case

NSR – Increasing biogas production sustainably

Biogas answering renewable energy demands

NSR, a progressive waste recycling company operating in Southern Sweden, is one of the leading biogas producers in the country. The company has made its mark on sustainable waste management based on high levels of reuse and recycling. NSR’s biogas plant uses a full circle process, in which biogas energy is extracted from the substrate, and the remaining digestate is used as a biofertilizer on local agricultural farms. The procedure helps to minimize the amount of waste going to landfill.

NSR’s biogas plant in Helsingborg processes 70,000 tons of organic substrate each year, and expects to make four million Nm3 of upgraded gas in 2012. NSR’s long-haul plans are set even higher: the company aims at increasing the production of upgraded gas from four to eight million Nm3, which means doubling the biogas plant capacity.

Biogas digestion product (BDP) technology increases organic loading rate

For Irene Bohn, who works as a research scientist in NSR, the criteria for finding the right solution are clear. “Our aim is to get the best utilization of all the resources we have for the most beneficial environmental effects.” NSR has already enhanced its biogas production in Helsingborg by using a biogas digestion treatment, which is based on Kemira BDP technology. The Kemira BDP technology makes use of the combination of iron, acid and trace elements which boost the biogas production. Through the use of this treatment, NSR has lifted the organic loading rate of the plant by 33% and improved its biogas production significantly.

Process flexibility and stability from BDP treatment

The BDP treatment stabilizes the biogas production process and eliminates some of the earlier problems. ”Before adding the BDP 825, increased levels of volatile fatty acids (VFA) made the process unstable”, says Irene Bohn. “After the BDP treatment the VFA decreased and we could increase the organic loading rate, which resulted in much more biogas being produced.” Furthermore, NSR’s process engineer Marcus Möller points out that the treatment also allows greater flexibility. “The process is far less sensitive to changes and possible upsets. The whole line is now more robust and tolerates variations and swings much better.”