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Water Treatment Trial 3 Mile Creek, Waihi Beach Prepared by Paul Scholes, Environmental Scientist

1 Introduction _____________________________________________________________ 2

2 Treatment Products _______________________________________________________ 3

2.1 Ensol 1000___________________________________________________________ 3

2.2 Pond Treat PT-450 ___________________________________________________ 4

3 Method__________________________________________________________________ 5

4 Results __________________________________________________________________ 6

4.1 Bacterial ____________________________________________________________ 6

4.2 Dissolved Oxygen_____________________________________________________ 9

4.3 Conductivity________________________________________________________ 10

5 Discussion ______________________________________________________________ 10

5.1 Water Quality and Results Anticipated____________ Error! Bookmark not defined.

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1 Introduction

3 Mile Creek situated in Waihi Beach (Figure 1) has generally poor water quality and has an elevated faecal load. The pathogens indicated by sampling of the stream at the outlet onto the beach can pose a health risk to recreational users of water bodies. The creek has a low flow and is shallow and therefore is attractive to children which have a higher risk of being infected by pathogens associated with faecal contamination. The creek has a relatively short distance to travel before it reaches the coast, and much of journey is over flat land having a small gradient. Flow is affected by the aggradation of sand at the coastal outlet, the changing tides, and the input from springs and the Waihi Beach Waste Water Treatment Plant (WWTP). The discharge from the WTTP can double the flow in the creek. As the catchment is relatively small and the distance for water to travel from the upper catchment to the lower catchment is short (4 to 5 kilometres), water from the top of the catchment would take approximately half a day to reach the creek mouth (at an estimated 0.1 m/s stream velocity). The die-off rate for pathogens in the system is relatively small. Pathogens accumulate in the sediment, and as the system has a low flow they are not well flushed. This results in an accumulated reservoir of pathogens. To reduce the pathogen input requires reducing the faecal loading from both intensive livestock agriculture and the WTTP. Improving farming practices and the waste-water treatment process may only make small gains in improving the pathogen reservoir contained in the creek. The lowland part of the creek has degraded water quality in part due to the flow regime and other factors (e.g. channelisation, lack of shading, drain blockages and backflow, other contaminants (i.e. nutrients)). Gains in general water quality are likely to result in less bacterial pooling. The objective of the treatment trial is to test water treatment products to firstly see if they provide a mechanism to relieve the reservoir of pathogens, and secondly to improve the water quality of the creek. The underlying hypothesis of the trial is that treatment products will stimulate bacterial action in the sediments and sediment-water interface, displacing bacteria indicators of pathogenic species in the sediments. The trial aims to measure the impact of these treatments in a contained fashion.

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Figure 1: Location map of 3 Mile Creek, Waihi Beach.

2 Treatment Products

2.1 Ensol 1000

Ensol 1000 is a product designed to treat dairy effluent and agricultural waste by supplying large amounts of chemically bound oxygen and bacterial growth enhancers to allow waste to be digested aerobically with positive effects on the pasture that it is sprayed over. The use of Ensol 1000 has been shown to improve pasture quality, increase milk production, increased soil health, elimination of odours and greenhouse gases, and improved effluent quality from wastewater treatment ponds. Ensol 1000 supplies oxygen that is in the correct state and is available for bacterial action. Ensol 1000 does not supply dissolved oxygen (DO) but supplies a molecular active oxygen that some (the main bacteria normally found in human and animal waste) bacteria prefer over DO. Dissolved oxygen is essential for fish and other aquatic life to breathe. Many microbial bacterial forms require it, as well. The oxygen bound in the water molecule (H2O) is not available for this purpose, and is in the wrong "oxidation state". The low solubility of oxygen in water means that it does not take much oxygen-consuming life to deplete the DO. Ensol 1000 is based on a chemical called BM500 which allows for different mixing/concentration considerations, tuned for specific horticultural/agricultural requirements. BM500 is an industrial bio-stimulant. It is non-hazardous and completely biodegradable. Its properties allow for instant odour elimination upon contact with malodorous molecules and can be used in the treatment of liquid and solid organic waste. The formula is designed to hyper-accelerate the activity of indigenous microbes, mainly facultative anaerobes, inhabiting waste environments by providing an abundance of oxygen (electron acceptor) for metabolism to occur.

