Saturday, July 23, 2011

Annacis Island Wastewater Treatment plant

Secondary Treatment for metro Vancouver

Tucked away neatly on Annacis Island, metro Vancouver’s largest wastewater treatment plant is overwhelmingly large. The plant build in the 1970s originally only provided primary wastewater treatment. Almost 30 years later, before the turn of the millennium, it was upgraded to secondary treatment. Currently the plant cleans the water of over 1 million people. It received around 350 million liters per day in the summer and around 700 million liters per day in the winter. The plant is primarily cleaning influent from residents.

After the mechanical process of the primary treatment (primarily a physical separation) the water entering Annacis island goes through two secondary wastewater treatment processes. The first one is the trickling filter. This is done in towers filled with rocks. The water is expelled through a stream at the top of the tower, and then the water is allowed to flow through the rocks. From there the water is brought over to activated sludge tanks. Here natural soil bacteria are added to the water and they consume and dissolve organic material and consume whatever is consumable. What is left is called floc and this settles to the bottom of the tank. After this process is completed there are only approximately 4 parts per million (PPM) of total suspended solids making the water exceed the minimum standards of the of the Canadian Council of Ministers of Environment. At the end the water is disinfected by chlorine, removed of the chlorine and then pumped into the Fraser river.

The various sludge and floc remaining from the various processes is thickened and digested over a 20 day period, where it is then made into biosolids. The Annacis Island wastewater treatment plant trucks out 4 trucks full of biosolids every single day. The majority of it is trucked (with costs carried by the plant) in order to reclaimed strip-mines throughout the BC province.

Wednesday, July 13, 2011

Mixing water and oil

I’d seen it before, but that didn’t matter.  The huge gaping holes, the mounds of oily earth, the cutlines breaking up the boreal forest for as far as the eye could see.   Flying over oil sands mining and in situ operations north of Alberta’s Fort McMurray makes one think about the how impacts of our thirst for oil are felt. 

I traveled to Fort McMurray as an Associate with Waterlution, a national non-profit aimed at encouraging dialogue around water issues, at pattern-making and pattern-breaking and at exploring how to have a healthy and sustainable relationship with water.  Waterlution brings together members of industry, First Nations, non-governmental organizations, government and academia to discuss hot water topics in the areas where they’re happening. 

This workshop, “Drilling in the Oil Sands:  Water Usage, Development and Innovation”, took a group of 20 passionate and engaged individuals on a fly-over of open-pit and SAGD operations.  The reactions were varied, but everyone’s eyes were opened.  Throughout the weekend, the group was presented with perspectives from Cenovus Energy, The Pembina Institute, Alberta Environment, the Clearwater Heritage River Society and the Canadian Association of Petroleum Producers. 

The objective of the workshop was to encourage dialogue around some of the major issues associated with water use in the oil sands.  Some of the most prevalent topics of conversation and questions that arose over the three days were:

·      What are the cumulative impacts of in situ operations in northern Alberta?
·      What steps are industry members taking to protect water resources?
·      How is groundwater regulated?  What are the impacts of extracting groundwater and injecting disposal water?

Oil is typically extracted from oil sand in one of two ways: 

1.     Open-pit mining, which mines the oil sand deposits close to the surface by physically removing the processing the sand.  This type of operation results in large pits and often uses freshwater resources from surface waters.
2.     In situ extraction, which removes the oil from below the surface using steam, solvents or some combination of the two.  This type of operation has measurably less impact on the surface and often uses brackish (saline and not suitable for drinking or other industrial uses) water from aquifers.

Both of these types of operations must dispose of wastewater left over from the processing.  Open-pit mines store their waste in tailings ponds.  In situ operations inject their disposal waters back into aquifers. 

The workshop included a tour of Cenovus’ Christina Lake in situ operation to develop an understanding of oil extraction by steam-assisted gravity-drainage (SAGD).  These operations inject steam, generated from heated groundwater, underground to separate oil from the sand and pump the oil to the surface.  The water is extracted from aquifers, which in most cases are brackish.  Cenovus is taking great strides toward efficiency of water use in these operations, which helps to reduce the steam-to-oil ratio (SOR) – an important measure of water efficiency in in situ operations.  High efficiency SAGD operations have an SOR of about 2.5 (barrels of water per barrel of oil).  In comparison, open pit mines may have water to oil ratio of over 4.  In both cases, a proportion of the total water used to produce each barrel of oil is recycled and used multiple times in the process. 

All water use, surface water or groundwater, requires a license in the province of Alberta.  Surface waters are heavily monitored and regulated for quality and quantity, primarily because they are relied upon for industrial, agricultural and municipal uses across the province.  Groundwater is relatively poorly understood and poorly regulated.  Monitoring, modeling and regulation are becoming a priority, but with only a fraction of the 89 new proposed or approved in situ projects operating, there is some question what the long-term impacts might be considering the current lack of understanding of the groundwater system. 

This post is intended to provide a glimpse into oil extraction in northern Alberta.  Some resources that can provide additional information and perspective are:
One of the best ways to understand and to affect change around an issue is to engage in dialogue with the stakeholders.  Get out there, talk to people and use your knowledge, expertise and energy to get the word out! 

For your interest, check out Waterlution for information on upcoming workshops in your area, including an upcoming workshop on hydraulic fracturing for natural gas extraction in Fort Nelson, BC.