HOW TO MAKE
WASTEWATER REUSE
WORTH IT

The TAYA technology for wastewater treatment has been developed to meet the requirements for a decentralized WWTP, emphasizing simplicity of operation, process stability and reliability, low investment, and low operational costs, enabling easy and affordable autonomous wastewater treatment.
Decentralized WWTP enables wastewater reuse within the rural communities, increasing freshwater savings, due to the following:

• The local wastewater treatment delivers high-quality effluent level with no need to purchase tap water suitable for agriculture irrigation.
• There is no need to establish a large WWTP or to convey the wastewater through long pipelines, saving all related costs.
• Lower investment and operational costs are incurred on the end users compared to a centralized WWTP.

There are three major guidelines for designing a decentralized WWTP that can continuously operate in a remote location, supply a high-quality stable, and set a reliable effluent.

1. Low investment cost

It is important that the WWTP is constructed from local materials, mainly in developing countries to keep costs down.

Rural communities often use pond-based wastewater treatment technologies which do not meet the new effluent standards. Upgrading them via retrofitting to newer technologies can provide an economic advantage.

2. Low operational cost

Reducing OPEX in local plants depends on multiple factors ranging from labor and skill level, to sludge handling and waste disposal, due to the low capacity of the treated wastewater:
• Labor
• Skill level of operator
• Laboratory analysis
• Process support
• Equipment maintenance
• Chemical costs
• Secondary sludge produced
• Electricity consumption

3. Reliability and simplicity of O&M

A decentralized WWTP must be easy to operate, without the need for daily adjustments and maintenance by skilled labor in order to produce the effluent qualities required.

In practice these guidelines are translated into minimum electromechanical equipment, no chemical dosing, no secondary sludge handling, and small electricity connection as well as low electricity demand.

TAYA technology was developed under these guidelines to produce an aerobic anoxic, fixed film reactor, designed to reduce organic matter and nitrogenous compounds.

Using dual passive aeration units, wastewater is constantly circulated between two basins by first filling one basin, then the other.

As the basin is filled, the biofilm receives nutrients and organic matter. After draining the basin, passive aeration allows oxygen to be supplied and for COD oxidation and nitrification to occur.

TAYA technology allows for simultaneous nitrification/denitrification (SND) as it occurs during the drain phase, while denitrification occurs during the fill phase.

As in constructed wetlands, the TAYA design parameters are calculated to prevent excessive biomass growth. It allows minimum secondary sludge and maintains the system’s hydraulic conductivity.

INVESTMENT AND OPERATIONAL COSTS

Table 2. Operation cost comparison – MBR vs. TAYA

TAYA costs were also compared to activated sludge WWTPs located in rural communities in Israel.

Table 3. Operation cost comparison – Activated sludge vs. TAYA

CAPEX

Comparing investment costs for different technologies is complicated as the construction regulations and demands as well as materials and construction costs change in different countries.

The investment cost for TAYA is 25%-40% less in comparison with activated sludge WWTPs. As rural communities often use pond-based simple wastewater treatment plants, it’s possible to retrofit them and use TAYA treatment schemes for anaerobic ponds.