We use physics rather than chemistry to treat water.

5.Applications by Sector

Maritech’s physical treatment technologies are applicable wherever water comes into contact with surfaces that must remain clean. The following sections describe the specific challenges and solutions for each major sector.

5.1 Drinking Water & Sanitary Systems

Cold and hot water distribution systems in buildings — hotels, hospitals, public buildings and industrial facilities — are a primary risk environment for Legionella and other pathogens. Dead-end pipes, infrequently used outlets and temperature stratification in storage tanks all contribute to biofilm growth.

Physical treatment provides continuous 24/7 protection without requiring chemical dosing, thermal shock cycles or system shutdown. The result is a safe water system with substantial energy savings.

5.2 Rainwater Collection & Recycling

Rainwater harvesting tanks and recirculation systems used in agriculture, industry and building services are highly susceptible to algae growth (when open to the sunlight) and biofilm formation — particularly in the warmer months. Without treatment, algae blooms can block distribution lines, cause unpleasant odours and reduce water quality. After studying the installation and environmental parameters, we can offer systems that keep collection tanks and distribution lines clean without chemical or other additives.

5.3 UF Filtration & Reverse Osmosis Systems

Ultrafiltration (UF) and reverse osmosis (RO) membranes are among the most biofilm-susceptible components in any water treatment installation. Biofilm formation — the structured colonisation of membrane surfaces by microbial communities encased in extracellular polymeric substances (EPS) — is recognised as the primary driver of biofouling, which accounts for an estimated 45% of all membrane fouling events in water treatment systems.

Even a biofilm as thin as 10–20 µm can reduce membrane flux by 30–50% and cause a measurable rise in trans-membrane pressure (TMP), as the EPS matrix creates an additional hydraulic resistance layer and promotes concentration polarisation at the membrane surface. As the biofilm matures, quorum-sensing mechanisms allow microbial communities to coordinate gene expression, dramatically increasing EPS production and the structural resilience of the fouling layer. This makes established biofilms up to 1,000 times more resistant to biocides than their planktonic counterparts, rendering conventional chemical interventions progressively less effective over time.

From an operational standpoint, biofouling shortens membrane service life, increases specific energy consumption — studies have reported energy penalties of 20–40% in severely fouled RO systems — and drives up the frequency and chemical intensity of clean-in-place (CIP) cycles, with associated costs in reagents, downtime, and membrane degradation caused by repeated chemical exposure.

Physical pretreatment combining ultrasound and catalytic processes offers a compelling alternative pathway. Ultrasonic cavitation disrupts early-stage biofilm adhesion by generating localised shear forces and reactive oxygen species (ROS) at the membrane surface, inhibiting the initial conditioning-film formation that precedes bacterial attachment. Catalytic oxidation further degrades EPS constituents and targets the metabolic activity of sessile cells without the cumulative chemical loading associated with chlorination or alkaline CIP protocols. Together, these approaches demonstrably improve sustainable flux, extend membrane operational lifetime, and reduce both the frequency and the chemical aggressiveness of CIP interventions — translating directly into lower lifecycle costs and a reduced environmental footprint.

5.4 Industrial Water Systems

Cooling towers and heat exchangers

Cooling towers are widely recognised as the most significant environmental reservoir for Legionella pneumophila in the built environment. The warm, nutrient-rich water and large aerosol-generating surface area create near-ideal conditions for Legionella proliferation, particularly within established biofilms where the bacterium survives intracellularly within protozoan hosts such as Acanthamoeba spp. — a mechanism that confers substantial protection against both biocides and thermal disinfection. Epidemiological investigations consistently identify cooling tower bioaerosols as the primary transmission route in community Legionnaires’ disease outbreaks.

Beyond the microbiological hazard, cooling towers and heat exchangers are highly susceptible to the concurrent development of algae, scale and mixed-species biofouling. These processes are not independent: biofilm EPS matrices actively promote mineral precipitation by concentrating calcium, magnesium and carbonate ions at the surface, accelerating scale deposition and further reinforcing the fouling layer. The thermal consequences are well-documented — a biofilm deposit of just 0.5 mm on a heat exchange surface has been shown to reduce heat transfer efficiency by up to 25%, with corresponding increases in energy consumption and cooling load. Some studies report efficiency losses exceeding 90% in severely fouled systems operating over extended periods without intervention.

Ultrasonic and catalytic treatment systems address all of these failure modes simultaneously, preventing both biofilm establishment and scale nucleation, maintaining heat exchanger efficiency at or near design specification, and substantially reducing or eliminating dependence on biocidal cooling water chemicals — with consequent benefits for effluent quality and regulatory compliance.

