The Challenge
The client faced mercury contamination at 563.5 ppb in groundwater that required treatment before discharge to a river. Surface water discharge regulations demanded ppb-level mercury removal with absolute certainty that no secondary contaminants would be introduced.
The critical challenge was sulfide emissions. Mercury-selective resins like SIR-200 work by precipitating metals as sulfides, but product data sheets warned against potable water use "due to possible release of low levels of H₂S." For surface water discharge, even trace sulfide emissions could violate environmental permits and toxicity testing requirements.
Additional constraints included:
- pH range of 6.5-8.5 (higher than optimal for chelating resins)
- Need for accelerated flow rates (4 gpm/cu.ft vs. recommended 1-2 gpm/cu.ft)
- Extreme time constraints requiring rapid technical validation
- Limited water analysis data for complete system design
They needed definitive proof that SIR-200 could deliver ppb-level mercury removal without any sulfide emissions before committing to system design.
The Solution
ResinTech designed a comprehensive laboratory validation study to simulate the proposed system conditions and directly address sulfide emission concerns. The bench-scale test used neutral pH Camden city water spiked to 563.5 ppb mercury—matching the client's contaminated groundwater profile.
The study specifically tested:
- Mercury removal performance at accelerated 4 gpm/cu.ft flow rate
- Sulfide and hydrogen sulfide detection throughout treatment cycle
- Extended contact time effects (overnight soak testing)
- pH performance at neutral conditions
- Effluent quality suitable for surface water discharge standards
Testing included comprehensive analysis at multiple bed volumes (5, 10, 15, 20) plus extended overnight contact to simulate worst-case sulfide leaching scenarios.
The laboratory validation was critical for regulatory confidence. We needed absolute certainty that SIR-200 wouldn't introduce sulfide contamination in our surface water discharge application.
The Results
The validation study delivered exceptional results that exceeded all performance requirements. Mercury removal achieved >99.98% efficiency with consistent effluent levels below 0.12 ppb—well under regulatory requirements.
Critical Environmental Safety Confirmation:
- Zero sulfide detection: 0 mg/L throughout all bed volumes tested
- Zero hydrogen sulfide: 0 mg/L including extended overnight contact
- Surface water safety: Complete elimination of secondary contamination concerns
Performance Validation:
- Mercury Removal: >99.98% efficiency maintained throughout testing
- Accelerated Flow Rate: 4 gpm/cu.ft operation proven effective
- pH Flexibility: Consistent performance at neutral pH conditions
- Regulatory Confidence: ppb-level performance with zero environmental concerns
Client Impact: The validation study directly enabled system design and regulatory approval. Armed with laboratory proof of zero sulfide emissions, the client successfully obtained permits for surface water discharge and proceeded with full-scale system implementation.
Strategic Impact
This validation breakthrough has significant implications for mercury treatment in environmentally sensitive applications:
Technology Advancement: Proved SIR-200 safe for surface water discharge, eliminating a major application barrier that previously limited ion exchange technology for mercury removal.
Market Expansion: Opens surface water discharge applications previously considered off-limits due to sulfide concerns, expanding addressable markets for mercury-selective resins.
Regulatory Confidence: Provides definitive laboratory data supporting environmental permit applications where sulfide emissions were previously prohibitive.
Economic Benefits: Validated performance at 4 gpm/cu.ft enables more compact, cost-effective system designs compared to standard flow rates.
The successful validation positions ResinTech SIR-200 as the premier solution for mercury removal where environmental safety is paramount, backed by laboratory proof that previous sulfide emission concerns are unfounded.
