TECHBriefs www.burnsmcd.com A Burns & McDonnell Publication 2009 No. 3

Wastewater Treatment ChallengeNew Requirements for Cruise Ships in Alaskan WatersBy Steve Anzelc, PE, LEED® AP, Burns & McDonnelland Olga Stewart, Oasis Environmental Inc.

In 2008, cruise ships carried a million passengers to the pristine waterways of Alaska. These mobile luxury cities can hold up to 5,000 people on a ship equipped with everything from restaurants, salons and photo labs to medical facilities — all of which contribute to wastewater generation. A public initiative to keep the waterways pristine and protect sensitive marine life resulted in legislation mandating the strictest point-of-discharge water effluent requirements in the state of Alaska and possibly the world — with compliance to be achieved by the 2010 May-to-September cruise season.

LegislationDue to public concern regarding cruise ship industry practices, the Alaska Department of Environmental Conservation (DEC) created the Commercial Passenger Vessel Environmental Compliance (CPVEC) program. Through this program, the DEC issued a general wastewater permit in March 2008 with strict point-of-discharge effluent limits for large commercial passenger vessels (more than 250 passengers). These limits were created to meet Alaska water quality standards for treated sewage, graywater and other discharges into Alaska’s marine waters.

Because cruise ships were not readily able to meet the new effluent limits for ammonia, copper, nickel and zinc, an interim permit was issued for 2008 and 2009. The interim standards were designed to allow ships to discharge in Alaska while still aiming to meet the new effluent limits by 2010. Legislation is being considered that would allow a mix zone similar to that allowed for other land-based discharges. This allowance would make it easier for wastewater treatment equipment to achieve these limits, but the best available technology may still be needed.

Current Technology and the LimitsWith very low limits for ammonia and metals including zinc, copper and nickel, the current technology on the cruise ships is not consistently meeting these requirements. To assist the cruise lines in meeting the new limits, the Alaska DEC held a cruise ship technology workshop in February 2009 in Juneau and funded a feasibility study of technologies. The study provided insight into land-based and emerging technologies that may be able to be adapted to cruise line vessels to meet the standards.

Waste on Cruise ShipsAccording to a U.S. Environmental Protection Agency report, average sewage rates for cruise ships entering Alaska were 21,000 gallons per vessel per day, or about 8.4 gallons per person

Table 1: Cruise ship waste includes graywater, blackwater and other substances from a variety of sources.

Waste Stream Sources

Graywater: Sources from sinks, showers, laundry, galleys, air conditioners and salons. These can be held in tanks and then treated shore side or dumped more than 12 nautical miles at sea.

Blackwater (sewage): Sources from toilets and medical facilities that are typically held or treated and then discharged similarly.

Bilge water: Water collected at the bottom of the ship from the open spaces in the vessel. Water is held, treated, monitored and cleaned before discharge.

Sludge: Residue from the bilge water treatment system and fuel sludge, a portion of which may be incinerated

aboard and the remainder sent to an approved shore-side facility or discharged directly, depending on the concentration.

Hotel and restaurant waste: Includes paper, plastic, food, cans and glass, handled in various manners including incineration and recycling.

Hazardous waste: Includes chemicals, fluorescents, batteries, paints/thinners, galvanizing flakes from piping, photo shop waste, which is typically held for a land-based waste management center.

Incidental: Deck run-off, hull coat leachate and ballast water.

TECHBriefs 2009 No. 3 2 Burns & McDonnell

per day. It varies from ship to ship, but in general, the waste streams are separated into the categories listed in Table 1 on page 1.

Current TechnologyCurrent technology varies for each of the cruise lines and even within the fleets of cruise lines serving Alaska. Typical methods on cruise ships include a marine sanitation device (MSD) that performs solids screening, maceration or biological treatment of the blackwater or other sewage and chlorine disinfection.

Ships going to Alaska, however, treat the graywater in an advanced wastewater treatment (AWT) system. These AWTs vary but typically include screening for solids, biological treatment such as membrane bioreactors or moving-bed biofilm reactors for aerobic biological removal, followed by filtration such

as dissolved air flotation or ultrafiltration to reduce biomass and particulate, and, finally, ultraviolet disinfection of pathogens. Reverse osmosis (RO) is also used by some cruise lines on the low-concentration streams in conjunction with biofilters for the other streams. Even with this advanced technology, systems on the ship will require modifications and additions to meet the new regulatory limits.

