2013 Technical Session 19 - Wastewater Issues III

Tuesday, April 23, 1:55 - 5:00 pm, Columbia Room


Moderator: John Koch, HDR Engineering, Inc.

 

 
19.1 Discharge Compliance for Nutrients, Dissolved Metals and Other Anions

19.2 Lagoons Effluent Toxicity - When Meeting Your License Effluent Quality Isn't Enough

19.3 Reclaimed Water – Alternate Water Source to Meet Industrial and Other Non-Potable Demands

19.4 Removal of Contaminants of Emerging Concern in Sewage Lagoons

19.5 UV Disinfection for a Municipal Wastewater Lagoon Effluent – No Prior Filtration Needed?


Wastewater Issues III | 1:55 pm - 2:25 pm
19.1 Discharge Compliance for Nutrients, Dissolved Metals and Other Anions
Presenter: Karen McHale, Blue Water Technologies, Inc., Hayden, Idaho



Water discharge permitting requirements detailing metals, nutrients and other dissolved cation and anion levels for sewage and industrial dischargers continue to be a focus in the industry. A survey of the available technologies proposed for phosphorus and nitrogen removal as well as installations currently meeting these limits are particularly worthy of review. Phosphorus levels can vary significantly from region to region, but many provinces are considering limits below 0.1 mg/L, with Ontario considering future limits below 0.05 mg/L. These limits seemed difficult to meet 10 or 20 years ago, but presently they are being met cost effectively in several installations. Continuous backwash upflow sand filters are a convenient end-of-pipe technology for absorption of constituents including arsenic, selenium, zinc, cadmium, chromium, mercury, and many others. Additional design considerations can integrate biological remediation processes into the sand filters for conversion and removal of nitrates. Readily available alternative carbon sources, which alleviate explosion hazard design in all environments, join methanol as legitimate process options to achieving even the most stringent effluent nitrate requirements. Continuous backwash filters have the advantageous capability of facilitating simultaneous denitrification and adsorptive removal of dissolved constituents within the same unit process and vessel. Case history, design considerations and lessons learned from implementation of this technology will reveal the cost/benefit for water treatment methodology.

Presentation PDF
 


Wastewater Issues III | 2:30 pm - 3:00 pm
19.2 Lagoons Effluent Toxicity - When Meeting Your License Effluent Quality Isn't Enough
Presenter: Martin Hildebrand, P.Eng., Nelson Environmental Inc., Winnipeg, MB



Typically, lagoon systems across Canada have been designed to meet BOD and TSS limits but are not designed to produce non-toxic effluent throughout the year. Due to changes in federal requirements many lagoons are now required to address effluent toxicity. It is a poorly understood parameter, as many discharge licenses issued by provinces do not have explicit toxicity limits. Many lagoon facilities unknowingly exceed allowable federal toxicity requirements. The first indication of toxicity is fish kill in the receiving stream. With knowledge of the effects that ammonia concentrations, pH and temperatures have on lagoon effluent toxicity, operators can determine if they are releasing effluent that would fail a toxicity test and determine what upgrades, if any, are required to produce non-toxic effluent. Toxicity was taken into account when designing the upgraded wastewater treatment lagoon system for Glencoe, ON. The existing controlled discharge lagoon system, comprised of two facultative lagoons with twice a year discharge, was operating at maximum capacity. The process was converted from seasonal to continuous discharge to increase capacity. This required that the effluent be non-toxic on a year round basis. One of the existing facultative lagoon cells was divided into three cells and aerated. A submerged attached growth reactor (SAGR) system was added to provide nitrification, in order to meet effluent ammonia and toxicity requirements. Previous demonstration sites in Lloydminster SK, and Steinbach, MB have shown the ability of the system to consistently meet the target ammonia and BOD effluent levels following an aerated lagoon. 
1. Treatment systems must meet federal toxicity requirements in addition to provincial license requirements.
2. Existing lagoon systems often require upgrades to consistently pass toxicity test.
3. The SAGR is proven to be effective at reducing lagoon effluent ammonia and subsequently reducing toxicity.

