Sustainable wastewater treatment – The way to go
There has been negative perception of wastewater treatment for drinking purposes by the populace in many parts of the world because of the mentality that drinking treated wastewater can be likened to drinking one's pee. However, there is limited availability of potable water and wastewater treatment is important to the provision of adequate fresh water since salt water makes up about 97.5% of the world's total water resources. The available fresh water in the world is a paltry 2.5% of the total water resources and the accessible fresh water is an insignificant chunk of the fraction available. Therefore, it seems that wastewater reuse for potable (and non-potable) application is inevitable.
Wastewater derives its name from water containing wastes or water that has already been used for domestic, municipal, commercial or industrial applications. Wastewater treatment has been known to be the cheapest source of water production. However, treated wastewater still faces the challenge of lack of acceptance of many people due to its source except in Singapore and California where wastewater is currently being treated for potable uses. Therefore, the effluent form wastewater treatment plants are mostly used for irrigation, agriculture and associated purposes. Besides this, most wastewater treatment methods currently available require the use of energy from conventional fuels (fossil fuels). These fuels release poisonous and greenhouse gases such as carbon, nitrogen and sulfur oxides gases, and methane into the environment. These gases have deleterious effects on the environment. So, how can the wastewater treatment process be carried out without adverse impacts? Many people have proposed renewable technologies for energy supply to treatment plants and sustainable waste sludge disposal. As much as the proposals and research activities on sustainable wastewater treatment seem appealing for the future, the reclamation of wastewater would remain an environmentally-unfriendly process on the large scale if there is no will on the part of companies, governments and the populace to begin to do business in an unusual manner. Corporations and governments at all levels should begin to retrofit existing plants with sustainable features and incorporate non-conventional energy sources into newly designed plants. Renewable energy may also be generated for these plants from the biodegradable organic content of waste sludge from the plants through processes such as anaerobic digestion.
It is disheartening to note that our dear country, Nigeria, still dispose wastewater from washrooms, laundries and kitchen directly into surface waters without any treatment. Wastewater from commercial and industrial applications has also experienced the same fate without any plan by most environmental stakeholders to ensure safe disposal. The indiscriminate release of wastewater into the environment in many Nigerian cities has adversely affected sanitation and claimed the lives of many people through diseases such as cholera, hepatitis B and typhoid. The endocrine disrupting substances in untreated wastewater can alter the hormone system of human beings, resulting to reproduction predicaments, cancerous growth, and deformations of body organs. The metallic content of raw wastewater also causes serious health concerns for humans. For example, scholars at University Teknologi, Malaysia and Bayero University, Kano found out that the discharge of some heavy metals from wastewater into the River Challawa in Kano exceeded the maximum permissible limit given by the Federal Ministry of Environment and World Health Organization.
There are also several repeated cases of non-compliance of industries to safe discharge of wastewater by National Environmental Standards Regulatory and Enforcement Agency, NESREA. In many densely populated areas in Lagos State such as Badagry, Mushin, Oshodi and Ikorodu, most septic tanks and dry wells are in dilapidated conditions, leading to severe cases of groundwater contamination. Lagos State alone generates a massive 1.4 trillion cubic centimeters of wastewater every day, according to government statistics. It is however noteworthy that some places and companies in Nigeria have already decided to lead the course of treating wastewater in a way that protects our common future. Currently, there are wastewater treatment facilities in Tinapa in Cross River State; Maryland, Lekki, Abesan and Amuwo Idofin in Lagos State; and Wupa in Abuja.
Change of attitude towards wastewater treatment is the key. Government at all levels should begin to implement wastewater treatment and reuse programmes and policies. We, as Nigerians, should begin to be more concerned about how we dispose the wastewater around us. Without this, the preservation of our water resources and the environment for the future (and children yet unborn) remains an illusion. – Adewale Giwa