Winery liquid treatment processes

What are the key processes in winery liquid treatment?

1. preliminary treatment

2. primary treatment

3. secondary treatment

4. advanced (tertiary) treatment

5. post treatment

6. sludge disposal

Why do treatment processes widely vary in design?

due to:

• WW composition and volume

• treated WW quality requirements

• new & improved technologies

• variety of available processes

• scale

• chemical and resource availability

• designers opinion and bias

What are the key drivers of liquid waste treatment?

• end use (MOST IMPORTANT FACTOR)

  • all treatment options have strengths and limitations

  • in choosing treatment system - must minimise capital costs, operating costs and make system as automated and robust as possible

  • must be fit for purpose

What are the key quantitative indicators in liquid treatment?

• operators

  • need rapid and reliable quantitative indicators

    • to determine if effluent meets allowable thresholds

    • diagnose, optimise & troubleshoot the plant processes

  • key indicators:

    • pH, EC, DO, COD, turbidity

    • BOD - biological oxygen demand - useful indicator, expensive too large a lag time to assist with day to day management

    • COD suggested as a surrogate

    • Sodium adsorption ratio (SAR) of irrigation water provides a good indicator of potential damage to soil structure through repeated application of the wastewater (reuse and irrigation)

What is a woodlot and how are they used in liquid treatment/disposal?

a designated area, where WWW ends up being irrigated on (instead of vineyard)

long term impacts of major concern to industry and regulators

sodium ions present can accumulate in soil

• with time, sodicity causes dispersion of clay particles

• leads to surface crusting, reductions in water infiltration, water logging, erosion and poor soil fertility

What is the typical impact of WWW irrigation on groundwater nitrate levels?

• generally low risk

• small peaks of nitrate-N (max ~ 3.6mg/L) detected in shallow ground water

• levels well below 10 mg/L NO₃^--N (safe for potable use)

• lower than nitrate levels after typical urea application ~20 mg/L

What is the most persistent issue in WWW management and how should it be addressed?

• SALT most persistent problem

• best addressed by controlling winery practices

• reduced BOD/COD to simplify WW management and minimise wine loss

• rapid irrigation after minimal treatment is cost-effective

• requires monitoring to confirm consistency

What are the key challenges preventing effective waste minimisation in the wine indsutry?

• practices often ad hoc and inefficient

• lack of systematic methodology to target specific waste streams

• external motivations are often the main drivers

• failure to realise full potential due to lack of strategic planning

• industry needs to follow reduce, reuse and recycle principles

What is recommended for improving waste minimisation in wineries?

• adopt best practice principles - reduce, reuse, recycle

• implement systematic, targeted waste management approaches

• move beyond external motivations to internal sustainability strategies

What are key features of low-cost treatment systems for small wineries?

• designed for wineries crushing a few hundred to few thousand tonnes

• aim to minimise capital and operating costs

• system should be as automated and robust as possible

• prototype uses sedimentation/anaerobic digestion, low-level aeration, and a soil based WW bioremediation cell

• shows promising results for rural small WWW treatment

What treatment strategies are suitable for larger wineries?

Can afford more complex and costly systems

options include:

• conventional aerobic and anaerobic systems

• sequencing batch reactors

• combined anaerobic/aerobic systems

• artificial wetlands

each technology has its own +/-

During preliminary treatment of WW what is involved?

1. screens

   • gross solids removal (coarse)

   • suspended solids (SS) removal (fine)

2. grit chambers

   • remove sand, rocks, heavy material

3. pH correction

   • acid - HCl, CO2; base - caustic, lime

During primary treatment of WW what is involved?

Sedimentation

• rectangular/circular flow settling tanks with plates or tubes

• may employ coagulation and flocculation to enhance particulate removal

Removal of SS > ~ 1μm

Dissolved air flotation

• rectangular flotation tanks with skimmers

• may employ coagulation and flocculation to enhance particulate removal

removal of SS with poor settling characteristics

During secondary treatment of WW what is involved?

Biological treatment

microorganisms convert organic (& inorganic) wastes to harmless end products

2 types: aerobic (O2 present) and anaerobic (O2 absent)

Main processes:

• activated sludge

• oxidation ditches

• anaerobic digestion

• tricking filters

• wetlands

• lagoons/ponds

What are the key features of sequencing batch reactors (SBR)?