Systemic Approach to Achieving the New LimitsBefore modifying and adding new technology in an already tight space, a systemic- balance approach to the entire ship water and wastewater process is recommended. This includes identifying all sources of contamination, creating a block flow diagram with a balance of all contamination sources in and out, and evaluating the sources with the goal of making changes before adding equipment.

Steve Anzelc, PE, LEED® AP,is a senior project manager in the Burns & McDonnell Aviation & Facilities Group. He has 20 years of experience in design and project management of heavy industrial and metal finishing facilities, including management of hazardous process wastes. He has a bachelor’s degree in mechanical engineering from Ohio State University.

For more information, please e-mail: sanzelc@burnsmcd.com.

Alaskan cruises are an increasingly popular travel option, leading to concern for sensitive marine species.

Burns & McDonnell 3 TECHBriefs 2009 No. 3

Source evaluation identifies all sources of wastewater, such as showers, galley water, salons and laundry. This will include tracing back sources to potable water bunkered on the ship and water evaporated on board. It should also include identifying all potential sources of contaminants from cleaners, laundry, floor finishes, pesticides, rodenticides, industrial products and condensate. Another source may be leaching and impingement in piping (such as short-radius, 90-degree ells) and coatings. Unusual source locations may be identified, such as biological waste from an on-board movie theater converted for a cooking show.

After determining the sources, best management practices for operation should be used to reduce sources first. After reduction, product substitutions should be considered to replace chemical sources with less harmful products. Recycling and reuse technologies should also be utilized. With updates in wastewater treatment technology, drinking-standard water quality could be made from wastewater, but culturally it may be only acceptable to use this recycled water for technical water. Potential uses include deck cleaning, toilet flushing, cooling systems, and laundry. Another option could be recycling water for the pulpers for dish scraping. Some ships have implemented graywater recycling programs but could look for additional opportunities. Technology Changes to Meet StandardsAlthough they are not often required, land-based systems do exist to meet these low metal and ammonia standards. There is potential to adapt this equipment to ships, but the technology must first be evaluated for chemicals and flow rates specific to the ship through waste characterization and treatability studies.

Installing a pilot plant is highly recommended before full-scale production. In addition,

Olga Stewart is a junior engineer with Oasis Environmental Inc. She works on a wide range of projects, including the recent cruise ship project feasibility study for the Alaska Department of Conservation. She is a 2006 graduate of Lehigh University with a degree in materials science and engineering.

there are specific marine standards and approval processes that must be met before equipment can be certified for marine use (e.g. inclination, temperature, hydraulic and power considerations).

Compliance OptionsSome existing membrane bioreactors may be optimizable for retention and aeration to meet the new ammonia levels. New systems that may be feasible for metals removal include RO, ion exchange (IX) or a combination, and chemical precipitation using microfiltration followed by IX or RO. Electrodialysis may also be an option.

Numerous other emerging technologies are being considered but are unlikely to be adopted in time for the 2010 standards. Even existing land-based technologies may take a long timeto be adapted to ship use. Other optionsinclude upgrading the common ports tohandle the wastewater.

ConclusionCurrent on-board wastewater treatment technology has difficulty consistently meeting the new permit limits for ammonia, zinc, nickel and copper.

Following a February 2009 cruise ship technology workshop, legislation was introduced in Alaska to allow more time for cruise operators to meet the 2010 standards. House bill 134 relating to cruise ship wastewater discharge limits passed unanimously in the state senate in mid-April 2009, and passed the house 39-1 the next day. Governor Palin signed the bill into law on July 13th.

In order to protect Alaska waterways and marine life as technology is developed, cruise ship operators should take a systemic approach: first, evaluate the source contaminants and reduce, eliminate or recycle as much as possible. Next, optimize existing wastewater systems. Finally, as new technology becomes available, add it to remove the remaining contaminants.

TECHBriefs 2009 No. 3 4 Burns & McDonnell

Flexible Power Alternative Generation Sources for the Changing Power Market

By Robynn Andracsek, PE, Burns & McDonnell, William N. Dowling, Midwest Energy Inc., and Wayne M. Elmore, Wärtsilä North America Inc.