Ultra-pure water (UPW) systems

Semiconductor fabrication, pharmaceutical manufacturing and advanced electronics production impose some of the most stringent water purity requirements of any industrial process, with resistivity targets typically at or approaching 18.2 MΩ·cm and total organic carbon (TOC) limits in the low parts-per-trillion range. Paradoxically, ultra-pure water presents a heightened biofilm risk rather than a reduced one. In the near-complete absence of organic nutrients, disinfectant residuals and competing ionic species, oligotrophic and ultramicrobacteria — including genera such as Ralstonia, Sphingomonas and Burkholderia — are selectively enriched. These organisms are physiologically adapted to subsist on trace carbon sources at concentrations below 10 µg/L and adhere rapidly to pipe walls, tank surfaces and membrane housings, forming thin but metabolically active biofilms that continuously shed cells and dissolved organic matter into the product water stream.

Even low-level microbial contamination in UPW systems can cause wafer defects, endotoxin excursions in pharmaceutical-grade water, and failure to meet compendial standards. Chemical disinfection is largely incompatible with UPW infrastructure, as any residual introduces ionic or organic contamination that undermines the purity specification. Physical treatment — particularly ultrasonic disruption of early-stage biofilm adhesion combined with catalytic oxidation of trace organics — addresses this challenge without introducing any chemical load into the water matrix, making it uniquely suited to UPW applications.

Automotive paint lines

Modern automotive painting and coating processes are among the most water-intensive finishing operations in manufacturing, relying on multi-stage rinse circuits, phosphating baths and electrocoat systems that recirculate large volumes of process water (often tens to hundreds of m³/h per line). Biofilm formation in these recirculation loops is a well-established cause of paint defects, adhesion failures and surface contamination, with even low particulate loads (few hundred µm/L) linked to measurable increases in crater density and fisheyes.

Sessile microbial communities release EPS, metabolic by-products and lysed cell debris into the water column, introducing particulate and colloidal contamination that interferes with surface preparation, disrupts phosphate conversion coating chemistry and causes visible coating defects including cratering, fisheyes and delamination. The economic consequences are significant: biofilm-related contamination contributes directly to elevated product reject rates, increased rework costs and unplanned line stoppages, with some surveys reporting 1–5% of total coating-line OEE lost to water-quality and fouling issues.

Historically, chromium(VI) compounds played a dual role as corrosion inhibitors and biofilm suppressants in paint-line water systems, but growing regulatory restrictions and bans on Cr(VI) have removed this “built-in” protection. The resulting increase in corrosion risk and microbial growth in rinse circuits has forced plants to rely more heavily on complex inhibitor packages, higher-dose biocides and auxiliary treatments, raising both operational costs and waste-treatment burdens.

Conventional responses — periodic shock dosing with biocides or surfactants — carry their own risks of surface contamination and are subject to increasingly stringent discharge regulations on TOC, AOX and nitrogen/phosphorus loads. Continuous catalytical & ultrasonic treatment, integrated into rinse-water recirculation circuits, prevents biofilm establishment at source, leveraging acoustic cavitation and shear forces to disrupt early-stage cell adhesion. When combined with careful design of flow conditions we can maintain water quality and surface cleanliness without continuous chemical intervention, eliminating recurring biocide costs and easing compliance pressure — making them particularly attractive in the post-Cr(VI) era where alternative corrosion and biofilm control strategies are more complex and costly.

5.5 Marine & Shipping

Professional shipping

Commercial vessels face biofilm challenges across multiple systems: cooling circuits (box coolers, tube coolers, plate coolers), sanitary water systems, ballast water, and submerged structural surfaces. Biofouling on a ship’s hull increases hydrodynamic drag and can raise fuel consumption by 10–40% within months.

Maritech provides economical physical treatment that provides an alternative for chemical use.

Ballast water treatment

The IMO Ballast Water Management Convention (BWM D-2 standard) requires treated ballast water to meet strict microbiological limits before discharge:

• Toxicogenic Vibrio cholerae (O1 and O139): < 1 colony per 100 ml
• Escherichia coli: < 250 CFU per 100 ml
• Intestinal Enterococci: < 100 CFU per 100 ml

The combined ultrasound and catalytic treatment can reduce disinfection by-products (DBPs) — including chlorine and bromine compounds — associated with conventional ballast water treatment, reducing environmental impact. Maritech is actively developing integrated solutions for ballast water treatment system enhancement.

