A New Green Model for the Bioremediation and Resource Utilization of Livestock Wastewater

Abstract

The rapid growth of the livestock and poultry industries has resulted in the production of a large amount of wastewater, and the treatment of this wastewater requires sustainable and environmentally friendly approaches such as phytoremediation. A substrate-free floating wetland planted with water dropwort (Oenanthe javanica), a common vegetable in Southeast China, was constructed to purify a lagoon with anaerobically and aerobically treated swine wastewater in Suqian, China. The average removal rates of total nitrogen, ammonium nitrogen, nitrite nitrogen, and chemical oxygen demand were 79.96%, 95.04%, 86.14%, and 59.91%, respectively, after 40 days of treatment. A total of 98.18 g∙m−2 nitrogen and 19.84 g∙m−2 phosphorus were absorbed into plants per harvest through the rapid growth of water dropwort biomass, and the nitrogen accumulation ability was similar to that observed of other plants, such as water hyacinth. In addition, the edible part of water dropwort was shown to comply with the Chinese National Food Sanitation Standards and be safe for human consumption. Its low soluble sugar content also makes it a suitable addition to the daily diet. Overall, substrate-free floating constructed wetlands planted with water dropwort could be more widely used for livestock wastewater purification and could be integrated with plant–livestock production in China because of its high removal efficiency and recycling utilization of water dropwort biomass.

Trends and Causes of Raw Water Quality Indicators in the Five Most Famous Lakes of Jiangsu Province, China

“…Total nitrogen (TN) was determined using alkaline potassium persulfate digestion UV spectrophotometry (HJ636-2012). Total phosphorus (TP) was determined using ammonium molybdate spectrophotometry (GB11893-89), and chemical oxygen demand (COD) was determined using the acidic potassium permanganate method [25]. Concentrations of NH 3 -N were measured by Naismith spectrophotometry with medium-range (HI96715) (HANNA Instruments, Woonsocket, RI, USA).…”

Differences in Nitrogen and Phosphorus Removal under Different Temperatures in Oenanthe javanica Cultivars

“…Fresh plant samples were weighed, dried at 65 • C, and re-weighed to determine the dry biomass and moisture content. Dried plant samples were then used to determine the N and P contents in plants following the methods of a previously published study [20]. The N content was determined using the Kjeldahl method after digestion with H 2 SO 4 -K 2 SO 4 -CuSO 4 -Se, and the P content was determined using ammonium molybdate spectrophotometry after digestion with H 2 O 2 -H 2 SO 4 .…”

“…O. javanica is widely cultivated in East Asia, supported by decades of cultivars [18,19]. However, different studies have reported different removal abilities of O. javanica [17,20,21]. Different experimental set-ups may be the main reason for the different performances; however, none of the reports employed O. javanica cultivars, which should not be ignored as there are differences between cultivars.…”

Nitrogen removal and microbial mechanisms in a novel tubular bioreactor‐enhanced floating treatment wetland for the treatment of high nitrate river water

“…Floating treatment wetlands (FTWs), as an in situ ecological technology and alternative to traditional constructed wetlands (CWs), have been widely used due to reduced land use, lower investment cost, better maneuverability, and higher purification efficiency (Sun et al, 2021). By growth of aquatic plants on floating mats, FTWs capture nutrients and transform common pollutants into harmless byproducts through their plant root system and associated microbial communities in biofilms and zooplankton (Chang et al, 2017; Nsenga Kumwimba et al, 2021).…”