Today’s electric power industry is challenged by growing client needs, environmental regulations and an increasing focus on global warming. Wind generation is touted as a clean solution. The reality, however, is that while customers demand electricity 24/7, the wind blows sporadically.

Wind resources can be balanced with a flexible power plant capable of following wind generation. Such a plant must be capable of operating at reduced loads, cycling frequently on and off, and delivering the dispatching ability that wind lacks. Simultaneously, such a plant must complement the clean power attribute of wind energy. One solution is to balance the peaks and valleys of wind generation with blocks of efficient, lean-burning, natural gas-fueled reciprocating engines. Typical plant sizes range from 30 megawatts (MW) to 200 MW, using multiple engines from 5 MW to 16 MW each. This type of flexible power plant has numerous additional benefits (see Table 1).

The TechnologyThe gas-fired engine, built in large quantities of small MW units, is relatively new to the U.S. power-generation mix. These engines are four-stroke, lean-burn machines that are turbo charged, as opposed to naturally aspirated. There are a few vendors of these types of engines. Wärtsilä is one vendor. Other vendors not as prevalent in the U.S. include Caterpillar and MAN.

Rolls-Royce, Kawasaki and Mitsubishi also have large gas-fired reciprocating engines in development or recent production.

The Wärtsilä 34SG lean-burn gas engine uses the frame of the Wärtsilä 32 diesel/heavy fuel engine with its advanced integrated lube oil and cooling water channels. The bore has

been increased to 340 mm to fully utilize the power potential of this engine block. The Wärtsilä 34SG combines high efficiency with low emissions. The air-fuel ratio is very high and is uniform throughout the cylinder due to premixing of fuel and air before introduction into the cylinders. Maximum temperatures and nitrogen oxide (NOx) formation are therefore low, since the same specific heat quantity released by combustion is used to heat a larger mass of air.

Due to permitting requirements, the 34SG is normally installed in the U.S. with a selective catalytic reduction (SCR) system for control of NOx and an oxidation catalyst for control of carbon monoxide (CO) and volatile organic compounds (VOC). Table 2 shows the nominal, controlled emissions of the 34SG engine in parts per million (ppm). Not shown in Table 2 are emissions of particulate matter (PM10), which can be 3 to 5 pounds per hour depending on loads and circumstances.

Permitting RequirementsThere are three main federal regulations applicable to the 34SG engines: New Source Review (NSR), New Source Performance Standards (NSPS) for Stationary Spark Ignition Internal Combustion Engines (Subpart JJJJ), and National Emission Standard for Hazardous Air Pollutants (NESHAP) for Stationary Reciprocating Internal Combustion Engines (Subpart ZZZZ).

In attainment areas, NSR is implemented through the Prevention of Significant Deterioration (PSD) program. For a greenfield, reciprocating engine facility, PSD is triggered if emissions of any single criteria pollutant exceed 250 tons per year (tpy). Therefore, a greenfield facility can permit eight to 24 engines, depending on limits and run times, without need for a PSD permit. For a brownfield facility that is already a major source for PSD, a single engine at 8,760 hours per year of operation will require a PSD permit. A PSD application

Flexible Power Plants

•Easier to permit than traditional baseload power, even inside cities and non-attainment areas.

•Modular and easily expandable for future needs, requiring little or no water consumption.

•Engines are capable of wind following, continuous base load operation and a black start.

•Capable of providing ancillary services such as spinning and non-spinning reserve and up-and-down regulation.

•Production or absorbtion of reactive power, a valuable commodity in an organized, ancillary-services market and important for stabilization of the transmission system in the vicinity of significant wind resources.

Table 1: Flexible power plants have numerous potential benefits in the current and likely future power generation mix.