Recreational shipping

Pleasure boats, yachts and marina infrastructure experience rapid biofouling in warm harbour water. Physical treatment prevents hull fouling and onboard sanitary water tanks.

5.6 Agriculture

Drip irrigation systems are particularly vulnerable to dripper blockage caused by biofilm and mineral scale — a major source of crop loss and irrigation inefficiency. In greenhouse and hydroponic systems, biofilm-assisted clogging can affect 10–30% of emitters within months, with mixed organic-inorganic deposits (EPS, Ca-P, Ca sulphate, Fe/Mn oxides) reducing flow and creating uneven nutrient distribution.

Biofilms in irrigation pipes also act as pathogen reservoirs, sheltering Pythium and other root rot organisms that contribute to “crazy roots,” patchy growth and reduced yields. In saline or blended water systems, biofilms become more EPS-rich and resilient, further shielding microbes and reducing the effectiveness of chemical disinfectants. Ultrasonic and catalytic treatment can maintain open drippers by disrupting early-stage biofilm formation, improving the biological cleanliness of irrigation water without leaving chemical residues that could harm crops or soil microbiota. However, successful implementation requires sufficient flow past the transducer, protection of sensitive root zones from cavitation noise and periodic mechanical cleaning to remove mineralised biofilm that ultrasound alone cannot remove.

Rainwater storage ponds and basins used in open field and greenhouse agriculture suffer from seasonal algae blooms, especially when fertiliser runoff or leachate increases nutrient loading. Algal mats can clog filters, increase turbidity and create oxygen fluctuations that stress equipment and water quality. Ultrasonic transducers submerged in or mounted near the basin can reduce algal biomass by 70% in optimised systems, without the need for copper sulphate or synthetic algaecides that accumulate in soil and suppress beneficial microbes. Practical limitations include variable efficacy across algal species, poor performance in highly eutrophic or turbid basins, and the need for multiple transducers and correct mounting depth to avoid treatment shadow zones.

In systems using open-air basins or surface water, biofilm-protected irrigation pipes can also harbour waterborne pathogens such as oomycetes of the genus Phytophthora, which cause devastating root rot and foliar diseases in potato and tomato. Phytophthora infestans and related species release zoospores that require liquid water for dispersal and can survive in biofilm-protected niches, then be transported directly to roots or foliage during irrigation events. Under humid conditions (10–20°C, >90% RH), infections manifest as water-soaked, greasy-looking lesions on leaves and stems, leading to rapid yield loss if not controlled.

In parallel, poorly managed catchment water and open-air basins create a risk of protozoan or oocyst-forming contaminants (analogous in behaviour to Cryptosporidium) entering the irrigation chain, particularly where inlet hygiene is weak. Combined physical treatment helps mitigate these risks while avoiding the long-term ecological and residue issues associated with chemicals or copper-based algaecides.

5.7 Food & Beverage

Breweries and beer dispensers

In brewing, biofilm and the related deposit known as beer stone (calcium oxalate, CaC₂O₄·H₂O, plus proteins and minerals) accumulate in fermentation tanks, storage vessels, heat exchangers and dispense lines. Beer stone forms through the interaction of malt-derived oxalate, hard water minerals (Ca, Mg), alkaline cleaning agents and amino acids (proteins), especially under cool, low-turbulence conditions typical of cold-crash tanks and keg lines. Its porous, crystalline structure provides an ideal substrate for beer-spoiling bacteria such as Lactobacillus and Pediococcus, acetic acid bacteria and wild yeasts, many of which can grow in beer with 4–6% ethanol and persist despite regular CIP.

The practical consequences are off-flavours (sour, cheesy, rancid notes), shortened shelf life, foam instability and dispensing problems, as well as reduced heat transfer efficiency in scaled heat exchangers and increased cleaning costs due to aggressive acid-based descaling. The Brewsonic transducer — submersed in the cooling water tank or glycol loop of a dispense system — removes biofilm and beer stone continuously by using ultrasonic cavitation and shear forces to disrupt attached microbial layers and prevent crystal nucleation. Once the system is clean, it can operate in purely preventive mode, reducing maintenance frequency, chemical use and downtime while improving foam quality and pour consistency.

Note: after installation on older systems, loosened biofilm, proteins and particulate beer stone can flush into the first glasses drawn; these should not be consumed until the system has been cleared and the pour is stable.

