Joint Utility Board Sewage Treatment Plant: History, Treatment Process, and Performance Overview Presentation for: Public Viewing By: Clay Reitsma, M.Eng., P.Eng. Senior Manager, Engineering District of North Cowichan January 15, 2019 1
Presentation Outline • Site/Facility History • CVRD Central Sector Liquid Waste Management Plan (CSLWMP) • JUB Administration • Treatment Process Description • Performance of Treatment Facility • Questions 2
History • Jan 1961: Duncan constructed three6cell lagoon on Cowichan Tribes Reserve lands with outfall to Cowichan River. • Jan 1968: District of North Cowichan (DNC) constructed two6cell lagoon beside Duncan lagoon, on Cowichan Tribes Reserve lands, with separate outfall to Cowichan River. • Jan 1974: Surface aerators installed in Cell #1 and Cell #4. • Jul 1978: Duncan and DNC lagoons combined into a single plant with one new outfall to river. Joint Utility Board (JUB) formed. – The JUB Sewage Treatment Plant (STP) is run jointly by Duncan and DNC. 3
History • Oct 1979: Single permit PE61497 issued for joint operation. • Mar 1993: Cell #1 was dredged. • Dec 1993: New aerators added to Cell #2. • Jul 1998: Interim Lease Agreement signed. – Between Duncan, DNC, Cowichan Tribes and Tribes’ Certificate of Possession Holders. – 20 yr term (commenced Jul 1, 1996). 4
History • May 11, 2000: Ministry of Environment approved CVRD CSLWMP. • May 2000: Major upgrade to treatment system ($4,500,000): – new fine bubble aeration system – two 175 kW blowers – new screens and degritting facility – raised all berms – Cell #1 dredged 5
History • Dec 2001: JUB STP Capital and Operating Agreement signed: – Between Duncan, DNC, Cowichan Tribes and CVRD. • May/Jul 2002: CVRD CSLWMP amended: – Cowichan Bay sewer connected to lagoons. – Options other than water reclamation to be considered in order to reduce effluent phosphorus load to Cowichan River. • Oct 2002: Alum system installed to reduce phosphorus load to Cowichan River ($300,000). • Nov 2004: Cowichan Bay sewer system connected to JUB STP. Cowichan Bay STP (@ Hecate Park) decommissioned. 6
History • Aug 1, 2011: New lease agreement signed. – Lease between DNC/Duncan (the JUB) and Cowichan Tribes. – Lease is for the use of the land where the JUB STP resides. – Lease agreement is for 49 years with an option to renew. – Includes a commitment make reasonable effort to remove the JUB STP outfall from the Cowichan River in 10 years (by 2021). • 2010: Log jam/gravel removal at outfall pipe. – Removed large log jam/gravel deposit and installed erosion protection armouring and training spur ($880,000). • 2011/2012: JUB Dike constructed. – 900 m of diking constructed around JUB STP to protect it and Duncan/Reserve lands from flooding ($2,500,000). 7
History • Nov 2013: Capacity review undertaken. – Capacity of the plant increased by 25% (capacity based on Equivalent Residential Units or ERUs). – ERUs allocated to jurisdictions using the facility in proportion to their current ERU share. • 2016/2017: Upgraded screening and disinfection systems. – Upgraded to a finer screening system. – Removed gaseous chlorine/sulpher dioxide gas systems with liquid chlorine and sodium metabisulfite systems. – Installed new valve and flowmeter in outfall pipe. – Total cost: $920,000. 8
CVRD Central Sector LWMP • High level plan for the management of sewage in the core urban area of the Cowichan Valley. • Approved by the Minister of Environment on May 11, 2000. – Stage 1 completed Oct 1995. – Stage 2 completed Nov 1998. – Stage 3 completed May 2000. – Amendment #1 (2001): Connect Cowichan Bay sanitary sewer system to to the JUB STP. – Amendment #2 (2001): Allow for options other than water reclamation to reduce the JUB STP effluent phosphorus load to the Cowichan River. – Amendment #3 (2015; Approval Pending): Relocate the JUB STP outfall from the Cowichan River to Satellite Channel. 9
CVRD Central Sector LWMP • The Plan has three main goals: – To protect human health and the environment through the provision of appropriate liquid waste treatment facilities. – Reduce the liquid waste stream in accordance with reduce, reuse, and recycle. • The Plan recommends the following general actions: – Enact source control programs (bylaw/education). – Enact volume reduction programs (inflow and infiltration repairs, water conservation, education). In progress. 10
