Insulating buyers and sellers from a multitude of counter-party risks has been the essence of our existence for the last 35 years, and it still is.
The nonoperational expenses in the second quarter principally consisted of an $18.6 million asset impairment relating to our decision to rationalize our global office footprint in light of the new world we are living in.
Adjusted second quarter net income and earnings per share were $8 million and $0.13 per share.
Adjusted EBITDA for the second quarter was $57 million.
And lastly, we generated $236 million of cash flow from operations, which enabled us to continue to maintain more than $1 billion in total available liquidity, a critically important metric during this time period.
Consolidated revenue for the second quarter was $3.2 billion.
Our aviation segment volume was 690 million gallons in the second quarter, representing a sequential decline slightly less than the 65% decline forecasted on last quarter's call.
Although we experienced relatively strong volumes related to cargo activity in certain business and general aviation customers, commercial passenger activity remained at levels below 25% of normal activity, and that was the principal driver of the volume decline in the second quarter.
Volume in our marine segment for the second quarter was four million metric tons, down approximately 18% sequentially, driven principally by the negative impact of the pandemic, our core reselling activity, including sales to cruise lines, experienced most of the volume decline.
Our land segment volume was 1.2 billion gallons or and gallon equivalents during the second quarter.
That's a 50% decrease sequentially.
Consolidated gross profit for the second quarter was $214 million.
That's a decrease of 20% compared to the second quarter of 2019.
Our aviation segment contributed $92 million of gross profit in the second quarter.
That's down 35% year-over-year and basically flat sequentially, but significantly above the expectation shared on last quarter's call.
We also benefited from historic inventory volatility experienced during the quarter, whereas many of you know, crude oil prices started out at $20, then technically dropped to negative 40 and ultimately ended the quarter at just under $40.
The marine segment generated second quarter gross profit of $37 million, representing a slight increase year-over-year and generally in line with the guidance we provided on last quarter's call.
Our land segment delivered gross profit of $85 million in the second quarter, down 8% year-over-year.
Our core operating expenses, which exclude our bad debt expense, were $154 million in the second quarter, down more than $20 million sequentially and just below the guidance provided on last quarter's call.
With the broader learnings stemming from our ability to effectively operate many functions within our business with a remote workforce, we explored the opportunity to rationalize our global office footprint, as mentioned earlier, which we expect will result in additional annualized cost reductions of close to $10 million, while ensuring a healthy and agile work environment for our employees as we look toward 2021 and beyond.
Based on the actions taken to date and our continued efforts to identify additional cost-saving opportunities, we expect core operating expenses to be in the range of $149 million to $154 million in the third quarter, representing another sequential decline in operating expenses.
As a result, our bad debt expense increased to $25 million in the second quarter, principally due to the establishment of reserves related to a few notable bankruptcies in the commercial aviation market.
While our consolidated receivables portfolio was down from $2.9 billion at year-end to $1.4 billion in June and aviation's receivable portfolio is down from $1 billion to just over $400 million over the same time period, risk levels clearly remain elevated.
Despite the historic market conditions experienced in the second quarter, we still delivered $35 million of adjusted income from operations.
In the second quarter, nonoperating expenses, which is principally interest expense, was $14.9 million, which is down 15% year-over-year, primarily driven by a decrease in borrowing rates.
At this point, considering the current environment, it is difficult to forecast our effective tax rate for the second half of the year, but it is now more likely that our rate will be over 30% over the next two quarters.
Our team did a fantastic job managing working capital during the second quarter, resulting in $236 million of operating cash flow.
Our net debt position declined by more than $200 million sequentially to $450 million in the second quarter, again, due to our strong operating cash flow.
This resulted in a further decline in our net debt-to-EBITDA ratio to 1.2 times, and our total available liquidity remained at more than $1 billion consistent with or actually somewhat above our liquidity position at the beginning of the second quarter.
While the proceeds from the sale, which is expected to close within 90 days, will initially be utilized to repay outstanding debt, it also will provide us with additional capital to strategically invest in our core businesses.

Summary:
Adjusted second quarter net income and earnings per share were $8 million and $0.13 per share.