Advanced Wastewater Treatment Plant Plant Profile

Transcription

1 Advanced Wastewater Treatment Plant Plant Profile 2008

2 Brief History Wastewater treatment started in Penticton in 1948 with a Package Primary / Secondary plant at what is now the Alberni Lift Station. The existing plant location has had a Secondary Activated Sludge Treatment Plant since 1960, with a design capacity of 5.5 ML/d. In 1970, the plant capacity was increased to 8.2 ML/d with construction of additional primary and secondary clarifiers, plus chemical coagulation facilities for phosphorus removal. Between , a number of improvements and increases to the plant's treatment capacity were made to cope with increasing wastewater flows and loads. In 1985 the BC Waste Management Branch prepared a report which reviewed the requirements for discharge of municipal effluents to the Okanagan Lake system. It was determined continued surface discharge of treated effluent to Okanagan Lake, Okanagan River and Skaha Lake would be possible, provided advanced tertiary treatment was implemented to ensure high quality effluent. The report recognized that land application proposals would also require advanced tertiary treatment. Stanley & Associates Engineering Ltd. completed a Liquid Waste Management Plan for the City in 1987, and was subsequently commissioned by the City to provide design, construction management and plant commissioning services for a new Advanced Wastewater Treatment Plant (AWWTP). The new and expanded AWWTP, with biological nutrient removal, was constructed and commissioned in the fall of The plant is designed to treat 18.2 ML/d with a hydraulic capacity of 36.2 ML. After the plant was commissioned, an optimization study was conducted on the Bio reactor that showed a capacity up to 28.0 ML/day is available for the Bioreactor. The BC Ministry of Environment paid for 75 percent of the cost of the new facility through the Okanagan Water Quality Control Project. Original Plant Circa 1958 Located on Alberni Ave.

3 Collection System The wastewater collection system has eleven pumping stations. Two of these are larger in size using 50 and 60 horsepower pumps while the remaining are 3 to 5 horsepower. One larger station is located at the south end of the city using two water-cooled submersible pumps with a stand-by power plant. The other larger station located at the north end of the city has three submersible pumps with a stand-by power plant. New Alberni St. Lift Station Installation The Plant In 2007 the Advanced Wastewater Treatment Plant (AWWTP) received 4,950 Million Litres (ML) of influent from the sanitary sewer system. Compared to 2006 s influent flow of 5,061 ML. This decrease in flow may be the result of the Cities initiative in water conservation. The 2007 average daily influent flow rate was 13.6 ML/day. The average influent flow rate per person was 399 litres/day/person, based on the 2007 Penticton population estimate of 34,002 people (from BC Stats)

4 Treatment Plant Goals & Objectives completed for 2007 included Liquid Waste Management Plan completed and signed off by the Minister of Environment. Completed the Request for Qualifications (RFQ) process to select a qualified consultant to start design work for AWWTP upgrade. Earth Tech and Stantec were chosen. Completed the Request for Proposal process for Preliminary Design, Detail Design and Construction Management work for AWWTP upgrades. Earth Tech was chosen. Started Functional Pre-Design with Earth Tech, to be completed February Preliminary Design, Detail Design and Tendering of the Septage Receiving Facility completed. A three year training plan for staff is in it s third year and continues to promote the development and retention of staff. 100% of staff completed the 2.4 C.E.U. s necessary to retain EOCP certification. Construction of a chemical dosing facility completed at Lakeside North Lift Station, to correct an ongoing odour problem for residents of Lakeside Rd. 9 out of 10 capital upgrade projects planned this year were completed Creation of a Foreman s position and one added Operator III position were put in place to improve the staff structure for the AWWTP and to help attract and retain staff. Methane Gas Boiler replacement completed as part of the equipment replacement capital fund. Treatment Plant Goals & Objectives planned for 2008 Preliminary Design and Detailed Design for the AWWTP plant expansion. Continue with the annual equipment upgrading program that is set out in the budget, which is designed to maintain reliable and efficient operation of the AWWTP. Construction of a septage receiving facility at the AWWTP. Preliminary Design, Detailed Design and Construction of a new effluent line to south end of Penticton that will be used to expand the effluent irrigation system and effluent disposal in the busy summer months. Monitor dilution ratio s into Okanagan River Channel daily. Continue to introduce new technology into the treatment systems which will then help to produce safe waters. Support the direction from council for the sewer connection of the Penticton Indian Band areas into the WWTP. Maintain a full complement of staff to help support operation activities during the year in which larger capital projects are proposed. Finalize the operational certificate as part of the AWWTP upgrade. Meet the divisional performance measures that are set for the WWTP.

