Surface Water Filtration
Potpourri
Disinfection Requirements
LT1&2 ESWTR
Disinfection Byproducts Rule Stages 1 and 2

100

The maximum limit for combined filter effluent turbidity for a water system using conventional or direct filtration is ___________. For other types of filtration, it may be as high as 5 NTU.
What is 1 NTU

100

The monitoring plan consists of these five parts: System Summary, Water Source Details, Distribution System Details, and this:
What is Individual Rule Sampling Plans.

100

Disinfection profiling requires field sampling for these important parameters.
What is Disinfectant residual, Temperature, and pH (for chlorine only)

100

An outbreak of Cryptosporidium in this major United States city is responsible for the Long Term 1 Enhanced Surface Water Treatment Rule and the Filter Backwash Rule.
What is Milwaukee in 1993

100

This is the primary difference between the Stage 1 and Stage 2 Rules.
What is compliance in Stage 2 is based on the Locational Running Annual Average (LRAA)

200

For a water system using Conventional filtration, the combined filter effluent turbidity must be below this value for the 95th percentile.
What is 0.3 NTU

200

Violation of the total coliform MCL where fecal coliforms or E. coli are present in the distribution system is a __________ violation requiring public notice.
What is Tier 1

200

If a water system makes one of these changes, then this will be required: changes to the point of disinfection, switch to a different disinfectant, or a change to the disinfection process.
What is a Disinfection Profile

200

The results of source water monitoring under LT1ESWTR are used for this.
What is to Determine Bin Classification

200

The Disinfection Byproducts Rule is a companion rule to these other rules to prevent overdosing of disinfectants.
What are LT1ESWTR and LT2ESWTR

300

This type of notification must be sent out in the event of a 95th percentile turbidity violation for a combined filter effluent.
What is Tier 2

300

The Consumer Confidence Report (CCR) must be distributed by wholesalers to their suppliers by this date each year.
What is April 1st or a date agreed on by contract between the wholesaler and the supplier.

300

Technology isn’t perfect and sometimes chlorine residual monitoring equipment breaks down. Manual readings may be collected for a maximum of this many days before automated equipment must be placed back into service.
What is 5 working days.

300

Source water monitoring is required for this reason.
What is Systems with “dirty” source water may need to provide more log removal to protect public health.

300

Total Organic Carbon (TOC) percent removal requirements are based on these two parameters for source water.
What are source water TOC and alkalinity. As TOC increases, the percent removal requirement also increases. As alkalinity decreases so does the percent removal requirement.

400

Individual filter effluent turbidity must be recorded at least this often for systems using Conventional or Direct filtration treatment.
What is 15 minutes. However, continuous monitoring is required on each filter.

400

California has begun regulating disinfection byproducts (THMs and HAAs) in this type of water:
What is reclaimed or recycled water from wastewater treatment plants.

400

A water system measures a chlorine residual of 0.18 mg/L at the entry point to the distribution system. The operator increases the chlorine feed to the system. After four hours, the chlorine residual at the entry point reads 0.25 mg/L. What reporting requirements apply?
What is None. Chlorine residual was restored within the 4 hour window allowed in section 11.8(3)(d)(i)(A)

400

A Conventional Filtration system with a Bin classification of 4 must provide this log removal of Cryptosporidium.
What is 2.5 Log

400

Systems can qualify for reduced monitoring of TTHMs and HAAs when the LRAA concentrations have been below this at all sampling locations.
What are 40 ug/L for TTHM and 30 ug/L for HAA5

500

A system may report only the combined filter effluent turbidity instead of both combined and individual under these circumstances.
What is the systems serves fewer than 10,000 people and has two or fewer filters total.

500

The difference between measuring absorbance versus measuring true turbidity in Nephelometric Turbidity Units (NTUs).
What is Turbidity is measured at a 90 degree angle from the light source. Turbidity measures light scatter.

500

A water system collects 300 samples from the distribution system in April. 16 of them have no measurable residual. The following month, there are 18 samples with no measurable residual. What reporting requirements apply?
What is Notify the Department before the end of the next business day AND distribute Tier 2 public notices.

500

This table in the Colorado Primary Drinking Water Regulations includes a lists of treatment techniques and credits to achieve additional log removals required under LT1ESWTR.
What is the Microbial Toolbox (11.10(5))

500

Samples for disinfection byproducts must be collected at these times and locations.
What are the warmest months and the longest water ages