Gearing up for World Water Day 2017
World Water Day is held annually on 22 March as a means of focusing attention on the importance of freshwater and advocating for the sustainable management of fresh water resources. An international day to celebrate freshwater was recommended at the 1992 United Nations Conference on Environment and Development (UNCED). The United Nations General Assembly responded by designating 22 March 1993 as the first World Water Day. Each year, World Water Day highlights a specific aspect of freshwater. For this year the theme is “Wastewater”. It is our responsibility to reduce the quantity and pollution load of waste water we produce in order to protect our precious ecosystems. At the same time, we have to improve the treatment of waste water and safe reuse of it. ‘Waste Water’ is a timely topic to be addressed in a broad sense. In this regard, Education Times interviewed Dr.Sujithra Kaushalya Weragoda, Project Director (China Sri Lanka Research Grant Project) and Chief Engineer (Water Safety Plan Advisory Unit) at National Water Supply and Drainage Board of Sri Lanka.
Here’s some excerptions from the interview: QAs a whole what can consider as waste water?
Waste water, also written as waste water, is any water that has been adversely affected in quality by anthropogenic influence. Wastewater can originate from or a combination of domestic, industrial, commercial or agricultural activities, surface runoff or storm-water, and from sewer inflow or infiltration. On the other hand, it can be defined with simple words as water that is not clean because it has already been used in homes, businesses, factories, etc. Even though we simply say that consuming water, truly, we are not consuming water. We just use the palatability, drinkability or cleanness of water and discharge back less palatable or cleanness water which may not be suitable for consumption. This we call as wastewater. Generally, a human being may consume 140 to 160 l/day of water as direct consumption. We assume around 80% of this water will be producing back as domestic wastewater. But, indirect water consumption will be much higher than we believe. It is better to get more into the concept call ‘water footprint’ which describes the water consumption during whole manufacturing process.
QWastewater
generated by society flows back in to the ecosystem without being treated or reused. This can lead to deleterious environmental and medical impacts on the community. How do you see this situation in Sri Lanka?
As a civilized nation, we should always think that we are responsible for all waste we produce in day today activities. It can be in form of gas, water or solid. We have no right to dispose them back into the environment without proper treatment. What does it meant by proper treatment? Nature always well balanced. If we are disturbing this balance system, then it will damage the ecosystem. Sri Lanka, as a country has given very less priority for proper waste management. We treat only about 2% of the total domestic wastewater at the centralized treatment facility. But most of the developing countries have exceeded the margin of 10%. However, Sri Lanka has shown remarkable achievements in onsite treatment such as with septic tank sys- tems and soakage pits. However, the E. coli (indicating bacteria for contamination from human feaces) level of most of the water bodies has been recorded an increasing trend throughout the past. When we consider the groundwater contamination in municipal council area of Jaffna, over 60 % of the shallow groundwater has been reported for positive results in E. coli test. This indicates clearly that the soakage pits will not work when percolation through soil or groundwater table is high.
Unfortunately, the situation in industrial and commercial wastewater treatment is also not to a satisfactory level. Even though, there is much legislation related to the control of wastewater discharge, the responsible authorities are not yet empowered enough and no effective mechanism has been established to monitor and claim from polluters for damage.
The awareness will work better in than just empowering regulations alone. We shall change the mind set of all Sri Lankan by giving meaningful thoughts of treating wastewater. Because, waste you discharge today will return back you tomorrow as a disaster. If we do not understand this truth, the tomorrow will not be good for all living in here. Once a philosopher named Hippocrates, who is considered as the father of modern medicine, explained that if someone wants to know of the health of a group of people, then go and check air they breathe, water they drink and soil where they live. We have enough lessons to learn from the past. Impacts from recent past diseases such as Minamata (name of the contaminated bay) and Itai- itai (means pain is impossible to bare in Japanese) which caused due to pollution of water from discharging of mercury (Hg) and cadmium (Cd) respectively. Hence, we shall not repeat the past again back and need to give proper attention to maintain a healthy ecosystem.
QWhat about the opportunities from exploiting wastewater as a resource?
Wastewater is itself treated as a resource. There is no term as waste and all waste can be used to recover resources much more efficiently than recovering from the nature. Domestic wastewater carries high amount of carbon and it can be converted to biogas which is a good solution for energy demand. Most of the wastewater treatment facilities in developed countries will ensure to have anaerobic digesters for sludge treatment as this process will produce almost 70% of the energy need in the wastewater treatment plant itself. Industrial wastewater is a very good source for recovering metals. All the materials in wastewater can be recovered very efficiently than from natural sources. Extracting valuable metals such as chromium and nickel from metal plating industry would be a good exercise to practice by waste management authorities. Reclaimed water, after an appropriate treatment process will be a good source for consumption in water scared area. As an example, the surrounding areas of Olympic ground in Beijing constructed in Year 2008, named Bird’s nest uses reclaimed water from Beijing wastewater treatment facility. The drinking water available as NEWater in Singapore is another good example to understand the extend that we may use treated wastewater in our day today practices. The USEPA urges in establishing wastewater treatment facilities, which treat human and animal waste, to be viewed as Renewable Resource Recovery Facilities that produce clean water, recover energy and generate nutrients. Numerous individual products can be recovered from wastewater treatment plants, including biodegradable plastics, adhesives, and enzymes useful in biomedical applications. Additionally, several carbon based materials such as biopolymers, PHAs and others, are present in domestic wastewater and perhaps biosolids. However, it is always advisable to promote cleaner production technologies where as possible to reduce waste generation itself. It is intended to minimize waste and emissions and maximize product output. In addition, 4R concept (Reduce, Reuse, Recylc and Recover) is also being applied to minimize waste generation.
QWhat are the facilities /technologies available in Sri Lanka to treat waste water?
You may find most of the conventional technologies used in world to treat wastewater is available in Sri Lanka at different scale. However, we shall understand the importance of having appropriate technologies as most of the facilities have not become sustainable in use. Wetlands and waste water treatment pond systems would be low cost and robust treatment methods. These are engineered systems which based on the natural treatment. As examples, you may find these are being operated in Rathmalana and Kataragama respectively. This would be good enough to treat municipal wastewater if you have enough lands. In addition, you may find conventional treatment technologies as tricking filters in operation in Hantana housing scheme in Kandy. Moreover, we may go for compacted systems such as activated sludge processes (ASP) in urban areas. The wastewater from Sri Dalada Maligawa premises is being treated by a sequential batch reactor (SBR) constructed near the access road to the Museum. Centralized wastewater treatment facility in Biyagama Export processing zone consists of an extended aerated system (oxidation ditch) as the main treatment unit. Sirimawo Bandaranayake Hospital in Peradeniya uses a rotating bio contactor (RBC) for the treatment. Anaerobic filters also can be used together with septic tanks in treating domestic wastewater.
QHow about the applicability of waste water reuse (treated wastewater) in our country? For which fields?
Water reclamation is a very well developed concept. However, advanced treatment techniques, which consume high cost, may not be appropriate techniques for us. The treated wastewater after secondary and tertiary treatment methods can be reused in landscaping, irrigation, fire fighting, toilet flushing etc after proper disinfection. However, you shall follow the wastewater reusing guidelines and standards very carefully.
QHow does NationalWater Supply and Drainage Board contribute in solving waste water issue in Sri Lanka?
By designing and constructing centralized wastewater collection and treatment facilities, providing expertise knowledge and awareness as needed, maintaining wastewater treatment facilities, etc.