Utility – industry symbiosis
HIAS IKS and IVAR IKS are two inter-municipal companies that treat a total load of 570 000 pe municipal and industrial wastewater. The WWTPs are in the process of converting from chemical phosphorus removal to enhanced biological phosphorus removal (EBPR). HIAS is implementing an innovative continuous moving bed biofilm reactor (MBBR) process in collaboration with their partner, the SME Hias How2O. Biogas is produced by digestion of the sludge. Pilot trials with struvite precipitation for P-recovery have been performed and will be implemented in full scale to recover 18-30 tons P/year. Sirkula is a state-owned company in the supply chain producing biosolids from various organic waste including wastewater sludge, and responsible for collection of household waste and operation of several recycling stations for handling of source separated waste fractions. At IVAR, there is co-digestion of food waste and sludge, and the biogas is adjusted and mixed with natural gas in a mixed energy grid for the region. The SME HØST AS (earlier Norsk Jordforbedring AS) produces pelletized organic fertilizer from the residual sludge.

Objective
Demonstrate solutions for: i) Phosphorus recycling to agriculture based on innovative continuous MBBR process for EBPR; ii) Production of both organic and balanced inorganic fertilizers; iii) Increased support to the gas-based regional energy grid.

Key stakeholders and partners
Sirkula, HØST, Grødaland industry park, Felleskjøpet (agriculture supplier), SINTEF and NTNU.

Stavanger and Hamar case – innovative actions
HIAS is implementing an innovative continuous MBBR process for enhanced biological phosphorus removal (EBPR) in collaboration with their commercial partner Hias How2O. A sludge processing line for recovery of P from the EBPR sludge will be established. Biogas is produced by digestion of the sludge. Pilot trials with struvite precipitation for P-recovery have been performed and will be implemented in full scale to recover 18-30 tons P/year, corresponding to 200-350 ton struvite/year at HIAS IKS. Recovered struvite will be processed to obtain a quality required for application as a fertiliser. Sirkula will address new pathways for distribution of the product to the agricultural sector. IVAR IKS has invested in new plants during the recent years for wastewater treatment, sludge treatment, handling and treatment of solid organic waste. All processes are designed and operated for maximizing reuse of energy and nutrients. At IVAR IKS, process solutions to maximize the impact of available carbon for energy production, minimize operational problems of unintended struvite formation and harvest the nutrients for industrial use will be demonstrated. The demonstrations will show how to establish an optimized resources recovery considering different local conditions.

Outcomes
The goal is to reach the total phosphorus discharge limits without using any chemicals for precipitation. The existing production of organic fertilizers and inorganic fertilizers in the Minorga process will be improved by use of P and N from the treatment plants. P-recovery (> 50%) by struvite precipitation will be demonstrated. Struvite, biomass and organic waste streams will contribute to production of a peat-free biosolid (or organic fertilizer) in compliance with upcoming revised regulations and appropriate to meet the needs of agriculture and produced soil.