Digester wastewaters are by-products of biogas production in anaerobic digesters. They require treatment prior to disposal. To meet regulation compliance, treatment options range from minor interventions such as selective contaminant removal, to major interventions such as minimum and zero liquid discharge (MLD/ZLD).
Ammonia Wastewater Treatment
Solutions for selective removal of ammonia/ammonium
There is no one-size-fits-all solution to removing ammonia from wastewater. Saltworks can help you understand your options, including hybridizing solutions with biological treatments to boost capacity and reliability, or provide entirely non-biological pathways.
Ammonia (NH3) is critical to many industrial and agricultural processes. As a serious and common water pollutant, it is becoming more heavily scrutinised and regulated. High ammonia concentrations can prevent the discharge or reuse of many waters.
Biological treatment is widely used to remove ammonia from wastewaters and can produce harmless nitrogen gas. However, biological treatment systems can be stretched by increases in industrial wastewater volumes, ammonia loads, or organics.
Saltworks can help you to meet your ammonia challenges by providing new treatment systems or expanding existing ones. We reduce the load on your biological assets.
Choosing the Right Treatment
Saltworks optimizes ammonia treatment and boosts ammonia capacities. Our engineers start with a comprehensive mass and energy balance review, with economic mapping of alternatives. Once complete, we provide:
- Targeted ammonia removal.
- Removal can be packaged with a SaltMaker crystallizer solution, removing waste brines from your system and producing a re-usable ammonium solid salt.
- Ammonia concentration with XtremeRO advanced reverse osmosis, while producing a clean freshwater permeate for re-use or discharge.
- Converting ammonia to nitrogen gas via chemical or electrochemical methods such as breakpoint chlorination.
Reverse Osmosis for Ammonia
RO treatment of ammonia requires specialized knowledge and plant configuration. Saltworks installs RO systems engineered to reject ammonia, operating at over 98% recovery. The result is clean freshwater that can be discharged, while wastewater is concentrated 50 times!
RO has moderate capital costs and very low operating costs assuming brine management costs are low. However, RO is sensitive to water type. It works best with non-scaling waters with TDS < 80,000 mg/L and when low-cost options for ammonia brine management are available.
We can help you to consider your options—and if warranted, deliver an ammonia RO concentrator plant. We can also help with that final 2% concentrated ammonium waste.
Ammonia wastewater is also treatable with chlorine (gas or hypochlorite), with simple equipment. Breakpoint chlorination is when there is sufficient chlorine to react with all present ammonia. Products include non-toxic chloramines, harmless nitrogen gas, and hydrochloric acid (wastewater becomes acidic).
Breakpoint chlorination is an excellent polish, removing virtually all ammonia and beneficially sanitizing the water. However, it requires appropriate safety training and equipment and chlorine consumption is directly proportional to ammonia mass, so for some wastewaters it can require large, expensive quantities of chlorine.
Because of relatively high operating costs but low capital costs, it is best suited for low ammonia levels (e.g. < 50 mg/L NH3) or low flow rates (i.e. < 10 m3/day), especially when the need is periodic (e.g. 10% of the year).
Contact us with your ammonia wastewater chemistry, flow rates, and treatment goals for an options assessment today.