ผลของความเข้มข้นของน้ำเสียต่อประสิทธิภาพการบำบัดของพื้นที่ชุ่มน้ำเทียม ที่ปลูกพันธุ์ไม้ชายเลน เมื่อใช้ระบบกะ / ชีวรัตน์ ศิลปรัตน์ = Effect of wastewater concentration on treatment efficiency of constructed wetland planted with mangrove species using batch system / Cheewarat Silaparat
The experiment was conducted in 25 cement blocks of 1 X 2 X 0.6 meters each. The study was designed using 4 mangrove species (Rhizophora mucronata, Avicenia marina, Bruguiera gymnorhiza, Cenops tagal and without plant as a control) and 4 wastewater concentration (normal wastewater (NW), 2, 5 and 10 times higher total nitrogen and total phosphorus of nonnal wastewater (2NW, 5NW and 10NW) and seawater as a control). Wastewater was retained within the system for 7, 5 and 3 days. The experiment was conducted in a greenhouse at Royal Laem Phak Bia Environmental Research and Development Project in Petchaburi province. The results indicated that all plants had ability of municipal wastewater treatment in constructed wetland higher than control (without plant) unit. The removal percentage of the experiment sets planted with mangrove species for BOD, total nitrogen, amonium, nitrate, total phosphorus, ortho-phosphate were 23.39-94.32,48.72-88.68, 29.61-96.30, 13.33-79.16, 75.22-92.57 and 74.79-92.53 % respectively. According to wastewater concentration, the removal percentage of all treatment units received low concentration wastewater was higher than higher concentration wastewater. Moreover, the removal percentage of 7 day- detention time was higher than the 5 day- and 3 day- detention time, respectively. After receiving wastewater, organic matter and nutrients (total nitrogen and total phophorus) accumulation in surface soil layer increased significantly with concentrations of wastewater. Soil irrigated with 10NW had the highest contents of organic matter and nutrients. Organic matter and nutrients were accumulated higher on the surface soil layer than the sub soil layer. After treating, nutrients concentration in plants were analysed and found that plant cultivated with wastewater had higher nutrients than seawater. The highest growth rate and biomass found in Rhizophora mucronata. The results suggested that the constructed wetland planted with mangrove species was effective for removing nutrients from wastewater. Therefore, the use of mangrove plantations for municipal wastewater treatment is applicable.
