APOC Technology
Indice degli argomenti
-
The APOC system stands for “Anaerobic digestion”, “Photocatalytic Oxidation” and “Constructed wetland”, the three components of the eco-innovative wastewater treatment system proposed by the AQUACYCLE project.
APOC technology has been currently validated at demonstration level in operational environment (TRL7) (APOC demo plant of 5 m3/d treatment capacity in Blanca Wastewater Treatment Plant in Murcia, Spain, by ESAMUR). Two further APOC demonstration plants with a capacity of 10-15 m3/d are under construction in the Tripoli region (Deddeh Koura), Lebanon, and Zaghouan (Bent Saidane), Tunisia. The responsible partners are the Lebanese University and the Tunis International Centre for Environmental Technologies (CITET)".
Anaerobic treatment and constructed wetland are two mature and commercialized technologies with wide applications in the wastewater treatment market, that are combined with a novel solar disinfection/photocatalytic oxidation process towards the treatment of municipal wastewater at a level that satisfies the most stringent standards for reuse.
The APOC system is considered an integrated system that treats wastewater, both black and grey water, mostly at community, or even larger, scale, particularly promising for decentralized treatment implementations. It comprises of three processes, the anaerobic digestion (AD), the constructed wetlands (CWs), and a solar process based on the photo-Fenton technique for the cost-effective treatment of urban wastewater, with minimal operating cost and maximum environmental benefits. The three components can be modified by the plant designer, depending on the influent characteristics and the treatment objectives. Specifically, different types of AD reactors and CWs can be applied, whereas the post-treatment in a novel solar raceway pond reactor (RPR) is a distinctive feature of the APOC system.
APOC can be then designed for a single objective, which then would be just to treat water, or with multiple objectives, whereby treating water is always included. Engineers should seek however, multi-objective solutions. The most important criteria that must be assessed in process analysis and selection of APOC system include a) process applicability, b) applicable flow range, c) applicable flow variation, d) influent wastewater characteristics, e) climatic constraints, f) energy requirements, g) operating and maintenance requirements, h) complexity. Along this direction, the implementation of the APOC system has shown that all three components have to be designed to operate over a wide range of flowrates.
The distinctive features of APOC technology make it eco-friendly, efficient and cost-effective as it is based on natural systems, it uses less chemicals, runs on renewable energy (solar irradiation), produces biogas, fertiliser and a clean water for reuse in agriculture, in domestic, industrial or other applications, and the constructed wetland thrives as a habitant, an ecological tourist attraction aside from being a climate change mitigation measure. In comparison to conventional domestic wastewater treatment processes and other tertiary water reclamation methods APOC is characterized by distinct attributes in relation to cost, social acceptability, simplicity of design, construction, operation and maintenance, hydrogeological conditions and local availability of materials and skills. These attributes are related with the innovative and effective combination of processes which are less intensive, consume less energy, based on natural processes and result in products of significant added value (biogas, solid fertilizer and clean water for reuse).
Fields of application
APOC is an eco-innovative wastewater treatment process scheme for sustainable treatment and reuse of municipal wastewater in small and medium size.
Beneficiaries
The beneficiaries include the staff of public and private entities, sewerage companies, engineers, constructors, operators of wastewater treatment plants (WWTPs), the farmers and the general public/local community. For the latter, the APOC system contributes to the provision of an additional water supply that would otherwise be lost, thus preventing the high cost of importing freshwater and conveying it over a long distance. In areas where the water demand is not met: Additional revenue from the sale of reclaimed water and savings in the form of avoided or delayed costs of developing new fresh water sources and less treatment of surface water abstraction. For farmers, the APOC system provides an alternative water source for irrigation, that is readily available all year, as well as additional source of fertilizer (solid digestate) and nutrients, lessening the need to apply synthetic fertilizers. A decentralized APOC reuse system could reduce the impact of combined sewer overflows emissions and recharge local rivers to maintain the ecology and enable aquifer recharge. Improvement in public health, by protecting downstream water supplies from contaminations (and so, indirectly decreasing the costs of treatment for those downstream communities.
References/online resources
https://etraining-aquacycle.eu/elearning/apoc
https://bpinventory.com/best-practice/apoc-eco-innovative-wastewater-treatment-process-scheme-sustainable-treatment-and
Contacts
Konstantinos Plakas
📧kplakas@certh.gr