Dairy and food processing

Biofilm contamination in food processing environments leads to product spoilage, shortened shelf life, batch recalls and health risks. In brewery-linked or dairy processing plants, biofilms can persist in crevices, valves and gaskets, then re-seed process lines and packaging equipment, contributing to contamination events. Physical treatment methods — such as ultrasonic systems, advanced oxidation and mechanically enhanced cleaning — can reduce the duration and frequency of chemical CIP cycles, lowering downtime and water use while maintaining the microbiological cleanliness required by food safety regulations.

5.8 Fuel Storage

Modern fuels — especially biodiesel and blended fuels with increasing bio content (EN 16942:2016) — are significantly more susceptible to microbial contamination than traditional mineral diesels. Biodiesel (B100) and blends such as B20 can show microbial loads exceeding 10⁵ cells per litre after 60–90 days of storage, with acidity and water content rising by 1.5–2.5× compared with baseline conditions. The fuel-water interface in tanks becomes a hotspot for biofilm-forming “diesel bugs” (bacteria, yeasts and fungi such as Pseudomonas, Acinetobacter, Hormoconis resinae and Fusarium), which use free water and organic fuel components as their growth medium.

How biofilms and “diesel bug” form

Temperature fluctuations cause fuel tanks to “breathe,” drawing in moist air that condenses on tank walls and forms a water layer at the tank base. This water layer, combined with the presence of biodiesel-derived fatty acid methyl esters (FAME), provides both nutrients and hydration for microbial growth, accelerating biofilm formation on steel, plastic and gasket surfaces. Within days to weeks, slimy biofilms and “rag layers” appear at the fuel–water interface, acting as a continuous source of sludge and particulate matter.

In a recent study on diesel-biodiesel blends, B20 showed higher microbial diversity and faster early-stage colony growth than B0, while B100 suffered the most severe fuel deterioration after 60+ days of storage, with visible biofilm mats and dramatic increases in water content and acidity. Such biofilms shield organisms from conventional biocides and mechanical cleaning, allowing them to re-establish rapidly after treatment.

Practical problems caused by biofilm and diesel bacteria

The consequences of diesel bug contamination are both technical and economic:

• MIC corrosion: Sulphate-reducing bacteria (SRB) and other biofilm-forming species generate hydrogen sulphide (H₂S) and organic acids at the tank bottom, driving microbially influenced corrosion (MIC) of steel and brass components. In marine and industrial storage tanks, MIC-related wall thinning has led to catastrophic leaks and unplanned tank replacements, with repair costs often running into tens of thousands of dollars per site.
• Sludge and blockages: Biofilm-derived sludge and “gels” can reduce fuel flow by up to 80% in heavily contaminated systems, rapidly clogging filters, injectors and fuel lift pumps. In one documented case, a manufacturing plant saw 100% of its fuel filters plugged within two weeks due to microbial sludge, forcing emergency fuel replacement and over 75,000 USD in lost productivity.
• Engine and generator failure: Stagnant fuel in standby power systems (hospitals, airports, data centres, public buildings) is especially vulnerable because long-term idling allows biofilms and sludge to accumulate without the flushing effect of regular use. When these generators are called on during an outage, clogged filters or injectors can cause fuel starvation, rough running, black smoke episodes and, in extreme cases, complete engine failure.
• Fuel quality and regulatory issues: Microbial activity degrades fuel by increasing water content, acidity and particulate matter, shifting properties beyond specifications for ISO 4406 cleanliness and EN 590 / EN 14214 limits. Contaminated fuel may also trigger warranty disputes with engine manufacturers who can detect biofilm residues, sludge signatures and MIC-type corrosion in fuel injection hardware.

Ultrasonic treatment and verification

We can prevent microbial reproduction and disrupt early-stage biofilm and algae growth without chemical biocide or additives. In experimental and patent-based designs, ultrasonic systems operating in the 20–42 kHz range have been shown to reduce microbial counts in diesel and biodiesel blends by enhancing cavitation-driven cell lysis and turbulence at the fuel–water interface. In practice, such systems are most effective when combined with periodic water sounding and draining, because residual water layers continue to supply microbes, even under ultrasonic treatment.

The ASTM D7463-08 test method can be used to quantify microbial levels in fuel samples, providing a standardised way to verify the effectiveness of the treatments. ASTM D7463-08 measures adenosine triphosphate (ATP) in fuel and water phases, correlating ATP levels with viable microbial load and enabling operators to trigger cleaning or treatment cycles before filters plug and engines fail.

5.9 Swimming Pools & Jacuzzis

Conventional pool and spa treatment relies on chlorine at levels that cause skin and eye irritation and generate trihalomethane (THM) disinfection by-products. Physical and electro-chemical treatment (Cu) allows chlorine levels to be significantly reduced while maintaining full hygienic standards, improving bather comfort and water clarity.