• can be operated as aerobic or anaerobic systems

• provide similar COD removal in both modes

• can tolerate shock loads (e.g., variable WW strength 0:25:1 to 5:1 COD:BOD)

• generate high volatile suspended solids concentrations in sludge

what are the main advantages of SBRs for WWW treatment?

• single reactor handles equalisation, clarification and biological treatment

• high operating flexibility and control

• small footprint (space efficient)

• capital cost savings due to integrated design

What are the main disadvantages of SBRs?

• require high operator skill - timers and control systems

• high maintenance needs

• risk of floating or settled solids being dishcharged during draw/decant phases

• risk of aerator plugging

• may need additional flow equalisation after SBR

what are the key operational features of membrane bioreactors?

• adjustable solids residence time

• can be used in both aerobic and anaerobic modes

• allow for thigh control over biological treatment conditions

• submerged mode is generally preferred due to lower fouling rates

what are the main challenges or problems associated with MBRs?

• membrane fouling biggest issue

  • caused by slime polymers in supernatant

  • capsule polymers around bacteria promote flocculation and fouling

• granulation of cells is poorly understood

• SRT (solids retention time - average amount of time that solid particles (like microorganisms) spend in the treatment system), particle size, SS, low food-to-microorganism ratios

How can filterability be assessed in MBR systems?

• filterability is a key performance factor

• measured by analysing EPS - extractable polymer substances

• EPS is primarily composed of proteins and polysaccharides

What is involved in anaerobic digestion?

Complex process

• results in breakdown of organics : harmless end products CH4 and CO2

• production line of microorganisms

• sumarrised as:

carbohydrates, fats proteins → volatile fatty acids → CH4, CO2, H2S

needs steady conditions - sensitive to pH, temperature and shock loads

low energy use

What are the operating modes of anaerobic digestion?

1. conventional

   • continuous or intermittent feed

   • no solids separation

   • retention time ~ 30 days

2. anaerobic contact

   • separation and re-circulation of seed organism

   • retention time reduced to 6-12 hrs

   • CH4 production = 0.4 m3 gas/kg COD removed

During advanced/tertiary treatment of WW what is involved?

Biological nutrient removal

microorganisms used to remove N and P by combination of aerobic, anoxic and anaerobic treatment processes

• N removed as gaseous N2

• P removed as M/O biomass

• N and P responsible for eutrophication and algal blooms in receiving waters

• treatment steps may be separate or combined

• BNR may also be combined with secondary treatment

What processes (during advanced/tertiary treatment) can be used in the removal of N from WW?

• breakpoint chlorination → NH3 removal (ammonia)

• chemical coagulation → organic N removal

• ion exchange → NH3/nitrate removal

• filtration → organic N /nitrate removal

• air stripping → NH3 removal (ammonia)

• electrodialysis → NH3/organic N/nitrate removal

• reverse osmosis → NH3/organic N/nitrate removal

What processes (during advanced/tertiary treatment) can be used in the removal of P from WW?

Lime or alum precipitation with sedimentation and filtration

when is chemical/physical treatment used in WWW management, and what does it achieve?

• used when re-use or restrictive discharge standards must be met

• involves a combination of chemical and physical methods

• provides water suitable for:

  • re-use applications

  • discharges with strict quality requirements

• goes beyond what secondary and nutrient removal can achieve

During post treatment of WW what is involved?

Disinfection

• chlorine

• chloramines

• hydrogen peroxide

• chlorine dioxide

• ozone

• ultraviolet light

During sludge disposal of treated WWW what is involved?

• concentration

• stabilisation

• conditioning

• dewatering

• final disposal

During concentration in sludge disposal of treated WWW what is involved?

• clarifiers - sedimentation thickening

• flotation thickening

• centrifugal thickening

• gravity belt thickening

During stabilisation in sludge disposal of treated WWW what is involved?

reduce pathogens, eliminate odours and minimise putrefaction (decay/rotting) potential

• anaerobic digestion

• lime stabilisation

• composting

• heat treatment

During conditioning in sludge disposal of treated WWW what is involved?

for dewatering

• chemicals - lime, chlorine

• heat treatment

During disinfection in sludge disposal of treated WWW what is involved?

• chemical - lime chlorine

• incineration

• high energy ionisation

• pasteurisation

During dewatering in sludge disposal of treated WWW what is involved?

• vacuum filtration

• centrifugation

• filter press

• sludge drying bed

• heat drying - fluidised bed

During the final disposal in sludge disposal of treated WWW what is involved?

• incineration - land disposal

• fertiliser

• land disposal