10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
These 10 free MOLO questions are organized by exam domain, so you can see how each part of the Manager of Landfill Operations blueprint is tested. Reveal the answer and explanation under each question.
An employee is found unresponsive inside a leachate pump vault at a U.S. landfill. A remotely sampled atmosphere contains 11.2% oxygen, with no combustible-gas or hydrogen-sulfide alarm. The employee is not attached to a retrieval line. A coworker offers to enter wearing an organic-vapor cartridge respirator. What should the manager do immediately?
Correct answer: A - Prevent coworker entry and activate the designated confined-space rescue service.
Two wells lie along an established groundwater flow path and are screened in the same aquifer. Their surveyed measuring-point elevations use the same datum. At Well A, the measuring-point elevation is 150.0 m and depth to water is 10.2 m. At Well B, the corresponding values are 146.5 m and 4.0 m. Measurements were taken together before purging. Which hydraulic interpretation is correct?
Correct answer: B - Well B is upgradient; its hydraulic head is 142.5 m.
A survey identifies 600,000 m³ of remaining permitted airspace below the final cover. Future operational cover and internal roads will consume 20% of that volume. Waste-only in-place density is 0.75 tonne/m³, and annual disposal is 90,000 tonnes. The next phase needs three years for permitting and construction after the project starts. Assume constant tonnage and density, with no future settlement credit or scheduling contingency. Which estimate belongs in the capital plan?
Correct answer: D - 4.0 years of capacity; start the next-phase project within 1.0 year.
Next year's landfill funding plan assumes 60,000 billed tonnes, $1,200,000 in fixed operating costs, and variable costs of $22 per tonne. It also requires a $300,000 closure and post-closure reserve contribution that is not included in those operating costs. Net gas-sale revenue of $180,000 is available to offset the funding requirement. With no other revenue or planned surplus, what minimum tipping fee funds the entire plan?
Correct answer: C - $44 per tonne
After a technician increases vacuum at an interior gas-extraction well, methane falls from 52% to 34% by volume and oxygen rises from 0.4% to 7%. Repeat readings confirm the change; adjacent wells are stable, and temperature and carbon monoxide have not increased. How should the manager direct the initial correction?
Correct answer: B - Reduce vacuum at that well, check for air entry, and remeasure after the adjustment.
A groundwater laboratory reports benzene as 'ND (<10 µg/L)' at a compliance well. The applicable groundwater protection standard is 5 µg/L. No more sensitive result is available. Which conclusion is supported by this report?
Correct answer: C - Compliance is unresolved; an analysis capable of evaluating concentrations below 5 µg/L is needed.
An HDPE liner seam passes its air-channel pressure test, but a destructive sample fails the project's peel-strength acceptance criterion. The construction quality assurance plan requires both forms of acceptance. Before protective material is placed over the affected seam, the manager should require:
Correct answer: B - Documented repair and successful retesting of the affected seam under the approved plan.
During dry weather, verified leachate head in one drainage sector rises from 0.12 m to 0.42 m while flow reaching its sump declines. The sump remains at its normal low level, its pump passes a functional test, and downstream storage has ample capacity. Other sectors are unchanged. Which fault best explains the combination of findings?
Correct answer: A - An obstruction in the collection path between the affected sector and its sump.
A U.S. municipal solid-waste landfill may accept only nonhazardous waste. A proposed industrial sludge produces no drops in a properly performed paint-filter liquids test, but its representative TCLP extract contains 8.0 mg/L of lead. The waste is subject to federal hazardous-waste characteristic rules, and no exclusion applies. The generator argues that dewatering made it acceptable. How should the load be classified for this acceptance decision?
Correct answer: A - D008 hazardous waste; the negative paint-filter result does not make it eligible for this landfill.
At 8 a.m., a neighbor reports a strong landfill-type odor at her home at 5:30 a.m. Waste receipt did not begin until 7 a.m., but gas collection operates overnight. She reports no acute symptoms, and there are no current emergency alarms. Which reply best combines accountability with an evidence-based response?
Correct answer: D - We will check overnight records and wind conditions against your report and call this afternoon with what we find.
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