CVRD Central Sector LWMP • JUB STP – Reduce phosphorus discharge to River. Done. – Sample and monitor Cowichan River water annually upstream and downstream of the discharge. Done. – Develop Biosolids Management Plan. • Cowichan Bay System – Connect to JUB STP and decommission Cowichan Bay STP. Done. • Maple Bay Servicing – Plan for future provision of collection sewers within Maple Bay pumped to Maple Bay Road sewer system. Partly done; new STP in Maple Bay. 11
CVRD Central Sector LWMP • Rural Area Servicing – Protect rural areas from urban type development. – Assess problem septic areas. – CVRD to develop brochure for on6site sewage system management. – The CVRD to plan to accept boat pump out discharges at Cowichan Bay wharf. Done. • New Treatment Plant and Outfall (Long Term) – Investigate sites for a new STP to service 70,000 people. Existing plant currently serves about 26,000 people. Done. – Investigate outfall routing options for the removal of the Cowichan River discharge and for a new discharge to Satellite Channel. In progress. – Undertake a public education and consultation process to support the treatment plant site selection and outfall study work. Outfall in progress. 12
JUB Adminstration • What is the Joint Utility Board? – DNC and Duncan are co6owners of the JUB STP. – Board members from DNC and Duncan Councils (2 members each). Chair position rotates annually. – Board oversees the management of the JUB STP. – Board recommendations referred to DNC and Duncan Councils for approval. – CVRD Area D, CVRD Area E, and Cowichan Tribes are users of the facility and send non6voting members to the Board meetings. Their input at meetings is considered by the Board. 13
JUB Administration • How are things paid for? – JUB STP capacity is expressed in Equivalent Residential Units (ERUs). – ERUs have been allocated to each jurisdiction using the facility. – Capital projects funded based on ERUs owned. – Operation funded based on ERUs connected. – 12,762 ERUs of 17,300 ERUs of capacity being used as of Dec 31, 2017. 14
JUB Administration 15
JUB Administration 16
The Treatment Process 17
Substances the Lagoons are Designed to Treat Wastewater (NOT Storm Water) Stormwater should NEVER be directed to a wastewater treatment plant. Organics (Carbonaceous Biochemical Oxygen Demand 6 CBOD5) Organics can reduce dissolved oxygen concentrations in rivers, stressing fish. Total Suspended Solids (TSS) TSS can clog spawning beds. Total phosphorus (TP) TP can causes excessive algae growth in rivers, reducing dissolved oxygen concentrations, stressing fish. Bacteria and Viruses (Indicator Organism is Fecal Coliforms 6 FC) Bacteria/viruses can cause health issues in recreational waters and can render shellfish inedible. 18
Treatment Flow Path Cell 1 Cell 2 Cell 5B Cell 5A Cell 6 Cell 4 Cell 3 19
Treatment Unit Processes The treatment system has many different components that work together to treat the wastewater. They include: Screening Removes larger inorganic material (plastics, rocks). Degritting Removes heavier/finer inorganic material (sand). Oxidation Converts organics to micro6organisms for subsequent removal by sedimentation. Settling Settles out micro6organisms. Alum Addition Removes phosphorus. Chlorination Kills bacteria and viruses in the process water. De6Chlorination Removes residual chlorine byproducts from the effluent prior to discharge to the river. 20
Treatment Unit Processes Screening & Degritting De- Cell 1 Chlorination Oxidatio n Cell 2 Cell 5B Oxidation Cell 5A / Settling Disinfectio n Cell 6 Settlin g Cell 4 Cell 3 Settlin g Alum Addition 21
Treatment Unit Processes: Screening Removes larger inorganic material (plastics, rocks). • Fine perforated plate screen screens out larger inorganic material. • Screened wastewater passes through to the degritting process. • Captured solids (screenings) are washed, pressed/dewatered, and conveyed into a covered holding container. • A fan draws odourous air from the system and scrubs it through a biofilter. 22
Treatment Unit Processes: Degritting Removes heavier/finer inorganic material (sand). • Total of four grit channels. • Flow velocity is maintained at 1 ft/sec to allow heavier/finer inorganics to settle. • Grit is removed from the channels monthly and deposited into Cell 6. 23
Treatment Unit Processes: Biological Oxidation (Cell 1) Converts organics to micro6organisms. Cell 1 Cell 2 Cell 5A/5B Cell 2 Cell 1 Cell 3 Cell 4 • Wastewater flows from the grit channels to Cell 1. • Purpose is to convert organic matter (which exerts an oxygen demand in receiving waters) to micro6organisms (which will settle in subsequent ponds). • By settling out the micro6organisms in subsequent cells, the organic matter is removed from the liquid. 24
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