But as he retires this year, aged 55, instead of seeing a rise in enrolment from 1,550 to 2,000 as he hoped, the number of pupils has plummeted to 560.
"Enrolment has declined radically as a result of inability of parents to pay tuition fees, building and maintenance costs, textbooks and school uniforms," says a frustrated Khaemba.
"Drop-out rates have also shot up as a result of Aids. Most of our pupils have been orphaned by Aids and there are many families being headed by children as young as 11-13."
The fact that Butula is still one of the largest schools in the region, reflects the fall in enrolment nationally from 95 per cent in 1985 to 75 per cent last year, a lower level than in 1980.
According to a United Nations report, poor governance, corruption, and Aids have resulted in economic stagnation. "A high level of poverty has also been occasioned by harsh climatic conditions and debt payments," said the report. In 1998 the government spet four times as much on servicing debt as funding education.
Since 1997, aid from donor governments has been suspended until World Bank demands for measures against corruption, poor government and lack of transparency in financial management are met.
Only 40 per cent of one million pupils who enter school each year complete the primary cycle. Drop-out is highest among girls. "In some districts 80 per cent of girls drop out before they complete the eight years of primary education," says education secretary Wilfred Kimalaat.
With 80 per cent of education spending going on teachers' wages, schools are starved of funds for construction and maintenance and it is common to have pupils study under the shade of a tree.
To compound the problem, the number of Aids orphans is expected to rise from 860,000 to 1.5 million in 2005. Many of those will drop out to earn money for their families or care for ill relatives.
Teachers have also died in large numbers - five to six die a day from Aids - depriving the system of staff.
As the world goes to Dakar the goal of illiteracy eradication for Kenya seems to be further away than ever.