5 Headwork s and Primary Treatment Headwork s & Primary treatment consists of the following: three Archimedes screw pumps, mechanical bar screen, Pista degritter, six rectangular primary clarifiers, two flow equalization basins and two sludge fermenters to supplement the phosphorous removal process. The existing digesters from the old activated sludge process are now used for primary sludge digesting and some secondary sludge (RAS) digesting. Primary Tanks with Odor Control Covers Secondary and Tertiary Treatment Secondary & Tertiary treatment consists of biological phosphorous and nitrogen removal, based on the modified University of Cape Town (UCT) process. This is followed by two secondary clarifiers, plus three low head sand media filters with automatic backwash. Bioreactors

6 Disinfection Method Chlorination consists of three chlorine contact tanks followed by de-chlorination with Sulphur Dioxide. Chlorine Contact Tanks Sludge Conditioning and Composting Consists of the primary sludge being fermented, and then treated by anaerobic digesters. The methane gas produced by the digesters is used for plant buildings and sludge process heating. Mixed Liquor Suspended Solids (MLSS) is thickened in a settling tank (2% solids), gravity belt thickened(6%), belt filter press dewatered (13%) and then composted at our compost site at the landfill. Composting is by static pile aeration method, which produces a Class A compost. This conditioning / fertilizing product is recycled to City Parks, landscapers, the public and orchardists for agriculture use.

7 Gravity Belt Thickener/Belt Filter Press Effluent Irrigation System The treated effluent can be stored in two emergency on-site 36,000 m3 storage basins for re-use. Irrigating with the effluent is done by three 60 hp 8 stage vertical turbine pumps. Maximum pumping capacity is approximately 100 l/sec. In ML went out for Irrigation, accounting for 12.2% of the total plant flow. The city currently irrigates the Penticton Golf and Country Club (29.1 hectares) and King s Park (5.1 hectares). Kings Park

8 River Outfall In 2007 the AWWTP discharged 4,415 Million Litres (ML) of effluent to the Okanagan river channel. The AWWTP average effluent discharge flow to the Okanagan river channel in 2007 was 12.1 ML/day, compared to an average effluent discharge flow to the Okanagan river channel of 10.8 ML/day in Okanagan River Outfall Plant Staffing The plant staff includes one (1) Wastewater Foreman, two (2) Wastewater Operator III s, one (1) Wastewater Operator II, two (2) Wastewater Operator I s, one (1) Okanagan University Water Quality Student, one (1) Millwright, one (1) Electrician, and the Wastewater Treatment Supervisor. Odour Control Systems Three types of systems control plant odours. Odours are removed from the concrete covered fermenters, the fabric covered primary / equalization tanks by a positive displacement blower discharging into the bioreactor aeration system. Digester hoppers and degrit building have odours removed by activated carbon canisters systems. The Headwork s area has a Sol-Air odour control unit which utilizes Ultraviolet light to neutralize odorous gases. Process Control The Supervisory Control and Data Acquisition (SCADA) system consist of Wonderware software, controlled through Modicon programmable logic controllers. Alarms at the plant and lift station communicate through a wireless modem system.

9 Effluent Quality The treated effluent has less than 0.2 mg/l total phosphorous, less than 5 mg/l BOD and TSS, less than 1.0 mg/l ammonia as nitrogen, and fecal coliforms shall not exceed 2.2 MPN per 100mL. This quality of effluent is required to protect and preserve both the highly valued trout and kokanee spawning resource and the recreational value of the Okanagan river channel. Effluent Sample 2007 Completed Projects The following repairs and replacement took place in 2007 for the Advanced Wastewater Treatment Plant: Primary Tank #4 rebuilt ($8,359) Primary Tank #5 rebuilt ($8,359) Sludge conveyor relining ($2,429) Lakeside North pump rebuilt ($1,988) Wilson St. pump rebuilt ($1,875) Staff Innovations for 2007 Installed washer and dryer to clean uniforms resulting in a $3,000-$4,000 / year savings over outsourcing of laundering. Restructuring of the AWWTP staff, which included a new Foreman s position to define a clearer hierarchy was put in place in October and has worked well. In

10 addition to aiding with attraction and retention, it also created two Operator III positions. Two new Suspended Solids meters were purchased and installed on the Bio-reactor, to help reduce the daily lab routine. These meters have also helped operations understand what happens with solids throughout the day and night, as our grab samples in the past were always taken at the same time. BCWWA conference in Penticton with two staff members competing in Top Op s challenge. Confined space entry/rescue, Hazard Identification/Risk Assessment and Chlorine leak response training by STC Consulting (Kelly Kaye). Two day course attended by all WWTP staff. Chlorine Leak Response Training Conversion of a slide gate in the Chlorine Contact tank to an overflow gate was envisioned and completed in house saving the purchase of a new gate. Methane gas scrubber was designed by staff while viewing a similar scrubber in another WWTP. This has allowed boiler cleaning intervals to increase by 300%.

11 Purchase of a utility vehicle to allow staff to clean storage ponds safely and efficiently, has allowed the City to ensure that if required the storage ponds will perform as intended. Cleaning of Emergency Storage Ponds Planned Projects for 2008 The Wastewater Treatment Plant has $90, (Capital) budgeted this year for equipment repair/replacement. The following projects are scheduled: Screens building roof replacement Replace Moyno pump press Replace one set of gas detectors Purchase one set of primary chains Replace primary tank odour tarp Replace sludge conveyor gear box Replace safety equipment Tie in Digester to SCADA $15,000 $16,000 $5,000 $12,000 $2,000 $2,500 $5,000 $20,000 For more information contact: Berne Udala, Wastewater Quality Supervisor berne.udala@penticton.ca