The pilot project AWAREGIO („Modular wastewater treatment processes for the reuse of wastewater, nutrients and energy as an opportunity for small and medium-sized enterprises“) aims at the development of innovative, modular wastewater treatment methods to reuse water, wastewater nutrients and energy, opening up new market opportunities for small and medium-sized enterprises (SME), especially in areas affected by water scarcity or structural change in crop production, fish farming and drinking water substitution. In cooperation between research institutes from Aachen and Leipzig, small and medium-sized enterprises from Brandenburg, Saxony and North Rhine-Westphalia and the Left Lower Rhine Water Association (LINEG), a modular research plant with attached aquaponics was built on the area of the waste water treatment plant “Moers Gerdt”.
The multi-stage, modular wastewater treatment system is based on resource-sparing technologies and should enable a high degree of flexibility with regard to the types of reuse. The aim is to reuse 90% of the treated wastewater. Thereby nutrient use and (partial) desalination play an important role, as do resource efficiency in wastewater treatment and recycling, in order to increase water availability in the various uses. The intended scope of application is to be municipal wastewater treatment both in urban areas and in rural areas.
The approach enhances regional development in the following ways:
- development of modular wastewater treatment technologies, adapted to sparsely populated regions,
- enabling of new business opportunities in aquaponics/hydroponics-based production,
- employment effects in enterprises in the water treatment sector and
- strengthening of resilience against water scarcity and water resource depletion in the light of overuse and climate change.
In order to ensure the high demands on the hygienic and product qualities for food production and support of drinking water supply under real operating conditions, AWAREGIO develops and tests practicable analysis and monitoring methods.
Thanks to its resource-sparing and low-maintenance design, the proposed plant concept can also provide new impetus for the reuse of municipal wastewater in arid emerging and developing countries. The planned use of the pilot scale testing and demonstration plant for the training and further education of international specialists and executives will help to familiarize regional decision-makers with innovative wastewater technology solutions in Germany.
The pilot plant
The municipal wastewater of the wastewater treatment plant’s grit chamber serves as an input to the pilot plant. The treatment of the wastewater takes place in a multi-step, modular system (see following picture). After primary wastewater treatment, different secondary treatment techniques are used in parallel.
The primary wastewater treatment combines an Anaerobic Baffled Reactor (ABR) and Anaerobic Filter (AF) with an anoxic Moving Bed Biofilm Reactor (MBBRD) and a Trickling Filter (TF) to ensure an energy and cost-efficient as well as low-maintenance primary treatment of the pilot plant.
A range of secondary treatment modules producing different effluent qualities (Q) are being evaluated. An operationally simple approach (Q1) is a Constructed Wetland (CW). As an alternative approach (Q2), the operability of an UV disinfection unit is being assessed. More sophisticated secondary treatment options producing higher effluent qualities (Q3 and Q4, respectively) are an Ultrafiltration (UF) and a downstream Low Pressure Reverse Osmosis (RO) module. Additionally, nitrogen- and phosphorous-recovery for agricultural fertilizer application is obtained in a physico-chemical post-treatment of the RO-concentrate (Q5).
In the greenhouse of the AWAREGIO pilot plant site four separate aquaponics systems are operated utilizing the process water Q1 (CW), Q2 (UV), Q3 (UF) and well water as a reference.
The RO concentrate should again be oxidatively processed to reduce the inert COD before it is recycled or discharged (Q6).
For the sewage sludge resulting from the steps of primary treatment, the options are disposal or – if necessary, subsequent stabilization or dewatering (Q7) – agricultural utilization. This can be done directly or after thermal conditioning (e.g., mineralization).