Rouse Co. profits before non-cash charges increased by 20 percent in the first half to $6.3 million from $5.3 million a year earlier, the Columbia-based real estate development firm said yesterday. Second-quarter profits before non-cash charges were $3.1 million compared with $2.7 million in the 1978 second quarter.

Rouse cites profits in this manner because the company believes they are "the only meaningful operating results for a real estate developer," said Robert R. Threatt, Rouse's assistant controller. He said that Rouse believes that depreciation, the uld peak, if they have not already hit their limits. major traditional non-cash charge, isn't applicable to income-producing property.

The company's second-quarter net income rose to $760,000 (5 cents a share) from $669,000 (5 cents) a year earlier as revenue increased to $26.2 million from $24.4 million.

First-half net income was $1.53 million (11 cents) on $50.9 million in revenue compared with 1978 first-half net income of $2.50 million (19 cents) on $47.9 million in revenue.

In the 1978 first half, net income included a $1.46 million gain on translation of foreign debt related to property in Canada since sold.

Rouse's operating income was up 34 percent in the first half to $5.7 million from $4.3 million, and increased 27 percent in the quarter to $3.1 million from $2.7 million.

Rouse said it opened a new shopping center called Governor's Square in Tallahassee, Fla., this week and completed expansion of Highland Mall in Austin, Tex., last month.

Biosperics Inc. of Rockville turned in an 89 percent increase in profits for the first half of 1979, increasing earnings to $117,000 (16 cents a share) from $61,000 (9 cents) a year ago.

Revenues of the environmental services firm climbed 60 percent to $2.26 million from $1.4 million.

But inflation sent second-quarter net income down to $59,000 (8 cents) from $71,000 (10 cents) a year earlier as revenues increased from $790,000 to $1.22 million.

Biospherics President Gilbert Levin forecast revenues would top $5.5 million for the year and estimated earnings would amount to 56 cents a share compared with revenues of $3.7 million and profits of 40 cents a share last year.

BTR Realty Inc. reported its earnings fell to $46,000 (9 cents a share) from $384,000 (70 cents) a year earlier, as revenue dropped to $773,000 from $1.2 million.

For the first half of the year, the Linthicum Heights real estate developer earned $112,000 (21 cents) down from $422,000 (77 cents) in the same period a year ago. Revenues fell to $1.5 million from $1.9 million.

Capital Mortgage Investments reported it turned last year's $929,000 second quarter loss into a $2,000 profit this year and made a $251,000 profit in the first half of the year compared with a $111,000 loss in 1978.

The Chevy Chase real estate investment trust showed a $124,000 operating loss for the quarter, but nosed into the black because of a $126,000 gain on sale of property.

Capital Mortgage also announced that its $22,8 million loan from a group of five banks fell due on Aug. 1 and is being renegotiated.