Chikogu Ameso Vivien, Essandoh Helen Michelle Korkor, Donkor Emmanuel Amponsah, Nwude Michael Obiekwe
Regional Water and Environmental Sanitation Centre, Kumasi (RWESCK) Department of Civil Engineering College of Engineering, Kwame Nkrumah University of Science and Technology, P.M.B UP, KNUST, Kumasi, Ghana.
Department of Water Resource and Environmental Management, National Water Resource, Institute (NWRI), P.M.B. 2309, Mando Road, Kaduna, Kaduna State, Nigeria.
Heliyon. 2023 Jul 5;9(7):e17637. doi: 10.1016/j.heliyon.2023.e17637. eCollection 2023 Jul.
The reuse of treated wastewater for agriculture and other purposes is globally recognized as a reliable water source. Constructed wetlands are cost-effective and reliable green technologies for wastewater treatment, offering an environmentally friendly and affordable solution with minimal operational and maintenance requirements. This study assessed four wetland technologies (HFWSF, VFSF, VSSF, and HSSF) for treating greywater according to regulatory standards. The technologies effectively maintained pH levels, and both treated and untreated greywater samples met FEPA limits. They efficiently reduced dissolved and suspended particles, remaining below FEPA discharge limits for conductivity, TDS, turbidity, and TSS. However, elevated ammonia levels in both treated and untreated samples required additional treatment or mitigation. Sulphate levels were successfully mitigated, and phosphorus limits were met, with HFWSF already compliant even before treatment. Nitrate levels were reduced to meet FEPA limits, ensuring regulatory compliance. While BOD limits were met in both treated and untreated samples, untreated samples exceeded COD limits, necessitating more efficient treatment methods. HFWSF and HSSF complied with COD limits, whereas VFSF and VSSF did not. Both treated and untreated samples exceeded FEPA limits for oil and grease, indicating the need for additional treatment. Untreated samples exhibited high coliform contamination levels, underscoring the importance of effective treatment. However, all technologies successfully reduced coliform levels in treated samples, meeting FEPA limits and confirming treatment effectiveness. The combination of () in the horizontal subsurface flow constructed wetland improved pollutant removal, nutrient removal, and contaminant elimination. Incorporating water () with horizontal free water surface flow wetland technology demonstrated the highest efficacy in removing various pollutants. This combination outperformed other wetland technologies in effectively removing pollutants, including ammonia (60%), oil and grease (78.46%), COD (85%), TP (37.04%), FC (75%), and TC (79.59%), representing significant progress in greywater treatment.
经处理的废水再用于农业及其他用途在全球被公认为是一种可靠的水源。人工湿地是具有成本效益且可靠的废水处理绿色技术，提供了一种环境友好且经济实惠的解决方案，运营和维护要求极低。本研究根据监管标准评估了四种湿地技术（高负荷潜流湿地、垂直潜流湿地、垂直流湿地和水平潜流湿地）处理中水的效果。这些技术有效地维持了pH值水平，处理后的和未处理的中水样本均符合联邦环境保护局（FEPA）的限值。它们有效地减少了溶解和悬浮颗粒，电导率、总溶解固体、浊度和总悬浮物均保持在FEPA排放限值以下。然而，处理后的和未处理的样本中氨含量升高，需要进行额外处理或缓解。硫酸盐含量成功降低，磷含量符合限值，高负荷潜流湿地甚至在处理前就已达标。硝酸盐含量降低以符合FEPA限值，确保符合监管要求。虽然处理后的和未处理的样本均符合生化需氧量（BOD）限值，但未处理的样本化学需氧量（COD）超标，需要更高效的处理方法。高负荷潜流湿地和水平潜流湿地符合COD限值，而垂直潜流湿地和垂直流湿地则不符合。处理后的和未处理的样本油类和油脂含量均超过FEPA限值，表明需要进行额外处理。未处理的样本大肠菌群污染水平较高，凸显了有效处理的重要性。然而，所有技术均成功降低了处理后样本中的大肠菌群水平，符合FEPA限值，证实了处理效果。水平潜流人工湿地中（ ）的组合提高了污染物去除、养分去除和污染物消除效果。将水（ ）与水平自由水面流湿地技术相结合在去除各种污染物方面显示出最高的效率。这种组合在有效去除污染物方面优于其他湿地技术，包括氨（60%）、油类和油脂（78.46%）、COD（85%）、总磷（TP，37.04%）、粪大肠菌群（FC，75%）和总大肠菌群（TC，79.59%），代表了中水回用处理方面的重大进展。
