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• An MBBR20 was installed at EdgmondRoad, treating wastewater to a standard of less than 30 mg/l suspended solids, 3 mg/l ammonia and 15 mg/l biological oxygen demand (BOD).
• At Lower Penn, a D25 lamella clarifier was installed, and the effluent water was treated to meet a discharge consent of less than 45 mg/l suspended solids, 15 mg/l ammonia and 20 mg/l BOD.
• At Swinford, a D10 lamella clarifier was installed, and the effluent water was treated to meet a discharge consent of less than 25 mg/l suspended solids, 19 mg/l ammonia and 15 mg/lBOD
Paul Cree,Technical Sales Engineer at SPS, explainswhy these levels were so critical:“Itwas important to meet these exacting standards as both ammonia and highBODlevels are toxic to aquatic life. In the case ofBOD, the oxygen that is available in the water is being consumed by bacteria. If theBODgets too high, dissolved oxygen levels in the receiving water can decrease to dangerously lowlevels, threatening fish and other aquatic organisms. You also need to control the levels of suspended solids discharged, as they cause turbidity in awaterway,making it less transparent by blocking
sunlight.This can limit or prohibit the growth of algae and rooted aquatic plants. In rivers, gravel beds blanketed with suspended solids can inhibit or prevent the spawning of fish.” SPS also supplied a systemto treat sewage waters at SevernTrent Water’sAshby Folville site, providing a temporary solution while capital maintenance refurbishmentwas carried out byMWHTreatment on the trickling filters.AnMBBR20 and MBBR30were installed in parallel; a systemdesigned with a flowspit of 70:30 respectively, to treat the ammonia concentration in the water to less than 10 mg/l. The refurbishmentwork carried out by Nomenca, of humus tank scraper bridges at SevernTrent’s Barrowand Quorn sitewas supported by SPS through the installation of threeHB50Mlamella clarifiers, fed fromMT8 distribution tanks.
Lastly, the company provided a temporary treatment solution at SevernTrent’sCosford site. It was tasked with handling potable water containing suspended solids, all during the replacement of filter media, byMWHTreatment, on the existing wastewaterworks. One of the main substances of concern in the effluentwas manganese, which was treated by SPS’HB50MandMT8 tank to belowthe consent limit of 50mg/l. Andy Guy, ProjectManager atMWHTreatment, says:“Working alongside Siltbuster and sharing knowledge allowed these temporary treatment solutions to bewell planned and installed in a timely manner, ahead of several process critical refurbishment projects. Siltbuster’s modular systems have proven to be convenient, effective and excellent providers of site resilience.” Cree concludes:“The breadth of SevernTrentWater siteswe’ve supported during this complex programmeofworks, demonstrates the sheer versatility of our systems, the high standards they operate to and the critical role they can play in keeping sites compliant during maintenance and refurbishment. ”
Major role for wastewater epidemiology in tackling Covid-19
Wastewater-based epidemiology (WBE) has a significant part to play in identifying ‘silent’ Covid-19 cases in the community, research presented at the latest Water Action Platform webinar demonstrates. The regular webinars, which are open to all, are hosted by Isle chairman Dr Piers Clark and look at the new coronavirus and global pandemic through a water industry lens. Insights fromacademia and the experiences of utilities around the world are shared, along with expert analysis providing insight into broader developments in science and technology bringing change in theworld ofwater
andwastewater.Here is a round-up of learnings fromthe fifteenthWaterAction Platformwebinar, which took place on 23 July.
Webinar 15: Six key learnings
1. Virus found in Brazilian sewage months before first reported case Recent research fromthe Federal University of SantaCatalina in Brazil adds to the body of evidence thatwastewater has a role to play in identifying presymptomatic or asymptomatic cases ofCovid-19 in the community.Apreprint (not yet peer-reviewed) academic paper identifies the presence of the virus in two separate samples taken in state capital Florianópolis on 27November 2019 - two-and-a-half
30 drain TRADER | September 2020 |
www.draintraderltd.com
months before the first case was reported in the area - and in subsequent samples up untilMarch
2020.The research also shows the relationship between ribonucleic acid (RNA) detected in sewage and the scale of the outbreak.Water utilities around theworld are revisiting stored wastewater samples to help identify when the severe acute respiratory syndrome-related coronavirus (SARS-CoV-2) first appeared.
2.Wastewater epidemiology has major role in identifying‘silent’ cases The latest research showing the risk posed by“silent transmission”of Covid-19 fromasymptomatic and presymptomatic infections also helps make the case forWBE. Anacademic paper fromfour universities inCanada and the USA, featured on theWaterAction Platform, demonstrates that themajority ofCovid-19 infectionsmay be attributable to silent transmission from presymptomatic and asymptomatic cases. Presymptomatic stage and asymptomatic infections together account for over50%of
transmission.Consequently, even immediate isolation of all symptomatic cases is insufficient to achieve control. Symptom-based isolation needs to be supplemented by testing that identifies asymptomatic and presymptomatic cases to control the
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