Jozef Mendelevich, who spent 11 years in Soviet labor camps after the 1970 Leningrad hijacking trials, arrived here today to a tumultuous welcome.

Looking pale and thin, and older than has 30 years, Mendelevich arrived at Tel Aviv's Ben-Gurion airport and declared, "All my suffering has been worthwhile to be a citizen of Israel. And it is my hope to help in building a country of Jews to observe the commandments of the Torah." At his request, he was immediately driven to Jerusalem, where he prayed at the ancient western wall of the Second Temple, known as the Wailing Wall. Israeli immigration authorities presented Mendelevich with an immigrant's identity card as a crowd of Israeli relatives and friends cheered, stomped their feet and sang Zionist songs.

Jewish Agency Director Areyh Dulzin said, "Here's a fellow who struggled against a tremendous world power, and he is free. It is a wonderful lesson that he didn't give up. He didn't lose hope."

Mendelevich's arrival in Israel was all the more dramatic because of reports here last week that he had mysteriously disappeared from a Soviet camp in the Ural mountains, where he was sent in 1970 after being arrested in an alleged plot to hijack a Soviet airplane and escape to the West.

His release followed a prolonged international campaign of pressure on the Soviet authorities, spearheaded by Edgar Bronfman, the American president of the World Jewish Congress. Israeli sources said Bronfman's appeals to the Soviets were instrumental in Mendelevich's unexpected release. a

Mendelevich became devoutly religious while incarcerated, and refused to work on the Sabbath or eat food that he considered to be in violation of orthodox dietary laws. As a result, according to relatives here, he is in failing health. On his arrival at the airport, however, he smiled broadly and, speaking polished Hebrew, engaged in animated conversation with well-wishers. He was expected to go into seclusion for several days.