Biogas waste water treatment affordable, environment friendly

by Surekha GALAGODA

"There are many companies treating waste water with aerated technology, but none use bio gas technology," said Engineer, Athula Wijemanne.

Athula Wijemanne receives the Green Jobs Award from Environment Minister Anura Priyadarshana Yapa.

He said that (Upflow Anaerobic Floating Filter (UAFF) consumes energy, therefore it is costly compared to bio gas technology which consumes no energy as well as no moving parts.

It is a total bacterial treatment where the bacteria generates bio gas as a result of the treatment.

Wijemanne started research 20 years ago at the NERD Centre. He had been attached to the NERD centre for 25 years and was fortunate to work with world renowned persons like Engineer A.N.S. Kulasinghe.

He said that since he was successful with laboratory skills he had published many papers in international journals which paved the way for him to obtain a scholarship to AIT Bangkok where he obtained a masters degree in waste water treatment according to bio gas technology.

Many uses

During that period I did many studies on the application of this technology at field level, he said.

On his return he selected DC mills , bakeries, breweries and conducted field research related to these industries. The field level application was very successful which helped to apply the technology at full scale for rice, coconut, rubber mills, distilleries, breweries, garment factories as well as the hotel and meat industries.

The main advantage is that bio gas can be utilised for many other purposes which save more money for industrialists. In coconut mills the bio gas is utilised for thermal requirement of the mils while in rice mills it is used for cooking the meals of the workers. Rockland and Sri Lanka distilleries use bio gas to operate boilers.

Wijemanne. said that at household level also he had done some bio gas units using toilet waste water, solid waste water, kitchen waste water are sufficient to produce bio gas for cooking.

Rice growing areas

In addition the treated water can be used as liquid fertilizer for gardening which will give chemical free vegetables.

Waste water system according to Anaerobic filter technology at Soorya Rice & Rice Flour Processing Pvt Ltd Thamankaduwa, Polonnaruwa.

A bio gas unit

He said that at present there is a severe problem in the rice growing areas. In Polonnaruwa alone there are 200 mills emanating polluted waste water to the nearby irrigational canals.

As a result there are many problems to the environment which includes low paddy yield while the small rice plants die a natural death due to the use of polluted water from the canals for watering.

Soorya Rice Mill processes 1000 kgs of paddy per day while the waste water output is 80,000 liters. By using the bio gas technology they cook three meals for 100 workers.

In 2009 Wijemanne developed another technology to treat acidic waste water which comes from coconut mills, rubber mills and distilleries. All over the world prior to treating the waste water the acidic concentration is neutralised for which chemicals have to be used and this process is very costly.

According to Wijemanne his system is a methodology of feeding control systems. It eliminates all the money spent on chemicals to neurtalise the acidic condition.

He said that he has developed bacteria to digest the dye which is the poisonous waste water which comes from washing plants.

Wijemanne has also developed a special waste water treatment system for Pelwatta Sugar and Pelwatta Distilleries.

Awards

He has won many awards and certificates which includes the Green Job Award from Environment Minister Anura Priyadarshana Yapa.

Future plans

He said Sri Lankan industrialists spend a lot of money on waste water systems and his only aim is to make it affordable as well as give good returns for the industry. Therefore, he wants to further develop the technologies to be affordable and user friendly.

There are many soft loans to implement these environment friendly technologies and all industrialists can avail themselves of these loans.