FGD ZLD WASTEWATER MANAGEMENT

//FGD ZLD WASTEWATER MANAGEMENT

FGD ZLD WASTEWATER MANAGEMENT

Presentations made in Session I5 and I6 at EUEC 2015 in San Diego, CA

 

SouthernI5.1 Achieving FGD Wastewater ZLD through Encapsulation: Challenges, Benefits, & Technology Readiness
Morgan French, Research Engineer, Southern Company Services; Kirk Ellison
With impending changes to the Steam Effluent Guidelines, research to find technologies for FGD
wastewater is ongoing. In addition to wastewater treatment, zero liquid discharge (ZLD) technologies
are also being explored. Thermal ZLD technologies include evaporators, crystallizers, & spray dryers.
These are being used in the industry with limited success. However, there is limited experience using
these technologies on FGD water, & a liquid purge stream is usually required. All ZLD technology
approaches produce solid byproducts that pose significant disposal challenges. Currently, little
thought has been given to the characteristics of these byproducts, the long-term risks of their disposal.
However, there may be better methods to achieve ZLD. For example, some utilities have had varying
degrees of success combining their scrubber sludge, some wastewater, ash, & an encapsulation
agent to produce an encapsulated solid waste. However, many challenges still exist before such
an approach can be deemed commercially available. Work is needed to reduce water volumes,
characterize & stabilize materials, develop mechanical systems for mixing & transportation of materials,
create effective landfill placement & management practices, & prove long term sequestration of
constituents. This presentation will give an industry update on current knowledge & lay out a strategic
vision for the necessary research to be able to commercialize ZLD through encapsulation.
BlackVeatchI5.2 Integrating Zero Liquid Discharge (ZLD) Technology into the Design of a 6×800 MW FGD Retrofit Project
Mike Preston, Chemical Engineering Section Leader, Black & Veatch; Steve E. Russell
Wet Flue Gas Desulfurization (WFGD) systems produce a wastewater stream that has become subject to
increasingly stringent regulatory policy. This paper focuses on the challenges presented and the design
solutions applied to integrate Zero Liquid Discharge (ZLD) wastewater treatment into the design for a
6×800 MW FGD retrofit project. The project utilized physical/chemical pretreatment of the wastewater
followed by brine concentrators and crystallizers to achieve zero liquid discharge. Some of the unique
challenges to this application included treatment of multiple plant waste streams with varying quality,
limited upstream storage capacity, high system turndown and limited maintenance opportunities.
Additional technical items investigated included design integration between pretreatment and ZLD
systems, equipment layout, characterization and disposition of the wastewater and solid byproducts,
recovered water purity and recycling considerations, and various configurations for wastewater
treatment equipment.
carmeuseI5.3 Pozzotec – A Simple Path to Zero Liquid Discharge
Scott Fraley, Sr. Technical Specialist – FGT Markets, Carmeuse Lime & Stone
The last revision to the Clean Water Act was enacted in 1982. The standards set over 30 years ago
do not include arsenic (As), mercury (Hg), selenium (Se) and nutrients know by today’s standards to
be toxic. In order to address this, the EPA has established Effluent Limitation Guidelines (ELG) which
will be implemented starting 2017-2022 through the National Pollution Discharge Elimination System.
This program establishes national standards to specify control levels for liquid discharges from power
plants. Approximately 1,100 power plants will be regulated buy these rules Table 1: ELG Limits for FGD
Wastewater; Daily Maximum Monthly Average; Arsenic, total 8 μg/l 6 μg/l; Mercury, total 242 ng/l 119
ng/l; Selenium, total 16 μg/l 10 μg/l; Nitrite/Nitrate, as N 0.17 mg/l 0.13 mg/l. Most of the discussion on
how power plants will meet these new ELGs has been dominated with expensive waste water treatment
systems (WWT) and zero liquid discharge (ZLD) options. There is a more affordable technology which
takes effluent to landfill as a transportable solid. Let us reintroduce you to the pozzolanic reactions for
stabilization of solid and liquid wastes. Pozzotec is a term used by the cement and concrete industry
to describe material fixated using pozzolanic reactions with fly-ash, water and lime. Cement and
concrete made with fly ash are examples of sustainable development, whereby waste products from
one industry are used as feedstock for another industry.
DustexI5.4 Processing Power Plant Waste to High Marketable Commodities. An outlook.
Robert Bobeck, PhD, Process Development, Dustex
Annually, 25 million tons of FGD Gypsum is produced in the US. However, only approximately 12 million
tons per year of FGD Gypsum is consumed, primarily in wallboard and cement. A large underutilization
of utility by-product exists. A new process has been developed to economically convert FGD byproduct
into a fertilizer and high purity calcium carbonate. The utility industry can now generate a high
value marketable product from its waste or low value by-product.