Presentation PDF
 


Wastewater Issues III | 3:05 pm - 3:35 pm
19.3 Reclaimed Water – Alternate Water Source to Meet Industrial and Other Non-Potable Demands
Presenter: Adam Greenwood Greenwood, E.I.T., Urban Systems Ltd., Fort St. John, BC
Additional Contributors: John Kalinczuk, Ctech, Water Resource Manager, City of Dawson Creek



Northeast BC is the cornerstone for oil and gas activity in BC. In recent years, hydraulic fracturing, aka fracking, has increased the extraction of natural gas in the Peace Region, most notably the Montney Formation. For the Montney Formation, the BC Oil and Gas Commission forecasts that the water demands for fracking may reach 14 million m3/year, which is in addition to the existing agricultural, construction and rural/urban water demands. The City of Dawson Creek’s water source for potable and non-potable uses, the Kiskatinaw River, is prone to drought conditions and saw some of the lowest water levels on record in recent years. Rather than cut off water supplied to industry, the City explored ways to improve water use/management practices within their watershed. Now, six years in the making, the City, in partnership with Shell Canada, produces 4,000 m3/day of reclaimed water for industrial use. In this presentation, we will provide a brief history of the process that was undertaken to develop the first reclaimed water facility of its kind in a northern climate. We will then review the unique application of the different treatment technologies, including submerged attached growth reactors (SAGR), coagulation/flocculation and 10 micron disk filtration, from a design and operational perspective that was required to make this project a reality. We will also provide some insight into the future of reclaimed water in northeast BC.

Presentation PDF
 


Wastewater Issues III | 3:55 pm - 4:25 pm
19.4 Removal of Contaminants of Emerging Concern in Sewage Lagoons
Presenter: Craig Murray, M.Sc. Hydrology, Institute for Watershed Science, Trent University, Peterborough, ON
Additional Contributors: Chris Metcalfe, Ph.D., Professor, Environmental and Resource Sciences Programme, Director, Institute for Watershed Science, Trent University, Peterborough, ON; Md. Ehsanul Hoque, Ph.D., Postdoctoral Fellow, Worsfold Water Quality Centre, Trent University, Peterborough, ON



Many contaminants of emerging concern, including pharmaceuticals, personal care products (PPCPs) and endocrine disrupting chemicals, enter the environment through discharges from wastewater treatment plants (WWTPs). In small municipalities, sewage lagoons are often the only systems used to treat wastewater. We are evaluating whether sewage lagoons serving small municipalities in Ontario are effective at removing these contaminants. The sewage lagoon serving the village of Lakefield in Ontario was monitored to determine removals of selected PPCPs and a natural estrogen (i.e. estrone) by deploying passive samplers at three points in the lagoon. The highest concentration of a pharmaceutical was for ibuprofen in untreated wastewater during the fall monitoring period (i.e. 60 ng/L). Similarly, concentrations of three personal care products (triclosan, HHCB and AHTN) were highest during fall season, at 30, 1677 and 109 ng/L respectively. Removals were generally highest in the summer (i.e. >70%) relative to removals in the fall and winter. The concentrations of gemfibrozil increased in the wastewater as it passed through the sewage lagoon, which was attributed to de-conjugation of metabolites, and carbamazepine was persistent in the lagoon. This small sewage lagoon was as effective at removing PPCPs as many conventional WWTPs. We are continuing to monitor removals of these contaminants in the Lakefield lagoon and in two other sewage lagoons operating in small municipalities in Ontario.

Presentation PDF
 


Wastewater Issues III | 4:30 pm - 5:00 pm
19.5 UV Disinfection for a Municipal Wastewater Lagoon Effluent – No Prior Filtration Needed?
Presenter: Wayne Wong, M.A.Sc., P.Eng., Kerr Wood Leidal Associates Ltd., Burnaby, BC
Additional Contributors: Irfan Gehlen, P.Eng., Kerr Wood Leidal Associates Ltd., Burnaby, BC


This paper discusses the design of a UV disinfection system for the effluent from Fort Nelson’s municipal wastewater lagoon treatment plant, where the system was designed in such a way that a filter was not needed upstream of the UV disinfection process. Ultraviolet (UV) disinfection is an established technology to achieve disinfection and is advantageous in that it eliminates the need for chemical handling typically required in a chlorination/dechlorination system. UV disinfection also eliminates the risk of releasing residual chlorine to the receiving environment compared to a chlorination/dechlorination system. UV disinfection at the back end of a municipal wastewater lagoon system has been implemented in the past, but because lagoon systems generally produce a lower effluent quality compared to secondary or tertiary effluent, filtration is typically introduced upstream of the UV disinfection system to reduce the total suspended solids and increase the UV transmissivity in the lagoon effluent prior to disinfection. Disinfection by UV without filtration is an unconventional approach but can significantly simplify disinfection process requirements, and reduce both capital and O&M costs. In the design of the UV disinfection system for the Fort Nelson Wastewater Treatment Plant, comprehensive monitoring of the wastewater effluent was conducted during the conceptual and pre-design stages of the project to establish the design criteria for the UV disinfection system and confirm whether filtration could be eliminated. The monitoring program was instrumental in establishing that UV disinfection could reduce fecal coliforms to meet regulatory requirements without requiring filtration upstream of the UV system.

Presentation PDF



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