Introduction
AquaClean had been successfully applied to treat very polluted flowing river. The main objective of River Remediation is to bring the polluted river back to its ecological balance by means of biological process. The end result should improve the water pollution parameters such as BOD, COD, TSS etc significantly and bring back the aquatic life to the river.

No bacteria can survive in very toxic environment. AquaClean is able to adapt to moderate toxicity. The best gauge is to conduct simple laboratory trial to check on the survival rate of the bacteria in the water sample. AquaClean bacteria works well for COD below 10,000 mg/l which is suitable for most polluted rivers. However, it has no effect on silt and suspended non-organic matters such as soil and sand particles. ACIT will not restore silty water to clear water as the silt are mostly soil particles that at bio-non-degradable.

Fundamental of River Remediation

Pollution is best treated though bioremediation at the source. The river will not be polluted if there is no discharge of untreated water into the river. In most cases, it is not feasible to ensure that all water discharged to the river meets regulatory requirement. For a larger river with multiple tributaries, treatment can be done on each tributary before water enters the main river.

For cases where there are multiple untreated water inlet points along the river, the complete river can be treated as a plug-flow reactor where in-situ treatment can be carried out.

AquaClean River Bioremediation takes on a complete natural biological approached via four processes:-

1. Bioaugmentation with AquaClean ACF-32 biological product.

2. Installation of our unique designed biomedia to prevent the complete loss of the beneficial AquaClean bacteria during high flow. The biomedia serves as home to the bacteria and act as filter to trap the organic waste to provide nutrient for the bacteria to multiple. The excess cultured bacteria will slough off and flow along the river and degrade the organic waste as the water flow along the river.

3. Introduction of aquatic life into the river such as fishes and snails to maintain the ecological balance after the polluted river had been improved to a level suitable for higher form of aquatic life. Introduced surface water plants such as heliconia plant to beautify the river and help to further absorb the organic waste such as excess phosphate in the river that are not readily degraded biologically. The roots of the floating plants also servers as additional biomedia for AquaClean bacteria.

Treatment Procedures
Treatment at Source

For treatment at the source, if feasible, is the most economical method is to have retention pond just before the polluted water enters the river. This is applicable to sources of polluted water that can be consolidated into a pond before discharge into the river.

The pond size should have an average retention time of 12 to 24 hours and of channel type design. The pond can be open excavation on ground with about 2m deep. Example, for an average flow of 1,000 m3 per day of polluted having average COD of 500 mg/l. A 2m deep open channel of 75m long by 10m wide is sufficient. 40 m3 of our unique biomedia should be installed in the retention pond. In the absence of the retention pond, the tributary that leads to the river can be used as retention pond and treatment can be done in-situ at the tributary.

Treatment along the main river

For short rivers less than 5km, the complete river zone can be treated as a single plug flow reactor. For longer rivers, divide the treatment zone into multiple zone each with about 10 to 20 hours flowing time. Example: 20km long 25m wide 1m deep with 180,000 m3 per day flowing rate, average flowing speed is 5m per min, 15 hours flowing time is about 4.5km. The river can be divided into 4 treatment zone. Similarly, appropriate amount of biomedia should be installed along the river.

Biomedia Computation

Our unique biomedia is 100% made from nylon rope and string. The media is delivered in length of 1m, 2m and 5m length. It is to be installed vertically at about 170mm interval in a rectangular frame of about 5m long x 2m with suitable height to suit the river water depth condition. The unique biomedia provide an approx surface area of 180 m2 per m3 of frame. The biomedia has a BOD degradation rate of 40 g/m2. day of media surface when used with ACIT treatment. Computation of biomedia requirement is based on 50% of total BOD degraded by biomedia.

AquaClean Dosing Recommendation

Dosing rate of AquaClean product is independent of pollution level as bacteria will multiply in the polluted water environment to its own optimum population level. Dosing is generally based on estimate water volume in the treatment zone or daily flow volume whichever is higher. Higher dosing rate is recommended at zones upstream than zones down stream as some bacteria upstream will flow to zones downstream.

The table below only serves as a general guide for dosing recommendation:-

The above dosing rate is recommended for daily dosing. For very slow flowing river with retention time more than 24 hours per zone, the dosing can be consolidated into few days per dosing to save labor cost. Alternatively, automatic continuous dosing is highly recommended if feasible.

Example of Dosing Computation for 20km long river with varying flow rate and river profile:-

Introduction of Aquatic Plants and Animals

Attached photos are some recommended proposal. The amount of plant is to be determined at site.