivery to the consumers. It’s a combination of chlorine and a very small amount of ammonia while chloramination is the process that adds chloramine to drinking water.

Chloramine is a more stable and persistent disinfectant. It preserves the quality of purified water as it travels through the distribution system and reduces the taste and odour of chlorine in tap water.

Chloramination helps to reduce disinfection by-products such as trihalomethanes (THMs) in the water. THMs are chemical compounds that form when chlorine reacts with naturally occurring organic substances in the water.

Apart from Hydrated Lime, liquid aluminum sulphate, aluminum chlorohydrate, chlorine and polymer, other chemicals used for water treatment are Sodium Silicofluoride (a source of flouride to prevent tooth decay) and ammonia NH3 (react with chlorine to foam chloramine to help prolong the residual chlorine in the distribution system).

Average month bill

The average monthly bill Sarawakians pay for clean water is RM12.60 with the minimum charge of RM4.40 in any one month for Miri and Limbang areas (domestic rate) which for some is still affordable.

According to the Auditor-General’s Report (LKAN) 2017 Series 2, available on its website from earlier Dec, 2018, Laku informed that water production was based on demand by consumers and in the water supply industry, consumers are encouraged to reduce consumption and wastage to help the agency reduce production costs.

For 2015 to 2017, Laku has used 13.70 million kg of chemicals for water treatment purposes and based on the audit analysis on the use and distribution of chemicals in the same period, the Lambir Water Treatment Plant in Miri used 8.24 million kg or 60.1 per cent of the total use of Laku chemicals.

According to Laku, the high use of chemicals in Miri is due to the poor water quality in swampy areas, requiring higher doses of chemicals to treat the raw water for safe drinking.

The students with their teachers and parent-teachers’ association members and the plant’s staff after the educational tour.

Save our rivers

Considering how tedious the treatment process is from the moment the raw water is pumped from the river, the rainwater catchment for urban dwellers may not be suitable due to the acid rain phenomenon which can occur through the presence of nitrogen dioxide gas, the result of combustion of petrol in engines. Thus, we are relying on river water.

There are countries which have used water from the sewage system, processing it by reverse osmosis to produce drinking water. Although this is a good alternative, the resulting water has zero mineral and trace.

Relying in this type of water can cause some chronic health problems, especially in the muscular and bone defence systems.

It’s time for all Malaysians to help rehabilitate rivers in the country which are dying. Processing river water so that it will be safe for consumption requires a long and thorough process and the dirtier the river, the more chemicals are needed to get clean water which also means high production costs.

Stern action should be taken against polluters. People should realise that polluting the rivers will result in contamination of the water and this will directly affect the food chain and cause various diseases.

Rivers, being the main source of water supply, must be well managed to prevent not only chemical and silt pollution but more importantly, also increase in the costs of treatment and water supply to the detriment of consumers.

Source: http://www.theborneopost.com/2018/12/16/avoid-pollution-wastage-to-prevent-water-crisis/