6. Threats: Legionella, Algae & Corrosion

6.1 Legionella Pneumophila

Background

Legionella pneumophila is a gram-negative, aerobic, rod-shaped bacterium (1–2 µm) and the causative agent of Legionnaires’ disease — a severe and potentially fatal form of pneumonia — and the milder Pontiac fever. More than 50 Legionella species are known; L. pneumophila accounts for the majority of human cases.

Legionella is naturally present in surface water and soil, but becomes a public health threat when it colonises man-made water systems where conditions are favourable for explosive growth. The Philadelphia epidemic of July 1976 first brought the bacterium to public attention.

Growth characteristics

High-risk environments

• Cooling towers and HVAC systems in power stations, factories, hotels and hospitals
• Hot and cold water distribution in large buildings — particularly dead-end branches
• Public showers and shower systems not used for extended periods
• Jacuzzis, spa pools and steam rooms (ideal temperature and aerosol generation)
• Hospital water systems (particularly high risk for immunocompromised patients)
• Exhibition and trade fair venues that undergo periodic refurbishment
• Sediment at the base of tanks and heat exchangers — calcium scale provides shelter

Conventional control methods and their limitations

• Thermal shock disinfection (65–70°C for prescribed durations): energy-intensive; does not reach dead legs; biofilm insulates bacteria
• Continuous chlorination (3–4 mg/L): suppresses but does not eliminate growth; generates chlorinated by-products; corrosive to some materials
• UVC irradiation (254 nm): effective for planktonic bacteria; cannot penetrate biofilm
• Chemical shock disinfection (sodium hypochlorite, hydrogen peroxide, chlorine dioxide): costly; generates disinfection by-products; corrosive at effective concentrations

Physical treatment approach

Biofilm formation is the primary mechanism enabling Legionella colonisation in engineered water systems. By eliminating the biofilm substrate, Maritech’s technologies remove the protected environment that allows Legionella to survive, and disinfect by way of copper ionization.

Supporting research: NCBI studies 19854466 and 19962336; European ECDC Legionella guidelines.

“Prevention is the key to an effective solution.” — A reactive approach to Legionella is always more costly and disruptive than a continuous physical prevention strategy.

6.2 Algae

Overview

Algae are photosynthetic microorganisms that have existed for over 3.8 billion years. With over 300,000 known species (of which only ~30,000 have been studied), they represent extraordinary biological diversity. While algae are valuable as a potential biofuel and oxygen-producing resource, uncontrolled growth in industrial and recreational water systems is a serious problem.

Classification by pigment

Growth requirements

• Light (photosynthesis is the primary energy source)
• Carbon (CO₂ from water or atmosphere)
• Nitrogen (nitrate, ammonia, urea)
• Minerals: magnesium, potassium, calcium, phosphate
• Trace elements: aluminium, zinc, copper, iron

Optimal water temperature range: 15–35°C. Algae consume atmospheric CO₂ (carbon sequestration) and produce oxygen, making them ecologically important — but this same metabolic activity makes them problematic in closed or semi-closed water systems.

Problem environments

• Ornamental and fish ponds — toxin risk and pH fluctuations
• Man-made swimming pools and natural ponds — aesthetic problems
• Cooling water circuits — industrial installations / cooling towers
• Rainwater collection and recirculation systems — filter blockage and contamination
• Open reservoirs used in agriculture and horticulture — dripper blockage risk

6.3 Corrosion in Water Systems

Forms of corrosion

Microbiologically Influenced Corrosion (MIC)

MIC is the most insidious form of corrosion in water systems because it is driven by microbial activity within established biofilm. Sulphate-reducing bacteria (SRB) produce hydrogen sulphide (H₂S) as a metabolic by-product, which attacks steel directly and accelerates electrochemical corrosion. The result is localised pitting that can penetrate pipe walls far faster than general corrosion models predict.

The conventional response — increasing chemical dosing — can be counterproductive: many biocides are themselves corrosive at the concentrations required to penetrate biofilm. Physical biofilm prevention eliminates the primary condition for MIC without chemical risk.

A word on frequencies

Not all ultrasonic frequencies produce the same effects. Our systems are engineered to deliver specific frequencies and combinations that simultaneously target multiple mechanisms: cell wall resonance (algae destruction), acoustic cavitation (microbubble generation), and mechanical stress induction. Frequency selection is critical — a single-frequency system cannot replicate the multi-functional effect of properly combined broad-spectrum transducers.