WTTP Trial site

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The addition of treatment products to relatively small portions of water within the creek pose almost no risk to alteration of the overall state of the creek in terms of water quality and ecology. Ensol 1000 is designed to hyper-accelerate the activity of indigenous microbes, mainly facultative anaerobes, inhabiting waste environments by providing an abundance of oxygen (electron acceptor) for metabolism to occur. The uniqueness of Ensol 1000 is that it is produced by a chemistry technique in which the reaction is endothermic (energy absorbing). For every molecule of this chemical, six atoms of oxygen are available for microbial usage compared to two atoms for metal peroxides and four for permanganates. In order for bacterial respiration or metabolism to occur, electron acceptors are required in the oxidation (metabolism) process. The most energetically favourable electron acceptor is oxygen (O2), nitrate (NO3) being next, and sulphate (SO4) being the least energetically favourable electron acceptor. Ensol 1000 is a non-biocide, non-enzyme, non-bacterial, non-volatile, pH neutral liquid. Its reaction with organic material is the same as nature’s reaction, only highly accelerated by the addition of large amounts of oxygen. A 96 hour LC50 fathead minnow test has been performed. The mortality rate was 20 percent after 96 hours at a concentration of 750 mg/L. At a concentration of 400 mg/L no mortality occurred in the 96 hour test period. These concentrations are still well above the around 20 mg/L expected to be used for the trial.

2.2 Pond Treat PT-450

There are a range of microbes and enzymes discovered in the natural environment that perform essential activities in the aquatic environment to maintain a balanced system. In the natural environment, both bacteria and the enzymes they produce play a significant part in biodegradation. Bacteria produce the enzymes essential for metabolising the food source (organic material) into energy necessary for further growth of the living organism. The enzymes facilitate the phase of metabolism in which complex compounds are broken down into simpler ones (catabolism). This in turn speeds the process of converting the food source into available energy supply for the bacteria. By utilising this process the cellulose material of the blue-green algae would be broken down, with the additional benefits of a steady reduction of solids, biofilm and nitrates. Biodegradation technology has been employed for many years in the waste water sector. Utilising synergized blends of scientifically selected and adapted bacteria, enzymes, and nutrients, wastes associated with domestic, municipal, commercial, and industrial waste systems are readily transformed to waters of an acceptable standard to be put back into the natural environment. Treatment of 3 Mile Creek with non-pathogenic bacteria and enzymes will help to augment and accelerate natures own biodegradation process, resulting in the reduction of nutrients, organic material and improved water quality. There are a range of different products on available in New Zealand. The one to be trialled was originally called Microzyme Pond Treat from Biocare, but the company has gone through rebranding and the product is now called PondTreat (PT-450) from Envirozyme. The product is a blend of naturally occurring, scientifically selected microbes and enzymes formulated to aid decomposition and digestion of the biomass that builds up on a pond or lake bottom (sludge). Six facultative and aerobic microbial cultures make up PondTreat which are selected to be effective over a range of substrates to produce the enzymes amylase, protease, cellulose, liginase, xylanase, pectinase, lipase and kerainase. These enzymes work to break down leaves, fertiliser and other runoff, fish and bird wastes, and other organic and inorganic material contained in sludge. The standard microbial count of PondTreat is around 2.0 billion cfu/g.

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The Pond Treat bacterial treatment is a non-toxic, non-pathogenic, natural water treatments method. Bacteria augment the already existing bacteria helping with nutrient and carbon cycling, thus limiting available food for blue-green algae is well as breaking down the algae themselves. How they Work A period of time after introducing the specially selected bacteria into the lake waters, the spores will vegetate (go from dormant to active) producing specific enzymes, and degrade or digest the available organic material and seston. The introduced microorganisms are capable of exponential growth, doubling their numbers every twenty to thirty minutes. Microorganisms play a vital role in the normal biological cycle by converting soluble organic compounds into new bacterial cells and inorganic elements. This natural biological process provides conversion of waste organics (animal and plant life) to carbon dioxide and water. These bacteria are naturally occurring strains found in soil and water. They have been selected because they are safe and stable; non-pathogenic; non-toxic; and facultative (capable of growth with or without oxygen) and are not genetically modified. These products include basic spore forming, waste degrading strains of bacillus to reduce organic loadings in the water column, preventing a build up of sludge on the pond bottom. When used, the nutrients dropping to the pond bottom are so reduced that the anaerobic sludge dwelling bacteria is unable to form toxic hydrogen sulphide gas and sludge accumulations are reduced. There is limited knowledge on the extent and role of bacterial communities within water bodies. However, it is likely that naturally occurring bacterial communities are also being impacted by nutrient loading and changes in algal communities. Hence, using bacteria to reduce organic material and use excess nutrients will eventually help restore other aquatic communities including the natural bacterial ones.

