Treatment of Storm Water from Agricultural Catchment in Pilot Scale Constructed Wetland

Abstract

Constructed wetlands as a treatment system are widely explored in different climate conditions and established to be effective in pollution removal from water environment. This study aims to demonstrate the performance of pilot-scale subsurface flow constructed wetland for storm water treatment in Latvia. The catchment basin was located in a farmyard of agricultural area and storm water was collected from the impermeable pavements. Storm water was accumulated in an open pond and periodically pumped above the filter part of the subsurface flow constructed wetland. Grab samples were collected once or twice per month at the inlet and outlet of the treatment system during a period of 73 months from year 2014 to 2020. Water quality parameters as nitrate nitrogen (NO3-N), ammonium nitrogen (NH4–N), total nitrogen (TN), orthophosphate phosphorus (PO4-P), and total phosphorus (TP), total suspended solids (TSS), biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) were monitored. Water level at the inlet structure was automatically measured and flow rate was calculated based on the Manning equation for partially filled circular pipes. Results showed the reduction of average concentrations for all parameters during the study period. However, in some sampling cases concentrations increased at the outlet of the treatment system and can be explained by influencing factors of farming and maintenance. The treatment efficiency of NO3-N, NH4-N, TN, PO4-P, TP, TSS, BOD5 and COD concentrations was 17 %, 68 %, 55 %, 78 %, 80 %, 57 %, 80 % and 74 %, respectively. The study site demonstrated a potential to improve water quality in the long term.

Constructed Wetlands for Reclamation and Reuse of Wastewater and Urban Stormwater: A Review

“…In an integrated constructed wetland system fed with runoff from farmyard, the system showed high capability of removal of diverse pollutants including TSS (93.7%), COD (94.9%), BOD 5 (97.6%), ammonia (99%), nitrate (74%) and molybdate reactive phosphorus (91.8%) (Mustafa et al, 2009). Together, a number of studies reported a high percentage removal of key pollutants namely TSS, TN and TP in urban stormwater by CW systems (Choi et al, 2021;Dharmasena et al, 2021;Grinberga et al, 2021). Moreover, the effectiveness of CW systems for the removal of organic pollutants [PAHs, PCBs and emerging contaminants including pharmaceutical and personal care products (PPCPs)] is not fully understood yet which should be investigated in future research.…”

“…Schmitt et al (2015) reported that the stormwater pollutant removal performance of a hybrid CW system consisting of sedimentation pond (SP) and a SFCW was very high, i.e., >90% TSS, 70-98% COD, > 79% TN and >77% TP. In a pilot-scale HSF CW system treating agricultural runoff, the decontamination efficiency of stormwater wetland for various pollutants was very high, i.e., 74% COD, 80% BOD 5 , 57% TSS, 80% TP and 55% TN reduction was noticed (Grinberga et al, 2021). Choi et al (2021) employed a HSF CW system for treatment of runoff from road and parking areas, and the stormwater wetland was effective for removal of various key chemical contaminants namely TSS (71.2%), COD (57.2%), nutrients including TN (~46%) and TP (~55%) (Choi et al, 2021).…”

Bibliometric Analysis and Comprehensive Review of Stormwater Treatment Wetlands: Global Research Trends and Existing Knowledge Gaps

“…The stormwater treatment wetlands monitored by Grinberga et al (2021) showed relatively lower mean pollutant removal efficiencies, ranging from 17% to 80%. It was highlighted that the poor pollutant removal performance of the system can be attributed to the low influent pollutant concentrations caused by stormwater dilution [88]. Some studies also reported negative removal efficiencies or higher outflow concentrations after receiving treatment from stormwater treatment wetlands.…”

Flood Influence Characteristics of Rail Transit Engineering of Tunnel, Viaduct, and Roadbed through Urban Flood Detention Areas

“…Aspects of engineering management: the optimal operation modes of urban detention basins [8] and the use of detention basins for flood mitigation and urban transformation [9]. Related results include: a oneand two-dimensional model is used for the calculation methods of flood influence [10]; an intensity-time-frequency curve of storm models is established for the excess runoff from the Abukuma River [11]; contributions of DOC are studied from surface and ground flow into lakes in Lake Võrtsjärv (Estonia) [12]; and constructed wetlands are used for a flood treatment system in Latvia [13]. In conclusion, most results focus on flood calculation, influence analysis, optimal design, and engineering management of urban detention areas.…”