Burns & McDonnell 5 TECHBriefs 2009 No. 3

Power

8,439 kWhgross 5 15 26 1.1 10

NOx CO VOC Formaldehyde Ammonia

consists of the following and takes nine to 18 months to permit:

• Determination of Best Available ControlTechnology (BACT) on a case-by-case basis, taking into account costs as well as energy, environmental and economic impacts

• Demonstration that the increase in emissionswill not cause or contribute to an exceedance of the National Ambient Air Quality Standards (NAAQS) or PSD increment

• Analysis of the impairment, if any, to visibility, soils, vegetation and growth

NSPS are applicable to more than 80 types of equipment, including Subpart JJJJ for Stationary Spark Ignition Internal Combustion Engines. The Wärtsilä engines are subject to the NSPS Subpart JJJJ limits for non-emergency spark-ignited natural gas engines greater than 500 horsepower manufactured after July 1, 2007, and before July 1, 2010, for current installations. The applicable limits are as follows:

• 2 g NOx/horsepower-hour (160 parts per million by volume, dry (ppmvd) at 15% O2)• 4 g CO/horsepower-hour (540 ppmvd at15% O2)• 1 g VOC/horsepower-hour (86 ppmvd at 15% O2) The 34SG meets these limits.

NESHAP, also known as Maximum Achievable Control Technology (MACT) standards, are also applicable to numerous industries and types of equipment but specifically address hazardous air pollutants. The NESHAP for Stationary Reciprocating Internal Combustion Engines

(Subpart ZZZZ) is applicable to spark ignition, four-stroke, lean-burn (4SLB) stationary, reciprocating, internal combustion engines, such as the 34SG. Per Table 2a of Subpart ZZZZ, the engines must reduce CO emissions by 93% or more or limit the concentration of formaldehyde in the exhaust to 14 ppmvd or less at 15% O2. The 34SG meets these limits with an oxidation catalyst.

The 34SG is not subject to the 40 CFR Part 75 Acid Rain regulations, since each engine generates less than the acid rain applicability threshold of 25 MW. However, a new unit exemption application form must be submitted to U.S. Environmental Protection Agencybefore operation.

Case Study: The Goodman Energy Center The Goodman Energy Center began full commercial operation in September 2008 after a construction period of 16 months including installation of Wärtsilä 34SG engines (see Figure 1). The facility was permitted under a state permit and was not subject to PSD. During the 2008 summer months, the plant was run primarily for peaking and test purposes. Either the capacity/energy was needed and couldn’t be found elsewhere, or the cost of energy from the energy center was lower than what was available in the market or under other supply contracts.

Since then, the plant has been run for a variety of reasons, including:

• To supplant other resources that wereunavailable or on forced/planned outage.

Emissions for Natural Gas-Fired Wärtsilä 34SG (ppm)Table 2: In U.S. installations, SCR systems further reduce

emissions of the Wärtsilä 34SG lean-burn gas engine.

TECHBriefs 2009 No. 3 6 Burns & McDonnell

• To produce less expensive energy. (Even when gas is more expensive than coal, the heat rate at Goodman is comparable to that of a coal-fired unit.) A typical net plant higher heating value heat rate is less than 8,800 Btu per kilowatt-hour for this type of facility.

• As local generation to mitigate transmission issues, usually for planned outages of transmission lines.

• To manage net hourly interchange in responseto rapid and unexpected changes in wind farm output.

• To replace generation or transmissionschedules curtailed by the regional reliability coordinator.

Absent from this list are extended run times to support wind generation. So far, Goodman hasn’t been needed to stabilize voltage — the area hasn’t experienced instability in transmission voltages because of the wind facilities in the region. This is due largely to the fact that Midwest Energy is not an independent balancing authority but rather part of a larger balancing authority. Accordingly, the center does not have to manage the area interchange at the level of adjustments every few seconds.

Other environmentally friendly qualities of the plant include:

• Nearly-zero water consumption — crucial in arid western Kansas

• Low emissions — the air permit allows over8,000 hours/year of operation at full load; it is not expected to run that much

• Use of vegetable oil as insulating oil in sometransformers, avoiding the risks associated with an oil spill for those transformers

• Use of recycled crushed concrete both asan initial and final area and roadway surface material; all concrete was crushed locally as debris from other construction projects, greatly reducing the hauling of crushed rock material from distant quarries

• Use of flyash as a soil stabilization treatmentduring construction

Similar FacilitiesTwo facilities in Texas, similar in composition to Goodman, are in the final stages of receiving a PSD construction permit. Both facilities are existing PSD major facilities, and the addition of the gas-fired reciprocating engines necessitated a PSD construction permit. South Texas Electric Cooperative (STEC) in Pearsall, Texas,

Pollutant

g/bhp-hr 0.084 0.3 0.3

NOx CO VOC

Table 3: BACT determinations by the Texas Commission of Environmental Quality are reflected in recent draft permits for Wartsila 34SG installations in Greenville, Texas, and Pearsall, Texas.

