Modern urban wastewater management to ensure a sustainable future for Miri City

By Dr. Henry Foo Chee Yew and Ir. Ts. Dr. Tan Inn Shi

Urban wastewater management is a crucial aspect of urban planning and development, and Miri, a coastal city in the north of the state of Sarawak, Malaysia, is no exception. With a population of over 350,000 people, the city generates a significant amount of wastewater that must be treated and managed effectively to protect public health and the environment.

The primary sources of wastewater in the city include domestic sewage, industrial effluents, and stormwater runoff. The city’s current wastewater management system is divided into two parts – the collection system and the treatment system.

The collection system consists of a network of pipes, pumps and lift stations that collect wastewater from homes, businesses and industries and transports it to the treatment plants. The collection system is managed by the Miri City Council, which is responsible for maintaining the system and ensuring that it is functioning properly.

The treatment system, on the other hand, is responsible for treating the collected wastewater to remove pollutants and contaminants before releasing the water into the environment. To ensure the discharged treated wastewater meets the requirements of the National Water Quality Standards (NWQS), both centralised and decentralised initiatives have been adopted to address the needs of urban areas that tap into the main sewer networks, as well as rural areas and low-income neighborhoods that do not.

An example of a centralised wastewater treatment plant (WWTP) is the Miri Centralised Sewage Treatment Plant at Pujut Bypass that has a capacity of 400,000 PE (population equivalent). Wastewater (grey water and black water) from kitchens, bathrooms, wash areas and toilets are collected via a sewer reticulation network and channeled to the WWTP plant.

Meanwhile, decentralised wastewater treatment systems (DEWATS) include the Miri Septic Sludge Treatment Plant which serve domestic/rural areas where wastewater is captured in septic tanks. Such plants are integral to Miri’s master plan for wastewater treatment where WWTP plants are not available or prone to failure.

Despite these facilities, the city still faces challenges in managing wastewater effectively. One of the significant challenges is the lack of public awareness about the importance of wastewater management. Many people in the city are unaware of the impact of untreated wastewater on the environment and human health.

Another challenge is the lack of proper maintenance of the collection system. The collection system is aging, and there are frequent leaks and breaks in the pipes, which result in the loss of wastewater and contamination of the environment. Limited funding for maintenance and upgrades of the infrastructure has further compounded the problem.

As the result, the city’s wastewater treatment capacity is inadequate to meet the growing demands of its expanding population, industrialisation and urbanisation. We can clearly see the consequences of inadequate wastewater treatment facilities which is evident in cases of water pollution as well as degradation of the ecosystem.

Researchers from Curtin University Malaysia have carried out assessments of urban lakes along the coastal region of Miri as well as river water at industrial areas on the northwest coast of Borneo. Based on a report in 2023, among 15 lakes studied, all 15 lakes are classified as suitable for irrigation use (class IV). Based on the water quality index (WQI), meanwhile, 14 of those lakes fall under the ’polluted’ index and one under the ‘slightly polluted’ index. It can be inferred that the lake water quality has been affected by both geogenic and anthropogenic impacts.

Apart from that, the water quality of 10 rivers on the northwest coast of Borneo were classified as Class III, which indicates slightly polluted water quality. Uncontrolled increases in industrial and plantation development near the water bodies may worsen the physicochemical and microbiological status of rivers, in particular the parameters of pH, total dissolved solids (TDS), salinity, electrical conductivity (EC), biochemical oxygen demand (BOD) and chemical oxygen demand (COD).

This alarming status is the result of unsustainable urbanisation on the environment. Hence, a proper management plan is needed to safeguard our water resources.

To address these challenges, the city needs to adopt a multi-pronged approach involving the government, private sector, and community. The government can provide financial and technical support for wastewater management initiatives. The private sector can invest in wastewater treatment infrastructure and participate in public-private partnerships to improve wastewater management in the city. The community can be educated about the importance of wastewater management and encouraged to adopt sustainable practices that reduce the generation of wastewater.

In conclusion, urban wastewater management is a critical issue that requires the attention of city authorities, policymakers, and the community. Miri, like many other cities in the world is grappling with the challenge of managing wastewater effectively. However, there are opportunities for improved wastewater management, such as the availability of new and innovative technologies and the implementation of a wastewater reuse programme.

As academics, we at Curtin University Malaysia are looking into new and emerging technologies such as membrane bioreactors (MBR), constructed wetlands (CW), ozonation, electrocoagulation, and forward osmosis. These technologies offer a range of benefits, including high treatment efficiency, low energy consumption, and reduced environmental impacts with greener processes.

As cities continue to grow and face increasing wastewater challenges, adopting these new technologies can provide sustainable solutions to ensure the protection of the environment and public health.

Dr. Henry Foo Chee Yew is a senior lecturer in the Chemical and Energy Engineering Department of Curtin University Malaysia’s Faculty of Engineering and Science where he is actively involved in teaching, research, supervising research students, and providing academic leadership and administrative support for the Department. His research focuses on applications of nanotechnology across various areas such as heavy metal ions removal, oil demulsification, dyes removal, air pollution control, membrane separation, bioplastics, biosensor and artificial skin. He was recently awarded a research grant to work on desilting and heavy metal content removal in the Baram and Miri rivers. This project will lead to the implementation of an integrated biocoagulant, ozonolysis, activated carbon and belt press system upstream of Baram river (belt press machine with biocoagulant for desilting) and downstream of Miri river (floating structure with ozonolysis and activated carbon for heavy metal content removal). Dr. Foo is a Chartered Engineer (CPEng) under Engineers Australia (EA) and also a Professional Technologist (MBOT). He welcomes opportunities for partnerships and collaboration from interested parties and can be contacted by email at

Ir. Ts. Dr. Tan Inn Shi is a senior lecturer in the Department of Chemical and Energy Engineering at Curtin University Malaysia. She holds a PhD in Chemical Engineering from Universiti Sains Malaysia (USM). Her main research interest is related to technology services regarding operations relating to product development (biomass and biofuel), which uses chemicals and enzymes for bioethanol and bio-monomer production. Specifically, she has developed a promising alternative approach for process- and time-efficient utilisation of algae waste by utilising a advanced two-step process (autohydrolysis and prehydrolysis and simultaneous saccharification and fermentation) to produce reducing sugar and L-lactic acid (L-LA). L-lactic acid is an inexpensive and sustainable single monomer of polylactic acid (PLA) and could be the answer to increasing the 3D printing industry’s demand for renewable feedstocks. She is a Professional Engineer under the Board of Engineers Malaysia (BEM), Chartered Engineer (CPEng) under Engineers Australia (EA), and a Professional Technologist (MBOT). Dr. Tan welcomes opportunities for partnerships and collaboration from interested parties and can be contacted by email at