By Chainga Zulu
Effective management of onsite sanitation systems in Zambia is critical to protect public health and the environment. Proper maintenance, regular desludging, and safe disposal of waste are important components of onsite sanitation management practices. Additionally, it is important to promote awareness and education among the population on the importance of good hygiene practices and the proper use and maintenance of onsite sanitation systems. Developing and implementing simplified guidelines and regulations for onsite sanitation management can also help to ensure safe and effective waste management practices in Zambia.
The Zambia Environmental Management Agency (ZEMA), established under the Environmental Management Act (EMA) No. 12 of 2011, is the public body responsible for an array of environmental issues, including regulating effluent discharge. In this respect, ZEMA is responsible for issuing waste management licenses to all sanitation service providers (including local authorities) to “reclaim, re-use, recover or recycle waste; collect of dispose of waste; transport waste to a disposal site; own, construct or operate a waste disposal site or transit, trade in or export waste.”
When it comes to feacal disposal in Zambian homes and neighborhoods, the country primarily has two sewer disposal methods: Offsite and Onsite.
1. Offsite has the sewerage reticulation system with pipes and sewer system managed by commercial utility companies.
2. The on-site sanitation system can be divided into two methods: the septic tank and soakaway method and pit latrines.
When pit latrines fill up, many households must empty them because of the lack of space to dig new pits. But whenever space permits especially in rural areas with very low population density and more land available, burying the latrine and building another one somewhere is an acceptable feacal sludge management practice.
Many of the new affluent residential areas that continue to spring up are not getting connected to the sewer system ultimately settling for septic tanks and soakaways. This creates an environmental hazard if not done correctly as effluent can percolate into the soil and contaminate the groundwater. They can also get flooded during rainy season, leading to environmental contamination and create a scenario where on-site sanitation becomes costly both in direct and opportunity costs. There are also settlements where the ground water table is very high. This makes septic tanks and soakaways unsuitable for on-site sanitation purposes.
This article addresses how a septic tank can be properly built and managed to ensure adherence to environmental concerns.
The common building practice in Zambia is to dig a 3mx3mx3m pit, though it can vary depending on the number of persons that will live in a particular house. For smaller homes, a smaller tank will be planned, and for bigger housing units like blocks of flats and other multiple dwelling units, a concrete work which will seal the waste into the ground is ideal.
Digging for the storage tank to be underground is ideal because you would not want waste to flow out or mix with other items in the compound like water sources or farms and vegetation as this could lead to contamination and disease outbreaks.
The Zambian building code recommends that sewage tanks and their attached soakaway systems be underground. These soakaway pits are then lined with block work to form the side walls of the tank. Looking at it from the top, you will think it’s a small room being built underground, of course it’s a room, just not rooms for human habitation! We also use reinforced concrete columns to make the corners.
The importance of these columns is for structural integrity and for prevention of lateral pressure which might bear down on the tank from the top. We also make a middle concrete beam to round the soakaway and septic tanks. These reinforced beams are needed to provide stability.
The next step in the construction of soakaways is the plastering; the plaster work is for the septic tank side, where the effluent is stored. It is important that the effluent will not seep through the tank walls and mix with the ground water in the surrounding areas.
The section of the soakaway where wastewater is meant to seep away is at one side, usually left open in between blocks to slowly let off excess water into the surrounding ground, as opposed to the soakaway where the effluent is supposed to be stored until they degrade.
The decking work on septic tanks is meant to form a rigid cover for the soakaway. That prevents the risk of people or other domestic animals from falling into the pit. The decking will also be reinforced like other decking slabs done in home construction. An opening is then left for the evacuation of waste when it gets filled. It is recommended that septic tanks and soakaway systems be constructed to last for a long time before evacuation, so that the inconvenience of evacuating waste regularly is reduced.
In conclusion, it is imperative that sanitation systems in the country are improved. A standard guide for soakaway construction should be developed and enforced.
Local authorities and CUs should claim their mandate and guide on where and how to construct septic tanks and soakaways to avoid pollution of groundwater. With population increase and new settlements developing, town planning becomes even more important to ensure that new settlements are properly designed and provide for various social amenities, including fecal sludge management. It is important to ensure every household is connected to a sewer system. As such, onsite sanitation now should be regulated and guided in accordance with the environmental regulations.