I5.5 Circulating Fluid Bed Evaporator for Power Plant Wastewater Treatment

Angelos Kokkinos, Chief Technology Officer, Babcock Power, Inc.; Matt Quitadamo
Utilities are under increasing pressure to supply power in the most cost effective manner while at the
same time eliminating pollutants that could be harmful to the environment. The EPA has proposed
several preferred alternatives for BAT that establish varying limits on discharges from each waste stream
including a “zero liquid discharge” effluent limit for all pollutants in fly ash transport water and waste
water. BPI has developed a circulating fluid bed (CFB) evaporator that uses the plant’s waste heat to
eliminate steam power plant generated waste water. Hot flue gas is taken from the boiler outlet and
is sent through a unique flow distributor/mixer to a circulating fluid bed reactor that contains fly ash.
Waste water generated by the plant from any source (e.g., wet flue gas desulfurization system, ash
pond waste water, etc.) is injected into the reactor where it is dried. The evaporated water containing
flue gas and fly ash is then sent to a particulate capture device (e.g., cyclone separator) where the
majority of solids are returned to the reactor and the gas stream including the evaporated water is
sent to the unit’s particulate collection treatment system for final collection. The waste solids are then
disposed using the plant’s existing dry ash solid disposal system. This presentation will provide a summary
of the proposed ELG regulations, a description and the technical basis of the CFB evaporator, and a
cost comparison of the process to other technologies.