3 Method

Two sediment samples and water samples were taken on 18 February 2008 in the Waihi WWTP discharge drain and these were analysed for faecal coliforms, Escherichia coli and Enterococci bacteria. Twelve open ended 20 litre plastic buckets were inserted into the sediments of the Waihi WWTP discharge drain (Figure 2). Buckets were inserted where practical into the clay base of the drain so they would remain fully submersed with minimum percolation. Upon settling a sample was taken from nine buckets for bacterial analysis and measured for dissolved oxygen concentration, conductivity, temperature and pH. Buckets water level was then measured and then all but three buckets (the controls) were treated. Three buckets were treated with 50ppm Ensol 1000, three buckets treated with 20ppm Ensol 1000, and three buckets with 2g of Pond Treat. Water samples were collected from the buckets over the next three days they were measured for dissolved oxygen concentration, conductivity, temperature and pH. Six days after treatment a final water sample was taken before sediment samples from the bottom of the buckets were acquired.

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Figure 2 Photos of buckets without bottoms inserted into WTTP discharge drain.

4 Results

This inaugural trial did not go to completion due to a combination of high seas and heavy rainfall flooding nine of the buckets in the lower drain. However, result from four days of sampling and the final results for the three buckets are presented.

4.1 Bacterial

Sediment and water samples were analysed by an IANZ accredited laboratory for faecal coliforms, Escherichia coli and Enterococci bacteria. Sediment results are presented in Table 3.1. Table 3.1 Indicator bacteria results for sediment sampling Location Date FC/100g E.coli/100g Enterococci/100g

u/s drain 18/02/08 90,000 140,000 16,000

d/s drain 18/02/08 160,000 35,000 5,000

Bucket 10- 20PPM Ensol 24/02/08 160,000 140,000 -

Bucket 11 – Pond Treat 24/02/08 90,000 27,000 -

Bucket 11* 24/02/08 30,000 - -

Bucket 12 - Control 24/02/08 160,000 300,000 -

Bucket 12* 24/02/08 160,000 - -

* sample of stirred up sediment Sediment results were largely compromised by a fresh occurring towards the end of the week long trial, making untenable to collect most samples. Although, two treated containers and one control were able to be sampled. Comparison of the indicator bacterial levels of the sediment in

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the drain at two locations with the drain results from the containers shows no distinctive improvement after treatment. However, water column sampling shows that indicator bacteria are being released into the water column. The greatest release of indicator bacteria into the water column occurred in containers treated with 50PPM of Ensol 1000. One of the three containers dosed at this rate was compromised during the trial, but the two remaining containers showed very similar results for thermo-tolerant bacteria (faecal coliform and E.coli). A similar pattern of bacteria release also occurred in the containers treated with 20PPM Ensol 1000. In the 50PPM Ensol 1000 treated containers E.coli increased almost 102 within two days of treatment, but crashed to less than 1 E.coli/100mL on day three. Enterococci (a sub-group of the faecal streptococci group) were less responsive than the therm-tolerent bacteria. One of the 50PPM Ensol treated containers showed on order of magnitude increasing enterococci after two days, with a similar response occurring in the Pond Treat containers. The control containers all showed a steady drop of indicator bacteria in the water column. Faecal coliforms showed the fastest rate of decline with E.coli and enterococci decreasing markedly after three days.

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Figure 3.1 Faecal coliform concentrations for 3 treatments and the controls.

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Figure 3.2 E.coli concentrations for 3 treatments and the controls.

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Figure 3.3 Enterococci concentrations for 3 treatments and the controls.