Figure 1: Wärtsilä 34SG engine installation at Goodman Energy Center produces clean, flexible power.

Robynn Andracsek, PE, is a senior environmental engineer at Burns & McDonnell. She specializes in air quality permitting for industrial and utility clients and is a frequent contributor to Power Engineering magazine. She received a bachelor’s degree in mechanical engineering and a master’s degree in environmental engineering at the University of Kansas.

For more information, please e-mail: randracsek@burnsmcd.com.

STEC’s Natural Gas-Fired Wärtsilä 34SG (g/bhp-hr)

Burns & McDonnell 7 TECHBriefs 2009 No. 3

is applying to install 24 Wärtsilä 34SG engines at its Pearsall Power Plant. The draft permit reflects the BACT determinations (in grams per brake horse-power hour (g/bhp-hr)) made by the Texas Commission on Environmental Quality (TCEQ) as shown in Table 3. Ammonia slip will be permitted at a pound-per-hour rate equivalent to 10 ppm. The second facility is GEUS in Greenville, Texas. The Greenville Engine Plant is co-located with the Greenville Boiler Plant and will consist of three Wärtsilä 34SG engines, with a possible addition of three

more engines in the future. An early draft of its permit shows BACT rates equal to STEC’s Pearsall plant.

Working with WindSpinning reserve is one operational mode that can work with wind generation. When operating in spinning reserve mode the plant is in operation at levels below its minimum load. Automatic signals from the grid dispatch center will increase the plant output if the grid requires additional energy. If system demand is falling

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Figure 2: Flexible gas engines provide black-start capability.

Figure 3: Flexible ramp-down makes gas engine installations suitable for wind balancing.

Wayne M. Elmore develops new power plant projects using Wärtsilä technology for the Midwest and southern United States. With 16 years of experience, he has worked on projects throughout the Americas and in Sweden. He has a bachelor’s degree in electrical engineering from Virginia Tech.

William N. Dowling William N. Dowling is vice president, energy management and supply for Midwest Energy Inc., a customer-owned electric and natural gas utility in central and western Kansas. With more than 30 years of industry experience, his responsibilities include resource and transmission planning, generation and control center operations. He also served as owners’ project manager for construction of the Goodman Energy Center.

Generator Power Ramp-Up, Goodman Energy Center #3, on Aug. 21, 2008

Typical Generator Power Ramp-Down, Goodman Energy Center #3, on Aug. 21, 2008

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2009 No. 3

• Wastewater Treatment Challenge

• Flexible Power

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and the plant is operating above its minimum load, plant output can be ramped down until the load is balanced or the plant’s minimum load is reached.

Balancing wind generation is managed on an hourly basis, not including any additional balancing for CPS1/CPS2 control performance standards. Having a plant like Goodman that can be started quickly with attractive ramp rates makes this management more feasible. With nine units, each rated 8.4 MW, the energy center provides flexibility in following changing wind conditions. This is due to the units performing well throughout the output range and very well at output levels above about 60%. Furthermore, units can be started or stopped fairly quickly, multiple times per day, with minimal impact on performance. This gives the Goodman center and Midwest Energy more flexibility than they would have with a single large combustion turbine (see Figures 2 and 3, page 7).

Keep in mind that the Goodman Energy Center has not been operating long and has limited run

times. The best example of a windmill-following Wärtsilä plant with some operating history is Plains End I near Denver, which consists of 20 18V34SGLN engines for a total of 111 MW. This facility has been operating since May 2002. The Plains End II extension was commissioned in summer 2008, consisting of 14 20V34SG engines, bringing the facility to a total of 227 MW. Plains End is owned by Cogentrix but is dispatched remotely from downtown Denver (about 25 miles away) by Xcel Energy. Plains End I has 5,000 to 6,000 running hours and is being dispatched to help mitigate windmill variability.

ConclusionA facility such as the Goodman Energy Center complements wind generation by providing rapid cycling in response to wind’s unpredictable nature. Blocks of small, efficient, lean-burning natural gas-fueled reciprocating engines can provide needed flexibility to the U.S. power grid.

NOTE: An excerpt from this article appeared in Robynn Andracsek’s monthly column for Power Engineering magazine in March 2009.