I5.6 ZLD Solutions for Power Plants

Philip Rader, Business Sales Manager, Alstom; Ray Gansley
Recent EPA liquid effluent discharge requirements along with economic incentives and environmental
stewardship have increased the need for power plants to develop strategies and take actions to
address liquid discharges from WFGD systems. This paper will review overall strategies to address this
need and will focus on the use of direct evaporation of WFGD waste water via spray drying. Two
installations and operations of systems that reduce and eliminate WFGD waste water using proven dry
FGD-type equipment at the 825 MW Cliffside 6 plant and at another major Eastern US power plant will
be presented.
PSAnalyticalI6.1 Online Monitoring of Hg, Se and As in FGD Wastewater Treatment Plants
Warren Corns, Research Director, PS Analytical Ltd; Bin Chen
The EPA proposed new rule (40 CFR, part 423) is an attempt to reduce the amount of toxic metals and
other pollutants discharged to surface water from power plants. Previous regulations do not consider
the additional burden of water discharge pollutants from air pollution control systems such as flue gas
de-sulphurization (FGD), selective catalytic reduction (SCR) and flue gas mercury control (FGMC). The
main pollutants of concern include metals (e.g mercury, arsenic and selenium), nitrogen and total
dissolved solids (TDS). Toxic metal discharges have a huge impact on the environment as they bioaccumulate
in wildlife and cause a wide array of human health issues. The new ruling would establish
new and additional requirements for wastewaters associated with FGD wastewater, fly and bottom
ash transportation water, flue gas mercury control water, combustion residual leachates from landfill
and surface impoundments, metal cleaning wastes and gasification wastewater. Depending on the
final options the best available technology (BAT) that is economically achievable will need to be
applied to reduce pollutant discharges. This is particularly challenging for dissolved forms of As, Se and
Hg as they are not removed by surface impoundments. PSA have a number of online and laboratory
measurement based on AFS and sampling solutions to confirm the efficiency of the wastewater
treatment processes and for compliance monitoring. These are outlined with recent experiences and
data from the field and pilot scale studies.
Burns & McDonnellI6.2 Minimizing the Cost of ELG Compliance by Reducing FGD Blowdown
Kristin Glikbarg, Associate Process Engineer, Burns & McDonnell Engineering Company, Inc.; Dave
Guinta
Proposed Effluent Limitation Guidelines (ELG) limits may require that Flue Gas Desulfurization (FGD)
blowdown be treated prior to co-mingling with other waste streams. Potential treatment options
include the following; Physical/Chemical Treatment for solids and metals removal, Biological Treatment
for removal of selenium and nitrates/nitrites, and Mechanical Vapor Compression Evaporation to
achieve a closed loop Zero Liquid Discharge (ZLD) FGD system. These compliance options vary greatly
in both capital and operating costs with ZLD being the highest cost option. As would be expected,
the cost of treating FGD blowdown is strongly correlated to the volume of blowdown being sent to
treatment. As an example, for a ZLD system, if the blowdown flow rate is cut in half the capital cost
will be reduced by approximately 30% and the operating cost will be reduced by approximately 50%.
Due to this strong cost correlation, utilities who implement wet FGD systems could benefit greatly from
reducing the volume of FGD blowdown. This paper will describe the various approaches that can
be taken to reduce FGD blowdown and estimate the associated cost savings for water treatment.
Potential FGD operating issues from reducing the blowdown rate will be discussed in detail, along with
possible solutions to resolve these issues. Additionally, testing procedures will be recommended which
can help predict the long term effects of adjusting FGD operating parameters.
SouthernI6.3 The Electric Generating Utilities Water Reserach Center
Morgan French, Research Engineer, Southern Company Services Inc.
Water management restrictions for electric generating units (EGUs) – nuclear, natural gas, coal and
renewables – are expected to increase through stakeholder pressures and new state and federal
regulations. In order to successfully transition EGUs into a future that limits traditional water-intake
volumes and effluent pollutant concentrations, Southern Research Institute (SRI) and the Electric Power
Research Institute (EPRI) have collaborated with Georgia Power Company (GPC), Southern Company
Services (SCS) and 14 other power generation companies to develop a Water Research Center (WRC)
focused on addressing these issues. Located at GPC’s Plant Bowen and operated by SRI, the WRC is
a resource that can be used to provide independent performance evaluations of technologies which
address water withdrawal, consumption, usage efficiency, treatment, recovery, and reuse throughout
the power generation process. The WRC has the capability to evaluate technologies in any of the
following focus areas: Cooling Water Management and Advanced Cooling Systems, Wastewater
Treatment (WWT), Zero Liquid Discharge (ZLD), Solid Landfill of Wastewater Treatment Residuals,
Moisture Recovery, Water Balance Modeling, and Carbon Technology Effects on Water Management.
The development of the WRC was based and designed on insights gained from 70+ discussions with
technology developers and area experts on the infrastructure needs for each focus area.
CooperI6.4 Online Multi-metal Water Analyzer Based on X-Ray Fluorescence
Troy Pittenger, Research & Development Director, Cooper Environmental Services; Josh Katz, Brian
Edge & John Cooper
Cooper Environmental Services has developed a near real-time continuous water analyzer based on
the merger of two previously proven instruments, the Xact 625 ambient metals monitor and the QAG
(Quantitative Aerosol Generator). The instrument can achieve sub-part per billion detection limits by
pre-concentrating the liquid sample onto a filter media where it is subsequently analyzed by X-Ray
Fluorescence. The instrument is capable of reporting up to 23 metal concentrations simultaneously
including selenium (Se), arsenic (As) and mercury (Hg). Performance data for this continuous water
analyzer will be discussed along with its applicability for the utility industry.
I6.5 Development of a New EPA endorsed Method for the Analysis of Flue Gas Desulfurization Wastewaters by ICP/MS
Richard Burrows, Corporate Technical Director, TestAmerica Inc
Air quality regulations in the USA require SO2 scrubbing for most coal fired plants, with the resulting
formation of Flue Gas Desulfurization (FGD) wastewaters. These wastewaters may contain significant
concentrations of a variety of toxic metals but their analysis by ICP/MS has historically been challenging
due to very high concentrations (up to thousands of ppm) of calcium, sodium, boron, magnesium,
manganese, sulfate, chloride, nitrate & other matrix components. The matrix is also highly variable, &
interference from molecular species on As, Cr, Cu, Se, V & other target elements (potentially resulting
in false positives) is a serious concern. This paper will outline development of a method utilizing aerosol
dilution, discrete sampling, & interference removal by kinetic energy discrimination collision cell
technology that provides a straightforward & rugged approach to the analysis of this complex matrix.
SRII6.6 Advanced Treatment of Flue Gas Desulfurization Wastewater Using Vibratory Shear Enhanced Processing Membrane System for Reuse or Discharge
Robert Strange, Associate Project Manager, Southern Research Institute; Behrang Pakzadeh,
Southern Research Institute; Larry Stowell & Angie DeSchutter, New Logic Research, Inc.; Richard
Breckenridge, Electric Power Research Institute; Jason (Xinjun) Teng, Southern Company Services
The revised EPA effluent limitation guidelines for steam electric power generating units may lower
discharge limits for mercury, selenium, arsenic, & nitrate/nitrite in the flue gas desulfurization (FGD)
wastewater. Vibratory Shear Enhanced Processing or VSEP from New Logic Research, Inc. is a new
generation membrane filtration system designed to handle high solids containing wastewaters that
uses intense shear waves on the face of a membrane. The shear waves are produced by the vibration
system. The membrane filter elements provide an open channel flow arrangement which eliminates
the need for pretreatment other than a strainer even when using RO membrane. A VSEP L series pilot
unit was evaluated at the Water Research Center at Plant Bowen, Cartersville, Georgia. The VSEP
system consistently met or exceeded treatment objectives. Test conditions & results of this treatment
approach to provide high quality water for reuse or discharge will be presented.

By |2018-06-22T21:40:53+00:00August 24th, 2015|Categories: Uncategorized|Comments Off on FGD ZLD WASTEWATER MANAGEMENT