4.2 Dissolved Oxygen

Dissolved oxygen concentrations in the WTTP discharge drain were very low, around 2 g/m3 to 3 g/m3, before the buckets were inserted. Temperature ranged from 18 to 19ºC. After 24 hours of treatment the control buckets show that dissolved oxygen (DO) concentrations were elevated compared to treatment buckets (temperature also elevated 20.5 ºC) with the bacterial treatment showing the lowest concentrations, as might be expected (Figure 4.1). DO concentrations for the next 2 days are elevated in comparison to the first day after treatment with most buckets having over 3 g/m3 DO. While DO measurements for Pond Treat buckets and control buckets on the 20 February have a variable range of DO concentrations, results for the 21 February show Pond Treat levels still to be much lower than the now elevated concentrations of the control buckets.

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Figure 4.1 DO concentrations for 3 treatments and the controls.

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4.3 Conductivity

The WTTP drain had an initial conductivity of around 250 to 650 uS/cm. Control and Pond Treat buckets remained around these levels over the trail. Conductivity in the Ensol treated buckets was greatly increased (Figure 4.2), however the conductivity in the Ensol treated 50PPMa bucket reduced dramatically on the second day of the trial, co-insiding with an observed lean of the bucket. This indicated the bucket has been moved slightly and increased leakage was occurring compromising the treatment.

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5 Discussion

The objective of the trial is to see if the pathogenic sediment reservoir can be significantly reduced by environmentally safe treatments. The trial measured the quantity of indicator bacteria in sediments and the water column to indicate the impact of treatments on the pathogenic sediment and water loads. It was originally envisioned that stimulation of the sediment microbial flora by treatment products would result if biological disinfection by a process of ingestion by antagonistic microbes (Davies-Colley, 2005). If stimulation of bacterial action in the sediments and sediment-water interface displaces bacteria indicators of pathogenic species then a marked difference in treated containers from controlled containers should occur. Sediment sampling showed no appreciable change in indicator bacteria concentrations after treatment, however this may be a function of the sampling method and/or rejuvenation of the sediment bacterial load from percolation of pore-waters into the containers. It may also be that the dosing regime was not strong enough to impact in the sediment reservoir. The treatments were successful in releasing indicator bacteria from the sediments into the water column, with the 50PPM Ensol treatment reaching the highest concentrations. The peak faecal coliform concentrations in these buckets reached around 1,500,000 per container, Assuming that the first 2 cm of sediment provide the repository for the bacteria (the approximate sample depth for sediment sampling) there is approximately a reservoir of 2,500,000 FC/container. Once bacteria are released into the water column the main mechanism for inactivation of bacteria is by sunlight (shorter wavelength visible and ultra-violet radiation). Sunlight distribution to the containers was not even due to the foliage on the banks of the discharge drain and this may explain some differences in bacteria numbers between replicates.

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Bacteria released into the water column must overcome the die-off rate to show an increase. In the case of FC peak release rate in the 50PPM Ensol 1000 was reached in two days and the quantity of bacteria found in the water column suggests that possibly over half of the sediments bacteria reservoir would have been mined of FC bacteria. This would depend on die-off rate, deposition and re-suspension rates. Unfortunately no sediment sample in the 50PPM was obtainable and the one 20PPM Ensol treated containers showed no lowering of its FC load. However, the release to the water column of FC bacteria was of an order magnitude lower and is not likely to have been enough to make an appreciable difference on the sediment load.

6 Conclusions

A 50PPM treatment of an isolated part of the Waihi WTTP drainage channel with Ensol 1000 appears to have been successful in releasing enteric indicator bacteria to level that will relieve the contaminated sediments of their pathogen load. The water treatment product treatment Pond Treat may also have some merit in the release of faecal streptococci bacteria to a similar level as Ensol 1000 (at the 50ppm treatment rate). It is considered that once these bacteria have been mined from the sediment by microbial action and released into the water column there is a greater chance of rendering these bacteria inactive, predominantly via disinfection by sunlight. A further limited trial similar to the one reported on here may be required to further quantify sediment impacts of treatment on indicator bacteria populations. This would in turn increase the confidence to move to a trial of treatment of the discharge channel/3 Mile Creek.