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Hokkaido, Japan

Sharma P.K.,Hokkaido University | Takashi I.,Hokkaido University | Kato K.,Japan National Agricultural Research Center | Ietsugu H.,TUSK Co. | And 2 more authors.
Ecological Engineering | Year: 2013

This paper presents the effects of seasonal variations on the purification and removal efficiencies of a hybrid sub-surface CW system (VF-VF-HF) treating milking parlor wastewater at northern Hokkaido, Japan. VF(a) and VF(b) are gravel beds, each 160m2 in size whereas HF is sand bed and 336m2 in size. Daily mean air temperature at site showed a difference of 16°C between warm (May-October) and cold (November-April) periods. Average influent concentrations for cold and warm periods were: CODCr: 3749 and 4988mgL-1; BOD5: 1637 and 1395mgL-1; TSS: 661 and 862mgL-1; TN: 161 and 194mgL-1; TP: 23.9 and 31.9mgL-1 and total carbon: 1212 and 1715mgL-1. Average purification rates of BOD5, TSS, TP, PO4-P and total carbon fluctuated <2.5% between both periods. However purification rates of NH4-N and Organic-P decreased by 9.5% and 12% respectively during warm period. Average removal rates of TSS and BOD5 were unaffected between both periods, while that of CODCr, TN, total carbon increased by 3-4% during warm period. Hybrid sub-surface CW system achieved purification and removal rates of >95% for TSS and total coliform; >89% for CODCr and BOD5; >76% for TN and >72% for TP during both cold and warm periods. © 2012 Elsevier B.V.. Source


Zhang X.,Hokkaido University | Inoue T.,Hokkaido University | Kato K.,Japan National Agriculture and Food Research Organization | Harada J.,Hokkaido University | And 5 more authors.
Water Science and Technology | Year: 2016

The objective of this study was to evaluate performance of a hybrid constructed wetland (CW) built for high organic content piggery wastewater treatment in a cold region. The system consists of four vertical and one horizontal flow subsurface CWs. The wetland was built in 2009 and water quality was monitored from the outset. Average purification efficiency of this system was 95 ± 5, 91 ± 7, 89 ± 8, 70 ± 10, 84 ± 15, 90 ± 6, 99 ± 2, and 93 ± 16% for biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total carbon (TC), total nitrogen (TN), ammonium-N (NH4-N), total phosphorus (TP), total coliform (T. Coliform), and suspended solids (SS), respectively during August 2010-December 2013. Pollutant removal rate was 15 ± 18 g m-2 d-1, 49 ± 52 g m-2 d-1, 6 ± 4 g m-2d-1, 7 ± 5 g m-2 d-1, and 1 ± 1 g m-2 d-1 for BOD5, COD, TN, NH4-N, and TP, respectively. The removal efficiency of BOD5, COD, NH4-N, and SS improved yearly since the start of operation. With respect to removal of TN and TP, efficiency improved in the first three years but slightly declined in the fourth year. The system performed well during both warm and cold periods, but was more efficient in the warm period. The nitrate increase may be attributed to a low C/N ratio, due to limited availability of carbon required for denitrification. © IWA Publishing 2016. Source


Harada J.,Hokkaido University | Inoue T.,Hokkaido University | Kato K.,Japan National Agriculture and Food Research Organization | Izumoto H.,Hokkaido University | And 5 more authors.
Water Science and Technology | Year: 2016

This study evaluated the nitrogen compound removal efficiency of a hybrid subsurface constructed wetland, which began treating milking parlor wastewater in Hokkaido, northern Japan, in 2006. The wetland's overall removal rates of total nitrogen (TN) and ammonium (NH4 +-N) improved after the second year of operation, and its rate of organic nitrogen (Org-N) removal was stable at 90% efficiency. Only nitrate (NO3 --N) levels were increased following the treatment. Despite increased NO3 --N (maximum of 3 mg-N/L) levels, TN removal rates were only slightly affected. Removal rates of TN and Org-N were highest in the first vertical bed. NH4 +-N removal rates were highest in the second vertical bed, presumably due to water recirculation and pH adjustment. Concentrations of NO3 --N appeared when total carbon (TC) levels were low, which suggests that low TC prevented complete denitrification in the second vertical bed and the final horizontal bed. In practice, the beds removed more nitrogen than the amount theoretically removed by denitrification, as calculated by the amount of carbon removed from the system. This carbon-nitrogen imbalance may be due to other nitrogen transformation mechanisms, which require less carbon. © IWA Publishing 2016. Source


