How a Sewer Line is Revitalizing the Nairobi River and Its Surroundings.

The cheerful laughter of children playing outside signals a new beginning in the vibrant Thome neighborhood, a stark contrast to the troubling past marked by the perils of open sewers and flowing waste.

Just a few years ago, this now-thriving middle-class area was overshadowed by the unpleasant stench of raw sewage and the sight of open gutters filled with waste, creating serious health hazards, especially for children.

Nairobi’s sewerage system has struggled to keep pace with the city’s growing population, which has surpassed four million residents. The open gutters and flowing sewage in the capital contributed to a rise in waterborne diseases like cholera, typhoid, and dysentery, disproportionately affecting children.

In a bid to improve sanitation and waste disposal in Nairobi, the government partnered with the African Development Bank. The second phase of this initiative, known as the Nairobi Rivers Rehabilitation and Restoration Programme: Sewerage Improvement Project (NaRSIP), aims to increase sewerage coverage by over 50%. Launched in August 2020, it is scheduled for completion by December next year. The first phase, completed in 2017, raised the city’s sewerage coverage to 48% through the construction of 56 km of trunk sewers and 40 km of reticulation sewers.

As part of Phase 1, the Dandora wastewater treatment plant was expanded to handle 40,000 cubic meters of waste daily, while the Kariobangi plant was rehabilitated to manage 32,000 cubic meters daily, up from just 11,000 cubic meters.

The rehabilitation efforts fall under the Athi Water Works Development Agency, one of nine agencies created by the Ministry of Water. To effectively serve Nairobi residents, NaRSIP is divided into five sectors, covering Kahawa West and Sukari, Githurai 44 and 45, Mwiki and Clayworks, as well as the East and West regions of the city.

The transformation of these areas has been remarkable since the sewer lines were installed. The unsightly conditions of open sewers and floating waste are now history, replaced by cleaner air and a safer environment where children can play freely, alleviating parental worries.

Susan Gakii, a resident of Marurui Estate, recalls the difficult days of manually draining raw sewage with buckets, a task fraught with health risks. “We had to use buckets to remove sewage every 30 minutes, even from the toilets. Now, with the sewer line connected, life is simpler; children can play outside without fear,” she said.

Public institutions like schools and hospitals have also benefited. Karani Waruhiu, Head of IT at Ruaraka Academy, noted the positive impact of the sewer system on the school’s operations. “Before, we had to hire trucks to remove sewage during the rainy season, which strained our finances and disrupted classes. The new system has been a significant relief,” he explained.

Grace Muthoni, who oversees several apartments in Githurai, described the frequent drainage blockages prior to the sewer system’s installation. The new system has greatly improved sanitation, leading to better health outcomes and a notable decrease in reported illnesses.

The rehabilitation of the Dandora Sewage Treatment Plant aims to double its capacity. Located 26 km from Nairobi on Kangundo Road, the facility processes around 120,000 cubic meters of waste daily, accounting for approximately 80% of the wastewater generated in the city.

Duncan Kamau, a resident engineer for NaRSIP II Lot 1, explained the treatment processes involved, which include screening to remove large materials and biological treatment in maturation ponds to eliminate pathogenic organisms.

The project also includes constructing secondary reticulation sewers to fill gaps in the sewer network, particularly in informal settlements like Kibera, where sanitation is a critical concern. To promote ecological health and combat climate change, the strategy incorporates tree planting along sewer lines and the conversion of biogas to energy, thereby reducing greenhouse gas emissions.

As of now, Lot 1 is approximately 74% complete, with no raw sewage being released into rivers. The other four lots serve Nairobi’s informal settlements, channeling sewage to the Dandora Waste Water Treatment Plant for safe processing before being released into the Nairobi River.

With Nairobi housing about nine percent of Kenya’s population—tallied at 47 million in the 2019 census—rural-to-urban migration has intensified the city’s sanitation crisis, straining existing facilities and jeopardizing public health, the environment, and the economy.

Bonnie Nyandwaro, the infrastructure development acting director at the Athi Water Works Development Agency, highlighted the urgent need for the project. “Pollution and degradation are severe in the five rivers flowing through Nairobi. Our goal is to raise sewerage coverage from 48% to 55% within the city,” she said.

Upon completion, over 400,000 residents will gain access to improved sanitation services. Currently, the project is 82% complete, with sewer networks being established in areas like Githurai, Kahawa West, and Mwiki Clayworks, effectively eliminating open sewage flows into the Nairobi River.

Nyandwaro emphasized the health benefits of the project, stating, “In areas connected to the sewer system, no cholera cases have been reported. Our aim is to reduce health risks, particularly for children and young mothers, by improving sanitation.”