The problem of effluents from F&D industries
Urban Waste Water Directive in practice virtually obligates all European SME industries that generate more than just 150 L/day to treat wastewater under their own responsibility and costs. National legislations can be even more restrictive. As proved in the EC report on The European Environment, the control of water pollution is costly due to high cost of investment and operation of treatment plants.
Today, European F&D industries have two options to treat wastewater:
- Centralised wastewater treatment: When many industries are located in the same place, a public wastewater treatment plant can be built nearby for the joint treatment of their effluents. F&D SMEs have to pay an important treatment fee, depending on the amount of water and its COD. The operation of these plants is often the responsibility of municipal authorities, which usually lack financial resources and administrative competence to complete treatment works.
- Decentralized wastewater treatment at their own facilities: almost only large F&D companies and the biggest medium-size enterprises can afford their own wastewater treatment plants. Their large effluent volumes dramatically reduce relative investment costs. The smaller the plant, the more expensive it is to treat a given volume of wastewater due to high initial investment. This results in either excessive water treatment costs that weaken productivity of SMEs, or cheap low-efficiency treatment that needs to be complemented by paying additional centralized treatments. In the worst case, deficiently treated wastewater is dumped to rivers.
Anyway, both options have important limitations:
- Limited biomass activity
- Higher investment costs: to maintain a higher biomass amount a bigger reactor
- Low reactor stability: Any sudden change in wastewater quality (pH, COD, bacterial nutrients), quantity or seasonality, impacts directly on methanogenic bacteria.
- Sensitive to toxic H2S. Hydrogen sulphide is particularly relevant in Food & Drink industries due to the use of sulphites and SO2 as food additives
- Very susceptible to acidification: lowering the pH (acidification inhibits methanogenesis until the system collapses.
The European Environmental Agency data show that efforts to reduce wastewater pollution at the F&D SMEs facilities before it enters the common treatment system are often cheaper than building new plants. This is true only if cost-effective decentralized solutions, as PhasepliT, are techno-economically available.
The proposed solution
PhasepliT goal is to clean wastewater in a decentralized way to comply with wastewater regulations. It will develop a wastewater reactor pack customised for its installation at small and medium Food and Drink companies. PhasepliT innovation relies on a triple solution to reduce investment, operation and maintenance costs of F&D SMEs and generate biogas:
A. Separation of the acidogenic and methanogenic steps. In this way, both phases can be optimized separately and therefore increase their efficiency and produce more energetic biogas. With an improved bacterial activity, smaller reactor volumes are needed, which will reduce the total size and therefore the capital investment.
B. PLC/SCADA control of PhasepliT reactor using fuzzy logic to ease operation and replace skilled worker’s costly services, thanks to the benefits of more easier monitored and controllable variables arising from phase separation.
C. Novel design SME-focused to:
- Maximizing biodegradable COD removal from wastewater in the F&D highest priority sectors (Fruit & Vegetables, Fish & Seafood and Drinks).
- Minimizes size of initial investment and operational cost during the working lifetime in comparison to current market alternatives.
- Minimizes pay-back period and provides enough renewable energy to cover its own energy consumption and generates a surplus of electricity and heat for saving energy in other stages of food processing.