Best Calculators for the PE Exam 2026: All NCEES-Approved Models Compared
Video
A water treatment plant has a flow rate of 2.5 MGD. If the desired chlorine dose is 3.5 mg/L, what is the required chlorine feed rate in lb/day?
Pe Env Water
Question · Medium
OSHA noise limits
Short
Complete guide to every NCEES-approved calculator for the 2026 PE exam. Side-by-side comparison of TI-36X Pro, Casio fx-115ES Plus, fx-991CW, TI-30XIIS & more — with discipline-specific tips for Civil, Mechanical, Electrical, Chemical, and Environmental PE exams.
Blog
Chlorine Feed Rate Formula
Water
Flashcard
What is the primary purpose of coagulation in water treatment?
Question · Easy
1972 permit program that regulates point sources releasing contaminants into waters of the United States.
Water quality
Guess the Term
Chapter 0: Introduction & Exam Overview
0.1 PE Environmental Exam Format & Strategy
Study guide
Cheat sheet
A wastewater treatment plant has an influent BOD5 of 250 mg/L and an effluent BOD5 of 20 mg/L. What is the BOD removal efficiency?
Read the clue and guess the term in 6 tries.
Game
Hydraulic Detention Time
In an activated sludge process, the mixed liquor suspended solids (MLSS) is 2500 mg/L and the return activated sludge (RAS) flow is 40% of the influent flow. What is the approximate solids concentration in the return sludge?
Question · Hard
Enforceable federal drinking-water standard set as close to a non-enforceable health goal as feasible using the best available treatment technology.
Which of the following is the most effective method for removing Giardia cysts from drinking water?
BOD5 (5-Day Biochemical Oxygen Demand)
A stormwater detention basin is designed to detain the runoff from a 10-year, 24-hour storm event. What is the primary purpose of this design?
Five-day, 20°C laboratory test of the dissolved gas that microbes use while breaking down organic matter in a water sample.
0.2 How to Study & Use the NCEES Reference Handbook
What is the typical hydraulic retention time for a conventional activated sludge process?
Swap tiles to line up three of the same term.
Term Match
Jar Test
The groundwater at a site has a total dissolved solids (TDS) concentration of 1200 mg/L. According to the standard USGS salinity classification, this water would be classified as:
Flow-through bed of a porous adsorbent, made from coal, peat, wood, or coconut shells, used to remove organic chemicals from drinking water.
A primary clarifier has a diameter of 80 ft and a depth of 12 ft. If the flow rate is 5 MGD, what is the surface overflow rate?
T10 / Baffling Factor (Actual Contact Time for CT)
Under the Safe Drinking Water Act, which of the following is classified as a primary drinking water standard?
1972 federal statute that set the basic structure for regulating releases of pollution into U.S. surface bodies and for setting quality standards for those bodies.
Chapter 1: Water Quality, Regulations & Supply Hydraulics
1.1 Water Quality Standards, CWA & SDWA
What is the typical food to microorganism (F/M) ratio for a conventional activated sludge process?
Flip two cards at a time to find matching terms.
Term Pairs
MCL vs. MCLG
Which disinfection method produces the fewest disinfection byproducts (DBPs) in drinking water?
Federal law that gives EPA authority to control hazardous waste from generation through transportation, treatment, storage, and disposal, and also frames management of non-hazardous solid waste.
Waste management
Under RCRA, which pH criterion makes an aqueous waste exhibit the corrosivity characteristic of a hazardous waste?
Pe Env Waste
Lead Action Level (Lead and Copper Rule)
A landfill receives 500 tons/day of municipal solid waste. A new cell has interior dimensions of 300 ft x 300 ft x 45 ft and the compacted waste density is 1,200 lb/yd3. Approximately how many days will the cell operate before being filled to capacity?
SW-846 Method 1311 test that measures how readily organic and inorganic substances can migrate out of liquid, solid, or mixed wastes.
1.2 Water Supply Hydraulics & Pipe Networks
What is the primary purpose of a landfill liner system?
Find five hidden terms in a grid of letters.
Term Search
Nitrate MCL in Drinking Water
Landfill gas typically contains what approximate percentage of methane?
Natural byproduct of decomposing organic material buried in waste sites, composed of roughly half methane and half carbon dioxide.
Which of the following is NOT a method of hazardous waste minimization?
Loading more…