Sharma P.K.,Hokkaido University | Sharma P.K.,Graphic Era University | Takashi I.,Hokkaido University | Kato K.,Japan National Agricultural Research Center | And 3 more authors.
Ecological Engineering | Year: 2013

A hybrid sub-surface constructed wetland (CW) system consisting of 2 gravel filled vertical sub-surface (VFa & VFb) beds, each 160 m2 in size planted with Phragmites australis and a sand filled horizontal sub-surface (HF) bed, 336 m2 in size, planted with rice was operated from 2007 to 2010 for treating milking parlor waste water in Hokkaido, Japan. Hybrid CW system received huge fluctuations in average yearly inlet loads for TSS (526.0-1259mgL-1 & 2.7-9.0gm-2d-1), BOD5 (1,080-2,114mgL-1 & 8.4-14.4gm-2d-1), COD(1,962-7,085mgL-1 & 14.5-50.0gm-2d-1), TN (116.0-243.0mgL-1 & 0.8-1.6gm-2d-1), NH4-N (54.0-90.0mgL-1 & 0.40-0.64gm-2d-1), TC (1,022-2,215mgL-1 & 6.0-15.1gm-2d-1), TP (15.3-41.7mgL-1 & 0.11-0.28gm-2d-1) during study period. Average yearly purification and removal rates were least fluctuated for TSS (95.7-99.4%); moderately for BOD5 (86.1-95.7%), COD(87.5-96.1%) and TC (79.5-91.3%); highly for TN (72.6-90.6%), NH4-N (62.9-85.3%) and TP (64.8-87.2%). A sharp decrease in TP purification and removal rates were observed in 2008 due to sharp decrease in influent TP concentration in 2008 compared to 2007. OTR values for VF(a), VF(b), HF bed and total system were observed as 21.7, 19.3, 4.8 and 12.3gO2m-2d-1 respectively. Average k value of hybrid CW system for BOD5, TN, NH4-N and TP during study period were 7.0±1.8, 7.4±3.3, 5.6±4.1 and 4.9±2.0myr-1 respectively.Average concentration of TSS, TP, TN and NH4-N in the final effluent for all years were below the discharge limit value of: 150mgL-1 for TSS; 8mgL-1 for TP, 60mgL-1 for TN and NH4-N. However, average BOD5 and COD concentrations could not meet the discharge limit value of 120mgL-1 during 2007 and 2008. © 2013 Elsevier B.V. Source


Zhang X.,Hokkaido University | Inoue T.,Hokkaido University | Kato K.,Japan National Agriculture and Food Research Organization | Izumoto H.,Hokkaido University | And 5 more authors.
Environmental Technology (United Kingdom) | Year: 2016

This study followed three field-scale hybrid subsurface flow constructed wetland (CW) systems constructed in Hokkaido, northern Japan: piggery O (2009), dairy G (2011), and dairy S (2006). Treatment performance was monitored from the outset of operation for each CW. The ranges of overall purification efficiency for these systems were 70–86%, 40–85%, 71–90%, 91–96%, 94–98%, 84–97%, and 70–97% for total N (TN), NH4-N, total P, chemical oxygen demand (COD), biochemical oxygen demand, suspended solid, and total Coliform, respectively. The hybrid system’s removal rates were highest when influent loads were high. COD removal rates were 46.4 ± 49.2, 94.1 ± 36.6, and 25.1 ± 15.5 g COD m−2 d−1 in piggery O, dairy G, and dairy S, with average influent loads of 50.5 ± 51.5, 98.9 ± 37.1, and 26.9 ± 16.0 g COD m−2 d−1, respectively. The systems had overall COD removal efficiencies of around 90%. TN removal efficiencies were 62 ± 19%, 82 ± 9%, and 82 ± 15% in piggery O, dairy G, and dairy S, respectively. NH4-N removal efficiency was adversely affected by the COD/TN ratio. Results from this study prove that these treatment systems have sustained and positive pollutant removal efficiencies, which were achieved even under extremely cold climate conditions and many years after initial construction. © 2016 Informa UK Limited, trading as Taylor & Francis Group Source

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